| Author | Message | ||
     Patrick Lockyer. Experienced User Username: pat_lockyer Post Number: 8 Registered: 9-2004 |
R Chapman. With regard to compression ratios calibrated and fixed. Camshaft alters dynamic compression. As this was delt with by myself and confirmed by world experts stating you were incorrect on the Swammestien site please address your query on that site it is only fair to all those concerned. | ||
| Robert Chapman Prolific User Username: shadow Post Number: 74 Registered: 5-2003 |
P Lockyer, I find your post ambiguous, 1) "With regard to compression ratios calibrated and fixed" do you mean CALCULATED and fixed,is this a statement or a question.Is this your position?. 2) "camshaft alters dynamic compression" are you agreeing or disagreeing,what is your position?. My understanding of your position on this subject from previous discussions was that Compression Ratio is FIXED by the dimensions of the cylinder and the combustion chamber and is constant.Is that a correct summation of your understanding?. I dont recall anyone discribing themselves as "world experts" making any contribution to previous discussions,we did have an American contributor who said "I have raced all around the world in my 8000BHP drag car and I can tell you 100% that compression ratio is FIXED and never changes" he also said "every engine tuner on this planet knows it". Really. The previous discusssions were not concluded,infact as I recall you were asked to quote the actual contents of a paper written by a Dr Eng, you put forward as an expert, but failed to do so. So I would suggest that in fact it was you who failed to produce any relevant technical infomation to suport you opinion,as has been the case on previous occasions. | ||
| Patrick Lockyer. Experienced User Username: pat_lockyer Post Number: 10 Registered: 9-2004 |
Robert Chapman Look on the Swammelstein site,your query's are all answered there, and your failings on the topic for all to see!!!! Remember this is a general discussion THREAD! | ||
| Robert Chapman Prolific User Username: shadow Post Number: 75 Registered: 5-2003 |
Patrick Lockyer, I will take that as a yes then shall I ?. That is, you stand by everything you stated so emphatically on this subject. COMPRESSION RATIO FIXED NOT DYNAMIC ,I beleive was your headline proclamation. I can very well understand your reluctance to continue this discussion on a moderated forum were abuse and will not be tolerated. You are quite right this is a technical topic and should be posted under the technical section of this forum. I shall start a new thread there under the heading COMPRESSION RATIO. I will put forward your position so confidently stated by yourself that comp/ratio is calculated from the static volume of the cylinder and combustion chamber and cannot change,it is FIXED. I look forward to a intelligent factual technical exchange. | ||
| Bill Coburn Grand Master Username: bill_coburn Post Number: 255 Registered: 4-2003 |
So do we you two. A very interesting topic to the poor dumb amateurs such as myself. | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 12 Registered: 9-2004 |
No Bill,never ever think you are a poor dumb amateur. You are a polite honourable well respected gentlelman in my veiw for what it is worth. This interesting topic was delt with on the Swammelstein site many months ago. With robert chapman shown to be incorrect, not by me alone but by all the many world wide contributors. He has now dragged the topic up in his own words. He has now got a problem what to do to save face. The many folk and i,i am sure will will not be proved wrong. (Message edited by david_gore on September 16, 2004) | ||
| Robert Chapman Prolific User Username: shadow Post Number: 79 Registered: 5-2003 |
No Bill, dont put yourself down I could not stand it,you are kind,wonderful,sincere,articulate,tall,slim, young,handsome,not to mention quiet and retiring. | ||
| Mark Peacock Prolific User Username: takemehomejames Post Number: 31 Registered: 4-2004 |
Gentleman, just out of interest check out this website for your compression drama's http://www.victorylibrary.com/mopar/cam-tech-c.htm | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 354 Registered: 4-2003 |
By the way, Mark, at the bottom of the page in your link is a picture and link to: “How to Work With and Modify the Turbo Hydra-Matic 400 Transmission”, by Ron Sessions. I have been using that book for many years. It is applicable to all 3-speed Shadows and Spirits etc. I find it far more practical and useful than the normal Crewe workshop manual which waffles on about many unimportant things. Session's book even lists our transmissions and codes. The Crewe workshop manual is useful as a reference when it comes to R-R specifics (very few if any apart from the modulator part number), but Ron Session's book is really excellent as the primary reference. As you know, transmission spares are available at any transmission shop or Holden dealer. I bought mine at the Automotive Book Shop in Military Road, Neutral Bay, Sydney. | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 13 Registered: 9-2004 |
Thank you Mark,lets see if R Chapman can agree now ref your link,confirming theoretical or mechanical c/r[advertised static or nominal] is clculated and fixed. Also camshaft alters the dynamic compression ratio and not the c/r. many thanks.PL. | ||
| James Aitken New User Username: james_a Post Number: 5 Registered: 7-2004 |
We obviously have two blokes here who both know what they are talking about but simply don't understand what each other is saying. This is an argument about terminology that has got out-of-hand and personal, not a technical debate. Why don't the two of you call it quits on this topic before it becomes consumingly destructive? Alternatively, agree to leave out the personal swipes and stick to the technical.  By the way, Mark's link is a very interesting read - good find! It is one of the few references I have seen that explains the second-order piston oscilations in layman's terms. This is what makes the 90-degree V8 engine inherently the smoothest possible configuration. (Although the author does not make the latter point.) I guess this is another topic for debate. | ||
| David Gore Moderator Username: david_gore Post Number: 307 Registered: 4-2003 |
James, Thank you for your common-sense comments; I have found it extremely difficult to moderate this exchange given my reluctance to censor what are clearly strongly held points of view yet I had concerns about whether anyone else knew what was being discussed and whether intervention could be justified on this basis. Your contribution to the technical content indicates there are users who understand this topic and who will make informative suggestions that will arouse the curiosity of others to delve into a topic they might otherwise have ignored. | ||
| Robert Chapman Prolific User Username: shadow Post Number: 81 Registered: 5-2003 |
Hi David, It seems two posts have gone missing somewhere. I wondered if they have moved to another section of the forum.The first one this was from P.Lockyer to me, giving me a reference to a book by Harry Ricardo and the second was my reply to Pat asking for more details. | ||
| Robert Chapman Prolific User Username: shadow Post Number: 82 Registered: 5-2003 |
Hi James, Thanks for your input. I would like to say to you that firstly I do not see this discussion as one of differing terminology. The terminology used to discuss both positions is very clear and unambiguous. Pat has stated categorically that CR is Fixed as calculated by the formula CV+SW divided by CV=CR and is not changed by camshaft,throttle position ,VE or any of the other conditions you alluded to in your previous post. Secondlyhe has stated that a camshaft change cannot alter compression ratio.(Because it is fixed). These are his clearly and vigorously stated opinions. I was vilified on the Swammelstein site for holding a contrary opinion and I have raised the discussion on this moderated forum so the conclusions could be reached on technical merit rather than by the person with the loudest voice. All I seek to do is give the technical reasons in defence of my opinion. | ||
| Robert Chapman Prolific User Username: shadow Post Number: 83 Registered: 5-2003 |
Hi Pat, Yes thanks to mark,now you have read the article it is all starting to dawn on you that what I have been saying all along is CORRECT and now you are starting to alter your wording. Before you said CR had nothing to do with Volumetric efficience. Before you said there was no such thing as THEORETICAL CR,you said the engine runs on the calculated CR and it was constant.FIXED. Before you said there was no way a camshaft could alter CR now you have read about inlet event timing it has all started to dawn on you,sorry to late.If you think this article in any way endorses what you originally said I suggest you read it again, more slowly. | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 15 Registered: 9-2004 |
Robert Chapman. Until you can grasp the fundamentals,compression ratio is calculated and fixed,and that the cam shaft alters dynamic compression. To try to explain any technical workings with you would be a waste of time,do not agree. I seem to think i have heard this from a highly respected engineer in the USA as words of wisdom to you on the Swammelstein site! when the topic was delt with and concluded many months ago. Maybe it would help if i made contact with him to help you. | ||
| James Aitken Experienced User Username: james_a Post Number: 7 Registered: 7-2004 |
Stepping in again at the risk of getting my nose punched (metaphorically) it might be useful at this point if Robert & Pat both clearly define what they mean by the term “Compression Ratio”. Bearing in mind that a ratio is by definition a linear mathematical relationship between two quantities. For example: “Gear ratio” is the relationship between input and output RPM of a gearset “Air-Fuel ratio” is the mass flow of air compared to the mass flow of fuel Please both define your meanings of “Compression Ratio” in these kind of terms. | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 16 Registered: 9-2004 |
Hi James no ploblems no stern words. Compression. Compare to gear ratios!: FIXED:auto-transmissiom epicyclic gear ratios. DYNAMIC: effect of the torque converter. Now to bed a heavy weekend. Thanks for your interest on this topic. | ||
| James Aitken Experienced User Username: james_a Post Number: 8 Registered: 7-2004 |
Thanks Pat(hope you slept well). However, not quite what I was asking. I was more looking for your definition of the "ratio" part. For example, I think we all agree the theoretical (or calculated) compression ratio is the ratio of the volume inside the cylinder at BDC compared to TDC. What two values are you comparing when you say "dynamic" compression ratio? Similarly for Robert - what two values compose your definition of "compression ratio"? | ||
| David Gore Moderator Username: david_gore Post Number: 309 Registered: 4-2003 |
Robert, My apologies for not responding earlier but I have been away at a family wedding over the weekend. The two posts you asked about are in the Silver Shadow Technical Section in a thread entitled "Compression Ratio" - I suggest all users interested in this topic should also read this thread as well but please keep postings to this thread. | ||
| Robert Chapman Prolific User Username: shadow Post Number: 84 Registered: 5-2003 |
Hi James, I think it is obvious that (as you said)we all know what CR is and how it is calculated,but that is not the point of dispute hear. This comes from Pat's categorical statements 1)CR IS FIXED,it does not change ,the CR you get from the theoretical calculation is what the engine runs at ALL the time ,it is not and cannot change as the engine is running(dynamic).this is impossible he said how can the dimensions of the cylinder and the combustion chamber change. 2)A CAMSHAFT CANNOT CHANGE THE CR,this is a new one on me he scoffed ,do tell us all how that can be! But now he has seen your first post were you confirmed what I had said about this being dependent on the amount of air inducted and reading the post put on by Mark he has started to change his story as I have experienced before when he is loosing a technical debate. The other give away sign of course is when he becomes patronising and rude .(ref to his post about strobe/dwell timing)this demonstrate the mans true colours and limited technical understanding of the internal combustion engine. His last words to me on that particular subjct were "and as for chapman I will get back to him with an answer as soon as I can" that was about 6 months ago, and I am still waiting! Pat does not understand that the theoretical CR is just that THEORETICAL and is never achieved by your every day road going normally aspirated engine such as the RRV8 for instance.The best volumetric efficiency these engines can hope for is about 80% at max torque .The valve event timing used in these engines that gives them great low and mid range torque prevents the volumetric efficience increasing the effective CR at higher engine speeds . | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 17 Registered: 9-2004 |
Give a long enough rope and you will hang your self. well your words brought in for your easy way out no way. Remember post 5/5/04 from me.Quote:Hi Robert [no scoffing manner by the way] in reply to your question do i understand the dynamic c/r but the use of the word dynamic is completly incorrect note. This measure is static and as a result of engine geometry and not dynamic behviour. This is a fancy name for compression pressures. So please tell me how a camshaft can alter the compression RATIO. Regarding the dragging up of the post on the strobe dwell timing with the warning intervention of the moderator. I see no problem as it it a warning to the diy folk to carry out the proceedure at there own risk. My words were strong as it was the only way to endorse the subject,on that i apologise but not to you. As I was taught by a very professional engineers with regard to diagnostics,one off the sayings that is true today, and i will remind you:The machine is only as good as the operator. I am sure some professionals in the instition would only be to pleased to hear from you on your inserted words as a engineer. Regarding the answer to you on how the dist curve test can be carried out with a electronic tool [top secret] on the car to tell you no way. You can do it the old way and cost the customer pounds,you do not worry about time it seems. Regarding the shouting i was imformed that to shout on a thread you use capital letters i have only used a few compared to yourself!!!!!!!! | ||
| James Aitken Experienced User Username: james_a Post Number: 9 Registered: 7-2004 |
Hmmm... it seems the only choice here is pistols at 20 paces or swords?  | ||
| David Gore Moderator Username: david_gore Post Number: 311 Registered: 4-2003 |
I think it is now time to bring this topic to a conclusion and I will allow both protagonists one more unedited [libel/abuse/denigration excepted] post each after which I will be editing posts to their inherent technical content. I would like Robert to comment after reading the reference book detailed by Pat and for Pat to provide the definitions requested by Robert and James. With regard to the use of capital letters in posts signifying shouting; I suggest the use of capitals by both contributors is to highlight significant points and not an indication that they have lost self-control. | ||
| Robert Chapman Prolific User Username: shadow Post Number: 86 Registered: 5-2003 |
David, I would be only to pleased to comment on the reference book quoted by Patrick (a very rare edition that I just happen to have in my collection and one which you would have heard me quote from before)but I have not had a reply to my request for detail about where this infomation is in the book. | ||
| James Aitken Frequent User Username: james_a Post Number: 11 Registered: 7-2004 |
Robert, Take a peek under the "Compression Ratio" thread uder the "Silver Shadow" heading and you will see the reply you seek. I suggest you overlook the way in which it is presented. I do not have that book and so cannot look it up. Is there any way a part of that reference can be shared - without getting into strife for copyright breaches? Personally, I would like to see the moderators combine this thread with the above mentioned one and change the name. I feel for Robert's sake the title of this thread is a little unfair - or at least threatening. How do you feel about that, Robert? | ||
| Robert Chapman Prolific User Username: shadow Post Number: 87 Registered: 5-2003 |
Patrick, Well yet again another long post, that is completely bereft of any technical content,technical reasoning or explanation. Of course your reason is clear ,if you dont give any detailed response you cannot be challenged . Firstly lets look at your proposition that CR is calculated from the static dimensions,fixed and not dynamic,(does not alter during running). What you are saying is that the CR calculated from the formula CV+SV DIVIDED BY CV=CR.Lets look at what assumptions are made in this formula. 1)That the complete space above the piston at BDC to TDC is completely full of air at atmospheric pressure (SV swept volume). 2)That the space above the piston at TDC (CV combustion chamber volume) is also completely full of air at atmospheric pressure. 3)That both valves are closed at BDC. Clearly this is theoretical because, firstly during normal engine operation 100% filling of the cylinder (volumetric efficiency) is never achieved(normally aspirated engines)only by highly tuned engines and over a very narrow rev range. Secondly because engines don't have both valves closed at BDC on the induction stroke/start of the comp stroke. Obviously the CR calculated theoreticaly is not the FIXED ratio that the engine runs at. How does a camshaft alter CR Pat asked, Well lets look at the maths and geometry Pat mentioned . Using the spec's from a RR 6750cc engine of say 9:1 CR. Bore =104.14 stroke =99.06 Swept volume of piston =843cc combustion chamber volume =105cc Take a sheet of paper and draw a vertical line about 12 in long . Draw a circle 99.06mm in DIAMETER (this is the stroke) so that the bottom of the circle intersects the lower end of the vertical line. From the bottom of the circle measure up the vertical line 6.5in(this is the centre to centre length of the con rod)and make a mark at right angles across the vertical line.(This is the BDC position of the piston). With a protractor mark 60 degrees ABDC, (this is when the inlet valve closes)now with a compass set at 6.5in measure from the 60 deg mark to the vertical line,draw a line at right angles across the vertical line. The measurement between the to lines across the vertical line should be 21.59mm. This shows that the crankshaft has rotated though 60 degrees of the compression stroke with the inlet valve still open ,because of the geometry the linear movement of the piston has been 21.59mm. What this means of course is that the effective swept volume has changed, since no compression can take place until the inlet valve is closed.The dimention has changed from the STATIC MEASUREMENT of 99.06mm to77.47,now lets see what that does to that FIXED ratio. The swept volume now is 659cc,therefore 105+659 divided by 105=7.27. So now this FIXED CR is now only 7:1. This clearly shows that the late or early closing of the inlet valve has a dramatic effect on comp ratio and that choice of camshaft can alter the comp ratio. Other factors also vary the CR,among them throttle opening and engine speed,in short volumetric efficiency.The closer to 100% filling of the cylinder the closer to that THEORETICAL CR. I must admit I have found it very hard to concentrate on this tonight,after watching on the news about the American man executed today by having his head sawn off it makes one realise how futile and meaningless this all is. | ||
| David Gore Moderator Username: david_gore Post Number: 312 Registered: 4-2003 |
Hi Robert, Thank you for your explanation which corresponds exactly to the process of graphically calculating valve events for reciprocating steam engines where these events are used to control the power output of the engine by cutting off the steam supply early or late and allowing expansion of the steam contained in the cylinder to occur for either maximum efficiency or maximum power [i.e. the compression ratio in the cylinder changes with differing volumes of admitted steam entirely as a consequence of the valve timing]. The steam engine valves are able to be varied by different types of linkages from the piston rod/driving wheels to the valve chest. I believe you have proved your point and now await Pat's response. | ||
| Robert Chapman Prolific User Username: shadow Post Number: 88 Registered: 5-2003 |
David and James, I have reread the chapter Pat has quoted and there is absolutely nothing in it that remotely covers the question . I believe I can make a photo copy of this chapter available to you both for your verification, because I can tell by the composition of his transparent post he is going to say "it's all in there you just can't grasp it". | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 20 Registered: 9-2004 |
As this is my last post on the subject on this site I would first like to quote some previeous posts from Robert. Ref your post 6/5/04 on the Swammelstien forum: quote Pat with respect no one disputes that the formular for the c/r is sv+cv divided by cv but the crucial description of the result is theorectical not "static" this is completely incorrect note and why is it called ? Dynamic is I suggest exactly the correct word for something that happens and changes whilst the engine is running. My reply to this is dynamic compression ratio should not be confused with cylinder pressure. Cylinder pressures change almost continuously due to many factors including rpm, intake, manifold design, head port volume and efficiency, over lap, exhust design, valve timing, ie camshaft position and many other factors. Dynamic compression ratio is determined from measured or calculated values that are the actual dimensions of the engine. Therefore unless variable cam timing is used, just like the static compression ratio, the dynamic compression ratio is fixed when the engine is built and never changes during the operation of the engine. This confirms that the camshaft will alter the cylinder gas pressure not compression ratio. Ref your posting 10/5/04 on the Swammelstein site. Quote: the motor vehicle has been the essential ref book. Joint authors, K Newton, MC, BSc, ACGI, Ceng, MI, MechE professor, Mechanical Engineering, The Royal Military College of Science. W StEEDS, OBE, BSc, FIMechE, Professor of Mechanical Engineering, The Royal Military Collage of Science. T K Garret, Ceng FIMechE. Editor of Automotive Engineer. Quote; with spark ignition engine boosting the pressure in the induction system has the EFFECT of increasing the compression ration end quote. Effect does not mean altering the Compression Ratio. One thing is for sure. Once the inlet valve has closed and until ignition occurs, the fuel-air gas will obey the combined gas law, P1xV1/T1=P2xT2/V2. V1 (starting volume) and V2 (final volume, ie combustion chamber) are fixed by the geometry of the bore and head, and when the inlet valve is fully closed. If the inlet valve closes after BDC as they are usually set to do, the starting volume V1 will indeed be effectively reduced. The ignition timing has little effect as it is set to give maximum force when the piston is some way down the firing cycle. Virtually no gas has had time to burn before TDC regardless of the ignition timing advance. Without splitting any more hairs, I agree that V1/V2, the nominal compression ratio may be greater than this reduced ratio. V1 is the bore volume + the combusion chamber volume, so the compression ratio is simply (Bore volume at inlet valve closure + Combusion chamber volume)/(combustion chamber volume] However, since the inlet valve always closes at the same point in the cycle of a fixed-cam motor like in a Silver Shadow, this reduced ratio cannot change. To explain the disagreement in terminology: The starting pressure and temperature at the point that the valve closes can be anything from a vacuum on overrun, partial vacuum on light throttle or even more than atmospheric due to gas flow dynamics caused by camshaft profiles and induction configuration (and by boost in a forced induction motor.) Engine designers use all sorts of tricks to optimise smoothness and power with valve timing overlaps and the rest, but once that valve is fully closed it's all over, and the volume ratio takes over. There is negligible heat loss to the cylinders during the compression stroke as it is all too fast, so the changes will be almost entirely nil.The change in temperature and pressure until ignition is solely governed by the laws of physics: the ratio of the volumes is defined by the combined gas law. As outlined, the starting temperature and pressure once the valve closes may be anything, but the starting values and the fixed effective compression ratio determine the final values. I shall not bother quoting elementary school physics books or advanced books on thermodynamics to prove the point. Now we come to Boyle's Theorem and compression ratio re posting 11/05/04 Swammelstein Site! David Gore has spoken steam! (Message edited by david_gore on September 23, 2004) | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 21 Registered: 9-2004 |
Phew thats out the way. Robert, as it was you who first told me to read more slowly and i might grasp it i felt i could only return the complment!as i put the posting up after you asked me for more details on Chapter pages in the book on valve springs,re thread oil seals,i inavertantly put it under the compression post thinking it would help you but alas i have not been able to see much on the compression fixed saga in the book. But you must have seen the spring Chapter, i will refresh your memory it is chapter V111 page no 226 Have been in the atic many more books found. I will help you realy no more. | ||
| James Aitken Frequent User Username: james_a Post Number: 12 Registered: 7-2004 |
Reading the last few posts, I stand by my earlier statement that the underlying issue here is terminology. Robert & Patrick have different values making up their ratios. Robert's ratio is the cylinder pressure at TDC compared to atmospheric pressure. Patrick's ratio is the cylinder pressure at TDC compared to cylinder pressure at inlet valve closure. Taking these two very different ratios, BOTH are correct in their assertions of being fixed or variable. Robert's ratio will change according to throttle setting, RPM etc because these all impact upon the amount of charge inducted and hence the final pressure at TDC. Patrick's ratio filters these effects out because his starting point is when the cylinder is already charged and hence his ratio is fixed. The final question, obviously, is which definition of "Compression ratio" is correct? | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 22 Registered: 9-2004 |
James,as i sugested from the start,this should have been delt with on the Swammelstein World wide Site as it is only fair To the many folk who confirmed and contributed to this topic and also to the odd one or two who tryed to put a spanner in the works. I once again thank all of you including robert whose incorrect battle statements of words would not have made this so interestingly possible. Now please the real experts do have your say as i have been told as you can see it is my last posting. | ||
| William H. Trovinger II Grand Master Username: bill_trovinger Post Number: 158 Registered: 8-2003 |
Robert & Pat: Over the years I have found advise from both of you very helpful, so please do not either take the following in any negative light: Is not enough, enough? This thread started on Swammelstein a while ago. I have followed it “all the way”. At some points it has been very interesting and provided me with new knowledge (something we must all look for wherever we can find it) but at other points it has become a “turn-off”. At least in my limited DIY opinion your discussion has now reached a point it either belongs in an engineering chat room or on Dr. Phil, I will leave it to other as to which. I hope to see you both continue to contribute to both forums (especially when I need help  ) but I hope this topic is now closed. Kindest regards, Bill | ||
| John Dare Unregistered guest Posted From: 144.138.194.45 |
Thank you Bill T, however I believe that the decision to "close down" a spirited debate should rest solely with the forum moderator/s without prompting from contributors. I am not a fan of the Swammelstein forum for it is not moderated, thereby allowing defamatory (possibly actionable!)posts . Moreover, I have to contend with the incessant pronouncements and edicts from the usual "authorities" from which (sadly) there appears to be no escape. BUT even when the compression ratio question is bought to finality, we still have the valve spring (location of) issue (see post re cutting oil consumption on R-R V8s) for as I understand it, another member intends to trial the procedure outlinded in the factory TSD (as proclaimed) which effectively abolishes any positive locating medium at the base of the spring. Having read the pages from Ricardos book (as proffered by another contributor) I can see NO reference (implied or otherwise) which suggests that a valve spring does NOT need to be seated and LOCATED, thereby ensuring that it will be centrally maintained, relative to the attendant valve guide/valve. However, if I have missed it/"misunderstood" it, OR if there is another recognized book which endorses the foregoing concept, then I will glady quote it to all current auto manfrs. so that they can abolish valve spring seat "spacers/locators/distance pieces/centralizers" (whatsoever called) in order to save a few dollars per car. The millions saved per annum will provide due royalties which will allow me to retire in magnificent splendour. (Message approved by david_gore) | ||
| Robert Chapman Prolific User Username: shadow Post Number: 89 Registered: 5-2003 |
Phew indeed Pat,that must have been exhausting for the person that really wrote it,and there's no prizes for guessing who that was. It was not up to your usual standard , which we have all come to recognise. | ||
| David Gore Moderator Username: david_gore Post Number: 313 Registered: 4-2003 |
It was not my intention to "close down" this debate but merely to remove the emotional content which was beginning to detract from the technical content. Both Pat and Robert are able to continue to contribute freely to this discussion with the one condition being any emotional/personal content will be edited by me to keep the technical content to the forefront of this topic. I suspect many readers may have found these exchanges fascinating for the level of feeling involved however at the end of the day we are responsible for maintaining standards commensurate with those of our Club. I believe we have extended the traditional Australian "fair go" to both contributors and I trust they recognise and appreciate this tolerance. | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 24 Registered: 9-2004 |
Robert My daughter actually.but i do not mind nit picking. | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 25 Registered: 9-2004 |
John Dare. I agree the moderators should have full power to do as they think fit. The time they put in is there own spare time and remember all unregisterd guests posts are correctly approved or not. It is there progative to do as they think fit and not for us to judge them. However your comments with regard to the Swammelstein Site i will not hear of. Kees Scherer has a wonderful site with freedom of speech as the debate on the compression saga many months ago has shown. I personaly had many private emails on the subject and have learnt a great deal by the real experts world wide i may add. Remember you don't have to look at the site if you don't like it,i realy think you could do something better than write a load of rubbish criticising another forum. | ||
| John Dare Unregistered guest Posted From: 144.138.194.8 |
Thank you Patrick. I fear you have misunderstood my post, for I was NOT in anyway being critical of THIS forum and/or the moderators. I DID criticize ANOTHER site (where defamatory posts have been noted) and do so under the auspice of freedom of speech to which you allude and no doubt embrace. But woe is me, for seemingly I am "wrong" yet AGAIN, as I appear to have been in relation to ALL of the following topics where I was VIGOUROUSLY attacked by the usual suspects. 1/ "GM" engine conversions (you cant do THAT!) 2/ Magnetic "clip ons" for oil filters (a "dumb" idea!) 3/ Spin on oil filters (no quicker/easier to change(??) 4/ Hydraulic fluid/s. ("the book" says!)/ valve spring base location (ongoing). But hope "springs" eternal, for ONE day I will suggest SOMETHING that wont result in a phalanx of inbound fire where certain individuals object merely for the sake of, the message appearing to be; "WHATEVER you say, I am agin it, for I am an expert and youre not" (Message approved by david_gore) | ||
| Patrick Lockyer. Frequent User Username: pat_lockyer Post Number: 26 Registered: 9-2004 |
John "merely for the sake of it" All i can say To you "RUBBISH". (Message edited by david_gore on September 25, 2004) | ||
| Robert Chapman Prolific User Username: shadow Post Number: 92 Registered: 5-2003 |
Yes Patrick , Thats more like it,the constructive, reasoning and articulate style of debate we have come to recognise. | ||
| John Dare Unregistered guest Posted From: 144.138.194.186 |
Quite so!. When faced with RECORDED facts, assorted "experts" often exhort, "Rubbish", which from their own, often uninformed point of view, is easier (and "safer") than debating the point or issue as advanced. I know of one R-R "expert", who merely parrots, "you dont know what you are talking about", and is known to have delivered such a profound response (up to 12 times in succession) until such time as the "opponent" is subdued, or like myself, loses interest or simply cant be bothered anymore.In either case the "expert" achieves his intended objective. This forum deserves better and upon accessing the various "Range Rover" forums (which are HUGE!) I have not YET (touch wood!) noted the presence of any "authoritive" global "experts" or assertive dominant "grandstanders" whose mission in life appears to be to demonstrate that they know "all", as opposed to the rest of us who, well..we know very little. In all the excitement, I forgot to mention previously (24/9) that I was also "wrong" on the Shadow pitman arm issue (TWO more detected recently!) and the COMMONLY known (and somewhat "accepted") problem of noisy (compared to say, "Holden/Chev./Ford" etc) differentials. Each point was simply and conveniently dismissed as, "Not a problem" (steering failure occurs ONLY whilst parking (NO it DOESNT!) and "find a Shadow with a QUIET differential" (How patient are you?) HHhhhmmm... back to my "Range Rover" forums, methinks. (Message approved by david_gore) | ||
| Patrick Lockyer. Prolific User Username: pat_lockyer Post Number: 38 Registered: 9-2004 |
Ho ho ho. Had enough of the Range Rover Forum John. That never lasted long,shame on you. Still have a howling diff. mine are both quiet Yipeeeeeee! | ||
| John Dare Unregistered guest Posted From: 144.138.194.64 |
As I own different makes/models of cars, I regularly visit and contribute to the various help and information forums relating thereto. I find them to be most informative and suggest a brief visit to the best known "Range Rover" (once described as the R-R of 4Wds!) forum; www.lro.com, whereby one may readily observe the manner in which informed, articulate and dare I say, educated (OR at LEAST, well mannered!) people, are able to conduct and express themselves. Moving on. I have never had to endure what could, in any way, be seriously described as a "howling" differential (Shadow) but rather one which tends to exhibit a barely audible "hum" at at around 75kph. I had the crown wheel and pinion reset (slight improvement) by a R-R specialist who worked on Shadows upon their introduction here; 1966/7. Whilst employed by the then local, state (Factory appointed!) agents, he had performed similar "corrective" work (to differentials) WHEN the cars were NEW and UNDER WARRANTY. This common and well known characteristic has NOTHING whatsoever to do with "maintenence" or other fanciful notions as tirelessly advanced by self taught "experts" who seek to dominate a given forum by assailing us with "INcorrect FACTS". Fortunately, am able to identify oxymorons and morons alike, when I see (or hear) one, and for that, I remain eternally grateful. (Message approved by david_gore) | ||
| Patrick Lockyer. Prolific User Username: pat_lockyer Post Number: 97 Registered: 9-2004 |
J.G.Dare. For you info,as you cannot read the above posts,i will repeat it to you. Compression Ratio's are calculated and fixed. Camshaft alters dynamic compression. Confirmed by world authoritys and myself. Read the above posts many times and slow you will grasp it,if not you could put your query on the Swammelstein site and i will deal with it in no uncertain terms with you there. I am sure we have heard enough of your ramblings here. (Message edited by david_gore on November 25, 2004) | ||
| John Dare Unregistered guest Posted From: 144.138.194.186 |
Thank you Patrick. I understand quite clearly what you are saying, THIS being what was originally advanced, however you initially denied (absolutely) the concept or indeed any notion, that the camshaft could alter compression ratio; of any kind. It was only AFTER you were challenged (and duly INFORMED) that you moved your position to ruefully agree with that which was being proposed. You would have seen the light as it were, had you taken counsel from your compatriot, BOB/UK, who (after OPENLY declaring HIS qualifications) stated that on his car, at idle/throttle closed, the comp. ratio(dyn.) was probably in the vicinity of 2 to 1. This was the hint that you appeared to have blissfully missed during your abject failure to understand the question at issue. I note with considerable interest that the postings on this subject which WERE listed on the Swammelstein site, HAVE BEEN DELETED therefrom. Given your preference, if not fixation, with that particular site (in marked contrast to your curious and notable absence from RREC/RROC;US and BDC forums, perhaps you can explain the mysterious absence of the many postings hitherto posted BY YOU, upon that forum. I have reserved my own view as to the most likely reason/s, but will of course allow you the opportunity to enlighten me once again; as best you can. John; with due respect to the differences in opinion between you and Patrick; I must suggest that the removal of posts from the Swammelstein site by Kees Scherer was possibly not because of content but due to server storage capacity and probably hacking problems - it is my understanding that Kees has ongoing difficulties with his service providor and administration of his forum which cause it to "lock-up" at regular intervals as occurred recently. The fact that this Forum does not have these problems is a credit to the efficiency and skill of our Administrator who keeps a low profile behind the scenes and is truly a "quiet achiever". To settle any questions; I am not the Administrator just a Moderator!! (Message edited by david_gore on November 25, 2004) (Message edited by david_gore on November 25, 2004) (Message edited by david_gore on November 25, 2004) (Message approved by david_gore) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 106 Registered: 9-2004 |
I will second that,the moderators coment. | ||
| Martin Cutler Frequent User Username: martin Post Number: 12 Registered: 10-2004 |
Ok, Here's one for all you ex-perts. Why, when you are testing compression, is it common practice to hold the throttle fully open? I could never work that out. Marty | ||
| John Dare Unregistered guest Posted From: 144.134.147.40 |
Thank you Patrick. I remain confident as to the most likely reasons for the sudden deletion of your posts (on this topic) from the Swammelstein forum, and like most aware readers will reserve my own opinion. But worry not that said content has been struck out, for all of the crucially relevant evidence remains on THIS forum. On 25/11 you stated (in part) at line 4; "Camshaft alters dynamic compression". On 21/9 at 04-23am, your opening paragraph clearly disputed the existence of DYNAMIC compression (ratio), suggesting said term was merely a substitute for compression PRESSURE; refer lines 5 to 8 (inclusive) in your own words. This clear statement caused you to ask (at line 9) "So tell me how a camshaft can alter compression ratio". Return now to 25/11 wherein you stated (correctly) at line 4; "Camshaft alters dynamic COMPRESSION",the clear inference being compression RATIO. You have indeed answered your own question, albeit in a somewhat tortuous manner. (Message approved by david_gore) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 115 Registered: 9-2004 |
Just seen the posting,so reply in haste. Sorry should be pressure,can only blame the GLENFIDDICH. J.G.Dare Get your self on the Swammelstein forum if you want to clarify your nick picking of the subject. Martin it is to open the butterfly fully on the carbs so as to allow a more accurate and consistent figure on all cylinders when testing. It is always good practice to make sure you have a good battery and starter to begin with on testing. (Message edited by david_gore on November 30, 2004) | ||
| John Dare Unregistered guest Posted From: 144.138.194.174 |
Thank you Martin;post 29/11. When testing for compression pressure (psi etc) the throttle is held fully open in order to induct a full volume of air into the cylinder whilst engine is cranked several revolutions etc. (Message approved by david_gore) | ||
| John Dare Unregistered guest Posted From: 144.138.194.135 |
Thank you Patrick. I was on the cusp of asking if the absence of your reply represented a "TIME to CONCEDE" (your own words I believe) however you have now done so yourself (thank you) thereby vindicating the position so clearly advanced on this subject by QUALIFIED professionals. Given the admitted reason for your temporary distraction/oversight etc, I can forgive you for "missing" one post,but nevertheless feel obliged to invite your attention to yet another (recent)post that you may have also overlooked; see under "Oil consumption" thread. Repetitious content deleted by moderator (Message approved by david_gore) (Message edited by david_gore on November 30, 2004) | ||
| Martin Cutler Frequent User Username: martin Post Number: 13 Registered: 10-2004 |
Thanks for the answer guys. I would have thought that as long as the same amount of air is drawn into the cylinders, ie, same for each cylinder, then you would get a reading that would be useful. Butterfly opened or closed, the cylinder is still going to draw mixture from the carburettor. As long as the method is the same for each cylinder, I thought you would still get a reading you could compare to the other cylinders. I will get someone to hold their foot on the throttle next time I do a compression test. Out of interest, I get a reading of around 100psi on the MK VI, (all nice and even), around 120psi on the MG Magnette, and 170psi on the Laverda race bike, (12:1 pistons and Axtel cams). One that surprised me was my old Holden EJ ute, now sold. It had a well worn old grey motor, pushrod 6 cylinder ex Buick for those not in Oz, and the readings where around 145psi! I expected the thing to be clapped out, I wonder if the standard cam in a grey motor has a very short overlap? The static compression would be fairly low I would assume. Thanks to the moderators for allowing this topic to continue. Apart from all the shinanigans, this is quite an interesting thread. Marty - definitely an amateur! | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 117 Registered: 9-2004 |
J.G.Dare. Frightened to go on the Swammelstien site!!!! I do not need to SWANK about my qualifcations. Still can't grasp the oil retaining plate as your mate Robert Chapman has said,read it more slowly!!!!!!!! | ||
| Robert Chapman Grand Master Username: shadow Post Number: 122 Registered: 5-2003 |
Patrick Lockyer, Oh what a tangled web we weave, when first we practise to deceive!} It matters not how slow or fast you read YOUR post of 21/9/04 when YOU QUOTED to me YOUR post that said"SO PLEASE TELL ME HOW A CAMSHAFT CAN ALTER COMPRESSION RATIO". Obviously implying that you did not think it possible, upholding your position(often stated by you)that a camshaft could not alter the dynamic ratio. Well you asked and I told you, THEN you started to change your tune,saying "I knew that". In your own words "given enough rope" your own words have come back to prove you not only wrong but not man enough to admit it. You now put forward this pathetic disingenious excuse which must be pellucid to all that have followed this thread. Nothing you can post now can reverse the fact that you were wrong from the very start of your tirade. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 121 Registered: 9-2004 |
As you may have been aware i am bombarded with a lot of information} that tries to deter me and others from the original postings. To clarify the position, my summary of my statements is as below:- Compression ratios are calculated and fixed. Camshaft alters the compression pressures. Moderator's Opinion: This topic has suffered for its entirety from misunderstandings about terminology especially the essential difference between theoretical, actual and "dynamic"[my term for what is actually measured with a compression gauge] compression ratios. 1. The dynamic compression ratio is simply the measured compression pressure [psi, Kpa or Bar] divided by the absolute air pressure at the time of measurement. For example; if the compression gauge reads 145psi at standard atmospheric pressure(14.7psi); the dynamic compression ratio is145/14.7=9.86. 2. The theoretical compression ratio is Cylinder Volume at point of maximum piston travel[BDC - Bottom Dead Centre]/Cylinder Volume at point of minimum piston travel [TDC - Top Dead Centre] 3. The actual compression ratio for a given camshaft profile is Cylinder Volume at point where inlet valve is fully closed/Cylinder Volume at TDC In future, I trust we all will clarify our definitions before engaging in complex debate. (Message edited by david_gore on December 01, 2004) | ||
| John Dare Unregistered guest Posted From: 144.138.194.52 |
Thank you Patrick. I do not fully understand that which motivates you to suggest that THIS issue (on THIS forum) be transferred to a remote European site, especially when, at last viewing, your own contributions are missing. If you are dissatisfied with this forum, why not access, say your OWN (local) R.R.E.C (UK) forum or the R.R.O.C (U.S) FORUM?. Your notable absence from those sites remains a source of concern and curiosity to me. Again,I regret I do not understand what you mean by "SWANK about" any qualification/s that you may have. I have simply asked that you let us know what they are and suggest that even a brief resume may serve to substantiate the merit and validity of the offerings which you continue to advance on a wide range of "R-R" related issues. (Message edited by david_gore on December 01, 2004) (Message approved by david_gore) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 125 Registered: 9-2004 |
J.D. dare. Dissatisfied with this forum never it is one of the best around. Run by the hard working folk behind the scenes who do not SWANK about there qualifications. Who do you think you are with your cunning inserted words. I will not waste time with your postings any more and hope you leave other folk alone so this forum can flourish with helping folk with there cars. | ||
| John Dare Unregistered guest Posted From: 144.138.194.131 |
Thank you Patrick. I will conclude from your response(1/12) that you do not possess ANY formal automotive related qualifications. John, I have removed the remainder of your message as it is predicated on your conclusion above. Patrick has indicated he does not wish to become involved in a debate on the value/standing of whatever qualifications and experience he has and we should respect this - this refusal should not be construed as proof that he does not have any qualifications as should be confirmed by your own legal experience. I am also of the opinion an on-going debate of this type is not appropriate for this forum. I believe you both have had ample opportunity to display your knowledge in relation to R-R/B motor cars and the "silent majority" of our participants have already formed an opinion on your and Patrick's credibility which is unlikely to change as a result of further debate between you. (Message edited by david_gore on December 02, 2004) (Message approved by david_gore) |
