| Author | Message | ||
     Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 527 Registered: 4-2015 |
Re: 1959 Silver Cloud I - Chassis LSMH109 Upon starting the engine when cold, I get a tapping that seems to be coming from top of engine and which slowly goes away as the engine warms. My first suspicion is that it is a valve clearance too wide and that as engine warms, clearance closes and tapping goes away. Is it also possible that a push rod is sticking and thus causing the excess clearance and thus the tapping, and that as the engine warms, the push rod becomes free and the valve clearance adjusts and the noise goes away? Anyway, in any event, I desire to first check the cold inlet valve clearances as they are relatively easy to get to. The exhaust valves are not convenient, so checking them will be secondary. The questions are, first, how to turn the engine crankshaft in order to be sure that the pushrods are resting on the flat of the cam? On my earlier cars, Dawns, and Pre-War, this is simple as there is provision for inserting a hand crank from the front in order to turn the crankshaft. Clearly if the spark plugs are removed there will be no compression which will allow the crankshaft to turn freely, so that is a given first step. On the Cloud however there in no provision for a hand crank, so what is the proper method to turn the crankshaft? Pushing on the fan blades may or may not be sufficient to affect the crankshaft, but I also am concerned that this is ill advised even with the spark plugs out and compression released. Yes, or no?? Another method would be removing the ring gear cover and using a pry bar on the ring gear, but this is necessarily awkward without an assistant. Cranking with the starter is a third option, but does not have the fine control probably necessary. Next question: Service manual says to turn crankshaft until the valve to be tested has opened and closed and then "one half turn further". With the engines that can be hand cranked, this is easy to observe. If it is acceptable to use the fan, the problem then becomes how to tell what "half a turn" is. Likewise with levering the ring gear or using starter motor...how does one tell when you have gone that additional half turn rotation? Here is the real question: Is it possible to tell when a given valve has opened, closed, and then an additional half turn by observing the other valves? My suspicion is that when any given valve is at full open, that is, at top of cam lobe, there is another that is precisely on the cam flat. So...is that a reliable method of determining the proper position, and if so...what is the correlation between the valves? That is, when, for instance, #1 is full open on cam lobe, what is the correlating valve that is on the cam flat? Is this the best way to locate the cam flat, or is there another better method??? I trust that I am articulating this situation properly? . | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1216 Registered: 4-2016 |
Hi Christian. I've had a lot of success by removing all plugs, and using a spanner or socket (depending on accesability) on the alternator nut. If your belt is well tensioned it should turn over easy. I follow the firing order, and do one cylinder (both valves) at a time buy using an indicator in the spark plug hole to indicate top dead centre on the firing stroke. This is basically the half turn they are describing. | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 528 Registered: 4-2015 |
Patrick... Alternator nut. Good idea. I presume that one should turn that nut in the direction to tighten the nut lest one loosen it in the process of turning the engine were one to turn it the other direction? As to the idea of probing for TDC... how does one know you are TDC on firing stroke rather than TDC on the exhaust stroke? I suspect that looking at the distributor rotor arm would be the clue...if TDC on firing, the rotor will be pointing to the wire going to that cylinder? I would still like to know about the correllating "other" cylinder idea. My recollection is that pairs of pistons are always moving together with one firing and the other exhausting. What is the firing order? That may help me figure it out. Tomorrow if I have time, I will look at the distributor as that will help me figure out the firing order. . | ||
| Richard Gray New User Username: mooney1el Post Number: 3 Registered: 8-2016 |
From my saved notes: Silver Cloud I and Bentley S1 Firing order for Series 1 models is 1, 4, 2, 6, 3, 5 Contact breaker point gap 0.019" to 0.021" Spark plug gap 0.025" Ignition timing 2 degrees BTDC} Richard | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1218 Registered: 4-2016 |
Christian, Your spot on with the rotor arm mate, just start at 1 (as Richard has kindly supplied the firing order for us) and away you go. 1 then 4 then 2 etc. When the piston indicator shows the piston at TDC, and the rotor on that cylinders spark plug lead, adjust away. However, you should only need to look for rotor position number one, as the rest will follow suit in the firing order. The only thing that you need to know, is: Are the tappet settings you have a hot or cold gap. This is very important. My 25 Chevrolet is 4 and 6 thou hot. I adjusted them cold once, and after it warmed up they were all riding big time and was running very badly. Id rather hear a slight tap from the rocker arms than silence. Once the plugs are removed it usually does not matter which way the alternator nut is turned, it should spin over quite freely. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1751 Registered: 6-2006 |
Make it simple for yourself. Start at cylinder one and work back. A little more engine turning but simple as. Screwdriver in cylinder. Move to TDC. Valves closed.? Adjust. Can't see how a push rod would stick. Followers or valves maybe. | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 407 Registered: 10-2008 |
I seem to remember a posting regarding adding a small amount of ATF to the oil to stop this tapping, due to cam followers ,if I remember the article correctly. My S1 has the same symptom cold, and I was going to try adding a small amount of ATF to the oil at the next change. Turned the engine with a socket on the crankshaft nut and just followed the manual; helps if you have an assistant .Exhaust valves are easiest done with a mirror. Remove the wash bottle and get a mirror cut to the length of the tappet chest. Just a matter of getting used to working with a mirror image. Mark | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 408 Registered: 10-2008 |
This is the article: http://au.rrforums.net/forum/messages/30/22866.html#POST41094 Mark | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 529 Registered: 4-2015 |
Mark... Thanks to the link to other thread. I had already tried about a cup or two of ATF but to no avail. In that thread Norman Geeson's mention of "shuttlecocking" is a distinct possibility and fits with what I was referring to as a sticking push rod...amateur description of possible cause on my part. I was simply suggesting that "some" component was sticking, causing the tapping, which diminishes once engine warms. Norman...is there any test to isolate this condition of "shuttlecocking"? Would the existance of a "shuttlecocking" tappet have any discernable affect on the inlet valve clearance...assuming that it the inlet that has the issue, rather than the exhaust? Question restated: Would the presence of "shuttlecocking" affect the related (be it inlet or exhaust) valve clearance? I suspect that the cure for "shuttlecocking" is an extreme measure involving disassembly of engine? Is it an issue that can be lived with as long as one is gentle upon starting the engine and until it has warmed sufficiently that the tapping has quieted? Once warm, I never hear any such noises and assume therefore that the issue is temporary and temperature dependant. Yes, No? . | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 530 Registered: 4-2015 |
Richard... Thanks for the firing order. Perhaps it now makes sense. Regarding the "correlated" piston issue, 1 and 6, 4 and 3, 2 and 5, all travel up and down together but with each at opposite functions. When one is TDC firing, the correlated piston is TDC on exhaust. Is this vision correct? Paul... Your suggestion is still confusing because when any pair of correlated pistons is at TDC, the inlet valves for BOTH are closed. The firing piston for obvious reasons, and the exhausting piston because it is the exhaust valve for that piston that is open. So...you still need to determine which of the two are on the heel of the cam...or are they BOTH on the heel of the cam? ...hence, my confusion... . | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 531 Registered: 4-2015 |
Patrick... Valves get checked cold. (Inlet .006", exhaust .012", or .015" for long term, high speed conditions...read: modern day, highway driving, as I recall.) Hence the problem. I cannot demonstrate the noise to the local RR/B technician given that by the time I get there, the engine is warm and I would have to leave it overnight just so it would be cold the next day. Similarly, I cannot take it in for them to do the valve clearance checks as it would again have to be left overnight in order for the engine to be cold the next morning. Taxi back and forth whenever I leave a car for them adds $100 to the bill...an additional expense I try to avoid when possible. . | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1225 Registered: 4-2016 |
Christian, At least if you get the clearances done properly, and the noise is still there, you can then rule this out as the cause. If the noise is better or gone, then you are looking in the right place. Have you ever used a long screw driver or an automotive stethoscope to listen to the various engine parts whilst the engine is running? This may help start to pin point a location as sometimes as we all know, noises can travel. | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 532 Registered: 4-2015 |
Patrick... Yes, Yes, No, and Yes. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1117 Registered: 9-2004 |
To rule out or confirm things like piston slap[engine clapped], small end wear, valve spring loss of tension, excessive wear or broken valve guide etc, to find the cause of the noise [if it is at the top of the engine] on the inlet side of a specific cylinder I have ran the engine up and with a piece 6 thou shim steel run it through each inlet tappet until with luck it goes quiet and confirms excess clearance as the cause. This must be carried out from cold and before the engine heats up. Exhaust is more of a job! | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 533 Registered: 4-2015 |
Patrick... That test procedure is worth trying, but is of course limited to the short period of engine warm up. I would estimate that it takes only 3-5 minutes for the components to warm sufficiently and the tapping goes away audibly, but should be enough time to run that check. Thanks. . | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1226 Registered: 4-2016 |
Yes it would be Christian. Good luck. | ||
| Christopher Unregistered guest Posted From: 5.80.18.233 |
Very possibly a slightly "loose" bottom tappet,(cam follower). (Message approved by david_gore) | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 535 Registered: 4-2015 |
While trying to observe other "symptoms", the following came to my attention: First, the tapping upon starting engine in morning when cold is intermittent in intensity. The morning I was provoked to start this thread it was quite noticeable which raised the concern level. The subsequent two mornings it has been considerably quieter, yet present with bonnet open and deliberately listening...just not so alarmingly loud. Second...and a new twist...even after the engine is at operating temperature, the noise is not so much a "tap, tap, tap" like a tappet tap, but more of a "tick, tick, tick" which occurs under acceleration and diminishes once throttle is released. Since it is engine bay oriented and the "listener" is in the cabin, it is only noticed when the sound "bounces" back, as in the case where I am passing, say, a wall on the driver side. Today I found a stretch of road with a median concrete divider barrier to the left of me (remember I am in US and we drive on the right) so with window rolled down, the sound leaves the engine, bounces off the wall, and can be plainly heard...and can be induced with acceration and goes away as soon as throttle is released. This experiment was carried out at about 15-25 mph and is rpm related as when gears changed, the tick followed the rpm. To me this seems odd. If a tappet noise, would it be acceleration related? Seems to me that loose tappets would tap all the time irrespective of acceleration or decceleration. Does this ring any bells for anyone else in terms or correlation and cause...and of course remembering that with a 60 year old engine, there could be multiple issues and so the cold start tapping and the acceleration dependent ticking may not be in any way related. These sorts of things never manifest themselves when a mechanic is around so I'm just thinking out loud and solicit ideas. . | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1235 Registered: 4-2016 |
Christian I've heard cracked exhaust manifolds and manifold gaskets do this mate. Worse when cold, not so bad when hot, and of course throttle related. | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 410 Registered: 10-2008 |
Christian, check the manifold to downpipe gaskets. Mark | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1119 Registered: 9-2004 |
Worth a try, retard the timing about 5% and see if noise disappears. | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1236 Registered: 4-2016 |
Christian, When searching for an exhaust leak like this, a long piece of 1/4 (6mm) inch plastic tube held into the ear as you run it around and under the manifold and behind any hot boxes is very effective. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1120 Registered: 9-2004 |
Hopefully it is a cracked manifold or gasket. The retarding would stop the kick of the small end or alter piston slap if the cause. Have had a clicking sound that turned out to be a top broken piston ring that was working its way out of the top side of the piston! | ||
| Christopher Unregistered guest Posted From: 109.148.48.221 |
Minor noises arise if the grade of the engine oil is changed to a less viscous type. The flat chill cast bucket tappets slide inside cylindrical bores, and when new had a very close fit such that if the block was heated, one that was a grade too "tight" would seize. The tappets were graded .00025" between on and the next in a range from 1.8675" to 1.8825". The bores wear bell mouthed and a larger tappet than the one installed may cause a seizure. Of course it is only a "remote" suggestion, but tappet rattle is a common feature of the engines. Then again it could be worn rocker shaft bushes or a piston ring breaking up. (Message approved by david_gore) | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 536 Registered: 4-2015 |
Good suggestions and ideas, all. Thanks for the input. While Patrick L is hoping it is simply a (probably astronomically pricey) cracked manifold, and Christopher's are in the "I sure hope I don't have to go there" realm, I still haven't really gotten out of the wishful thinking corner where "hopefully" it is simply my vivid imagination. I washed the Cloud today. Cars react to being clean, don't you know! Subsequently could not replicate the tick, tick, tick. Of course I really did not try either! I did not want to disturb the revelry of not hearing it so avoided roads with adjacent walls to the left. Anyway, the ideas of exhaust leaks may be onto something because indeed there is a subtle and barely noticeable exhaust leak. I have just finished a $2.2RRU rebuild of the waterpump which began a dripping leak several months ago. Washing the car made no difference. Waxing the car was similarly without effect. Depleting the bank account to the enjoyment of the local RR/B shop did however resolve that issue...and I even got new belts and upper hoses! The old belts were so hard, brittle, missing chunks, and generally beyond their "end of life" stage that the noises they created were quite offending and effectively masked all others within the engine bay. Once those issues were resolved, the technician (been fixing my cars for 35 years now) alerted me to the very subtle exhaust leak, now apparent, but we passed on the opportunity to get it up on a rack and really give it a look-see. Anyway...therein may lie one of the possible causes of the acceleration responsive ticking noise. Sounds logical. Patrick R...thanks for the idea of the diagnostic tube. The noise is so imperceptible...but definitely there...that such will probably be necessary. Oh...and reality interfered with the turning the engine issue. Alternator is inaccessibly hidden below the AC compressor, as is the nut on front of crank, and I forget about the power steer pump, but in any event, once spark plugs are out, the amount of effort necessary to turn the assembly will be known and perhaps simply pulling on the belts will be sufficient. Later on that... . | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1240 Registered: 4-2016 |
Keep us posted Christian | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1122 Registered: 9-2004 |
To keep it really simple, have known a small stone flint type and other foreign bodies that have stuck on the inside of a drive belt making a clicking noise on startup. | ||
| Martin Taylor Frequent User Username: martin_taylor Post Number: 63 Registered: 7-2013 |
Pull one lead at a time to kill the ignition on each cylinder during warm up, this will stop the ticking on the affected cylinder as fuel will be unburnt. Usually a manifold gasket, pull the lead off the dizzy not the plug so you are not holding a live lead. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1153 Registered: 9-2004 |
Time has passed so what was the outcome of all the advice given on this tap tap click click. For the record! | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 550 Registered: 4-2015 |
Nothing to report as yet. Been tied down with other life priorities. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1228 Registered: 9-2004 |
"pull the lead off the dizzy not the plug so you are not holding a live lead." But where is the spark going and what other probs it may well start! C/H have you got your car priorities sorted now. | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 573 Registered: 4-2015 |
Gosh, no, I'm sorry to report that I am buried in other stresses and non-RR related issues and simply rotated to another RR to drive while I await time to proceed further with the Cloud. It is not that I am failing to report the resolution and thus leaving everyone hanging, but rather that there has simply been no opportunity to proceed on the issue. . | ||
| Bill Vatter Frequent User Username: bill_vatter Post Number: 58 Registered: 9-2004 |
Christian, Have you found the answer yet? The problem is your rocker arms. Take off the rocker arm set, 5 nuts on studs holding the shaft at each pedestal. Now look carefully and feel the place where the rocker arm contacts the end of the valve stem. Notice the dished place where the rocker arm has worn? When you use your feeler gauge to set the clearance, the feeler gauge is bridging the worn place, and as a result the clearance in the worn place is greater than what you are measuring. To fix it, you need to stone the end of the rocker arm to have the entire surface match the worn place. Free hand works fine, but you should try to keep the original contour of the rocker arm end. If the wear is very great, your grinder with a fine stone will make it quicker. Take off no more than necessary. If you need to remove more than 0.010 inch, the surface hardening of the rocker arm is close to wearing through, and you may want to have your machine shop re-harden the rocker arm ends. Regarding the change in valve train sounds as the engine warms up: Both pushrod and block expand with increased temperature. However, the block follows the temperature of the coolant while the pushrod follows the temperature of the oil. When the engine is fully warmed up the clearance is little different than when the engine is cold. However, because the coolant warms up quickly while the oil warms up slowly, there will be time during warmup when the block has expanded more than the pushrods, and the valves will become noisy. If you hear a valve sound click-click-click-silence-silence-silence-click-click etc. you are hearing the tappet rotating, and the tappet for some reason has become not quite flat on the end where it rides against the camshaft. As the tappet rotates, the clearance changes. | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 608 Registered: 4-2015 |
Follow-up: Issue seems to have gone the "self healing" route. Before I found the time to look further into valve settings or any other observations, the symptoms have vanished so there no longer remains anything to examine. While that may seems to be good news, I would perhaps rather to have been able to determine the source of the symptoms and thus be able to say that the issue has been solved, rather than simply gone away...or dormant. Just the same, it is nice to not have to listen to the clicking/tapping noises. Thanks for everyone's ideas and suggestions. . | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1395 Registered: 9-2004 |
That is good and bad news. Good news if the valve was sticking with engine miss fire that has now vanished. Bad news if the piston ring was working its self to the piston crown and has now broke off. |
