| Author | Message | ||
     Martin Cutler Prolific User Username: martin_cutler Post Number: 228 Registered: 7-2007 |
Chloe must know i want to sell her, and made her feelings felt! One second powering up a hill as per normal, next nothing! Switch turned off. At first i suspected a fuse, but all ok. Spark at the points, no spark at the plugs. The button is delco remy, with a carbon brush installed it the circuit. Rotor button from B319LH is a different design, smaller, i swapped it in and the car ran, sort of, seems to be shorter. What does the carbon brush do? Should I take the carbon out of the circuit? Interesting problem. Cheers Marty | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1164 Registered: 2-2013 |
Martin any chance of a photo of the button/carbon brush? | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 969 Registered: 4-2015 |
The carbon piece is critical as it provides electrical connection between top of rotor and the cap. Design not critical. In emergency I once used a $4 brush from a Dremel tool. . | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1167 Registered: 2-2013 |
Oh I get it, you mean the carbon button. No it can't be. Martin if it is then you definitely need to leave the carbon in the circuit My view is you need the correct rotor button for the distributor as anything else may result in too high a resistance in the circuit. I do hope we are talking about the same thing as I have never heard of the carbon button being called a brush. | ||
| Carl Heydon Prolific User Username: car Post Number: 161 Registered: 2-2004 |
Without a pic we're guessing. I wonder if it may be a rev limiting rotor but probably just a resistor rotor | ||
| Martin Cutler Prolific User Username: martin_cutler Post Number: 229 Registered: 7-2007 |
Can I send you the photo in an email vlad then you can post it for me? Technically inept here🙂 | ||
| Martin Cutler Prolific User Username: martin_cutler Post Number: 230 Registered: 7-2007 |
my email is martincutler@optusnet.com.au Send me an email and I will reply that way you don’t have to put your email on the forum if it is a private one | ||
| David Gore Moderator Username: david_gore Post Number: 3042 Registered: 4-2003 |
Martin, I am also happy to help in situations like this - just send me a PM through the forum and I will respond appropriately as I have software capable of processing most if not all posting requirements and stable high-speed internet connections. Unfortunately Vladimir is in outback Queensland with very basic internet connections, I have had to help out on several occasions when he wanted images posted in the forum for this reason. | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1169 Registered: 2-2013 |
Thanks for that David. I have sent my email to Martin so soon hopefully we will get a look at this intriguing item. Telstra is bitterly despised by everybody here at the moment as it is operating a third world service reception wise and fobbing its complaintants off to its not so efficient Phillipino call centre the staff in which while polite have zero concept of outback Australia. I have the ombudsman breathing down their neck but sadly the ombudsman is a toothless tiger. Naturally I blame the swine that dwell in parliament for the mess. Somebody will perish out here and the lawyers will move in to feed on Telstra's corpse before the fools get it right but I guess one should expect a pure form of incompetence from a billion dollar company that has all the humanity of a large Australian bank. | ||
| christopher carnley Unregistered guest Posted From: 86.188.39.9 |
He is talking about the original pattern rotor with the thin carbon suppressor in series. (Message approved by david_gore) | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1186 Registered: 2-2013 |
Well if its got a suppressor on it then the resistance could be too high causing misfire but if he is talking about the spring loaded carbon button then that can't be removed at all without causing huge resistance in circuit. Just fascinated by the term "brush" and so far no photo of the thing to my email or put up by the moderator. Of cause if you bridged the suppressor such would cause amazing amounts of radio interference. | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 970 Registered: 4-2015 |
Vladimir... I have been traveling to my hunting lodge in Montana to get things squared away for the Winter hence no prompt reply. In electric motor speak, a "brush" is the graphite carbon thingy that rides on the rotating commutator. My point is that the electric motor brushes on the little hand held Dremel moto-tools can be "field expedient" modified to work in the EPW and pre-war caps that have the removable carbon contact. It is a bit fussy in that the moto-tool brushes, while the proper diameter, are square rather than round. Carbon graphite is very soft and a bit of filing with small file rounds them up and then you need to further modify the spring to fit into the orifice in the cap. As long as the spring contacts the center terminal in the cap and the carbon cylinder thingy contacts the metal top of the rotor, it works just fine. In "25 words or more" that explains the reference to "brush". It will be interesting to see photos of the items referred to by Martin. I also wonder what he meant by running "sort of" when he swapped the piece from another of his Bentleys. Without a bit more clarity from his end and given that he had spark at points but not at plugs, I would tend to think something else is the culprit...loose wire, condenser, or coil. I had a similar "failure to start" after years of flawless running in my EPW Dawn which was cured by switching to the spare condenser. Started instantly. We all await further developments from his end. . | ||
| Martin Cutler Prolific User Username: martin_cutler Post Number: 231 Registered: 7-2007 |
Hi guys, Vlad should have the photos now. Just to confirm both cars are delco remy, b319lh runs the smaller rotor button, b256md runs the larger one with the carbon “suppressor” or whatever you want to call it. Instant loss of power while under light throttle. Spark at the points no spark at the plugs. Put the smaller rotor button in, car ran enough to get it back in the shed but haven’t investigated further, possibly running on 3. My first thought is to remove carbon thingy from the rotor button, or bypass it by soldering a wire in there. Might be a slightly different model dissy as smaller rotor button may not be contacting the centre electrode on the cap. Cheers. Marty | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1187 Registered: 2-2013 |
Martin I have the photos. I must be blind but I see no " carbon thingy " on either cap. Looked at Mark 6 Workshop Manual and the rotor button on left the small one seems to be the right one but basically the manual is useless for correct rotor button identification. I would test both with ohms metre to look for high resistance and or open circuit. Also, check distributor shaft bearing movement ie is there any horizontal movement in the shaft? Pretty sure these distributors needed am few drops of oil in the top of shaft every service oil change interval. Also, check for damage to carbon button inside centre of distributor cap and cleanliness of each contact for each cylinder. In the trade only the right rotor button for the right distributor shaft is used. I will go back again an look at these photos so see if I can find the elusive brush. | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1188 Registered: 2-2013 |
Martin if what you are calling a brush is the dark matter existing between the chrome centre pick up and the brass piece at the end which comes in close contact with the 6 contacts inside the distributor cap then you could bridge it if you can stand heaps of radio interference. Never seen a rotor cap with a built in suppressor in over 40 years of mechanical trade! Its pretty dodgy brothers to be using incorrect rotor button as too big a button would destroy the distributor cap and too small a button would mean crazy too much resistance. But you got her home and that's the main thing. Good luck. | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1189 Registered: 2-2013 |
Wiil email photos to David to get put up to intrigue other contributors. | ||
| David Gore Moderator Username: david_gore Post Number: 3048 Registered: 4-2003 |
And here they are - looking forward to the identification from "those who know".......    | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1998 Registered: 9-2004 |
This is a common failing usually caused by the plugs taking a high KV. The purpose of the carbon resister is to stop interference when a old valve type radio is fitted. The position is shown in red!  | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1190 Registered: 2-2013 |
Patrick, good show there.Again I and perhaps others learnt something we did not know. Now Martin do the ohms check on that rotor button and if you have open or too high resistance then you could bridge the carbon thingy with a wire soldiered between the chrome and the brass bits. Maybe you will need silver soldier - just google that but I would not use a gas soldier tool but a good electric iron as the gas tool will melt the rotor button if its plastic and if its bakerlite well I don't know. Once bridged if you have radio interference you could use either a screw in suppressor in series on the coil to distributor lead or a late model lead that uses bendable carbon wire instead of copper wire. The correct repair of course would be to buy a new and correct rotor button which you are most unlikely to find at Repco. Good luck and thanks for the intriguing post. But I would not call it a brush. | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 971 Registered: 4-2015 |
Martin... These are aftermarket non-original parts so I suspect that you have replaced the original distributor and that it came with its proprietary rotor and cap? What does the underside of the cap look like? All along I was thinking that you had a factory proper installation. Having aftermarket modifications changes everything. . | ||
| Jim Walters Prolific User Username: jim_walters Post Number: 206 Registered: 1-2014 |
The one on the right is commonly used on Triumph Spitfires with Delco distributors from 1965 to about 69 or 70. The caps used with these have a fixed carbon brush in the centre as opposed to one with a carbon brush on a spring. After 1970 or so they switched to a Lucas distributor. I've seen the round one too on something other than RR but can't place it right now, it'll probably come to me in the middle of the night. SRH8505 SRC18015 SRE22493 NAC-05370 www.bristolmotors.com | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1999 Registered: 9-2004 |
Jim, Delco Remy, common as you say on triumph but more common on the Bedford Vauxhall range of vehicles [General motors] crap distributor IMO. | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1192 Registered: 2-2013 |
There was a book rather large that wreckers in NY used to refer to and I forgot the name and the one I had I gave away. The wreckers called it the bible. In it you could look up lots of parts on one car and the book would tell you what other model car used that part. I really don't recall if the book had a "Foreign" section which is what they called anything made outside USA. Going one step further you could write to Delo Remy with the serial number off the distributor. Some companies will assist. However, if they have gone broke well it will be just the cost of a stamp. | ||
| Kelly Opfar Prolific User Username: kelly_opfar Post Number: 213 Registered: 7-2004 |
Vladimir, the book you're thinking of is called Hollander Interchange. They're still around: https://hollanderinterchange.net/catalog/index.php?cPath=21 http://www.BritishToolWorks.com | ||
| Vladimir Ivanovich Kirillov Grand Master Username: soviet Post Number: 1194 Registered: 2-2013 |
Well perhaps one of our American friends either has one (and I can just imagine Killer Kowalski in beavering though one now given his British Car fetish.) Or perhaps somebody stateside can go visit the local wreckers. Yes Kelly that is the one - funny how you know you have forgotten the name but when you see it decades later you remember it. The Hollander is a serious publication (as My little KGB Lieutenant would pronounce.) | ||
| Martin Cutler Prolific User Username: martin_cutler Post Number: 232 Registered: 7-2007 |
Hi guys, the rotor that failed was on the car when i bought it in 1992, i didnt know it was after market. The smaller one is as supplied by introcar in the uk and is identical to the rotor on b319lh. So if both these are aftermarket, what does the correct one look like? | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2000 Registered: 9-2004 |
Ah the old brain was looking for Delco Remy, of course they went to the newer name of AC Delco. A look in the book of many  A clearer view.  The one listed is DB 400. made DR. Will do a cross check time permitting. | ||
| christopher carnley Unregistered guest Posted From: 86.188.39.62 |
The correct original rotor is as the left hand, big one, and as I said previously with the carbon R F suppressor. The Triumph pattern one is on th right. (Message approved by david_gore) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2001 Registered: 9-2004 |
Looks like the original is NLA but the one that supersedes it is the AC Delco. https://www.ebay.co.uk/itm/Rotor-Arm-Delco-DRB703C-820445-DB400-CR6000-/362219077593 Use carbon resister HT leads to get over the interference problem maybe! | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 972 Registered: 4-2015 |
This is assuming that the original style distributor is still in place. With two sixty year old RR/B (with two different aftermarket rotors) there is no reason to assume that. While it is possible that someone has installed incorrect rotors in original distributors, it is also possible that both distributors have been changed. It is equally possible that you have original distributors with aftermarket rotors.(i.e. proper replacements, just not visually the same as the original as factory issued.) My cars have all original components and that may be why yours did not look right. They may in fact be proper replacements, just not OEM. It is important to get the facts straight and source the proper rotor for whatever distributor is present. Martin, can you provide photos of the distributors showing the name plates? Also photos of inside of distributor caps? This will likely assist identifying the current state of affairs. Also, PL's data implies that the rotor was changed on the R Type which may be the reason your two cars have two different rotors. Is one a Mk6 and the other an R Type? . | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2002 Registered: 9-2004 |
Original distributor, if you have this type of cap you will have the original DR type of distributor! The r arm posted will be the one to fit. Now where is that DR distributor!!!!!! https://www.holden.co.uk/displayproduct.asp?pCode=cd876pt | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 580 Registered: 10-2008 |
FS supply both types of rotor shown in the photos.Apparentley, the small type is now supplied by Bentley for all 6cyl cars. Mark | ||
| Norman Geeson Unregistered guest Posted From: 81.99.138.38 |
I am astounded that hardly anyone seems to have seen a RD 8550 rotor arm, which is the one fitted with the carbon suppressor. Even more so, since no one appears to know the reason for its existence, even though it was introduced part way through R type production and was the sole rotor fitted to Silver Cloud 1 engines. My conclusion is that hardly anyone has seen an original R type or Silver Cloud 1. The original rotor fitted to Bentley MKVI / Silver Wraith was R 3795 in 1946, but it was initially intended for the R-R B40 four cylinder engines. This rotor was similar to the non-suppressed rotor shown in the presented photographs. It was supplied as an official spare part until February 1960. In mid 1950 the rotor was transformed into RD 6376 most probably to fall into line with all the other distributors Delco were producing with a 0.953 inch rotor pitch radius. In the early 1950’s through 1954 the 405 line TV sales rocketed in the UK and it was found necessary to suppress the ignition to prevent interference. The RD 8550 was placed into production about October 1953 having a suppressor built into the rotor specifically to deter TV interference, although it performed a similar function with radio. This RD 8550 was the last rotor to be fitted to any post war R-R six cylinder engine and covered production right up to the end of the Silver Cloud 1 and the last of the line Silver Wraith LWB. In February 1960 R-R decided to stop supplying the R 3795 and supplied the RD 8550 supressed rotor for all post war six cylinder car engines. When R-R Crewe divested themselves of pre-1955 parts supply the non-suppressed rotors were again offered as an option along with the RD 8550. The weakness of the RD 8550 suppressed rotor was the movement of the carbon suppressor due to centrifugal force, a very good reason not to attempt to repair a faulty rotor. I have witnessed many of these rotors explode and blow the distributor cap apart and this is the main reason owners fit the non-resistor rotor used in the 70’s Vauxhall Viva/ Bedford HA van engines with the 0.953 inch rotor pitch radius. N.B The earlier rotors had a 0.958 (-3) inch rotor pitch radius and this was changed to 0.953 (-10) inch part way through RD 8550 production. For the sake of clarity the later 0.953 figure has been used in the above text. A closer rotor tip to cap contact assists with smoother idling as R-R found in the late 1930’s. (Message approved by david_gore) | ||
| Jim Walters Prolific User Username: jim_walters Post Number: 209 Registered: 1-2014 |
Thanks for the clarification Norman. I knew the RD8550 and RD3795 were standard RR rotors but I didn't know the suppressed rotor was for television interference and not radio. I am sure I have seen this type of rotor on another application, I think it was the same or at least very similar to one used on a vintage American car although I can't recall which one. SRH8505 SRC18015 SRE22493 NAC-05370 www.bristolmotors.com | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2003 Registered: 9-2004 |
I had always been taught many years ago that the rotor arm suppressor was mainly for the radio suppression. The HT lead screw in suppressor and or the plug lead caps if fitted were for the TV suppression Silver Dawn-Silver Wraith and of course the Bentley MK6 all with the DR dist fitted! Watching the coronation on the TV in 53 was the boom year for the start of HT suppression on cars! | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 973 Registered: 4-2015 |
Oh! The HORROR if it!! Never thought it would happen, but it did!!! Much to my chagrin, I was wrong...sad but true...and when it happens, you need confess, and I do. In my defense, however, I will write it off as having to many RR/B and apparently not enough brain cells to go around. Anyway, all thru this thread and in my mind's eye I have been thinking of the rotor and removable spring loaded carbon graphite center contact in the distributor cap of the pre-war chassis, not the EPW chassis. I have three pre-war and a 1955 Dawn here in Montana and today when I popped open the cap of the Dawn, I saw the RD8550 rotor essentially the same as the smaller teardrop shaped one in the photos but with a smaller contact button. So there it is. Martin's rotors are indeed correct but this brings us back to his original problem which as been overlooked in this illuminating thread...especially Norman's historical report...that is, the cause of his Bentley's FTP? Let's get back to that and see if we can help resolve that issue. Here is the summary: He has a Mk6 and an R-Type that performed properly. Suddenly the Mk6 has a total FTP and will not start. He switches to the smaller rotor from the R-Type and the Mk6 runs "sort of". In order to determine whether the larger Mk6 rotor is defective, he should put it into the R-Type that ran fine with the smaller rotor. If the R-Type runs, the rotor is not at fault. If not, the rotor is seriously suspect and then there remains the issue of why the Mk6 does not run smoothly with a "known good" rotor from the R-Type. The fact that the smaller rotor worked fine in the R-Type but not so much in the Mk6 also lends credibility to the FTP being due to something other than the rotor. Have I got this analysis correct? Perhaps Martin will do this test and let us know the results? . | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2004 Registered: 9-2004 |
Simples, the coloured red part of the rotor arm in the above posting is the suppressor/ resister that has let go...... Cripes just get a ohms meter out and test if you cannot see the failed part. How is the 1934 Phantom II coming along, how time flies. | ||
| Jim Walters Prolific User Username: jim_walters Post Number: 210 Registered: 1-2014 |
And do the standard test for a dead shorted rotor if there is continuity through the carbon. Hold the high tension lead from the coil to within a quarter inch of the centre of the rotor (where it would normally contact the cap) and have someone crank over the engine. If sparks jump to the rotor it is dead shorted and faulty. Rotor on distributor shaft and cap off obviously. SRH8505 SRC18015 SRE22493 NAC-05370 www.bristolmotors.com | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 974 Registered: 4-2015 |
PL... Yes, indeed. Martin can simply check the suspect rotor with a meter, but that would be too easy...and requires having and/or finding the meter. Much more fun to be switching components around! In any event, further diagnosis is in Martin's corner from here. The Phantom II has remained in California while I have been moving other cars and equipment to Montana. Now that Winter snow and cold will shut that relocation effort down imminently, I'm back to CA for the duration and further investigations on the PII are somewhere on the to-do list. . | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 975 Registered: 4-2015 |
Jim... You lost me on that test procedure. Wouldn't it be easier to just check for continuity thru the rotor, that is, from the button at the top center thru to the metal at the end of the rotor arm? Presumably if there is continuity the rotor is good, but if the suppressor is defective, there should be no continuity. Your spark test seems to only check that spark is coming from the coil (and is bypassing the distributor cap and carbon insert where it would normally pass) but does not verify that it is passing thru the rotor. Seems that the test is checking the cap and center carbon, but not the rotor, or do I simply not grasp the technique? In any event, continuity thru the cap to the rotor is one of the possibilities that needs to be checked and eliminated as a source of the FTP. If cap continuity is intermittent, that could be why the engine only "sort of" runs, even with a "known good" rotor. More for Martin's investigations!! . | ||
| Martin Cutler Prolific User Username: martin_cutler Post Number: 233 Registered: 7-2007 |
Sorry I’ve been away on the bike rally for the last week, pulled the rotor button apart, the carbon suppressor has brass end caps and has zero conductivity. Will change to the solid type rotor button and let you know how I go | ||
| Martin Cutler Prolific User Username: martin_cutler Post Number: 234 Registered: 7-2007 |
I just tweaked the small cap and the car runs smoothly, very happy. Both delco remy distributors are model number 656RD. Cheers Marty | ||
| Martin Cutler Prolific User Username: martin_cutler Post Number: 235 Registered: 7-2007 |
I can heartily recommend the Mita Mita pub to stay at, great food, nice people, comfortable rooms and surrounded by fantastic roads in the Victorian high country. Took my 1979 Laverda Jota and had a ball. They even had cold beer!!!) |
