| Author | Message | ||
     felipe heuser Experienced User Username: felipe Post Number: 126 Registered: 07-2017 |
Greetings everyone… Would be very grateful if someone could shed some light regarding a problem on a 1960 S2 engine running a bit rough… Clearly present whilst idling, yet steadily, however more apparent when accelerating in low speeds and causing some vibration, until reaching higher speeds in fourth gear, then running smooth without judder… Never coughs or sputters with no reduced engine performance at any time…always starts straight away, even when parked for weeks…oil pressure and temperature are correct and no black smoke… The irregularity is always present with stop and drive in town… Many thanks | ||
| David Balfour Frequent User Username: sidchrome Post Number: 213 Registered: 02-2009 |
Hi Felipe, I have had exactly the same problem for the entire time I have had my 1961 SC2. I have had the transmission overhauled, rebuilt the drive shaft (including correctly packing out the detroit coupling and replacing the UJs), new spark plugs, new coil, Pertronix ignition, service kit through the SU's, all new tyres, etc, etc., with no change. I saw a heritage video and/or read about a vibration issue on a brand new 1957 ish Chrysler running a Detroit coupling with a vibration issue that manifests itself as a shudder that disappears at high speed as does yours, as does mine. Guess what it turned out to be on the Chrysler? A faulty crankshaft harmonic vibration damper! It's almost never mentioned on the V8, but I am now wondering if this could be the cause of my issue, as it was on the V8 Chrysler. If the rubber goes hard, there is no damping effect at all, and resonance is highly speed and load affected. My car has had a full engine overhaul done in the U.S.A. 20 years ago, but I do not know what was done with the damper, as it was well before I had the car. I would guess nothing was done. It is on my elimination list now - at the top now in fact. I know it sounds crazy considering all the other possible issues, but for me there is little else to consider. The transmission guy even pulled the transmission out a second time and fully stripped it to find - nothing. I'd be very curious to know if this has been an issue for others. | ||
| Jeff Martin Experienced User Username: jeff_r_1 Post Number: 178 Registered: 07-2018 |
Probably not as crazy as you think, problems with the straight sixes and their dampeners can cause this problem as described and are prone to failure due to their complexity and neglect, mostly due to lack of oil changes and short runs. I wouldn't be surprised if the rubber in the dampener has become hard and stopped doing its job. Best look after it sooner then later due to the torsional stress on the crank shaft. | ||
| felipe heuser Experienced User Username: felipe Post Number: 127 Registered: 07-2017 |
Hello and very grateful for the information...not familiar with this damper... Can one troubleshoot the problem before replacing to be sure the issue is with the damper? Haven’t exchanged spark plugs for example…and can replacing be a DIY job? | ||
| Trevor Pickering Experienced User Username: commander1 Post Number: 180 Registered: 06-2012 |
Had this problem on my S3 and it turned out to be a bad connection on the solenoid. May be worth a look! | ||
| David Balfour Frequent User Username: sidchrome Post Number: 214 Registered: 02-2009 |
Hi Trevor, to what solenoid do you refer? | ||
| Trevor Pickering Experienced User Username: commander1 Post Number: 181 Registered: 06-2012 |
The strater solenoid The main power supply for all the electrics on the car is taken from this point and this wire was loose on my car causing an intermittent slight misfire. I cleaned the connections and tightened everything and that cured my problem. | ||
| NormanGeeson Unregistered guest Posted From: 81.99.74.184 |
The initial post contained the following comment “Clearly present whilst idling……” At the moment I cannot see how this could be connected with a prop shaft drive line fault. Unless it is caused by an external engine problem the original comments seem to point to an issue upstream of the initial gearbox reduction gear pack. That is all connections within the engine and gearbox idle train. Before taking any further action I would check the following:-- Ensure all the engine and gearbox mountings are intact by gently lifting the engine. Ensure the engine is square in the frame with the drive shaft aligned correctly. Measure the run out of the flywheel rim by rotating the engine by hand. Measure the run out of the flywheel rim at two engine speeds, say 750 / 2000 rpm. Ensure the crankshaft damper is in good condition and secure on the crankshaft. Take particular care that the exhaust has no blockages and is not in contact with the chassis etc. Note that a number of S2 were fitted with S1 front silencers. (Message approved by david_gore) | ||
| David Balfour Frequent User Username: sidchrome Post Number: 215 Registered: 02-2009 |
Hi Norman, The "clearly present whilst idling" may be just a red herring. It is easy to link a rough idle in your mind to a shudder when driving, but I have had both smooth and rough idling, dependent on engine tune, but the shudder did not change, and that the shudder only occurs at specific load, and engine speed, and road speed conditions, which makes it very difficult to rule things in and out. I do also take heed of your comments about all of the items listed, and especially the exhaust. Someone had previously welded the exhaust mounting directly to the chassis near the rear muffler, and I was sure this was going to be the cause, but when fixed there was no obvious change. I don't know about Felipe's S2, but the level of vibration transmitted to the cabin in my SCII at idle is excessive I think, and probably yet another clue. The rear engine / transmission mounts have been off my car many times with the transmission removal, and appear OK, as does the front, but I've never had it off. I wonder how a bad harmonic damper would present itself on the V8. Has anybody had this occur? | ||
| felipe heuser Experienced User Username: felipe Post Number: 128 Registered: 07-2017 |
That would have been my next query regarding rough idling which is present however not excessively, however no vibrations and only when accelerating from stationary through to fourth gear once running 50+ km/h. | ||
| John Rowney Experienced User Username: johnrowney Post Number: 96 Registered: 02-2015 |
It might be worthwhile looking at a leak in the inlet manifold gasket. I had a similar problem with my 1978 Corniche DRH32489. See this forum's Silver Shadow Series with the post "Removing the Needle Seat from a Solex 4A1 Carburettor" The post has quite a few entries, so work from the last entry backwards to find the problem which is one of the things I fixed. | ||
| felipe heuser Experienced User Username: felipe Post Number: 129 Registered: 07-2017 |
Would replacing the harmonic vibration damper require a special tool? | ||
| David Balfour Frequent User Username: sidchrome Post Number: 216 Registered: 02-2009 |
Hi Felipe, Yes I think you will need: https://www.britishtoolworks.com/product-page/crank-hub-socket It's not a task I have undertaken on the cloud, but imagine that without that tool it would be very difficult. | ||
| felipe heuser Experienced User Username: felipe Post Number: 130 Registered: 07-2017 |
Thanks David...have contacted and seems that's the correct tool...found a used damper from a very respectable source...also read that second smaller metal ring is recommended to exchange however without any references...any ideas? | ||
| Jeff Martin Experienced User Username: jeff_r_1 Post Number: 180 Registered: 07-2018 |
Isn't a used damper going to have the same problem, either the rubber being too hard or to soft from age ? | ||
| John Rowney Experienced User Username: johnrowney Post Number: 98 Registered: 02-2015 |
Hi Felipe Have you looked at a leaking inlet manifold yet? Rather than go through my old post, I thought to save effort, I would briefly outline what I did for my 1978 Corniche DRH32489, as originally suggested by Steve Sparks. I had replaced the distributor internals, coil, HT leads, and had the carburettor overhauled - all for zero improvement in the idling. I was rather frustrated at this stage. I ran the engine until warm and the rough idle was present as normal. I squirted carburettor cleaner around the inlet manifold gasket areas. When the carburettor cleaner got into the areas with the damaged gasket, the engine revs went up and the roughness went away. The reason is that the carburettor cleaner is additional fuel and increases the richness of the mixture, which had been leaned off dramatically by the addditional air sucking in through the damaged gasket. I cleaned up the areas around the leaking gaskets and filled the gaps with silastic and let it cure overnight. The next day the car ran beautifully, with no leaks in the inlet manifold. I had the silastic removed and got the gaskets replaced and the car has never been running smoother. Using the carburettor cleaner on the inlet manifold will tell you instantly if a leaking gasket is the source of the idling roughness. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2415 Registered: 09-2004 |
Would it not be worth connecting the car up and check for % Co variation at idle first after checking the dwell scope etc is within limits. BTW while carrying out spray some wd40 around the manifold when on idle and note any changes to rule out the previous posting possibility! Cripes keep it simple I have seen many specialist folk make a mountain out of a mole hill costing £sssss without doing the basics first! | ||
| felipe heuser Experienced User Username: felipe Post Number: 131 Registered: 07-2017 |
Many thanks for all recommendations… After tedious research and correspondences, find the damper is not a common topic or practice with relatively limited knowledge or detailed replacement procedures…(Britishtoolworks is well informed) and it goes without saying can cause crankshaft issues if left unexamined… I would also query a used damper, but new not available from four suppliers approached… Haven’t had time to inspect anything so far, however tomorrow finally mechanic is stopping over to test drive and troubleshoot the suggestions offered here…will report back… | ||
| felipe heuser Experienced User Username: felipe Post Number: 132 Registered: 07-2017 |
We can now scrap the damper issue…however gained an understanding about something I was totally unaware of…great forum! Mechanic took car out for a test drive and after checking basics found it was misfiring…checked HT leads and sparkplugs…replaced all plugs and adjusted carburettor…running smoothly! | ||
| Jeff Martin Experienced User Username: jeff_r_1 Post Number: 183 Registered: 07-2018 |
That's great news ! How old were your leads and were they of the resistor type ? What was adjusted on the carbs, running rich/lean and/or unbalanced ? | ||
| felipe heuser Experienced User Username: felipe Post Number: 133 Registered: 07-2017 |
Age unknown of the leads…however look relatively newish and possibly replaced by last owner prior to my purchase in 2017... they’re the cooper type and all passed the test… however the one sparkplug was bad… Sorry, didn’t inquire my (retired R-R) mechanic so can’t respond to the carburettor adjustments… | ||
| Grassetto Eugenio New User Username: grassetto Post Number: 35 Registered: 05-2012 |
My car has got a rough idling when cold. I found out that the choke butterfly opens after one minute and it comes rought. If I close it manually theengine becomes smooth. In my car S2 Standard 1960 B60BS the choke coil has two coils not one as shown in Flying Spares part photo. One coil the more external is to keep the butterfly closed the other one to keep it opened. Is it possible to delay the opening of the choke butterfly? I've noticed that the load of the coils can be adjusted slackening a bolt. Is my sistem wrong? In the shop manual the system is different.  | ||
| David Hughes Experienced User Username: wedcar Post Number: 144 Registered: 07-2004 |
Grassetto On this website there is a well explained procedure for setting the Automatic Choke. Best to read and go through the whole article before making any adjustments, page K16 of the Cloud 2 workshop manual (fuel system) begins the procedure. Regards David | ||
| Grassetto Eugenio New User Username: grassetto Post Number: 36 Registered: 05-2012 |
Dear David thank you, but I'm not able to find the web site. Which one? | ||
| RR Forums Administrator Board Administrator Username: admin Post Number: 120 Registered: 10-2002 |
I think he means another website: "The Rolls-Royce and Bentley Technical Library", but hasn't provided an actual link to the document in question. https://rrtechnical.info/sc/sc1/wshop/10.pdf | ||
| David Gore Moderator Username: david_gore Post Number: 4157 Registered: 04-2003 |
Thanks for stepping in for me as I have been travelling all day and didn't have the opportunity to answer this request until now. | ||
| ChristopherCarnley Unregistered guest Posted From: 109.159.182.205 |
See "Main Page", on this site. Post War Technical Library TSD,s 003. https://rrtechnical.info/sc/03_silver_cloud.html (Message approved and added to by david_gore) | ||
| Grassetto Eugenio New User Username: grassetto Post Number: 37 Registered: 05-2012 |
Hi to everybody , I've studied the Technical library you have suggested. My car behaves differently. Maybe the choke solenoid is broken. I start the engine, the butterfly is closed, the fast idle is ok , but after only one minute the butterfly starts to open gradually, the engine slows down and become very rough. I close manually the butterfly and engine immediately runs smooth . The choke solenoid gets electricity form the thermal delay switch, but apparently nothing move on it. Should come out a pushing rod? Or should create a magnetic field to attract or push the butterfly lever? I don’t know but nothing seems to happen to it. there is no move on it, no magnet field. | ||
| Grassetto Eugenio New User Username: grassetto Post Number: 38 Registered: 05-2012 |
Greetings to everyone. During the Christmas holidays I got plenty of time to study and investigate the system. Solenoid alone works. When engine is cranked it is grounded by the thermal switch terminal B, it operate and keep the choke butterfly closed. But soon after, terminal B gives 12 volts and solenoid is off. Butterfly, I've removed the additional coil, gradually opens end engine get rough. I operate at 15 Celsious. The otter should close the circuit, grounding the solenoid through the thermal switch. If otter close terminal B of thermal switch is grounded and solenoid keep the butterfly down. In my car the otter doesn't close the circuit, likely because 15 Celsious is too warm. Please advise. How should I test if the faulty device is the otter or the terminal switch? |
