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Toby Bovingdon
Unregistered guest
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Posted on Friday, 13 June, 2008 - 05:01:   Edit PostDelete PostView Post/Check IP

I have a 1986 Rolls Royce Silver Spirit, Chassis no GCH16193. It is running very rough and have had the carbs rebuilt. Also had the air filter, fuel filter, oil filter, leads, belts, dizzy cap replaced. Then found the vacuum ignition was inoperative. This was then replaced. Now the garage is saying the distributor needs replacing.

It drops a cylinder when driving in traffic. My friends in the club believe it is a set up issue and have advised not to buy yet another part.

Any suggestions would be great. The car has done 114,000 miles and I have full history, including the build records. The car has been completely reliable in the past 14 months of ownership.
Thanks in advance
Toby Bovingdon.

(Message approved by david_gore)
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Bill Coburn
Username: bill_coburn

Post Number: 974
Registered: 4-2003
Posted on Saturday, 14 June, 2008 - 17:12:   Edit PostDelete PostView Post/Check IP

Toby/ This is an example of 'leaving it all to my mechanic' which seems to have been a past affectation of many owners. Most of us as I understand it are not is a position to give anyone carte blanche to fix their car unless you can afford to have these people go on a voyage of discovery at your expence.

Assuming these people are capable of rebuilding SU carburetters and replaced the plastic float in the fuel chambers which leak and also checked that the base plates of the carburetters are not warped and leaking, you can reasonably assume the fuel side is OK.

On the electrics, if you replaced the cap also get a new rotor. They have the habit of leaking juice through the body to the central shaft and you finish up with either no spark or a poor one. I am wondering now where you are, probably the UK since all '86 cars I thought had switched to fuel injection. Anyway back to the distributor. Be very careful when you extract the rotor. They are meant to be pulled off and a drop or so of oil inserted underneath to lubricate the centrifugal weights etc under the base plate. Most service people can't be bothered doing this and the rotor glues itself to the upper shaft. If you do not poke a screwdriver down into the guts of the unit and hold the shaft down while pulling on the rotor you will pull the whole lot free since on this model the upper part of the shaft is held in place by a plastic plug which is not no longher available. As to a vacuum advance failure depending on the original market for which the car was built certain distributors had the unit disconnected since it gave an unwanted performance.

You will probably find the distributor is worn internally allowing the shaft to wobble. Also the technology of the firing unit is as old as Methuselar. We fit Bosch distributors here with an upgraded coil and you have a new car. To replace the old igniter with genuine, costs an arm, a leg and seven fingers!
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Mark Aldridge
Unregistered guest
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Posted on Saturday, 14 June, 2008 - 19:56:   Edit PostDelete PostView Post/Check IP


Which Bosch distributor do you use and does this require any modification. Does this fit Shadows?
I advised Toby to stop spending and contact this forum. One point that may be relevant, is that as the car misfires the driver's side exhaust emits a lot of black smoke and smells of petrol.

Look forward to your reply,

Mark Aldridge

(Message approved by david_gore)
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Martin Cutler
Frequent User
Username: martin_cutler

Post Number: 77
Registered: 7-2007
Posted on Thursday, 19 June, 2008 - 20:54:   Edit PostDelete PostView Post/Check IP

Hi Toby, you don't mention replacing the plugs. This might be a good first step. Also, when they replaced the leads and cap, did they buy made up leads or make the leads up? If only one bank is not getting spark, check that they put the leads in correctly, and that they are not chaffing where they fit around the back of the head, and that they are fitted correctly into the lead holders. When you pull the plugs, the condition of them will tell you which ones are not firing, as they will be sooty and wet. Bill makes a good point about the rotor, If you are going to do one, you may as well do both. Do you still have the old cap? Was it cracked, or was it replaced in the vain hope it would fix the problem. I bought a new cap for my Bentley 12 years ago, it's still sitting on the shelf.

Good luck, and report back on what you find.



P.S. If it was a worn out distributor, it would misfire on both banks, not just one.