|Posted on Saturday, 07 April, 2001 - 12:42:
After having the cylinder head off, and overhauled by our local RR dealer. My car has started to run on when the ignition is turned off. We have tried all sorts of things to resolve the problem. From basic adjustments to trying the 98RON fuel that BP are selling.
The head was skimmed and the steel type cylinder head gasket fitted. I may need to have a thicker gasket made and fitted.
The head was cleaned and new valve guides, seats and valves fitted to allow the car to run on unleaded fuel. If anyone has any ideas it would be appreciated.
|Posted on Saturday, 07 April, 2001 - 12:44:
David, what sort of compression pressures are you running now. With a skimmed head and a thinner gasket you may well have induced 'dieseling'. In the absence of any other bright solutions I would get a copper asbestos gasket made they are only about $50 and fit it. Head off and on should not take more than 2 hours with a mate to help.
Incidentally you might check that all the water holes are intact in the head. I have twice come across these welded up to induce a faster warm-up. Unless you hold the gasket against the head it is certainly not obvious.
When you take the steel gasket off check the inner edges of it for evidence of severe burning. Although I have nor seen it on an RR an exposed thin steel gasket edge can glow red hot during running and act as a very effective igniter.
|Posted on Saturday, 07 April, 2001 - 12:47:
Many thanks for your comments, I am not sure as to the exact compression ratioo. But we have com to the conclusion that the head has been skimmed and we need to have a thicker gasket produced. We are contacting the factory for advice with regards to the correct thickness of the cylinder head when new and this will indicate to us the thickness of the new gasket.
I have found an engineer in Perth (Western Australia) in fact just up the road from my home who has been producing gaskets for many years with oustanding results. He will make the gasket to suit the bore diameter also. I shall keep you posted as to the outcome.
|Posted on Saturday, 07 April, 2001 - 12:48:
One time Bill Coburn used one of my Copper and Asbestos R-Type head gaskets on an S1, and I recall it was successful (comment Bill?). New S1 gaskets are now also C&A as UE5053 steel gaskets are no longer available.
The C&A gaskets are freely available. I use UE5053s on my R-Type and have a private hoard of spares.
Compression is about 7.5:1 now (originally 6.75:1), but most S1s have 8:1 from memory with a steel gasket. I have experienced run-on with both types of gasket, but it always went away after use for some 100s of miles, so I would suggest you wait a while before removing the head again.