Peter Watkins-Groves

Thanks for all the suggestions and advice. I have decided it is a tight fitting inlet valve and have lapped the valve in the guide to give a few 10ths extra clearance. As I said at the start, the valves and guides were fitted 30yrs ago but never run in. So it will be finger in the

Sooty Dave but not sticky tar. Plugs indicate a slight richness which maybe because with the change of body to RMB Gentry style, little or no room is left for an air filter. So to combat a tendency to weakness through only having mesh filters fitted, I set the carbs on the rich side.

The valves fitted are standard steel/iron.

It's tarry Colin, but only that valve is affected as bad. Pretty certain its not the guide, if anything that is a close fit. I am leaning toward "Classiclifes" idea of gummed oil control ring on that cylinder.

I all ways used bronze guides on my motorcycles because they held oil better.

I must admit No6 inlet may be a little closer in tolerance than the others. But it is sticking on the tarry carbon build up I think.

Cheers fellows for the replies. The engine had been rebuilt before I got the car, but hadn't run for some 30 years since rebuild. The guy that was rebuilding the car died mid-way, and it stood in a barn from the 90s till I bought it in 2017. Sorting out what has been done and what hasn't has been a major task, but it is obvious that the engine was re-bored and new pistons fitted, valves and guides were also done, don't know about bottom end yet, so fingers crossed there. There is no extra oil feed. I have been half thinking of stuck rings, but at 72 didn't relish the thought of lying on my back and dropping the sump to find out. I have the head off at the moment as I have to clean up the valve area, when that's done I will do what I should have and test the compression on all cylinders. There used to be a product that you could buy that supposedly un-gummed sticky rings, can't remember the name, and I doubt that it was very affective, but will give the Redex idea a shot before I put the head back on, can't hurt. I did drain the old oil, and used a flushing oil to clean out the crappy build up of old emulsified gunge. Thanks again, will keep you posted. ps: Saw your club stand at Grimsthorpe/Baston car show and was impressed as you have a Peterborough section. May have to change allegiances.

Hello, My Vitesse engine Gentry has a problem on number 6 inlet valve. after only a few miles the valve is sticking open due to a thick tarry carbon build up. All other cylinders look okay except for normal carbon that I would expect after more miles. I have checked the carbs (Stromberg cd150s) and they seem to be in tune. Could the emission valve be allowing too much oil into the inlet manifold. the car has newish valve guides and valves. Any suggestions.