Worn Valves

[webmaster]

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Hi, Now this reply is just an observation regarding the on-going thoughts on unleaded petrol. When my "Penny's" cylinder head was 'unleaded'- on 11/9/2001, the exhaust valves at the time were in good enough condition to be reused after re-facing to the new hardened seats. I had previously been using additive.

This last winter, 4 years later, I decided to have new valve guides fitted to cure the oil drinking problem. The engineer doing the job, (a different one as the previous one had died), told me the exhaust valves were absolutely shot and not able to be ground in again. Fortunately, I had just bought a set of new exhaust valves from e-bay, and took them to him. He showed me the valves from the head, and sure enough they were badly worn. The hardened seats though were in perfect condition. After refitting it all the engine now starts and runs more like it was meant to.
So, although the seats were fine, does this experience mean that the exhaust valves will continue to be eroded by unleaded petrol? I fear so, and I will probably have to re-think the use of additives for future to avoid further valve head erosion. What do others think?
Has anyone else who have had unleading done had their heads off to look at the valves after a decent interval to look at their exhaust valves state? I have not heard of any sources of harder valves which would match the seats either. Others' input might be interesting. Tina

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A reply to Tina re worn valves.

I am sure it is not the petrol causing the problem , it is the hardened seats wearing the unhardened valves. I would never recommend hardening valve seats unless you can get hardened valves to match. Who knows of anyone making them for "our" cars?

So the best answer is to continue using "soft" heads and valves. Put in an additive if you wish but I suspect the differece in valve seat regression is minimal, particularly if you don't use for sustained periods above 3,000rpm

A friend in the USA has been running his TRs in the without lead or a substitute since 1981 when the last leaded petrol was sold there. He still can't see or measure any wear in his cars.

Consequently, I don't use an additive either

Phil