3.8 valve seats

[265bhp]

Dear all

Am I correct in thinking the 3.8 litre engines have hardened valve seats suitable for running unleaded...my memory from previous posts says yes, but I wanted to double check

Thanks in advance
Jonathan

[cactusman]

Xke heads are aluminium so they all had iron valve seats fitted from new. True they are probably not as hard as modern hardened seats but unless you are running at max revs they will be fine on super and you can always add a bit of castrol valve master plus...

[265bhp]

Hi Julian...good to hear..thanks

[cactusman]

No problem. There are other posts about valve seats. I am sure others will know more but I think the General view is that the original seats will last for years on unleaded for cars that just do a couple of thousand miles a year tootling to shows and holidays. There have been reports of replacement seats dropping out with obviously catastrophic results so if you do get yours done be sure they are done properly. FWIW my 3.8 has an unmodified head and runs fine on super 97/98 RON with castrol valvemaster. Whether that helps who knows but at £14 a bottle it is not a significant expense.

[richard btype]

Interesting point. Does anyone have a definitive answer to the question of the hardened valve seats? - I've heard strong arguments both ways. Seems to me however that unless you are running hard (unlikely in the UK) but might on a run through Germany, the hotter running could be an issue.

Castrol valvemaster is also my companion with Shell super unleaded and have never heard it pink, yet my OTS back in the 80's used to pink like mad in spite of it being run on leaded fuel with an additive...

[Hugo]

My thinking is that the problem is theoretical rather than practical. There was a bit of a panic when this subject first reared its head, but the consensus seems to be that unless you are going racing you won't have a problem. The answer in any case is simple - just keep a watchful eye on the valve clearances, and if they begin to close up, then you'll have to change the seats. I wouldn't change valve seats unless I had to.