Series 3 Big Valve Engine Identification

Just think how many perfectly good ones have been destroyed by banger racers, Jags used to be well popular.

Interested to know whats caused that around that exhaust valve seat? Looks like detonation or coolants found its way in? I suppose its seat out and welded?

Scott,

I sent the pictures to people who spend there lives reconditioning these heads. It would be prudent to get crack testing done they think.

The consensus of opinion at the moment seems to be this is pretty common erosion and acceptable in the case of this head.

This is because the valve seats are quite deep and there is plenty of grip left in the head to stop them moving.

It will not get any worse as long as the fuel air mixture is properly controlled (as it is with my throttle bodies and ECU).

The cause of the erosion is probably due to pre-detonation in the combustion chamber a long time ago (pinking).

So at the moment, I am being told to leave the seats in situ and get on with reconditioning as the seats are unlikely to fall out.

In other-words, I should just get on with it.

James,
Thats good to know, Cheers.

At least the waterways dont look badly corroded, thats good, so for a COMPLETE recon it may be ok, but you would need new caps & align bore (+ 2 camshafts)…even if you buy new camshafts, you would still be left with the issue of caps, which surely would only be economically obtained from…another used head !?

I have quite a lot of heads laying around, and while they mainly seem to suffer valve seat recession, and would want guide attention etc, I havent noticed the cam buckets or guides seem damaged or worn, that one appears to have the bucket guides missing on one side

GPB 200 or 20 would be insignificant if such extensive work is intended

funnily enough, whole used engines are usually cheaper, especially if seized, which brings me to another issue, which is the scarcity of good useable blocks

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Indeed, James…

…the only reason to change the seats are if they are worn beyond use - they ‘never’ fall out on an xk engine…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
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