Hi, I am going through a XUD7TE rebuild and have yet another particular question.
One exhaust valve sea looks like this:
I have tried hard, but pitting is too deep to remove by lapping. Also, looking at the pitted edge seat closest to head surface an edge can be noticed. This particular seat is slightly off-center towards camera.
How bad is this?
P.S. As this is not the first nor last question in this rebuild, maybe I should simply start a blog topic? Please advise.
You probably need the technical document for this engine. It will give the valve seat width and cutting angles. The normal cutting angles are 45 and 30 degrees, and then lapped to a perect fit.
Valve seat cutting gear is not cheap, last time I looked some years ago around 600 quid. So for this a specialist is probably cheaper. But try and find the data for the seat geometry first. It should also give max permitted wear.
Off centre wear may mean issues with either the valve or guide. If you're just going for an engine that should run OK then so long as you end up with a smooth ring around the seat the valve shoud seal OK, otherwise as mentioned machining or even a replacement seat may be needed, which will require specialist machinery. Where are you based, as there are various companies round the country that members here have used.
Mike Sims
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