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Side-valve valve inserts

Posted: Fri Sep 25, 2020 2:44 pm
by Mick Lynch
Advice sought.

The exhaust valve on cyl 3 has evidence of blow by both on valve and seat. I had very low compression on 3 (55 psi compared to 90 - 95 on the other three cylinders).

I’ve tried re facing the valve seat but there all I seem to be doing is chasing the burnt area and not removing it. I have stopped for now as the face is too large and I don’t have a top or bottom narrowing cutter.

Not wanting to just keep going at it for the sake of it and very aware it’s the block I’m eating into can anyone recommend a course of action?

Also are seat inserts available for these engines?

Attached photo. Blow by is approx 11 o’clock.

(The seat cutter I’m using is a 45 deg Neway CU122 and the guide is a solid 7mm taper guide both are a good fit)


Re: Side-valve valve inserts

Posted: Fri Sep 25, 2020 2:59 pm
by philthehill
You are wise to stop cutting away the block.
Any good machine shop will be able to source and fit valve seats to this engine.
Whilst the engine is in pieces I would have all four exhaust valve seats fitted with hardened inserts.
If you have any doubts speak with Rob Thomas who can be contacted via a MMOC PM.

Re: Side-valve valve inserts

Posted: Sat Sep 26, 2020 10:08 am
by RobThomas
Wot Phil said. Inserts are not hard to source and pretty much any engine shop can fit them. Get all 4 done at the same time. New valves aren't hard to find. Well worth doing.

Re: Side-valve valve inserts

Posted: Wed Oct 14, 2020 11:27 pm
by smithskids
Have to be careful not to break into the water space on some blocks, I remember an early article on the forum when unleaded petrol was being discussed.