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Tecumseh H35 exhaust valve play: what is excessive?

ryan68bug

Registered
I'm doing a full overhaul/blueprinting to spec job on an '87 H35 Tecumseh engine for a vintage mini bike restoration project and was wondering how to determine excessive valve play on the exhaust side. The intake valve is noticeably "snugger" in the guide than the exhaust valve, though I've yet to see if the exhaust valve is distorted or bent. Valve clearances on both were within spec.
The manual does not specify figures, just says if the play is excessive then a 1/32" oversize valve can be installed. But if it isn't necessary, then I don't want to have work done that isn't absolutely necessary.

I know Briggs manuals cite the use of plug gauges for determining valve guide specs, but nothing in my Tecumseh manual is to be found.

So how much play is too much? Thanks in advance!
 

Andrew Mackey

Moderator
Last Subscription Date
05/14/2017
If you can 'wobble the exhaust valve more than about 1/16", re-guide or replace with oversize. At higher speeds, the valve will not seat properly, and performance, and compression will suffer.:eek:
Andrew:D
 

ryan68bug

Registered
Out of curiosity, I rechecked the valves themselves, and my exhaust valve is .006" smaller than the intake on the stem (.244 to the intake's .250"). Is this normal, or is this wear? Anybody have new valves handy that they could measure for me, as I don't have this spec in my manual.
 
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