Quote:
Originally Posted by DJ S
So let me just make some clarifications on the situation concerning the valves. This engine has split valve guides and non-adjustable tappets. I removed the entire valve train for inspection. I noticed that #1 exhaust was severly pitted and worn, so I replaced it. I ensured to achieve proper valve clearance by grinding down the valve stem (.013"). This valve, however was tight in the valve guide but with some oil and movement, it began move easier, still not overly easy but it could be moved my hand. The other valves had far more clearance than they needed, which is why I couldn't make any adjustments. I reinstalled all the valves lapped them and reinstalled all the old valve springs. The reason I didn't overhaul the entire valve train is because this motor has several cracks on the exterior water jacket that can't be repaired because the remaining metal is too thin. So I used high-temp JB Weld to patch them for now just to get through this year, while rebuildig a motor over the summer, to be installed this coming winter.
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Hey DJ,
'and reinstalled the old valve springs'....
If you did not make sure that the OLD valve springs were/are all good (i.e.- via testing for equal seat pressure), there is your problem, IMO, especially at high speed, as you describe !
BTW...I think that you confuse, when you say that 'they have tooo much clearance and you cannot adjust that'. Why not ?
You can and maybe should have ground the seats while measuring clearance reduction. Especially , if you do not intend long time use of this engine due to other problems.
Excessive clearances plus any weak springs will not be good at high rpms, IMO.