Gentlemen: In anticipation of my first engine build, I am reading as much as I can on the subject. According to the "Engine Builder's Handbook", the amount bore taper should be next to zero. The author explains various ways a backyard mechanic can measure it with reasonable accuaracy. Sounds fairly straight forward. Can someone please tell me why I should bother measuring this? I have to believe most engines like mine (75K miles) have at least some taper. Why bother with compression and leak down tests when overboring seems inevitable? My plan was to replace the rings and bearings, retain the stock pistons, and build a fairly tame, performance-oriented engine. I realize quality machine work is usually the norm. However, by cutting my teeth a low budget project, it may make my experience a bit less stressful. Is this approach reasonable? Thanks in adavnce for your feedback:TU:
Plain and simple, if you are going to bore your motor for oversized pistons, then don't worry about taper...The taper will "disappear" when the block gets bored... If you are just doing a re-ring, then taper and out-of-roundness is a concern...A good machine shop should be able to hone the taper out, but the out-of-roundness is another problem...
David - Unless you have a 'nasty' ridge in the cylinders, you should be good with a re-ring/bearing job. If your engine was running good before, it should be even better after you deglaze the cylinders and put new rings in it. Our Buicks have a better nickle content in the blocks and don't 'bore themselves' like the 'softer' Chevy blocks will! Of course...there are always exceptions!:grin: I think you'll find there are plenty of folks on board that have done the same - and had good results.
Thanks Thanks, Scott and Jim, for your replies. Would either of you care to guess how much HP the stock pistons/rods (1970) can handle? Thanks again. :beer
I know we have several guys on board that have run some nitrous with a 70 GS spec 350 and had them live! Hopefully, they'll chime in here.:grin: The 73 and later 'capscrew' style rods are stronger - you might want to pick up a set of those (if you don't already have some). Just don't let the motor run lean and you should be OK!:TU:
