Hello, I am looking for any official Buick documentation concerning main and rod clearance for the 1971 350 engine. Thnx
It is a street car with a mild comp cam in it.. Been having some oil pressure issues at idle since the rebuilt, so I want to crosscheck the numbers before blaming the builder. He told me rods were set to 0.0023 and the mains to 0.0027...
Yeah..booster plate and a HV pump. New timing cover,(ATP), gives me 12PSI @800 RPM hot after HWY drive.. In gear about 10PSI.. Acceleration is fine, about 40PSI @ 2500RPM.. Oil 20w50
Yeah... nice misprint in the book fellas... .002 to .0023 is pretty good, BUT the top clearance on the shop book reads .0002" (two ten thousandths). Thats a bit of a squeeze. A fleck of dust between the shell and rod could make it all cattywampus. The mains at .0004" seem kinda tight too. ws
Usually 20w50 is taboo. too much load on the cam gear/distributor, but with the extra clearances probably ok just don't rev it till oil warms up.
Yeah, I know. I've been very careful with that pump and know about the cons.. thats why I am trying to figure out where I am loosing pressure.. would like to get back to the stock setup..
Thank you Larry, This indicates that I might have a pressure loss elsewhere as my numbers are not that off. Might be the cheap cover then..
Yes. Did you ever measure the clearances inside the pump? Do you have the stock pressure relief spring? Read, http://v8buick.com/index.php?threads/new-timing-cover-oil-pump-end-clearance-problem.357072/
All those clearances never get smaller after all the parts get to know each other during seating in process(run in). Couple tenths tighter would not hurt.
I did, also read the thread. And yes, the stock spring is still in there. The TA adjustable valve is going to be the next buy. Just wanted to make sure they built the engine right. Didn't want to make "another low pressure thread" out of this.
