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Low oil presure on rebuilt c90-8

and at 35 psi oil pressure the relief is suppose to start opening up.
There was about 2.5 # difference between the 3 with the fresno being the weakest... using a valve spring checker is not easy for this size spring and have it accurate.

Someday I will do a demo on how to build a -8 oil pump that should not wear out in 5000 hours and not require any bushings...
 
Can't washers be added to compensate for spring weakness? 5.75# @ 1.56" min. per the SM's spring specs. Lap the valve contact area for a good seal?

Gary
 
Why would thinner oil open the valve? Or is it leaking/poor seal to begin with? Check the sealing fit with that dye used for cylinder valve to seat facing.
 
Why would thinner oil open the valve? Or is it leaking/poor seal to begin with? Check the sealing fit with that dye used for cylinder valve to seat facing.
Possible bearing clearances are too much or case is loose on the cam journals? Hot opens up the tolerances? Dunno Gary
 
each of those.
if i remember right, i think compressed to a 1 1/2 there suppose to be 6 lbs. what are
The Fresno spring was 6.5 lbs at 1.5" and the others were a little more, the spring compressor kept spitting out the springs make for the search fun!thumbnail_IMG_1155.jpg
 

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I'd drain the multi-vis and replace with 50W oil. See if it makes any change. In my experience 20W-50 will loose some viscosity in 15-20 hrs (as shown by a gradual decrease in pressure until drained and replaced). I've assumed that's from the viscosity improvers being sheared some by the engine's gears. Remaining in oil grade is one criteria for determining oil change intervals. Some engines are harder on oil viscosity than others.

Gary
 
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