Oil pump shim

[Hammerhead]

(05-20-2017 )slowpoke Wrote:  just shimmed my oil pump again had 5 dimes, now upped to 8 soon as i start engine oil pressure only climbed to 32 psi (used to be 42 when cold) then fluctuated to 28 back to 32 up and down for about 4 minutes then climbed to 45 at 900 rpm once it settled i raised rpm to 1300 and it hit 51 psi. what pressure does the bypass ontop of oil filter blow of at. i pulled allen plug out to check thats its up datted it is. didnt try to pull it out though. could that be what caused fluctuation was a little scarry. bolts in oil pump o ring to out side by cotter pin. oil filter 2 days old.

Also, something else to consider is that when you pull the dogbone assembly from the pump, you are opening up the pressurized oil rifle system at is very lowest point. Gravity will dictate that oil will flow down and out the opening.
Once restarting the engine after this, there will be air bubbles and gaps in the system that need to be evacuated which will cause some slight fluctuations for a short time.
If this only happened on the first startup since the mod, I would figure that this is exactly what took place.