oil pressure on shp block

[ems]

engine has 80 psi idling hot,jumps over 100psi when reved up,all clearences were checked with dial bore gauage and were good,every thing was new also used new melling billit circle track pump,i put the high pressure spring in thought i might need it,i put both orings on the distributor if i take them off will it drop the pressure.

[lun40119]

What are the bearing tolerances, and what is the part number on the pump, and what oil is in it..........you are pretty vague with your description.

[ems]

.0025 on rods,.0025 to .003 on mains,20/50 vr1 oil

[ems]

oil pump 10050-700ct

[lun40119]

I just went through all this with mine. Yes, it is too much pump. I would take the high pressure spring out at the least. Mine was ok on the dyno, but in the car, it is actually cavitating, and loosing pressure. I purchased a 10552c select pump, and installed it. With 5w30 synthetic, I had around 85lbs with the 10550. Now that I have a 10552c it is around 78 lbs at 4500, and at an idle it is between 15-20lbs at 1000rpm. My bearings were .002-.0022 on the rods and .0023-.0025 on the mains.

Lets hear some more about this build :D

[ems]

pulled valve covers off every thing was wet but i was turning engine over with starter i did not see any oil coming out of the pushrods,guage was reading 80psi with just the starter (cold),should oil come out of the pushrods with the starter,cranked engine over for a long time and nothing,using comp 873-16 lifter,could this be the wrong lifter and causing my high pressure.

[lun40119]

Nope your high oil pressure is caused by your good tolerances, efficient oiling block, and way too big of a pump. Just got done with all this crap, trust me.....

[ems]

would you care if i called you.

[CNC BLOCKS]

Any time we have used a HV on our circle track engines we always drill another hole in the cover to create another bypass and by doing this we never saw the pressure go over 70 to 75 pounds when they were cold.

But since the 10% over volume pump came out we use alot of them on our engines with .0025 to .0028 oil clearance and Ford or AMC lifters.

[lun40119]

Up to you, number is in your mailbox....

[Awesome Bill]

Oil pressure is not controlled by the clearences, the pump spring or bypass controls this. The high pressure spring is most likely the problem. I would just run 10w30 VR1 or something and wait till is gets warm till you crack the whip. Or you could pull the spring.

[lun40119]

Oil clearances have nothing to do with oil pressure???????? Less clearance, equals restriction, restriction equals pressure????? Where are the new dyno vids of that 400 you were talking about????

[CNC BLOCKS]

Oil pressure is not controlled by the clearences, the pump spring or bypass controls this. The high pressure spring is most likely the problem. I would just run 10w30 VR1 or something and wait till is gets warm till you crack the whip. Or you could pull the spring.

Wrong as we have had guys call that have built Honda rod, 283 mains and have used a HV pump and at idle they ran over 100 pounds pressure and we sold them the Z-28 pumps reworked with and extra bypass in the cover and the problem goes away.

The oil pump can only bypass so much oil and if the engine can not consume the oil the pump puts out its going to run high pressure. I have seen this issue more then once.

[Awesome Bill]

Put 10w30 VR1 in this thing and you'll see the pressure come down a little. Pressure is controlled by the bypass spring pressure. Your high pressure spring is a little much but I would not get excited about it. Run the lighter oil and this will help. You can also put a 180-195° thermo in and watch it fall!