[70 lucerne lemans]

I was a little low at idle hot about 10-15 lbs in drive so I added a bottle of STP to my 15-40 Rotella cj-4 that already had a bottle of EOS, to thicken it up a little.I also adj.the lash on my solid cam.Now the pressure doesnt go below 40 lbs at idle.I cant believe 1 bottle of Stp could make such a drastic change.Any ideas?

[grandville455]

That stuff is thick! thats why I use a can 15 oz of marvel mystery with my rotella also..... Pontiac vitamins

[70 lucerne lemans]

Im wondering if something was stuck under the check ball on the oil pump and it dislodged.I cant believe 1 bottle of STP would raise the viscosity that much.

[gtofreek]

Originally Posted by 70 lucerne lemans

Im wondering if something was stuck under the check ball on the oil pump and it dislodged.I cant believe 1 bottle of STP would raise the viscosity that much.

It will do exactly that. The oil itself will get very thin when hot. All it takes is .0025 or more bearing clearance and you will have 15 lbs. or less when hot at idle. If it jumps right up to 50-60 lbs. when you give it gas, then I wouldn't worry about it. I would rather run it with 10-15 lbs. at idle than 40 with STP. At least with the oil alone you have plenty of oil flowing through the bearings to keep them cool. STP hinders this ability. If the engine had no bearing knocks, you have no problems other than an engine with worn bearing clearances. The engine could have came from the factory with .002 clearance and with only .00025 wear on each bearing shell will give you .0025 clearance and give you the kind of pressure you speak of. The oil pump is just not turning fast enough to create 60 lbs. This is pretty common.

I agree with Grandville 455 on the Marvel mystery oil. It's great stuff!

You can also try running 20W-50 oil also and pick the pressure up another 5-10 lbs.

[70 lucerne lemans]

This is a brand new short block with an eagle stroker kit so the clearances are a little more than stock.Im going to 20-50 next oil change,I just thought the STP would thicken the 15-40 up a little not a lot!

[big head]

My 462 runs 180 degrees, 30 weight oil and has 15 to 17 pounds @ idle,700RPM in drive.as they say,10 pds oil pressure for every 1000 rpm.As long as your pressure rises acordingly under load there is no problem.when I first rebuilt the motor it did hold 20 pds @ idle . but as clearances loosen up some, pressure might drop slightly.my engine has only 1600 miles on rebuild,no worries with 15 pds.. ps I live in florida where temps average 85 to 95 degrees air temp