Jeep Strokers

Have my new stroker 95% ready to drop in. Have the Melling Hi Vol oil pump installed. To keep it oiled and primed, I took an old distributor, took off the gear and have it installed in its housing. When I spin it with my 1/2 inch drill, and it really work to do it, I make 75 psi on my mechanical gauge at only about 500 rpm's. I get oil out of all the rocker pushrod holes after a minute or two. I'm worried about such a high pressure...will it drop to a more normal level once the crank is actually turning or are my clearances too tight. I had around .0015 to .002 based on my plastigauge readings on the crank bearings and I have 10w-30 plus 2 cans of comp cam break in additive in the pan. Do I have anything to worry about...Thanks

That is cold oil pressure and will drop when it warms up. You could possible also use a lower weight oil with all that volume.

IIRC mine was 40 when hot.

Kinda going "out on a limb" here, but I wonder what the pressure will do if you turn it over two revolutions (while priming). Will it make a difference if some of the bearings are not "clocked" with the oil passages in crank? You may have done that, but I didn't see it in your post.

I have turned it several times, but i"m alone and I cant spin the distributor, crank the engine and watch the oil pressure all at the same times. I do notice that at different crank positions, the oil comes out at different volumes from the pushrod holes

I used Brad Penn's SAE 30 break-in for the cam break-in, 100mi change, and 500mi change(well actually 600). I then continue to use their 10w30 Racing Oil. Even now, 2+years later, when cold, the psi is almost pegged--70, then drops to 35-40 when warmed up at idle, and will swing up to the 60s when reving at 3K. Maybe find a 5w30 or 5w20 that has some ZDDP, or else add it, if you are too worried about the high psi. Normal for a HV, so don't fret. In a few thousand miles when it breaks-in the tolerances will be a little looser too and the psi will drop.

I used a melling hv pump also,with 4000 miles my pressure is about the same as all the sbc ive built 40 hot idle and 55-60 at 2000 rpm or above.im going to put thinner oil in next time I change it,im running valvoline 10w40 with lucas zddp additive. I let my motor warm up good before driving,it will make 60-70 pounds cold at an idle,and hit 80 if your rev it cold.
The 406 im my camaro has been beatin on for at least 50,000 miles,drag raced,missed gears,valves floated and has always had the same oil pressure as my jeep does now,im sure you will be fine.

woodjeep wrote:Have my new stroker 95% ready to drop in. Have the Melling Hi Vol oil pump installed. To keep it oiled and primed, I took an old distributor, took off the gear and have it installed in its housing. When I spin it with my 1/2 inch drill, and it really work to do it, I make 75 psi on my mechanical gauge at only about 500 rpm's. I get oil out of all the rocker pushrod holes after a minute or two. I'm worried about such a high pressure...will it drop to a more normal level once the crank is actually turning or are my clearances too tight. I had around .0015 to .002 based on my plastigauge readings on the crank bearings and I have 10w-30 plus 2 cans of comp cam break in additive in the pan. Do I have anything to worry about...Thanks

I don't think so. Once you've got the engine running and broken it in, the bearing clearances will increase a little and the oil pressure will stabilize at a normal level. I also used the same oil pump and with 10W-40 oil, my oil pressures are 60psi cold idle/65psi cold at 2500rpm and 25psi hot idle/50psi hot at 2500rpm.

gradon wrote: when cold, the psi is almost pegged--70, then drops to 35-40 when warmed up at idle, and will swing up to the 60s when reving at 3K. Maybe find a 5w30 or 5w20 that has some ZDDP, or else add it, if you are too worried about the high psi. In a few thousand miles when it breaks-in the tolerances will be a little looser too and the psi will drop.

Hi pressure on mine too. drives at around 60-70 lbs. Hit 80 a few times!
Only about 50 miles on it. Standard Melling oil pump, 0.015- 0.002" bearing clearances, and even the Crower cam saver lifters, which I thought might bleed off a little pressure. Castrol 10w-30 with zddplus additive and Wix oil filter.

I did notice the plug on the oil pump was driven in a little too far, maybe 1/8" below the cotter pin. Relief spring? Is that causing the high pressure?

I would be more concerned about low oil pressure. Break it in!

Retlaw01XJ wrote: Hi pressure on mine too. drives at around 60-70 lbs. Hit 80 a few times!
Only about 50 miles on it.

Yeah, put some more miles on the engine to break it in properly. The bearing clearances will increase a little and your oil pressure should stabilize at a slightly lower level. You could also use a thinner oil after the break-in.

Yes, if the plug on the oil pump is stuck it will cause the oil relief pressure (max pressure) to be higher

SilverXJ wrote:Yes, if the plug on the oil pump is stuck it will cause the oil relief pressure (max pressure) to be higher

I didn't consider that it could be stuck....
What I meant was that the cap-plug on the pump is pushed in a little too far. I believe that is where the pressure-relief spring is located? The result would be a spring that is compressed a little more, resulting in more oil pressure.

Suppose I could try a 5w-30 in place of the 10w-30 that's in there.
My concern is the higher pressure is putting more strain on the cam drive gear and related items.

If the cap is not against the cotter pin it is stuck in the bore and won't move back, causing higher pressure.

There's a bunch of bearing lube in there too that makes your reading slightly higher. I'd check the oil pump and then run it. If it shows more than 55-60 lbs on a mechanical gauge (@RPM and temperature) adjust down with oil viscosity. The main concern being the distributor gear. I don't usually use HV pumps unless bearing clearances are .0025+ or there is a lot of big end side clearance or a combination of both that have a huge effect on flow. It's also best to increase the pan capacity to compensate for the increased oil that is in flow.