Thread: Oil pressure problem

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I have a 1955 Chevy street/strip car with a Dart shp 427 cu. in. GM SB. It idles at 25 psi oil pressure and goes up to 50 psi when I get to 2500 rpms but goes back down to 25 psi when it gets to 3000 rpm and beyond and stays at 25 psi until I slow down to 2500 rpm at which time it goes back up to 50 psi and stays there. I replaced the high volume oil pump with a standard pump like Dart recommends, I also replaced the pickup and the oil pressure gauge and it still did the same thing. My oil pan doesn't have a windage tray but it doesn't seem that their would be a windage problem when I'm just cruising down the road at 3000 rpm ( 4.11 rear ). Am I wrong?

sounds to me that you have a oil galley plug out your dumpping alot of oil some were galley plug out blocks has a hole in it. crank oilling holes not in the right. spot or when they drill the crank pins they hit a oling hole or bearing not covering the cranks oiling holes . lifters oil band dropping to low or to hi and dumping oil of lifter band .oil pump not setting on main cap flat .do you have the two plugs on the lifter cross over in the lifter valley ? and the 3 upper plugs in cam tunnel front under the timming set is this block a SHP or a little M ? dart block

no windage tray and a stroker that long could just be oil aeriation above that rpm and /or oil not draining back from heads fast enough-----

Thank you for the replies. It's an SHP block and I'll check for a Gallery plug problem.
If it's possible that it could just be a windage problem at 3000 rpm and above, I may check that first, even if that's not the problem, i'm still better off with a windage tray in the oil pan than without one.

do you maybe have one of those blocks that don't have oil drainback holes in the valley???

I'm not sure about the drain back holes on my shp block, I'll have to check. I have an oil pan with a windage tray on order, I think I'm better off with a windage tray in the pan than without one in it, so I ordered one, but the car has run fine up until now ( on the street and at the track ) without a windage tray in the pan, so I don't know why the pan without a windage tray worked before but doesn't work now. I'll try out the new pan when it's delivered and see what happens.

with the longer stroke crank in there plus rods so far out you got to notch hell out of the block shirk, rods going lots lower into pan /oil level you creat a lots more windage that foams/whips the oil into a mist


also on some of those longer stroke cranks, I've seen the rod oiling holes so far off location that the flow misses the rods-----also maybe excessive rod side clearance which would not only give a drop in pressure but add to the windage --------


also those longer stroke cranks require a smaller base circle cam which(as Pat said) can let the lifter groove come below the tappet hole-----do you have restrictors in the lifter galleys??

with the SHP block .i am thinking 4.000 crank and 4.125 bore small block.but sbc has small oil pan rail so you end up with alot of windage with a std base oil pan with no kickouts the side kick out pan with a tray built in pan like milodon 31167 or 31524 realy helps. i still think you may have other things you must look at as i out lined before i would be sold on the windaged only deal

also picpup could be too close to pan bottom

I do have a 4.000 crank and their are no restrictors in the lifter galleys. I ordered a matching pickup with the pan. Thanks again for the input and I'll advise what happens with the new pan.

Originally Posted by Easterner

I do have a 4.000 crank and their are no restrictors in the lifter galleys. I ordered a matching pickup with the pan. Thanks again for the input and I'll advise what happens with the new pan.

i never said restrictors i was talking about a plug left out or oil pump not sitting flat and other listed did you ever try a different oil gauge

I was answering Jerry Claytons question about the restrictors. I did try another pressure gauge and got the same readings. The new pan should be delivered tomorrow, I'll put it on and see what happens.

Originally Posted by Easterner

I was answering Jerry Claytons question about the restrictors. I did try another pressure gauge and got the same readings. The new pan should be delivered tomorrow, I'll put it on and see what happens.

if the lifter oil galleys had restrictors you would gain oil PSI maybe jerry was talking about restricted in the lifter valley oil drain back that starts at the heads and drains down threw lifter valley i tap heads and welded in bungs for drain back like this... did you weld the oil pickup on the pump and did you check thats your around 3/8to 1/2 from bottom of oil pan

Originally Posted by Easterner

.......I'll try out the new pan when it's delivered and see what happens.

Originally Posted by Easterner

......I ordered a matching pickup with the pan. Thanks again for the input and I'll advise what happens with the new pan.

Originally Posted by Easterner

......The new pan should be delivered tomorrow, I'll put it on and see what happens.

Seems to me like Easterner's trying to tell everyone that he's got a plan in place, has taken steps to get the parts he believes may fix his problem, and has committed to report back with the result once he's tried the new setup unless we've run him off by then....

Originally Posted by rspears

Seems to me like Easterner's trying to tell everyone that he's got a plan in place, has taken steps to get the parts he believes may fix his problem, and has committed to report back with the result once he's tried the new setup unless we've run him off by then....

well why he got the plan in place.... it sure would not hurt to check other things why your there .if he wants to thats up to him