I have a 1986 318 roller cammed motor. I want to use a non roller cam in it, but the standard hydraulic lifters for it won't cover completely the longer oil hole of the roller lifters, and therefore I get very low oil pressure. The engine is a brand new rebuilt. Any suggestions on how to resolve this matter? Does anybody make longer lifters to compensate for the shorter standard hydraulic lifters? I didn't realize this problem until I had the engine all together and ready to drop in.

Have you checked the oil pressure by priming the engine?

I got a 1991 360 roller motor with hydraulic cam and lifters and great oil pressure...

just using Sealed Power 20011 lifters from summit.

Thanks for replying. I primed the engine, and my oil pressure was about 25 lbs. I took the engine apart again, and put it back together with the same result. The reason I wander about the lifters is because I noticed when I put it together for the second time, that the lifter bore is longer on my engine and the lifter didn't completely cover the oil hole on the lifter bore as it did on the earlier 318 I had.

As you know 25 ain't gonna cut it. I dont have any mag experience but I cant see the lifter feed hole height being a problem at least as far as system PSI as long as there's no leak from the horizontle gallery cutouts past the lifter body OD unless I'm missing something especially with the poster above who swapped over and no problem. I'm assuming all gallery pipe plugs are there. I would confirm with another mech gauge at the top rear of the block & likely pull/check the pump relief valve/pickup for cracks but I'd eliminate everything else before I took the pan off again. I'd pull the intake & prime it & see what the lifters show for flow and if you could block the filter then see what you show for psi which would confirm the gauge (& the pump/pickup) by eliminating every potential downstream leak. The mini freeze plug that gets driven in the block from under the #5 main cap could only restrict flow if it was in the exact (improper) position partly blocking either of the 2 horizontle galleries out to the filter boss rather than being driven up to it's correct vertical height position inbetween the 2 galleries. Not likely but I'm just tossing stuff out. Holler with any news. EDIT the filter nipple is 3/4-16 so you could get a female cap to block it off there

Thanks for info. I'll keep working on it until I figure it out. Will let you know end result.

25 psi with a drill/primer tool is good IMHO.

as you know when it is running it will be at xxx on the gauge cold, then drop to xxx when hot.

10psi per 1000rpm is the rule of thumb..so no way a drill is turning it 1000 rpm so 25 psi is good on a slow drill.

when it is at idle at xx rpm and gauge shows xx on gauge, then rpms go up you see the gauge go up in the 40-60 psi range..higher when cold 70-80 psi.

this is what my fresh 318 shows so they will fluctuate some on psi due to gauge quality.

I have swaped a few flat tappet cams out of a roller block and go to stock roller lifters and visa-versa just need the correct pushrods.

the lifter bore is taller for the roller lifters and dogbones which fit into the machined top of the lifter bores. flat tappets do drop down in the bore but still should be the same as a non roller block.

can you post a pic of the oil hole not coverd??

I have a engine on the stand mocked up but no flat tappet lifter to drop in to compare them.

If you can only get 25 psi with a drill you got a problem in my opinion. Heck I primed my last eng by hand as I used a 3/8 ratchet with a 5/16 socket on my oil primer rod and turning it by hand I had up to 50 psi with no problem. Unless it a real weak air drill that wont turn much against the resistance of the oil and the pressure you should be able to get over 25 psi with a drill as long as the drill is strong enough as most electric drills are strong enough. Sure the eng turns faster but like I said on a fresh built eng I can always get way past 25 psi using hand tools. I remember well as I was curious how much I could get like that and thats why I tried it by hand and ratchet. And I did it all by hand as I did not use a drill at all I just turned the oil priming rod with the ratchet from the start of priming and got it up to 50 with no problem.
One reason I did this was because some years back I built a 460 for my buddies Mustang and it would only pull about 20 psi priming with a drill and I figured it was ok and would pull more psi running as it was a fresh build. I was wrong as it would only go to 25 to 30 psi tops even at 3000 to 4000 rpm. His buddy told him it was fine and I said no way and pulled the eng back out of the car. I ended up finding Launiti had the roller lifter instuctions wrong as the roller lifters were in with the oil hole in the lifter facing the galley oil hole in the block and it bled to much pressure up thru the pushrods to the rockers. I had to turn the lifters around and put the oil hole away from the galley oil hole and then 60 psi no problem. I could also get 50 psi by hand with that eng also when I fixed it. Ron