Cam swap cause Oil pressure change?

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chrgdrt

chrgdrt

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Sanity check here. Recently swapped from a HFT to SFT cam, the engine(340) had been sitting for a while but was running good when pulled. Swapped to a solid cam, had the heads gone over, valve job new spring and retainers. Cam break-in on the run stand went well, oil pressure right around 80psi @2500/3000 RPM's.
Engine now in the car developed an oil leak at the filter plate. Upon start-up pressure is @ 75/80 on the mech. gage at 1200rpms, zing it a few times and the pressure jumps to 100, then returns to 80. I'm guessing a stuck relief valv. Am I missing anything, hate to have to pull the pan now

Gary
 
Either that or the gauge? Was the gauge during break-in on the stand a different one from what is in the car? If so, substitute an another gauge in the car before you do anything else.
 
Fix the leak 1st, that's where you start.

My exp w/relief valve issue were always stuck at a lower psi, typically.
Like no more than 20 psi no matter rpm.
One time I just said fk it.. rev'd it up to 6500 at idle.... and bam, the psi jumped to normal again
Junk in the relief valve.
That motor in particular say on a stand in a bag under a tree for a year.. never run rebuilt short block 318, steel crank, big rods, cheap .020 pistons. Back up motor.
I took it apart, sanded some pits from moisture on journals, flipped the pistons direction for torque...through all the same bearings back in some used heads, new 340 cam n lifters and buzzed it 5800 rpm in front of a 4 spd. Still runs, parked it for the .410
 
MOPAROFFICIAL said:
Fix the leak 1st, that's where you start.

My exp w/relief valve issue were always stuck at a lower psi, typically.
Like no more than 20 psi no matter rpm.
Click to expand...
I did replace the gasket at the filter plate and it was fine until I rev'd it and the pressure pegged the gage, started leaking again. it won't hold over 100 psi I guess.
Something is causing excessive high pressure maybe a blockage somewhere in the oil passages.
 
chrgdrt said:
I did replace the gasket at the filter plate and it was fine until I rev'd it and the pressure pegged the gage, started leaking again. it won't hold over 100 psi I guess.
Something is causing excessive high pressure maybe a blockage somewhere in the oil passages.
Click to expand...
Turn the motor reverse rotation right after it's been run.
Maybe you can get the pump to push it out the way it came in.
 
were you the one who asked Nicks Garage that last night?
 
chrgdrt said:
I did replace the gasket at the filter plate and it was fine until I rev'd it and the pressure pegged the gage, started leaking again. it won't hold over 100 psi I guess.
Something is causing excessive high pressure maybe a blockage somewhere in the oil passages.
Click to expand...
I dont believe a blockage would cause your excessive pressure issue, it would just dump out the relief valve. If you have a blockage it will rear its ugly head in other ways like busted parts or tore up bearings.
 
512Stroker said:
I dont believe a blockage would cause your excessive pressure issue, it would just dump out the relief valve. If you have a blockage it will rear its ugly head in other ways like busted parts or tore up bearings.
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Right... if the relief valve was working the pressure would always be limited to that. So it does sound like the valve if it blew the filter gasket. Odd that it was OK on the stand, now I wonder about the stand gauge... 80 psi is not one of the standard pump springs... 72 and 55.

BTW, what oil weight OP? Just for info....not that I think it is the issue.

MOPAROFFICIAL said:
My exp w/relief valve issue were always stuck at a lower psi, typically.
Like no more than 20 psi no matter rpm.
Click to expand...
That's stuck open. His sounds stuck closed.
 
nm9stheham said:
Right... if the relief valve was working the pressure would always be limited to that. So it does sound like the valve if it blew the filter gasket. Odd that it was OK on the stand, now I wonder about the stand gauge... 80 psi is not one of the standard pump springs... 72 and 55.

might have been closer to 70 on the stand but not over 80 and didn't spike or leak like it is now.

BTW, what oil weight OP? Just for info....not that I think it is the issue.

cam beak-in was with 15w40 rotella then changed to 20w50 vr1 which has been run in this engine since first built

That's stuck open. His sounds stuck closed.
Click to expand...
 
OK, 15W40 to 20W50 does not seem to be enough of a viscosity change to make a 20 psi difference in pressure.
 
when I rebuilt my 340 I ordered a race pump from Mancini racing that was 20 years ago and I really don't know what I installed. But I will tell you that when the engine was cold it would Peg the 100 lb gauge every time, I have seeping problems and leaking problems from the 90-degree oil adapter every sense I can get it to stop for a while but it eventually starts leaking again. Taking into consideration that you now are running a solid flat tappet camshaft and have blocked off oil to the lifters it doesn't seem unreasonable for that to be your oil pressure
 
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Now it's been 20 years a few metal shavings through the system and it's still warms up at 80 lb of oil pressure and settles in at just under 70 when it warms up idols around 40 lbs. I'm not trying to tell you that your system is functioning as it should but this is my experience. I welcomed high pressure in a small block Mopar. Some people would tell me my pressure was way too high, my motor still going strong and there's where we rebuilt a decade ago. My two cents
 
SBM's never faired well with high pressure oil pumps. Most of the time there were just too many oil leaks. I've always run the high volume pumps without any leaks unless I got stupid & over tightened the oil pan bolts or forgot to tighten the valve cover bolts.
 
I would not even try to argue this point and when I go through my motor again that will be the route that I take. Just telling you my experience, if you can deal with the occasional leak or not so occasional LOL it will work!
K.O. SWINGER said:
consideration
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Demonracer said:
SBM's never faired well with high pressure oil pumps. Most of the time there were just too many oil leaks. I've always run the high volume pumps without any leaks unless I got stupid & over tightened the oil pan bolts or forgot to tighten the valve cover bolts.
Click to expand...
 
Demonracer said:
What oil pump are you running?
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Melling high volume 72 HV.
I'm not too concerned about the 80 psi @ start up, it's the 100+ when I rev it. seems something is sticking. always had good pressure before the cam swap. and i didn't think sft cams required blocking the oil thought that was only for Rolleres,
Gona try to get out to the barn this afternoon and pull the pan.

Gary.
 
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