318 oil pressure

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BigBlockMopar28

BigBlockMopar28

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Awhile back my 318la (87 truck block) jumped a timing chain, and bent 9 pushrods. The old pushrods were the oil thru type, the rockers have the drain holes for them aswell. Needed a set quick and the local parts house had factory length mellings, but they didnt not have the oil holes in them. Ran them anyway and its definitely alot less noisy than the old bent PR's, but the oil pressure is off. On the old bent pushrods, it would have 60psi on a cold start, and 35 at hot idle on any given day, idle @800 or so. With the new pushrods, it gets 50 on a cold start on a cooler day, 45 on a warm day, and at the absolute lowest, 15psi hot idle, idling around 500 according to the tach. I'm aware that this is a low idle but this thing has a little rear end play and likes to bang into gear from drive to reverse or vice versa when the idle is set to 800-850. Tach is running off of the output plug on my MSD, oil pressure gauge is a mechanical parts house gauge. The only noise I ever hear it make is what I would call a combination of the double roller chain, and general belt/pulley noise, no tapping or major signs of oil starvation. Just curious as to whether this should raise any alarm or not. TIA

Edit: Forgot to say but i'm running 10w40 conventional and have been since I got it.
 
Seems like using p-rods with no holes would help pressure. And I'm trying think where jumping a chain would effect pressure.

15 psi hot at 500 RPM is pretty darned good.
 
you are going to gall your rocker shafts.
 
are your lifters the oil through AMC/ Magnum style or have a solid cup?
Factory always had problems with pushrod/ rocker wear so perhaps the changed or was this motor rebuilt somewhere
the pushrod/ lifter should be different lengths
a good read on the 10-40 issue Big Block corvair is a proxy for flat tappet cam
Oil | Richard's Corvair
 
I would be worried why it bent pushrods. Oh yeah. Pistons hit valves. You done a compression test? Might want to.
 
jumped a timing chain so cracked a piston or bent a valve
I've seen bent pushrods when bad gas varnished up the guides and stuck the valves- but that's not it this time
you are so correct- needs some investigation
needs a valve job anyway
and what about all the nylou crap in the pan?
 
wait- LA= oil through the heads

my bad
 
YY1 said:
wait- LA= oil through the heads

my bad
Click to expand...
Also had me confused lol.

But for the record ive been running it like this for atleast 2 months now, and other than that pesky carb hesitation, its giving me no reason to believe that there are other issues. I was just purely curious about the oil pressure
 
Wyrmrider said:
jumped a timing chain so cracked a piston or bent a valve
I've seen bent pushrods when bad gas varnished up the guides and stuck the valves- but that's not it this time
you are so correct- needs some investigation
needs a valve job anyway
and what about all the nylou crap in the pan?
Click to expand...
Nylon crap was flushed out with diesel through the pan when the timing cover was off, and i flushed any remaining diesel with good oil.
 
Did you take the oil pump pickup off and check it for bits and pieces of nylon.
If not I bet it sounds like a baby rattle.
 
sireland67 said:
Did you take the oil pump pickup off and check it for bits and pieces of nylon.
If not I bet it sounds like a baby rattle.
Click to expand...
I did not, but I hear no rattling noises other than a loose exhaust hangar that likes to rattle at certain rpm's, lol
 
I guess I should have mentioned this before, but first start up with the new chain was 60psi cold. And was the same everytime it started cold until I finally changed the pushrods. The oil psi drop happened when I changed the pushrods.
 
Were the new pushrods the EXACT same length as the old ones? I gotta wonder if the plungers in the lifters are not a a different position and that is somehow causing extra oil flow through the lifters.

Or as suggested.. crap in the pickup just coincidentally happened to show up at the same time.

BTW, is your Mopar a blue 67 Coronet?
 
nm9stheham said:
Were the new pushrods the EXACT same length as the old ones? I gotta wonder if the plungers in the lifters are not a a different position and that is somehow causing extra oil flow through the lifters.

Or as suggested.. crap in the pickup just coincidentally happened to show up at the same time.

BTW, is your Mopar a blue 67 Coronet?
Click to expand...
Yes, they are the exact same length. Just these have solid ball tips at the end with no oiling hole, while the originals had a half circle kind of point, with the oiling hole. And nope, no Coronet here
 
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