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Oil pressure concern

N

nate halter

New member
Some of you know that I had a piston ring issue recently on my rebuild. Its all fixed now, not burning oil anymore however.... I am now having way lower than normal oil pressure hot at idle. I even used a mechanical gauge to double check it. I have the zzp oil volume kit installed on it and at idle im getting almost 0 oil pressure. I reused the rod bearing when I had the piston/rod out recently. Didn't seem necessary to replace when I had no bearing problem. Cold oil pressure is only at 50. Before this piston ring problem I had about 65-70 psi at cold startup and about 15-20 at hot idle. When I snap the throttle after warm idle this is an audible rattle sound coming from the engine which I know is not good. I even took the superchager belt off just to make sure it wasn't rotor rattle. Any ideas? Thank you very much I cannot tell you guys how frustrating this whole rebuild has been with problem after problem. Ive heard from alot of people that you should not rebuild these engines and im really starting to believe that.
 


around 20 psi hot at idle is rather normal. but the rattle part is not. i'd hoping for a flex plate issue of some kind.
 
I would check the oil pressure relief in the oil filter housing. It might have gotten stuck due to high oil pressure or metal from the rebuild.
 
if you had good Pressure before and not so great after WITH the rattle, I think its time for a shortblock. Good thing our area has a ton of 3.8's hanging out in the junkyards
 


I just don't understand what happened all I did was take the piston and Rod out in the cylinder put a new set of rings on that piston and now it has low oil pressure nothing else has changed
 
The rattle is only after the engine gets to operating temp and when the throttle is swatted real quick. I put 10w40 oil in it today and the warm idle pressure was up to 25 now instead of basically 0. Im wondering if I should put a new bearing in that rod. No bearings spun yet so thats good.
 
Did you replace the oil pump? When you rebuilt the engine, did you remove the balance shaft? I'd also check that relief valve. Can't hurt.
The rattle, to be honest, is likely a rod or two knocking. AKA, spun (or not quite yet spun) rod bearing.
 


The oil pump is new and yes I remove the balance shaft and drilled tapped and plugged the oil hole for the shaft. I drop the oil pan last night and took off the number 3 rod bearing cap and the bearing is all way down to the Copper already I'm not really sure what has happened to this engine I had all the machine work done and everything was inspect when I measured when assembling. I'm going to try to replace all the rod bearings and see how that goes none of the bearings have spun yet and the crank still looks good. If I still have a problem I'm just going to buy another engine because this once cursed LOL
 
rebuilds are hit or miss, even with all proper machine work being done. i vote used engine now. cause this one will only be an issue.
 
Careful....if a rod bearing gets too out of whack, it could cause the rod and cap to become stretched, or out of round.
 
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