Ive completly redid the engine again all new cam and bearings mains rod bearings the whole nine yards. now it runs great, but as before when its cold it sounds good all you can hear is the fan and exhaust. when it gets up to operating tempature the oil pressure drops to 0 and it sounds BAD you can hear every single rocker tapping. just like a bunch of sewing machines going full blast. I put another new oil pump in to no avail.Am so fed up with this junk im ready to trade it for a damm Chevy.My last thing to do is try thicker oil. I guess. Anyone ever have this problem?

 

Did the machinist or yourself put the plugs back in where the cam retaining plate is before bolting the timing cover on? I would check that 1st before giving up.

Also what is your cold oil psi?

Something got overlooked I would believe, and it wouldn't be the first time, for you, me, or someone else.

 

At this stage I cant say 100% I put the plugs in. But im 99% shure I did. The cold oil pressure is almost pegged on high, till it warms up then drops to 0. I had the shop install the new cam and bearings.If I only drive it 5 minuts at a time then let it get cold its fine. better off walking.LOL

 

Ok, when you installed 2nd oil pump, did you pull a bearing cap, and look for any signs of bearing failure? Loss of oil psi your mentioning would be evident if it were bearing failure, and any cap #1,2,4,5 would show it when inspected.

If it were me, I would pull water pump and timing cover and waste an afternoon or day, buy new timing cover gasket, and double check for the plugs.

Do you have any pics of your build, from beginning to end?

 

Yes I pulled #1 cap, the bearing looked brand new, no scars marks or anything out of ordnairy. They have less than an hour of run time. My other option is to take the oil pump pickup tube and the oil pan off and put them on 93 5.0 HO. out of a T-Bird,and use it.but I hate to downgrade.

 

Check your oil pres gauge. That could be the malfunction.

 

What about the oil pump shaft that does to the dizzy? Could it possibly be rounded off?

 

Was the oil pressure bad before your tore it down, or having this problem before the rebuild? And like everyone else said check the plugs. Double check the bearings, it would suck for it to be something silly like standard bearings on a undersize journal. Wouldn't be the first time someone did something like that.

 

I'd buy a Chevy.

 

got an old K5 with 454 automatic 35 super swamper tires. Id need a seccond job to pay for gas to get to first job.

 

plasti-gauge the clearances on the rods and mains.
I'm betting it to large and when the oil thins its loosing pressure to the top end.

Do one thing first. Change the oil filter.
I got hold of a Motorcraft FL1A many years ago that must have been the end of run for the element paper because it was not an element at all, but cardboard and starved the top end for oil.

If the machinist installed the cam bearings wrong it wil cause tis issue too.

one last thing my 5.0 lost oil pressure when it was warm and not idling, but with the rpm increased, with 20w50 oil I changed it to 10w30 and suddenly the issue went away, but I still am not sure why except te thinker oil could not be pulled through the pickup screen fast enough.

 

Did that whole nine yards include sending the shortblock to a machine shop?
Or did you just put new bearings and stuff in a well worn motor?

 

First, which oil pressure gauge are we talking about. Is it stock gauge or a mechanical one.
Seeing as though you said it sounds terrible after warming up, it doesn't matter. But the stock gauge is known for misrepresenting true numbers. The sender could be off.

Next is that oil pressure is a measure of restriction, not flow. So being cold the oil is harder to pump, and you get crazy high pressure, especially because the gauge taps off directly off the oil pump.
If cam bearings were in wrong, there would be no flow to them and you wouldn't lose pressure after warming up.
But on that note, if the plugs weren't in the cam galley then you'd have poor pressure even when cold because it's a huge leak.

Keep checking. Let us know what you find.

 

Did you check clearances of the bearings when you rebuilt it?

 

I have a 5.0 im my 88 It was rebuilt a few years ago no problems with the motor itself I just wish the guy I bought it from would have had new external parts sensors plenium etc. Maybe your machinist made a mistake after all we all are human. I would not give up either nor would by a chevy espicially not a truck unless it was from the forties on up to late 60's and thats just because they look cool. Just like the old fords. But I would by a ford all the way up to now. Actually If I was to buy another truck instead of a ford it wold be a dodge damn sure not a chevy. just saying