I think its time to admit defeat on my 5.3 build. I got the motor used, took to machine shop and had it bored .020 over, polished crank, cam bearings and heads done. I assembled it, used plastigage on bearings, rods in spec, main bearings were on the tighter side of tolerance but ok, i dont remember exact number. I put a btr truck cam in. I didnt know it had to be tuned for cam, so it did not get a 20 min break in cause it didnt stay running. I swapped factory cam back in. From day one oil pressure has not been great, around 40 on start up onced up good, around 10 at idle. I have checked with mechanical guage. I have done 3 oil changes so far, cut filters open, no chuncks just some glitter. I swapped in melling high pressure pump and a new oring. Pressure is a 45 accelerating, but still 10 to 15 at idle. Seems to have a slight tapping noise, i unplugged each plug wire to try to isolate it but made no difference. I am assuming main bearing issue, any other thoughts?

 

It's likely the o-ring at the oil pump pick up tube as this is the most common issue. But we are all going to want to ask some other questions.\

What where your oil Clearances?

Did you use a new cam retainer on the block?

What kind of oil pump did you use?

New barbel in the rear of the oil passage?

New cam bearings installed?

What type of oil?

 

I will look what tolerance was with plastigage, i wrote it down at my garage. I put in new cam bearings, regular oil pump at first and just swapped in mellings high pressure oil pump. I put new cam retainer plate. I put in new barbell but it went in hard. I can't remember for sure, but kind think I remember I very tiny sliver of the oring coming off when installing it. Mobli 1 5w 30 oil.

 

did you install the barbell correctly? And did u use the correct oring that was supplied with the melting pump? It comes with 2 o rings and the end of ur oil pickup tube determines which oring gets used.

 

*melling

 

Yes I am certain correct o ring was used. I know I put the barbell in facing the right direction but it's about the only thing I haven't replaced again

 

if u used a factory plastic barbell then it should have gone in fairly easy. Only barbells I’ve seen that are hard to get in are the billet aftermarket ones like this one in my build since they have a lot tighter clearance.

 

Yes it was a factory plug

 

I guess I will drop tranny and install new one.

 

Is there any type of test that could help determine if it's the barbell?