Oil pressure?

Currently my oil pressure hovers between 65-80. I've read varying opinions on where it should be, but I think it's too high given that the rear main seal/pan is leaking. What I'd like to try is adjusting first, and then replacing if necessary, my oil pressure relief valve.
I'm one of those guys who "knows just enough to be dangerous", so ill need a little help to do so. Can anyone supply a picture of the valve and location on a 304, and give some advise on adjustment? Thanks

 

A couple of things on this, I don't think the rear main seal or pan would leak from oil pressure, I think they leak from being worn out. I think the oil pressure is to get the oil through the various galleys/channels to the right parts of the engine and bearings. Also, I'm pretty sure the stock AMC oil pressure relief valve is not really adjustable except to change out springs that might be more or less firm to suit your application.

Is this a newly rebuilt engine or oil pump? That pressure is darn good for an AMC V8. Mine started out relatively high when newly rebuilt, but now with about 4K miles it's settled down to around 50. Another question is, do you have faith in your gauge? Is it mechanical or electrical?

 

It is a fairly new rebuild. I must have about 500 miles on it. Its a mechanical gauge, and im not sure if it's working properly. I have an electric gauge that i could check it against.

 

A mechanical gauge should be fairly reliable. Also, your peak oil pressure should go down as the engine temperature approaches the set point (ie 195F).

I don't think that 60 or 70 is so worrisome. I run 15W40 in my 304 year round, and the pressure reads that high when the engine is cold. I've taken the spring and piston out, and it's moving freely. I have an AutoMeter mechanical gauge. In my factory-new '73 304 I had a Stewart-Warner mechanical gauge, and it ran above 60 all the time.

If anything (other than wear) makes the rear main leak, it would be high crankcase pressure. If you have a lot of blow-by, or your PCV valve is stuck closed, that can force oil out. If it's a new engine and the rear main seal leaks, the seal was probably installed wrong. Certainly pan leakage has nothing to do with oil pressure.

 

I'll check the pcv valve. I really don't want to replace the rear main seal.
I run 10w30 in my rig since it is in Northern Maine and sees a lot of colder temps. Rotella T with a Baldwin filter. See any potential problems with that??

What would cause a lot of blow-by??

Can you run down the procedure of checking the pressure relief spring and piston(maybe with a picture)?? Like I said, I know just enough to be dangerous!!!
Thanks

 

What oil filter are you using - if Fram that maybe your problem, it was for me. 80PSI @ idle on a I-6. Also check the relief valve.

 

Baldwin filter..... id run a wix

 

I run Wix as well but under the NAPA Gold name-same filter and a little cheaper.

 

Baldwin is a good filter. I'd guess that switching to a Wix would have no effect.

You might get lower pressure with a Fram filter, but I don't recommend them. Sometimes a switch away from a Fram will boost oil pressure.

Instructions for removing the OP relief valve are in the TSM. If you read the TSM, you'd know that the relief valve is not adjustable, and that it has a maximum setting of 75 psi. I think the main danger of exceeding 75 psi would be in bursting the oil filter.

'76 TSM here - http://oljeep.com/gw/76_tsm/Section1B.pdf - any TSM from the AMC era will cover this part of the engine.

 

I've got 60-80 psi of oil pressure from a cold start with a Fram filter. 40-50 psi once warm

 

baldwin filters are widely used and well respected but ive seen more than one rupture thats why i run wix...

 

My tired 258 gets 60 on cold start and goes down to the notorious 10 when hot(idle) and 25 driving with Rotella T 15W40 on a new mechanical gauge. A full rebuild is coming soon.