AMC 401 Oil Pressure low ?

Push rod restrictors and enlarging drain back holes might increase pressure at higher RPMs in an engine that's having starvation issues with a wet sump and running prolonged high revs. Yours is definitely increasing with RPMs. Maybe a stiffer relief spring and an oil pump midplate from Bulltear for longevity. Take a look at your oil pump gasket thickness too when figuring pump gear end clearance.

AMC RICK 401 wrote: Guys, I know this has been discussed several times. Can someone give me the link to any oil pressure related info? Just fired up my 401 Race engine yesterday and hot idle at 1500 rpm oil pressure is at 25 PSI. Revving up it goes up to 45 PSI Cold start, 60 PSI Running Comp Cams 10-30 break in oil Thanks,

Who built the engine and what information did they use for bearing clearance? I'd start there.

-Steve-

pressure looks good to me, i'd have a think about volume as well, not just pressure

13 psi at 600 rpm idle, 37 psi at 1600 rpm or higher, max 75 psi, is what the 73 TSM says. A race engine would have more clearance and run a little less at low rpm. 25 psi @ 1500 rpm with break-in oil (what weight are you using?) sounds good, assuming you are running the engine a little looser as most full race engines would be. There is no set rule that 10 psi per 1000 rpm after idle is what you want, it's just a rule of thumb (developed with mostly Chevy engines). As long as it's got enough pressure to keep enough oil moving and everything well lubricated you're okay even if you don't reach 10 psi per 1000 rpm. Remember, larger passages and looser fits will need more volume of oil, but more pressure doesn't always equate to more volume. A high volume pump in an otherwise stock engine will typically produce more pressure, but only because the volume has to have somewhere to go, so it forces it along. That's not the intent -- the intent is to flood the larger clearances with enough oil to stay lubricated (despite the larger clearances).

A question was asked who built this engine.

I assembled the engine and documented my clearances.
all within specs.
My local machine shop did my machine work and is a close friend so we worked together on this project.

I have built several stock a slight modified AMC v8's over the past 40 years but this one is my baby and never spent the kind of money I have in this one . Hate to panic just need support from my fellow AMC family.

I will report back with results when I get final adjustments done and the oil in that I plan to run.

Thanks everyone for the insight and suggestions.