Troubleshooting valve train noise on my sons 400 big block Chrysler. Has new hydraulic lifters, cam. Pushrods are correct length (non adj rocker shaft/rockers).
Pulled the factory oil sending unit, put a tee in place and connected a guage. Needle wouldnt budge! Even when revving the engine. Thought maybe the passage was plugged somewhere. Pulled gauge off, ran engine with tee open. Did get a trickle of oil to flow when revving engine. No flow at idle rpm though. This tee is at top rear of engine, btw. Put a guage on with a lower scale, 1 to 5 psi. Read 1 to 2 psi at 1500 rpm!
Still wondering if the passage might be plugged, pulled a valve cover, and ran the engine with it off. No visible oil flow in valve train on top. Oil laying in head recesses, so some oil has gotten there at some time.
Funny thing is, this engine has had noisy valve train since he bought it. He has been driving it, and the engine hasnt siezed.
Anyone heard of an engine surviving on such low oil pressure?
Is it possible? any ideas?
The oil pump is external on these engines, and we are gonna pull it and check it out.

 

I remember that the Mopar stuff of old can run on low oil pressure, but I am sure that 2lbs is too low. I remember talking to a old timer about it and he said somthing like they run 5lbs at idle. Sorry for the vauge answer.

 

2 PSI at idle might be tolerable (I've seen quite a few worn motors that last a long time while triggering the low-oil-pressure or choke lights, which normally come on below 4 PSI). But, in those causes, the oil pressure builds quickly as the motor comes off idle. If you're seeing a relatively flat 2 PSI or so, there's a good chance that you've put some wear into the bottom end and you're lucky you haven't spun a bearing yet.

IMO, it's time to tear down this motor if it's worth anything to you.

 

I recall relating this (yawn...bedtime) story here some time ago. This however, was a sbc. Don't think mopar is as easy to oil as sbc, but anyhow.....

Some years ago, I was temporarily running a high mileage, loose 283 in my big block camaro. On one occasion, while doing 70-75 on freeway, (this with 3.55 rear, and no overdrive in those days) and I noticed the SW mechanical gauge reading 0# oil pressure. I remember tapping the gauge, thinking needle was stuck. I drove it this way, at freeway speeds, for maybe 45-50 miles. When idling engine, I heard what sounded like a main bearing knock. It burned a little oil, so I proceeded to check the dipstick. After dumping in 3 qts. of oil, the oil pressure come right back up to normal. Some time later, when an opportunity presented itself, to tear apart the engine, having remembered that incident, I noted the condition of the bearings and journals. No hint of operation with low, or no oil pressure, whatsoever. True story!

If that chrysler engine didn't have the hell run out of it, while operating with low pressure, chances are, no major damage developed.

 

I’ve tinkered with a ford 302 that eventually ended up lighting up the oil idiot light (I think it turns on at 2 or 4psi) at below 1500rpm. It lasted for 18K miles making probably 70 or more 12 second passes in a 3400# car like that till we put a mechanical gauge on it and found that it never got over about 8psi. When we tore it down it didn’t show anything but normal wear.