When I went to start my 455 this AM. I had 0 oil pressure, I immediately removed the oil filter and cut it open. The filter was clean (no metal). I replaced the filter with a system one and cranked the motor again, no pressure.
I went to AutoZone and bought a new oil pressure gauge and attached that to the motor, again no PSI. I removed the distributor and cranked the pump with my dewalt drill, no pressure on the gauge. when the drill is running you can feel the resistance on the pump so the pump is trying to move oil, in fact it has to be moving oil or there would not be the resistance.
Next I removed the lifter covers and ran the pump again. I got a very small flow on the right side, nothing on the drivers side.
I'm stumped, when I shut the car off the last time I drove it(4 days ago) everything was fine. Any Ideas? No oil on the floor under the car either.

 

Probably a stuck open oil pump pressure relief valve. Sounds as though you caught it in time. Has the timing chain ever been replaced? Have seen nylon teeth from worn cam gears block the oil pump intake screen. Does the shaft between the distributor and the oil pump look ok? How does the bottom of the distributor/shaft connection look?
Please keep us posted...

 

IF the bypass were stuck would I still feel resistance on the drill when running the pump? Timing gear and dist. gear are all fairly new (maybe 500 miles on rebuild).Timing gear looks great, haven't tore into the engine yet, maybe tomorrow.

 

Before you tear into it talk with one of the engine builders who's a member here. If it worked fine last trip, but now doesn't it seems like there should be a few places to start looking. Hopefully it is something simple like the oil filter bypass, which you can change without getting into the internals of the engine. I too have seen debris plug up the oil intake screen, but if you think the drill is moving oil then we're back to something is keeping the pressure from going up. Someone who's more familiar with the internal workings of your motor might be able to save you a bunch of time and maybe money trying to identify the problem. Wish I could be more help, but I don't know enough to help trouble shoot your problem. John

 

Maybe a loose ground or wire on the gauge? Are they aftermarket gauges

 

What type of gauge are you using? Have you tried a mechanical gauge to see if there is a change? If you had 0 oil pressure there would have been no flow to the rockers. How long did you run the drill with the priming tool?

 

X2 on the gauge, mechanical so you know for sure.
It takes a while to get oil all over the rockers. Don't use a cordless drill, my old faithful black & decker(not cordless) usually starts smoking by the time I get oil to the heads.

 

Great questions Billmerbach and Oldcutlass...were there any noises or was it just the gauge reading low? Has the pressure been tested directly at the oil sending unit with a mechanical gauge? It can be very difficult to get full oiling up top with a drill.

 

If you feel resistance when you spin the oil pump drive it's pumping oil. If the relief valve is stuck open then most of it is going straight back to the oil pan. A tiny amount will still be pushed around the engine but not enough to show any pressure on the gauge.
Incidentally I just use a speed brace and socket wrench to spin the pump, once I've wound it up enough to fill the filter I quit. Running the engine will push oil up to the rockers much quicker than endless spinning the pump drive, if it didn't our engines would be spending a lot of time with no valve gear lubrication. The mechanical action of the cam and lifters is what sends oil up there.
It's quick and easy to check the relief valve, I'd give good odds that's your problem here.


Roger.

 

How recently was this engine built?

 

First of all thank you all for your suggestions, I have read them all but unfortunately have not had time to answer each one. I am calling my engine builder today and asking him. I have a feeling he might have put an oil restrictor above the rear main and that may have worked loose. It looks as though I'm probably in for another engine removal. The engine was built late last year, and has run flawlessly since. The gauges are mechanical and are working properly (tested on another eng.) If the relief valve is stuck open or the spring broke I believe I'll still have to pull the eng. to get at it?
Once again thanks very much!

 

Sounds like the driver side rear galley plug came out. Very rare if it did. But that would be a place to look. No matter what things should be inspected.
There is no place for a restrictor above the rear main and if there was it would not cause severe loss of oil pressure.

 

That one or one of the front ones would be my guess. The engine is setting on the engine stand draining right now and tomorrow morning we will see. My fear is that nothing will be obvious and I'm not sure how to test the oil pump. Before we removed the eng. I removed the oil filter and tried to plug the hole to the pump on the eng. as my buddy slowly turned the pump with the drill and I could not restrain it, oil blew all over the place. Then we removed the gauge from the hose and ran the drill with just the tube for the gauge in place and it would barely fill the tube with oil!!

 

Well guys we finally have the answer. I had to remove the crank and there it was, the #1 main, cam oil restrictor came loose and blocked the left side gallery and oil pressure gauge from receiving enough oil to make any pressure! I removed it and put the engine back together in time to go racing last Sunday. Thankfully it was caught before it did any damage. I also replaced the oil pump (but didn't really need to) That's what eventually led me to the restrictor. I'm fortunate it was the front restrictor that came loose because if it had been any of the other 3 my oil pressure would have probably increased and I wouldn't have noticed it until it was too late. Thanks for all the reply's, I always appreciate any input I can get especially on a problem this perplexing.

 

Are those restrictors really necessary? I ask because I really don't know, but it seems like an accident waiting to happen.


Your oil pressure can't increase over the set pressure of the bypass valve, no matter what happens downstream of it.

Glad you got it fixed!

- Eric

 

Pressed in oil restrictors are bad news. You should have removed them all. And if a screw in restrictor came loose it wasn't tight to begin with and was ceryianly not loctited like it should have been. Glad you found your issue so easily and before you lost your cam & lifters on the drivers side.

 

I'm not sure if they're necessary or not but my builder likes them. I've had restrictors in all of my engines to date without a bit of trouble but this could be the last. My builder and I have yet to discuss this one. According to BTR they aren't needed. Once again thank you all very much for your input.

 

I take it these are meant to restrict oil to the cam?
Why not just turn the cam bearing 90 degrees and drill what ever size feed hole that you want to?
They sound pretty worthless to me.