The Stovebolt Site Forums The Shop Area Engine Shop Need some advice on blown oil filter can gasket

This is a newly rebuilt 292. The oil pump is NOT the high flow pump, with the extra height. Tried to start it up for the first time this morn, was successful, till I saw the oil gushing from the oil filter. I tightened down the oil filter (cheap Penzoil for break in) which did no good since the gasket was already gone. I replaced the oil filter with a Fram, it lasted a few seconds longer. The mechanical oil gauge screwed into were the oil pressure gauge fitting usually goes is pegged at 80 pounds. I'm thinking the pressure relief valve in the oil pump is not working. I'm hoping someone has a better idea than dropping the oil pan and replacing the oil pump.

Larry

Larry,

Wouldn't this mean a restriction down stream from the filter? The pressure relief valve wouldn't come into play unless the flow was restricted in the system after the pump. The filter is between the pump and restriction and is the weakest link. Could a plug or cover plate have been left on?

Stuart

Check your old filters and see if the o-ring is still on it. I have seen this several times where the old one stays on the engine and causes it to leak shortly after you start the engine. a double ring/gasket causes it to slip loose real easy.

Ed

Did you prime the engine before start up?

If you are reading 80 psi at the oil sender, (right hand side, towards the back) you must have oil everywhere in the engine, are the push rods and rocker arms getting oil?

I think you are right about the relief valve in the pump. No filter is going to hold 80+ psi for very long, so I don't think I would try a third one. Try pulling the distributor and tapping on the oil pump housing, the check valve may break loose. Other then that, pull the pan and have a look. Joe

I got a call from a fellow dirt track racer once, about an engine that would start, and then stall immediately. He thought it had carburetor trouble. After several attempts to start it, I told him to keep it running some way to warm it up. He cranked it off, and floored the gas. It shook and stuttered for about 5 seconds, and then the filter housing split, top to bottom. Since I was standing right beside the filter, on an open-wheel race car, I got a bath in 50 weight oil!

He had used a big block oil pump, and then shimmed the relief valve spring down tight. A 100-lb. gauge was pegged at idle speed, and the running pressure was probably close to 1,000 PSI. The stalling was being caused by the hydraulic lock and the engine's inability to turn the pump.

Drop the oil pan and check the pump. You've obviously got a blocked relief valve.
Jerry

Just a request to let us know what fixed your problem. With my limited experence I have not seen this problem and would like to know what fixed it. Thanks

Stuart, Got oil to the rocker arms.

Ed, The 292 uses the screw on filter. I should have referred to it as a screw on. my fault.

Joe H, Primed it with a cordless drill saw, till I saw 80 on the gauge, the drill was working so I backed off, 80 pounds cool. Tapping the oil pump is a thought.

Hotrod, The pump has 10k on it so I took it apart and cleaned it, sure hope I didn't shoot myself in the foot. Didn't shim the spring, did pull the spring and piston out. The motor started pretty quick the first time, but never could get it near idle after that hydraulics?? I guess maybe I should have primed it longer.

I'll let you know. I've got to find out for myself too.

Larry

I have always assumed that a properly functioning oil pump would never pop the relief valve unless there was some restriction downstream of the pump, or that the RPM's went high enough to outpump the system. From what I'm reading above, it sounds like the SOP is for the relief valve to be working all the time, or in some state of 'dump' constantly. Is this how it really works?

Stuart

Particularly on a cold engine with thick oil, the relief valve will operate pretty continuously. For oil pressure to build up at all, more oil must be supplied to the bearing than can be leaked away. If we supply one drop of oil to the bearing for every one that leaks out the side, the pressure would be zero, but the bearing wouls still be lubed properly. Bearing damage happens when we supply LESS oil than is being leaked. Once the parts, and the oil get hot, there's much less need for pressure relief. That's why cold engines with thick oil have high oil pressure.

If it were possible to maintain only one pound of pressure, consistently, under all operating conditions, the bearings would never be damaged and there would be no power loss from building up excess pressure. Since that's not practical, a little over-capacity is built into the pump, and the relief valve is there to keep the pump from operating in a hydraulic-lock situation.
Jerry

Dumn, I did it to myself again, best guess. I dropped the pan and pulled the oil pump out. The piston on the pump didn't appear stuck. I could move it, though it took a little more effort than maybe it should have. I removed the relief valve and it is possible to reverse it. I checked the factory manual and the piston it shows for the valve is different than the one I have. The manual shows a cylinder. What I have is hollow cylinder with one end closed and tapered to a 3/16 shaft about a 1/2 in. long. I had the shaft in the oil passage. I reassembled it with the cupped end in the oil passage. With the cupped end in the passage I'm thinking I should get more force on the spring. Anyone familiar with with oil pump relief valve?

Larry

The relief spring fits inside the cupped piston. If you install it with the spring bearing against the closed end, you'll have WAAAAY too much pressure, due to the spring being compressed too far. Be sure the valve slides freely in the bore. On the pumps I've assembled, it generally takes about 1/2" to 3/4" of squeeze on the spring to get the roll pin to install in the pump base. A firm push with the tip of a small screwdriver should unseat the valve and allow excess oil to flow back into the pan. Do you have the pump base installed in the right position? I think it's idiot-proof, but it's been a while since I had one apart. The output pressure should be able to bear on the end of the valve on its way to the oil passages in the block.
Jerry

Hotrod, When I blew the gaskets, I had the spring inside the cupped end. With the spring in the cupped end that puts the closed end with shaft in the output pressure. Seems to me that the shaft and the taper (about 45 degrees) would not be good to get full pressure on, then I could be wrong.

Installing the pump is idiot proof.

Maybe Stuart is right. There is something else blocking the oil gallery. I wire brushed the main gallery to the lifters and then ran a cloth thru the gallery. I'll order another pump tomorrow. I'l pull the relief valve out of this Hamburg high flow and see what it looks like.

Larry

Regardless of the shape of the end, the relief valve works on the cross-sectional area of the piston. A certain diameter of piston requires "X" amount of oil pressure to overcome the spring and regulate the pressure at that point. A restriction between the oil filter and the rest of the engine would simply cause the pump relief to operate at its set point, but would starve the engine for lubrication. The problem is almost certainly internal in the pressure relief system, so it's probably the wisest decision to replace the pump. Good call!
Jerry

I've put in a new stock replacement pump. When I primed I held the driver on it longer and didn't feel it start to work, like it did the first time. The oil gauge went to 80# and held. I idled it for about 5 minutes while I set the timing. No blown gasket. [Smile]
I just finished cutting the top out of a valve cover to put on while I adjust the valves. Don't know that I'll be able to (or want to in this heat) till Thurs morn.

Larry

An "engine running" valve adjustment is the worst possible way to accomplish that little task. It's messy and inaccurate. Use the companion cylinder adjustment procedure with the engine stopped that's been documented here countless times. It involves finding when a cylinder is in the overlap position between exhaust and intake, and adjusting the cylinder halfway around the firing order.
Jerry