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Question, oil pumps

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jlaird

jlaird

Great Pumpkin
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Is the cavity behind the oil pump under the can supose to have oil in it under normal operation. It has a drain back into the block but how does the oil get there in the first place. The pump has a gasket between it and the block.

I know what and how the pump works but am just a bit confused as to how and why oil gets behind it.
 
All I know is that if you leave that cover on the workbench, you get a serious oil leak. Probably a little more than you have been getting.I know an idiot that did that. I know him very well and that's all that I'm going to say.

Marv J
 
LOL, out of the woodwork they come.

We all learn from each others mistakes.
 
Jack,

Can you post a picture of the block cavity with the pump removed and a picture of the block mounting surface of the pump? It's been 10+, 20+, 30+, ... years since I have assembled one. I guess that excuses the memory lapse. LOL Checked the junkyard in the basement and didn't have one down there. The block drain is probably a just in case the pump leaks thing, but once they did that they had to put the can over the pump and block drain.

Phil
 
The drain hole is just to drain whatever little bit might leak from a poorly gasketed oil pump. Most times when you pull off the backplate the can is dry. Without the can, the little drain hole becomes an extra block vent. NOT GOOD!

Glen Byrns
 
Should the pump have any sealer between its two parts. It does not come with any? That has to be where any oil is comming from into the can. The pump is gasketed and sealed to the block.
 
Check for flat surfaces and for burrs. It should not require sealer, but a very thin coating should not hurt. You do not want to increase the internal clearances. A thin coat of high tack spray a gasket should be the ticket. Make sure the pump is fitting against the block properly and that the attachment screws are of the proper length as well.
 
Think I will do that in the morning.
 
The can is to catch any weeping oil and return it to the crankcase. There should not be large oil leaks from the pump. You need to make sure that there is no leak from the block to pump gasket, the oil pump to cover joint, or through the pump body or cover.

You need to visually inspect the oil pump body and cover for casting defects. Rare but not impossible, we received a water pump from Grainger with a casting defect that allowed air to be sucked into the suction side. To there credit and mine they cheerfully replaced the unit. The defect was small and I had to look closely for it.

I would fit the pump body on the block without the cover, install the pumping elements, and check to see that the surfaces of both elements are planar. This will assure you that the drive is fitting properly into the rear of the camshaft and not holding the pump body from seating properly on the gasket.

Check that you have annular clearance between the pump body and the diameter of the recess in the block to assure that the pump is not being held at an angle when trying to seat on the gasket.

CHeck the length of the mounting screws, to assure that you have proper compression of the casket.

What modification did you have to make to the pump? Which thread were the pictures in?

A lot of words. Hope this helps. Make sure you clean the grit up after lapping.
 
Jack,

Found the pictures where you ground the outside of the mounting ears. Make sure you have not displaced the metal or created burrs in those areas on the mating surface of the cover to oil pump body. This could cause a leak.

Phil
 
Ok, think I got it. Here is what happened, the bolts holding the pump on were a bit too long and bottomed in the holes. The pump was snug but not tight as the bolts would not go any further.

When I pulled the pump I noted that the bottom 1/8th inch of the bolts were striped clean where the hole had not been threaded to the bottom. Also noted oil leakeage through the pump bolt holes and the pump was not really solid in the cavity, it basicly fell out.

It has been remounted with a bit of RTV and it is tight now for sure for sure.

Think I cracked the oil pump cover sodder joint when I tightened the backing plate without proper clearance. Then I did a bit of grinding on the pump, out side of the bolt holes and it fit, by then it was too late the crack was in being.

Have a new backplate comming today on which the oil pump plate was brazed, that should hold it.

I feel that the problem is now solved and is only awaiting reasembly of the engine and reinstalling same to prove it.

Thanks for the assistance as always. Maybe this will keep someone else from haveing this problem.
 
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