oil pump square o-ring gasket

[harmony]

Does anyone have a source for the square o-ring that goes under the cap of the oil pump for the 251? ( 1948)

According to the parts catalog there are 2 different number. p/n 863 724 is used on engines up to 29948.  p/n 1124 984 is used on engine after 29948. 

I'm curious what the difference would be?  I'm also confused because my engine number has an extra number. 140909

I've tried the usual parts suppliers. But maybe I'm forgetting one.

 

Mine is dripping just a little bit and I cleaned off the area above it making sure it didn't come from the oil pan. 

[dpollo]

Try this.   remove the cover from the oil pump. ( mark it first so it goes back on the same way )  Wipe the surfaces clear of oil.

Spread a very small amount of the old Permatex number 2 Aviation Forma Gasket over the visible  surface of the o ring.   Replace cover.

[harmony]

16 minutes ago, dpollo said:

Try this.   remove the cover from the oil pump. ( mark it first so it goes back on the same way )  Wipe the surfaces clear of oil.

Spread a very small amount of the old Permatex number 2 Aviation Forma Gasket over the visible  surface of the o ring.   Replace cover.

I was thinking about that if I couldn't come up with a new one.  I have some of that Permatex aviation forma gasket.  I usually use one of those dollar store artist brushes( 1/4" wide)  to apply it.  They do a really neat and controllable job.

[Sniper]

You'll have to do some leg work but it's not unavailable.

 

https://www.mcmaster.com/o-rings/cross-section-shape~square/square-profile-oil-resistant-buna-n-o-rings/

 

[9 foot box]

   My oil pump had a drop of oil on the bottom bolt. I cut a couple paper shim gaskets and put them under the rubber one. 2.670” OD, 2.500”ID. It amounted to about a .012” shim. It’s tricky to get them in, because the gears want to fall out, but I used a couple pump bolts and some fine copper winding wire to keep them in place. I turned down two flat washers of those dimensions to cut the gaskets with an x-acto blade. Results may vary, but it worked for me. Rick D. It’s easier to take the pump off and do it on a bench.

Edited February 17, 2022 by 9 foot box

[Sniper]

The cover to gear clearance specification is .001", anything beyond that allows too much oil to internally bypass inside the pump.

[harmony]

12 hours ago, 9 foot box said:

   My oil pump had a drop of oil on the bottom bolt. I cut a couple paper shim gaskets and put them under the rubber one. 2.670” OD, 2.500”ID. It amounted to about a .012” shim. It’s tricky to get them in, because the gears want to fall out, but I used a couple pump bolts and some fine copper winding wire to keep them in place. I turned down two flat washers of those dimensions to cut the gaskets with an x-acto blade. Results may vary, but it worked for me. Rick D. It’s easier to take the pump off and do it on a bench.

That's interesting that your procedure worked for you.  As mentioned by Sniper there is very little wiggle room for altering the distance of the end cover.  I read in a previous post that someone tried putting a thin gasket in there and it caused all kinds of grief with the oil pressure.

[9 foot box]

   It’s just thin paper gasket material, placed in the groove of the pump, then put the ring seal on, then the cover. The rubber ring shrinks with heat and age. This way, it shims the rubber ring out, so it makes contact with the cover again. That’s the best that I can explain it.

[Sniper]

17 minutes ago, 9 foot box said:

   It’s just thin paper gasket material, placed in the groove of the pump, then put the ring seal on, then the cover. The rubber ring shrinks with heat and age. This way, it shims the rubber ring out, so it makes contact with the cover again. That’s the best that I can explain it.

 

Ah, it's not a gasket between the cover and pump housing.  It's essentially a paper washer in the o ring groove to space the oring out a bit more.  That explains the success you had.  ?

[Dodgeb4ya]

Those oil pump cover quad O-rings are out there...here's one...

I think AMS has them too...always around 12 bucks.

There always were supplied in the engine gasket sets....of course not anymore.