engine and drivetrain Oil Pump Shim Damage From Main Stud

[FB73tii]

My oil pump shims are showing damage from touching the top of my ARP main studs under vibration. Damage shown here is after only one hour run time (redline is 7800 RPM). I am concerned that rather quickly the shims will fracture, flap around, and drop metal bits into the oil pan. Considering cutting the shims with shears and hand-placing the bits on each side, thus eliminating the center portion. Don't really want to grind off the tip of the ARP stud, but could if need be. Anyone run into this and what did you do? Thanks.

--Fred '69 & '74tii

 

[Preyupy]

Trim the shim

[FB73tii]

Byron--Thanks for the quick reply! --Fred

[FunkyLaneO]

maybe drill a hole in the shim where the stud hits it? that is probably what I would try.

[FB73tii]

maybe drill a hole in the shim where the stud hits it? that is probably what I would try.

 

I don't have a way to do that without destroying the shim. These are very thin metal that would just wrap around a drill bit. A punch would be best, but I would be worried that too little width would be left and the shim would break under vibration anyway. This is for a race engine. An alternative is to go dry sump, which I have already done for my other engine. But that's some $$$ and not allowed in some racing classes.

--FB

[jimk]

Trim the shim

+1 Trim

[c.d.iesel]

I have a dumb question:

isn't the oil pump shims sandwiched between the pump and the block ?

it's not going anywhere?

have another photo of what is imprinting that mark ?

[FB73tii]

CD--About an inch of the shim is captured between the oil pump and the block on each side. Take a close look at the upper right of the photo above, you can just make out the overlap region around the two holes. The rest of the shim, about four inches or so, just floats freely between the two suspension points, above the oil pan and roughly below the #1 main bearing cap. Not sure if it touches the stud or has a small air gap. Anyone running ARP main cap studs in an M10 would have this issue, I would think. --Fred

Edited October 16, 2013 by FB73tii

[Preyupy]

Yes Fred, every race engine with a wet sump and ARP studs I have built has this problem.  I just trim the shim and be very careful when I put the pump on to make sure it stays aligned correctly.  I have also installed the shim and pump then reached in with a very small pair of cutters and trimmed it in place. 

[M3M3M3]

trim or just drill a hole where the stud would be.

 

i had to trim the edge on those in my S14 to clear the oil pump chain.

[FB73tii]

Marshall--As said above, I don't know how to drill a hole big enough in metal that is only 0.1 mm thick . Close to trying to drill a hole in tinfoil. I'll just snip as suggested.  --Fred

[TobyB]

Sharp hole punch on a soft metal surface?

 

t

[M3M3M3]

Just sandwich it between two other pieces of thicker scrap metal, clamp together and drill away.  Ez to drill thin metal....

Edited October 16, 2013 by mlytle

[FunkyLaneO]

Just sandwich it between two other pieces of thicker scrap metal, clamp together and drill away.  Ez to drill thin metal....

^^ That is how I do it.

[FB73tii]

OK, perhaps I'll try the "sandwich method" on a spare shim that I have. Would be nice not to have to hand place the shim ends each time I R&R the oil pump. Now that only the thin shim is available I end up with a few to get the desired shim thickness. --FB