Oil Pump Question (Small Block)

[cwestra]

When installing the oil pump in my 340 I noticed a gap between the main cap and pump interface.  It appears to be bottoming out at the drive post area.  Is this right?  Are there gaskets that go here?  I didn't recall having any when I removed it?

[426HEMI]

Yes there is a gasket that goes there. 

[cwestra]

Yes there is a gasket that goes there.

Thanks, found it.  Who would have guessed it was in the box (lol).  Still looks too thin to make up the gap difference though.  Is is supposed to be like that?

[72cudamaan]

Yep, needs the gasket, and no ther should be no gap ( big pressure leak).

[cwestra]

Taking a closer look at it, it appears that the new pump drive bushing installed my my machine shop is preventing the pump from seating.  It looks like the bushing is extending down a little too far.  Has anyone seen this before?

[72cudamaan]

Are you sure that a tap or 2 with a mallet wont seat that pump.  Looks like a tight fit.

[moper]

The pump should never be hit. You want to make sure the gasket surface is flush with the main cap. If there is a minor amount of machined area visible on the drive section I wouldnt worry. So long as the gasket surface comes together right. It isnt a pres fit there. Just a passage the oil pump passes thru.

[dodge freak 2]

Instead of striking the pump body--which might be fine to do--I would bolt the pump on without the gasket to see if you can easily get rid of that space. The brushing might easily move up a bit then with the gasket install there be aslight space in between the pump shaft and the brushing.

If it does not move easily you could break the pump and or main cap..I say no more than 15 lbs of torque I would push on the bolts. I would then take the block back to the shop. 

[72cudamaan]

Oh moper, notice I didn't say hit the pump. I said Tap WITH A MALLET. Obviously hitting it with a hammer could crack the ear.

[cwestra]

Drawing it down with the bolts does appear to close the gap up uniformly across the surface (w/o gasket).  I used my old pump just in case.  When I remove the pump the gap comes back so the interference area is flexing elastically, not plastically.  Hopefully this wont be an issue.  I am confident I'll have a good seal between the pump and main cap.  Thanks for all the help.

[moper]

Oh moper, notice I didn't say hit the pump. I said Tap WITH A MALLET. Obviously hitting it with a hammer could crack the ear.

It's only cast iron. Dropping it on concrete can be enough to render it inoperable. This does not require force of any kind (including pulling the pump down with the bolts) if everything is kosher. You set it in the hole for the drive and lower it onto the main cap where with no effort but your hand it should sit flat. Then start the bolts by hand. Things like dampners, piston/rod assemblies, setting thrust bearings... They all will take more... persuasion.  Not installing the oil pump.