SBC oil pump wobbles

[Callmewaylon]

Working on a 327. With the rear main cap torqued, the oil pump will wobble a tiny but when not bolted down. If I hold it down with my hand trying to apply equal pressure it still wobbles a bit. Both pump and cap are clean and I've tried several pumps. If I put the bolt in and start to tighten, no more wobble, but I'm thinking the main cap surface could be warped and cause an internal oil leak?

[BOOT]

A mirror or other flat surface and sand paper will flatten small stuff like that https://youtu.be/lp2AyejH2VU

[BOOT]

Also they make copper gaskets https://www.summitracing.com/parts/sum-111480

[Callmewaylon]

A mirror or other flat surface and sand paper will flatten small stuff like that https://youtu.be/lp2AyejH2VU

I thought about that, but I'm pretty sure it's on the main cap side so I'd have to be able to pull the stud the studs out. I think I'm overthinking and am just gonna send it.

[Tom68]

Working on a 327. With the rear main cap torqued, the oil pump will wobble a tiny but when not bolted down. If I hold it down with my hand trying to apply equal pressure it still wobbles a bit. Both pump and cap are clean and I've tried several pumps. If I put the bolt in and start to tighten, no more wobble, but I'm thinking the main cap surface could be warped and cause an internal oil leak?

Nicely caught, I use a smear of old school Hylomar brush on sealing compound on that connection. Pain to pull the cap and dowel to get it flat, but if you don't you'll always be thinking about it.

[Walter R. Malik]

There is probably something slightly amiss with the pump shaft or intermediate shaft.

[Tom68]

There is probably something slightly amiss with the pump shaft or intermediate shaft.

By wobble he means it rocks by hand on the main cap before pulling down.

[Walter R. Malik]

There is probably something slightly amiss with the pump shaft or intermediate shaft.

By wobble he means it rocks by hand on the main cap before pulling down.

OH ... I misunderstood.

[BillK]

I know you have probably already finished it up but I have had a couple that did the same thing and it turned out to be a slightly raised spot around each of the pins. You can barely hit the holes in the pump with a countersinking tool and then it sits flat.

[DCal]

Working on a 327. With the rear main cap torqued, the oil pump will wobble a tiny but when not bolted down. If I hold it down with my hand trying to apply equal pressure it still wobbles a bit. Both pump and cap are clean and I've tried several pumps. If I put the bolt in and start to tighten, no more wobble but I'm thinking the main cap surface could be warped and cause an internal oil leak?

This is a must fix in my opinion, oil pumps break occasionally from vibration so having it pulled down has to be putting an undue stress on the housing.
I've seen metal swell up around the dowels, you can check it with a machinist square or any rule that is flat .If the tool rocks or you can see daylight then relieve the pump hole with a round burr until it doesn't rock.