BBC "undercut" oil pump drive shaft
 

For a special application I need a BBC oil pump driveshaft that is turn down where it passes the oil pump body.

It is common to find the undercut shaft for a SBC but I am not finding one for a BBC.

Any ideas?

Re: BBC "undercut" oil pump drive shaft
 

Lathe.

Re: BBC "undercut" oil pump drive shaft
 

Dwight,

The question has been raised about what affect cutting the shaft will have on heat treatment.

As we understand, modifying an oil pump driveshaft is not to be taken lightly considering the potential consequences.

Any thoughts about the heat treat issue.

Re: BBC "undercut" oil pump drive shaft
 

Treat it again. If it is only surface treated (so you would machine the hardened surface away), then heat it up until it is red with a torch and dip it in a bucket of old engine oil. Otherwise, buy a shaft that is higher quality steel to start with. The original OEM shafts that were necked down were for the 400. I believe they used 1040 alloy rod that was quenched and then austempered, which would harden the material all the way through. Simple process if you feel it is worth it. Personally, I would not be concerned with the strength after machining.

Re: BBC "undercut" oil pump drive shaft
 

How much material must be removed?

Re: BBC "undercut" oil pump drive shaft
 

I am mocking this up again for another look and will post some photos soon.

Re: BBC "undercut" oil pump drive shaft
 

as Paul Harvey said, "now, the rest of the story"

In hindsight, I did not have a problem. The block is a Brodix SBC with raised deck and raised cam. Because of the raised cam, Brodix has it worked out to install a .350" thick spacer between the rear main cap and oil pump then drive it with a BBC driveshaft.

My perceived problem was because when mocking up and checking on the bench I used a rear main cap from a factory SBC block. At first, I did not realize Brodix had made allowances and everything was already as needed.

The oil pan was just hang on the Brodix block for protection and it came to me in a vision to actually check the block and cap that goes with the buildup :) !

Once I slipped the pan off I immediately realized the Brodix rear main cap driveshaft hole was about .250" larger than a factory cap.

Re: BBC "undercut" oil pump drive shaft
 

FYI, the new Melling Shark Tooth oil pump.

Also, it always interest me to see things in a view not usually seen. Note the oil pump and driveshaft angle.