BBC "undercut" oil pump drive shaft

Dragsinger · 02-01-2016, 11:28 PM

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?

Dwight Southerland · 02-02-2016, 08:57 AM

Lathe.

Dragsinger · 02-02-2016, 10:40 AM

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.

Dwight Southerland · 02-02-2016, 01:51 PM

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.

Dan Timberlake · 02-02-2016, 02:55 PM

How much material must be removed?

Dragsinger · 02-02-2016, 04:02 PM

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

02-01-2016, 11:28 PM	#1
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,759 Likes: 5 Liked 99 Times in 60 Posts	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? __________________ Larry Woodfin 471W

02-02-2016, 08:57 AM	#2
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 1,980 Likes: 53 Liked 724 Times in 177 Posts	Re: BBC "undercut" oil pump drive shaft Lathe. __________________

02-02-2016, 10:40 AM	#3
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,759 Likes: 5 Liked 99 Times in 60 Posts	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. __________________ Larry Woodfin 471W

02-02-2016, 01:51 PM	#4
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 1,980 Likes: 53 Liked 724 Times in 177 Posts	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. __________________

02-02-2016, 02:55 PM	#5
Dan Timberlake Junior Member Join Date: Oct 2015 Posts: 6 Likes: 0 Liked 0 Times in 0 Posts	Re: BBC "undercut" oil pump drive shaft How much material must be removed?

02-02-2016, 04:02 PM	#6
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,759 Likes: 5 Liked 99 Times in 60 Posts	Re: BBC "undercut" oil pump drive shaft I am mocking this up again for another look and will post some photos soon. __________________ Larry Woodfin 471W