Terrible drawback in my 454 project. As I was ready to assemble the oil pump to the rear main cap I noticed that the stud would not screw in all the way, hand turning it would just go in about two threads. Then I noticed a crack around the thread hole. It looks like a casting flaw or someone getting happy with the torque wrench at one point or another. The cap is no good!
Now my concern is if get a new main cap could I just take the old one out and torque it in or am I going to have to disassemble all the main caps and retorque everything even?
Im just concern that taking the old cap out might mess with the loading on the rest of the crankshaft.
Please any help would be appreciated, yeah Im new at this.

Thanks

Renzo

Originally posted by chevyguy8:
Terrible drawback in my 454 project. As I was ready to assemble the oil pump to the rear main cap I noticed that the stud would not screw in all the way, hand turning it would just go in about two threads. Then I noticed a crack around the thread hole. It looks like a casting flaw or someone getting happy with the torque wrench at one point or another. The cap is no good!
Now my concern is if get a new main cap could I just take the old one out and torque it in or am I going to have to disassemble all the main caps and retorque everything even?
Im just concern that taking the old cap out might mess with the loading on the rest of the crankshaft.
Please any help would be appreciated, yeah Im new at this.

Thanks

Renzo =
=
Renzo,
Is the crack just on the top couple of threads or down the side?
If it is the first couple of threads you can take the cap off & remove the cracked part & there will be plenty of threads left for a stud.
If it is cracked down the side of the threads you have a big problem :(
Changing the rear cap involves fitting a new one & having the rear cap line bored to match the block which can be done by a good machine shop. I have done it but is not a real simple deal.

I had the same problem on my SB. After removing the broken up pieces, the threads were just about even with the bottom of the cavity. I had a timecert installed and used a stud for mounting the pump. Make sure the stud/bolt (or timecert/helicoil) does not go through the other side and that there are no burrs or raised spots on the bearing support surface. My engine has been running for over 2 years, now, with no problems. It is a strip engine that sees 7000 a couple times on each pass. Much cheaper than replacing the rear main cap.

Thanks guys for your help. The crack is along(parallel) to the threads and it only lifted two of them. So I'm going to try your suggestions before I go and take everything apart.

Thanks again for your help. Im a bit relieved for now. graemlins/beers.gif

Renzo graemlins/thumbsup.gif