What is this?

[JBohannon]

At the bottom of the block about 2 or 3" directly above the oil pump I have a bolt. What is it and how tight should it be. Thanks. Joe B.

[JoeWay]

It should be a 1/8" pipe plug with a slot for a flat screwdriver. Put a thin layer of pipe dope on the plug. Use a regular screwdriver and snug it up pretty good. It doesn't need to be REALLY tight.

Joe

[pat in Santa Cruz]

assuming the threads are still as originally designed, Joe Way is right. I have seen cases where the threads were tapped out or even enlarged from 1/8th pipe thread to 1/4 or straight threads. This usually happens because someone erroneously thought the plug was a set screw for the oil pump or to plumb an oil filter. If this is the case, measures need to be taken to plug the hole, but not to allow the plug to contact the oil pump housing. Tightening a screw or plug against the housing can cause it to crack.

[JBohannon]

Thanks, It appears mine has been threaded to a 3/8 straight thread. I will put a short bolt with pipe dope I guess. Thanks.

[BILL WILLIAMSON]

In a pinch, run a 1/8 NPT die clear down on a 3/8" SAE bolt, & it'll screw nicely into the block hole without "buggering" up the threads. Bill W.

[Bob C]

Sponsored Links (Register now to hide all advertisements)

Why not just use the right 1/8" pipe plug, they are a little bigger than the 3/8" bolt.

Bob

[BILL WILLIAMSON]

Originally Posted by Bob C

Why not just use the right 1/8" pipe plug, they are a little bigger than the 3/8" bolt.

Bob

Sorry, Bob,
I didn't mean the bolt thing to plug the hole, the bolt thing was when you're in a pinch for a "tool" to lock the pump when droppin' the pan. Bill W.

[Bob C]

No problem Bill. I was just letting the OP know that the 1/8" pipe was larger than 3/8" bolt.

Bob