Bayrunner":3ttx2n97 said:
Please remember that pipe threads are different from machinist threads.
To prevent seapage, use pipe thread tap and get a 1/4 pipe plug from a decent hardware supply store. I actually went to Eastern Steel Fasteners and for .40cents picked up a stainles plug which has an allen recess head on it.
Cheers
Bayrunner correct me if i'm wrong.
I measured a spare block oil supply to the rocker arms on the block deck & it is close to .312-5/16"
The drill size for a 3/8-16 tap is .312"
The drill size for a 1/8" pipe tap is 11/32 or .343" thus you would have to drill the .312" to .343" for a 1/8" pipe plug.
If you use a 1/4" pipe plug the drill size to tap is 7/16"
Why would you want to drill an existing .312" hole to 7/16" to use a 1/4" pipe plug????
The 1/8" pipe plug still requires you drill the block to .343" to tap, thus creating more metal chips.
I agree the pipe plug would provide a better seal, but at the expense of more metal chips to cleanup.
I would not run the risk of enlarging a passage unless there is plenty of room before hitting the coolant area.
If properly sealed i see no reason to drill the block for the 1/8" pipe plug vs the 3/8-16" set screw. Falcon Man