[mikemustang289]

What size tap is needed to tap the oil dipstick hole in a roller 5.0 block. I am sticking with an early timing chain and need to fill the hole somehow.

 

[ujt389]

I just put in a wooden dowl with some silicone to help seal it.

 

[71hotrodpinto]

id say do it right and use a 1/8 NPT tap and then a 1/8npt plug.
Then use some teflon tape on it. A wooden dowel might last forever or it might last a week. Then its in the car and you cant get to it seal it up.
A $12 for a tap and some searching for the plug is worth the peice of mind for me.

 

[mikemustang289]

I can borrow a tap from work and get a plug at the hardware store, just needed to know the size. thanks!

 

[FEandGoingBroke]

about 5/16" to 3/8" isn't it? Somewhere in there... not many dip stick I've seen are much smaller or bigger....

FE

 

[71hotrodpinto]

1/8 npt ( national pipe standard) is not 1/8 of an inch in actuall diameter.

 

[mavman]

Nope...the minor diameter of the thread is close to 7/16, IIRC.

 

[pbrown]

My new replacement timing cover came with a press in plug for the dipstick hole. I used it to plug the block dipstick hole.