Thread sizes for the bolt holes for water pump on SBO?

[Minion1186]

Does anyone know off hand what the thread sizes on the oldsmobile blocks are? specifically the bolt holes holding the timing chain cover/water pump to the block. Someone before me decided to strip the cast iron threads in the block before I bought it, now the water pump leaks everywhere.

 

[Tank]

Well if they are stripped then what good does the thread size do? Just take a tap and die set and make them whatever thread size you want that works for you.

But for informational purposes: what year is the SBO block? that would determine Metric or Standard thread. Assuming it is Standard or SAE and if I remember correctly they should be one of the following:
( If it requires a 1/2 socket for the head of the bolt) then it is a 7/16-14 thread.
(9/16 Socket for the head of the bolt) then it is a 1/2-13 thread.

 

[FE3X CLONE]

All typical Olds blocks have SAE thread sizes for bolt holes going into things like the block or heads.

There are pretty much three sizes used on an Olds engine.

The lower timing cover bolt holes that go through the timing cover only are 3/8-16.

The (4) bolts that hold the water pump on around the water ports are 5/16-18

The smaller holes that go through the water pump and into the timing cover only are 1/4-20

A few other thread sizes:

Intake bolts into head: 3/8-16
Exhaust bolts into head: 3/8-16
Motor mount bolts into block: 7/16-14
Thermostat housing to intake: 5/16-18
Carb to intake bolts: 5/16-18
Accessory bolt holes on face of head: 3/8-16

Now things like the balancer pulley holes, water pump pulley holes, alternator to alternator bracket mounting holes/bolts, etc. could be metric bolts/studs depending on year.

As far as fixing it, I would use a helicoil so that you can keep the hole the same size as it was. That way you don't end up needing 2 different size bolts to hold something that originally only required one size.

 

[FE3X CLONE]

( If it requires a 1/2 socket for the head of the bolt) then it is a 7/16-14 thread.
(9/16 Socket for the head of the bolt) then it is a 1/2-13 thread.

Most of the SAE bolts I've dealt with take a socket as below:

1/4-20 would be a 7/16" socket.

5/16-18 would be a 1/2" socket

3/8-16 would be a 9/16" socket

7/16-14 would be a 5/8" socket

1/2-13 would be something like a 11/16" or 3/4" socket.

 

[Minion1186]

thanks