[RBAILEY]

I need to plug the water crossover/bypass in my timing cover as Im running KRE HP heads and don't have their new dropped crossover for the HP heads.

Mostly I have seen that most people are tapping for a pipe plug to acheive this.

I was wondering if anyone has tried drilling out for the nearest cup type plug ( like a 5/8 dia freeze plug) and plugging it that way.

[Probird]

I would just tap it. No chance of it leaking or coming out that way.

[tom s]

Tap it from the outside.Had a shop once do it on the inside and had to pull the water pump to get it out.Tom

[Half-Inch Stud]

Steel cupplug in a relatively shallow aluminum hole is dicey. Brass plug is slightly better and still dicey. Suppose a cupplug with a lip to positive-stop under pressure is good enough.


one time i used a nut and bolt sauced in rtv. It cleared the log and worked.
Later undid that in favor of a tapping and a plug.

That sort also had either no thermostat (most days it never warmed up !) , or a thermostat with a bypass hole(s). I forget how that played.

Noadays i keep the bypass active and use an unmodified 180 thermostat.

[lust4speed]

Not a fan of steel expansion plugs in aluminum if for no other reason than different expansion rates with temperature increase. Seems there would be a very high probability of the expansion plug being spit out. So easy to drill and tap for a standard 3/8" pipe plug -- and your choice of steel, brass, or aluminum.

[Tom Vaught]

Originally Posted by lust4speed

Not a fan of steel expansion plugs in aluminum if for no other reason than different expansion rates with temperature increase. Seems there would be a very high probability of the expansion plug being spit out. So easy to drill and tap for a standard 3/8" pipe plug -- and your choice of steel, brass, or aluminum.

X2

Tom V.

[b-man]

This 3/8 NPT plug has a 1/4” hole drilled in it to restrict the coolant flow but you get the idea.

[Probird]

Originally Posted by b-man

This 3/8 NPT plug has a 1/4” hole drilled in it to restrict the coolant flow but you get the idea.

He’s talking about the hole in the water crossover to intake

[Tom Vaught]

If the intake cross-over does not line up with the Timing Cover By-pass Hole the you may have to plug both pieces in the system: Timing Cover and Water Cross-over.

In that case you might have to plug both parts, as Bart showed (except without the
hole in the plug in the Timing cover).

Tom V.

[RBAILEY]

Thanks everyone., It sounds like the consensus is tapping for pipe plug. Problem for me is the hole is already to big for a 3/8 pipe plug tap. I'll let you know what I do. The next size up in pipe thread requires too big of a drill for any drill chuck that I have (1/2" chuck))

[b-man]

Originally Posted by RBAILEY

Thanks everyone., It sounds like the consensus is tapping for pipe plug. Problem for me is the hole is already to big for a 3/8 pipe plug tap. I'll let you know what I do. The next size up in pipe thread requires too big of a drill for any drill chuck that I have (1/2" chuck))

Erosion was the reason we put a drilled plug in my timing cover.

[lust4speed]

Originally Posted by RBAILEY

Thanks everyone., It sounds like the consensus is tapping for pipe plug. Problem for me is the hole is already to big for a 3/8 pipe plug tap. I'll let you know what I do. The next size up in pipe thread requires too big of a drill for any drill chuck that I have (1/2" chuck))

Doesn't help your problem, but I think you are looking at a 1/4" plug which is somewhat near a 3/8" diameter. The 3/8" plug is about 5/8" in diameter and does take a 37/64" drill bit. This is the same size plug adjacent to the distributor and also found in the rear of the block in the gallery passages. Might be worth your time to pick up a drill bit with a reduced shank or impose on a friend that can drill it out.

[RBAILEY]

Originally Posted by lust4speed

Doesn't help your problem, but I think you are looking at a 1/4" plug which is somewhat near a 3/8" diameter. The 3/8" plug is about 5/8" in diameter and does take a 37/64" drill bit. This is the same size plug adjacent to the distributor and also found in the rear of the block in the gallery passages. Might be worth your time to pick up a drill bit with a reduced shank or impose on a friend that can drill it out.

thanks. The hole is already larger than 37/64 @ 5/8

[RBAILEY]

Well I know the expansion plug idea got no votes but this is what I came up with. It's not a cup plug but it is of expansion design/function except it fits a whole lot tighter. Its thicker than any cup plug of that dia.

I used a tapered drift of the appropriate diameter to expand/stretch the diameter of the tube before installing it to create a very tight press fit in the 5/8 hole. I would say the 5/8 bore length was about .200

Note the copper cap-off nipple I used (dont know the correct name for it) is much thicker than typical 5/8 copper pipe.

We'll see and its something I'll keep an eye on until I can get one of those KRE dropped bypass crossovers for HPs. One thing for sure is pressure will not drive it out from the inside as the piece is like 1.250 long to the inside