8BA block leaking water from exhaust port ?

[dono50]

Gary,
My neighbor mad a plug that is very similar to your first suggestion. It threads into the head bolt hole and has a rounded plug end that rest on top of the hole.It leaves plenty of thread to insert a head stud. Same procedure that you used to fix a crack.
Will try and post a photo....Bob

[dono50]

Can't get a photo to post. If you want a photo send me your email address. My email is [email protected]

[Mike B]

Originally Posted by dono50

Can't get a photo to post. I[/EMAIL]

If you'd like, email a photo to me, and I will post it for you.

But all you have to do is look below your "post box"
and find the button "manage attachments"

Then "browse" on your computer to locate the pic (s) you want to post

Select Upload"

Then "submit reply"

[GOSFAST]

Originally Posted by dono50

Gary,
My neighbor mad a plug that is very similar to your first suggestion. It threads into the head bolt hole and has a rounded plug end that rest on top of the hole.It leaves plenty of thread to insert a head stud. Same procedure that you used to fix a crack.
Will try and post a photo....Bob

Hi Bob, at this point with all the info here I would be hesitant to try that fix. I assume your planning on that "plug" to simply have enough pressure on it to "seal" the hole??

I would say in that area you will see some very high temps, 1200+, and things will really be moving around.

The last method I mentioned I feel most comfortable doing (at home), drilling through the head bolt hole and lower hole and tapping it 7/16"-14 for the stud or short set-screw. This method puts the fastener directly in the bad hole and really has little chance of leaking regardless of the exhaust temps. A set screw would also eliminate the stud hanging in the exhaust passage.

I would attempt to stop the tap short in the bottom hole and have an inteference fit with the 7/16" threads.

Thanks, Gary in N.Y.

P.S. The nice part about tapping directly through the head bolt hole, using it as the tap guide, is the hole will be consistent all the way through. It will be an "uninterupted" thread across the exhaust passage. Again, Good Luck!

[Mike B]

Here's Bob's pics:
(kindy fuzzy)

[Russ/40]

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I don't understand how your going to implement that.

[dono50]

Originally Posted by Russ/40

I don't understand how your going to implement that.

The threaded end of the plug has a slot for a screw driver. It is installed first and the bullet shaped end rest against the 7/32 hole and seals it off.
The head stud is then installed and butts against the plug. There is enough threaded area to accept the plug and the head stud.

[dono50]

Originally Posted by GOSFAST

Hi Bob, at this point with all the info here I would be hesitant to try that fix. I assume your planning on that "plug" to simply have enough pressure on it to "seal" the hole??

I would say in that area you will see some very high temps, 1200+, and things will really be moving around.

The last method I mentioned I feel most comfortable doing (at home), drilling through the head bolt hole and lower hole and tapping it 7/16"-14 for the stud or short set-screw. This method puts the fastener directly in the bad hole and really has little chance of leaking regardless of the exhaust temps. A set screw would also eliminate the stud hanging in the exhaust passage.

I would attempt to stop the tap short in the bottom hole and have an inteference fit with the 7/16" threads.

Thanks, Gary in N.Y.

P.S. The nice part about tapping directly through the head bolt hole, using it as the tap guide, is the hole will be consistent all the way through. It will be an "uninterupted" thread across the exhaust passage. Again, Good Luck!

Gary,
If I understand correctly, I would not disturb the existing threads in the block. I would enlarge the hole in the exhaust passage with the appropriate drill size and run the tap thru the head bolt hole across the exhaust passage. If the hole is not dead center would I run the risk of breaking the tap?
Please explain how I get an interference fit.(not drilling completely through?)
I ordered a 1/16 NPT tap and plugs. I know it's the best solution if I am able to do it.
I also was thinking of tapping the small hole and using a 10-24 set screw in conjuction with the plug for the larger hole. Do you think that will work?
Bob

[GOSFAST]

Originally Posted by dono50

Gary,
If I understand correctly, I would not disturb the existing threads in the block. I would enlarge the hole in the exhaust passage with the appropriate drill size and run the tap thru the head bolt hole across the exhaust passage. If the hole is not dead center would I run the risk of breaking the tap?
Please explain how I get an interference fit.(not drilling completely through?)
I ordered a 1/16 NPT tap and plugs. I know it's the best solution if I am able to do it.
I also was thinking of tapping the small hole and using a 10-24 set screw in conjuction with the plug for the larger hole. Do you think that will work?
Bob

Hi Bob, this is an important step here. If you try the 1/16" pipe tap option first, with the 1/4" pilot hole, and for any reason it fails, short of breaking the tap in the bottom hole, you still have the 7/16"-14 bolt thread repair option. This is good. When you drill the 1/4" hole for the pipe tap you will see immediatley how the bottom hole looks. If it's not a "clean, solid, straight hole" I would not attempt this method. If the hole isn't "clean" it will make tapping new threads very difficult. It isn't mandatory to use a tapered reamer for the pipe tap, it will be fine, especially with the .250" hole.

I would also still recommend using that bushing, setting in the original head bolt hole I showed earlier, to drill the 1/4" pilot hole for the 1/16" pipe tap.

If this method fails due to the lower hole location/shape, just go to plan "B", the 7/16"-14 repair.

I'm sure hoping Vergil's measurements are "on-the-money" about the wall thicknesses?? If you have .330" (nominal) you will be good to go. The pipe plugs will be .300" long and fit nicely in the thickness of the casting if tapped to the correct depth! For this reason the pipe tap would be the better choice having more threads available, with the 7/16"-14 there would be limited threads. I believe it would still work but the smaller pipe thread would be better under these conditions. And now the entire repair is totally isolated, also very good.

As I stated earlier in the thread, I'm against using any smaller conventional machine thread (10-24, 12-24, etc.) tap sizes, these are very easily broken. Working "blind" at that depth through the OEM head bolt hole just raises the risks that much higher.

Also need to remember, the "driver" for the pipe tap will be very close to deck surface when the depth is reached for the plug??

Thanks, Gary in N.Y.

P.S. Just a couple tips for any hand tapping. First, when using the smaller pipe tap, go about an 1/8 of a turn at a time and back the tap up, go another 1/8 and back it up again. Stay with this procedure until the correct depth is reached for the pipe plug, this will help clear the chips and avoid breaking the tap, and second, cast iron gets tapped dry, no lubricant. Also, there appears to be some high nickel in these castings, this will have an effect on how the tapping "feels" when cutting threads. Just be careful!

[dono50]

Today, with following tools I repaired the hole in exhaust port/water jacket.
I used the method that Gosfast recommended and it worked out well.
Drilled the hole to 1/4 inch, tapped with a 1/16-27 NPT tap and used a 1/16 NPT plug with an allen wrench head.
Instead of sealer I used JB weld on the threads/hole and tightened the plug flush with the surface.
I used the 1/16 plug because all the work was performed thru the 7/16 head bolt hole with little clearance to spare.
Thanks to all that offered advice.This was a unique problem and the fix saved another flathead.

[Mart]

That's great - well done.

Mart.

[BILL WZOREK]

This has been a intresting thread / it shows what can be done / 1 Question with many answers.
With the care taker of another Flathead being able to pick & choose the best solution
For his ( OR HER ) Problem.

[GOSFAST]

Originally Posted by dono50

Today, with following tools I repaired the hole in exhaust port/water jacket.
I used the method that Gosfast recommended and it worked out well.
Drilled the hole to 1/4 inch, tapped with a 1/16-27 NPT tap and used a 1/16 NPT plug with an allen wrench head.
Instead of sealer I used JB weld on the threads/hole and tightened the plug flush with the surface.
I used the 1/16 plug because all the work was performed thru the 7/16 head bolt hole with little clearance to spare.
Thanks to all that offered advice.This was a unique problem and the fix saved another flathead.

Hi Bob, nice going, really.

After following you here, I knew you were capable and would get it fixed! There was never any doubt in my mind.

(Add) This post raises an extremely important point when beginning a build with an "unknown" block (or even a known one) with respect to magnafluxing vs. pressure testing. "Magging" this block alone would have NEVER revealed this issue, I realize it's an "odd" one, but it does raise a point. It would have "passed" fluxing but would certainly NOT have "passed' the pressure test. Don't let anyone try to convince you otherwise. To do both is OK, but the pressure test is "mandatory".

Thanks, Gary in N.Y.

P.S. You'll end up sleeping a lot better now! Enjoy the ride.

[john in illinois]

Dono glad you got it fixed. Very interesting thread.

John

[zzlegend]

Great. Good going dono. Glad it turned out. I have an 8BA sitting on an engine stand that I am going to get to one day. This will be one thing to remember when rebuilding gets closer. Mark.

[Russ/40]

Originally Posted by GOSFAST

(Add) This post raises an extremely important point when beginning a build with an "unknown" block (or even a known one) with respect to magnafluxing vs. pressure testing. "Magging" this block alone would have NEVER revealed this issue, I realize it's an "odd" one, but it does raise a point. It would have "passed" fluxing but would certainly NOT have "passed' the pressure test. Don't let anyone try to convince you otherwise. To do both is OK, but the pressure test is "mandatory".

Thanks, Gary in N.Y.

P.S. You'll end up sleeping a lot better now! Enjoy the ride.

I'll second that. I have an example on my run in stand. Passed mag, but later found a crack in the roof of the intake runner just below the valve. Block was never pressure tested.

[Russ/40]

Originally Posted by dono50

Today, with following tools I repaired the hole in exhaust port/water jacket.
I used the method that Gosfast recommended and it worked out well.
Drilled the hole to 1/4 inch, tapped with a 1/16-27 NPT tap and used a 1/16 NPT plug with an allen wrench head.
Instead of sealer I used JB weld on the threads/hole and tightened the plug flush with the surface.
I used the 1/16 plug because all the work was performed thru the 7/16 head bolt hole with little clearance to spare.
Thanks to all that offered advice.This was a unique problem and the fix saved another flathead.

Congratulations man! That is great. This has been very educational and interesting.

[El Rat]

It really is a simple fix. Since you seem to be reluctant to use a pipe tap ask a friend who may have some experience, or go to a local machine shop and ask to have someone come over after work and assist. Maybe it costs you 50.00 + parts but it won't take long. Need a 1/16 npt "tap" and an extension. Drill the hole to the correct size (easy to find that number). Screw an aftermarket 1/16" pipe plug (allen head) into the newly tapped hole with Permatex! Piece of cake...

[woodypecker]

Thanks to all for the education. I enjoyed reading every post. Most os all I am glad the block was saved.

[zzlegend]

dono50. Just curious if you are back up and running?