8BA block leaking water from exhaust port ?

[Vergil]

The casting is .330" thick where the black dot is right under the bolt head, uphill is a little thinner, downhill a little thicker. Picture is to be used and marked up any way one wants to.

Vergil

Vergil

[dono50]

Yes, someone drilled thru a broken head bolt into the water jacket.

[dono50]

The head bolt is bolt #1 on the head tightening sequence. On the passenger head it is located between and below the 2 temp. sensors.
Yes, the extra hole(holes} is on the far side of the exhaust port. It is a hole within a hole. Large hole is 7/32 diameter and the small hole( in the center of the large hole) is 9/64 in diameter and it's about 1/2 inch deep.
Someone drilled out a broken head bolt starting with a 9/64 drill then a 7/32 drill thru the broken stud into the water jacket.
Any repair has to be worked thru the 7/16 head bolt hole so it has its limits. I never used an NPT tap but might be the way to go, space permitting

[Marv]

If it were mine i would clean up the small holes with the correct size drill bits to get rid of rust. Then i would use a 1/16 " nickle 99 welding rod and weld the small hole up and leave the 7/16 hole alone.

[Henry Floored]

I had this happen to an 8BA I was rebuilding for a friend. I drilled and tapped a hole right through the crack. I screwed a bolt in there with sealer then had the block decked a little. I was going to do that anyway. The trick was to place the hole (fairly large, 7/16 SAE if I recall correctly) so that it intersected the headbolt hole. That eliminates the crack. Of course I had to drill and retap the headbolt hole as well. Simple stuff really. Don't forget to get some Moroso ceramic block sealer and follow the instructions. It works wonders. Send me a PM and I'll give you my ph.# if you want to talk.

[Bluebell]

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If the hole is smaller than the stud hole and directly in line. Then what about selecting a suitable type of tap. ( assuming you can get in there)
Run a tapered thread onto a suitable steel rod, and wind it in (with a sealing compound) tightening it from the out side. then grind the stem in the port, away with a die grinder.(assuming you can get in there) (pulling the off cut out to refit the head stud)
If it is not central to the stud hole, can you make up a pilot that sits in the head stud thread?
You might have to weld a stem on your tap (nice and straight) Don't tap in too far, so that the taper is in the tapped hole.
Just trying to come up with helpful suggestions.

[trainguy]

Working thru the 7/16 thd hole I would drill the 9/64 holt with a #21 drill[.159] and tap with a #10-32 tap.I would the dip a # 10 machine screw in green locktite and screw it into the taped hole, cut the excess of in the ex port and grind flush.

[Mart]

Looking at the sizes, here's what I'd do. (very similar to above.)

Either drill out to the tapping size and fit a 1/8 npt taper plug,

See what grubscrews are available locally, say 1/4 UNC or 1/4 UNF and drill with the appropriate tapping drill not quite through. Then tap almost all the way through, and put a grub screw in the hole with plenty of sealant.

I think the term grubscrew might be a UK term, it's a headless screw with a pointed end, normally with a hex socket in the end so you can wind it in place with an allen key.

Run some sort of sealer in the block as a precaution and you should be good to go.

The npt plug would probably be best, but would probably mean the head stud thread would end up oversize and would have to be repaired with a helicoil.

I think the fix should be quite simple.

Mart.

[dono50]

I believe 1/16 NPT plugs with allen heads are available. If the depth of the hole is only about 1/4 inch deep might be tough to get enough thread. I never used NPT but willing to try if guys with expertise in this area think it's possible.

[Mike51Merc]

I guess the lesson learned here is knowing the bolt length before drilling it out. That guy went way too deep on that one.

Look at www.locknstitch.com and/or www.irontite.com

What about silver solder or brazing?

[rotorwrench]

The only draw back on NPT is that they are better done if a person has access to some tapered reamers of the correct size. Cast iron is brittle and a straight hole will cause a heck of a bite with a tapered tap. To install tapered plugs is more dificult that say a grub screw (or set screw here in the US) with some high temp pipe sealant or thread locker.

[Russ/40]

I may have missed the statement, but I will assume the hole into the jacket is note tapped. I would use a pipe tap to give the hole a tapered thread. Then take a bolt of the same size and thread count as the pipe thread. On that bolt, put it in a lathe and at 1/4" from the end, cut the shank down to minimal diameter. The concept is to create a breakaway bolt that will fill the hole, and as it tightens will shear leaving the plug in place. Use loctite on critical section. Experiment in determining the necessary diameter cut to allow the shear, on some 1/2" flat stock.

[Mike51Merc]

Originally Posted by Russ/40

I may have missed the statement, but I will assume the hole into the jacket is note tapped. I would use a pipe tap to give the hole a tapered thread. Then take a bolt of the same size and thread count as the pipe thread. On that bolt, put it in a lathe and at 1/4" from the end, cut the shank down to minimal diameter. The concept is to create a breakaway bolt that will fill the hole, and as it tightens will shear leaving the plug in place. Use loctite on critical section. Experiment in determining the necessary diameter cut to allow the shear, on some 1/2" flat stock.

It sounds (and looks) like he can get a saw blade or a dremel in there to cut off the excess.

[Fe26]

Originally Posted by Russ/40

I may have missed the statement, but I will assume the hole into the jacket is note tapped. I would use a pipe tap to give the hole a tapered thread. Then take a bolt of the same size and thread count as the pipe thread. On that bolt, put it in a lathe and at 1/4" from the end, cut the shank down to minimal diameter. The concept is to create a breakaway bolt that will fill the hole, and as it tightens will shear leaving the plug in place. Use loctite on critical section. Experiment in determining the necessary diameter cut to allow the shear, on some 1/2" flat stock.

A simple and elegant solution.

[dono50]

MY neighbor suggested a pin with an interference fit and locktite for the small hole.
Any comments ? I pretty much ruled out the NPT because I don't feel I have the expertise

[Jack E/NJ]

I guess I'm still not quite sure of what you're trying to deal with. But a self-tapping screw with a bunch of sealer still seems like it oughta work with minimal fuss.

Jack E/NJ

[Bluebell]

Dono50, Do you think you can get in there with a die grinder and smooth out a plug?
I'd be trying to keep the hole as small as I could. I suggested a taper tap, so that the insert bites when it's nearly home. You can run a thread on a piece of rod and cut it to suit, so that it goes tight on the taper at the end of the thread.
Any how, good luck with what ever you decide.

[Russ/40]

Originally Posted by dono50

MY neighbor suggested a pin with an interference fit and locktite for the small hole.
Any comments ? I pretty much ruled out the NPT because I don't feel I have the expertise

Since your exposing whatever you do to the environment of the exhaust gasses, your seal must be to pretty tight tolerances, or any sealer you use will burn away, and your back to a leak. The pin idea can work, if it will stay put. That's what is compelling about tapping the hole.

As to my solution posted above, if you don't have the lathe, you could pull it off with a drill press and a good corner file.

[dono50]

Bluebell,no, can't use a die grinder. Working thru a 7/16 head bolt hole.
My friend has a lathe and will try and make a tapered pin. Got to decide whether to use steel or brass?
After I pin it I'm planning to use Gosfast 2 piece head bolt to seal off the repaired area but will use a stud instead of a headbolt. I think it's worth a try.
Thanks to all for the great ideas. Will tackle the job in a few weeks and keep FB advised of the outcome

[dono50]

One other question....Is the Moroso ceramic block sealer a liquid that will flow or the consistency of epoxy?