water seapage around head bolts

[Mike Wythe]

I have an atomic 4 gas engine in a cal 29 which was built in 1972.
I rebuilt the engine around 8 years ago, and since then is running like a Swiss watch.
Around 6 months ago I noticed a small amount of water seapage coming out around the 2 head bolts that hold the alternator mounting bracket(it could be one, or both head bolts).
There is no water in the oil, and the compression is right where it should be.
The engine runs so good that I can't believe there is anything major wrong.
My plan is to pull the head thinking that mabye there is a crack in the head gasket allowing water leakage from a water jacket, replacing the 2 head bolts in question, and having the head magnafluxed for any possible cracks.
My question is on the 2 head bolts. Are these bolts tapped into a water jacket? If so, this could be the source of the water problem.
If they are tapped into a water jacket what concerns should I take in replacing these head bolts?
Am I on the right track, or do you have reason to believe there could be another source for the water leakage?

Thank you,
Mike

[Don Moyer]

Mike,

Those head studs do indeed go into the water jacket, and your symptoms usually point to nothing more serious than leaky lower threads of the studs. You might be able to seal the studs by simply pouring some Permatex Aviation Brand sealer between the head and the stud and under the nut. In worst cases it may be necessary to remove the studs and reseal the lower threads. If you have a stud remover that grips the top of the stud, there is no reason to actually remove the head, which saves a lot of time and hassle.

Don

[Mike Wythe]

Thanks Don,

In anticipation of the problem, I did remove the head, and yes, the outboard bolt is extremely rusted. The inboard bolt looks fine and probably won't replace that one.
When replacing with a new bolt, what do you recommend? I was thinking about some type of sealing agent on the threads(permatex has quite a variety of products). Or would you insert flat out with no sealing agent?

One more if I may.
I removed the exhaust manifold to adjust the valves, and noticed signs of exhaust blow by(on the back side of the engine). When cleaning the flanges which join the engine block, they exibit some deteriation on the faces. When re-assembling, should I consider adding a high temp. sealant(if there is one)along with the new gasket, put on flat out, or consider replacing the manifold?

Thanks again,
Mike

[Don Moyer]

Mike,

You keep referring to the head studs as bolts. I hope this is simply a rhetorical oversight on your part because it is NOT a good idea to use bolts in place of studs.

To seal troublesome studs in the block, we usually go straight to JB Weld. This product seems to work both as a sealer and it also tends to strengthen the area a bit in the case of problematic threads in the block.

We also use JB Weld at times when a gasketed area is potted or otherwise not smooth.

Don

[John McMonagle]

I'm looking into purchasing a 71 Tartan 30 with raw water cooled A4
Engine stated immediately after sitting much of a year.
Runs nice, sounds great.

The surveyor ran it for a while in gear at the dock.
After it got up to temperature water started flowing out one of the studs that hold the alternator mounting bracket, just like described at the beginning of this thread other than the flow may be more.

Still ran fine.

No water in oil.

Am I likely to get away with Don's initial suggestion of pouring some Permatex Aviation Brand sealer between the head and the stud and under the nut?

A consideration is that I want to run it 100 miles asap.
If I need to pay the marina a lot to get the engine working the deal starts looking worse :-(

John McMonagle

[CalebD]

John,

Welcome to the Afourium.

Can't promise you any guarantees.
We had this same symptom last season - small amount of water near the alternator mounting studs. This had probably happened a few times before but we did not notice it. The engine ran pretty well until we developed what ended up being a compromised head gasket. We lost compression in 2 cylinders.
The fix for us seemed to be replacing the head gaskets which was not so difficult. To do the job you need the head gaskets from Moyer, a decent socket wrench set, a torque wrench & the Permatex goop. You also need some time as well as reasonable access to your A4's head.
However I'd try what our Guru, Don Moyer recommended above first. I did not have the stud removal tool and we knew that our head gasket had a problem when we lost compression in cylinders #3&4 so I didn't try Don's advice.

Anytime you have to pay a marine mechanic to work on your engine it is not going to be cheap, easy or quick. Most of us here do as much work on our engines as we possibly can. What we don't know how to do we learn from those who do know. This makes owning an Atomic 4 a lot cheaper but also teaches us as owners how to repair this old engine in a pinch.

The T30 is a nice boat. Good luck with it. Your engine and this forum will teach you how to care for it.

[John McMonagle]

As I did not own the boat yet I asked the marina to give me an estimate.
Fred the mechanic decided it was less work to fix then do an estimate :-)
He pull the stud and sealed it.
All good now :-)

I bought the Tartan 30 and working to get it ready for the trip home.

I was really pleased with the Manitowoc Marina.
They have been very helpful even though they didn’t make a lot off of me.

John