Head bolt water leak

[kenj]

Hi All:

First, to quote Homer Simpson (yet again!): WOO HOOOO!!!

I fired up my Flathead 6 for the first time ever (didn't run when I bought it) this morning! It actually fired up with little trouble, tho' I did cheat and use a little ether starting fluid, and the gas came out of a can instead of the fuel tank.

But it has two problems:

1) The #4 head bolt (as shown in the standard tightening sequence diagram) had a little water squirting from the split at the lock washer. After the block cooled, I drained it and removed the bolt- it is one of the ones which goes down into the water jacket. So my thought is that it just needs a better application of some kind of sealant on the bolt threads. Any thoughts on this?? Anyone?

2) It misses and backfires fairly badly at idle. I have tried adjusting the distributor (without a timing light), but the problem persists, although quite less. Again, any thoughts?

I suppose lastly this is an operator problem, but the manual says to retighten the head bolts when the engine is hot, but when I set my torque wrench to 70 ft-lbs and tried to do this, both bolts I tried turned about another full turn without offering any more resistance, and the second one actually felt like the bolt was going to break off or strip out. For the record, this block was nearly fully re-machined and all the head bolt holes were chased with a new tap; also, all the bolts are new.

I know this is a lot, and I haven't been able to contribute much to this forum, but any thoughts or related experience I will sincerely appreciate!

Thanks!

[Guest]

Hi Kenji, re machined heads can be a bit loose on the thread, try another bolt in the leack and some thread seal fluid, torque down in 10lb intervals, check you haven't nipped the head gasket. Backfire, what state is carb in? and timing without a light is possible, do a full static time and check the distributor has gone back the right way, they can be put in backwards.

A little spark gap that fits on the plug top is a useful tool and check the mix. If you can get a mobile tuner to the vehicle they could give you a lot of useful help straight away. You say the head has been re done what is the lower end and the rest of it like?

[Tony B]

Sorry Kenji, last post was by me. the site decided I had better log in again
Having a re- read what do you mean by "Nearly all re machined"?

[RANGER]

Blocks that have holes that thread into the water jacket are normally sealed with Permatex 3. It is still available and popular. During the War it was sometimes refered to Aviation cement, and there were three grades, the first two were in tubes and were #1, Hardening, #2, Non Hardening. #3 was the liquid that came in a can with a brush applicator fixed to the lid. It still is the best to use to seal threads which penetrate the water jacket. The Loc-Tites and Silicones do not do the job as well.
You mentioned "split lockwasher". Lockwashers of any type are a "No No" on cylinder head bolts or studs.

Check your TMs and Parts Manual and you will also see that no lockwashers are mentioned or shown in the photos.

[Tony B]

PS Ranger, stupid question, (and I may be sorry I asked) what is a "Toilet trainer"?

[RANGER]

Entry level Warbird Trainer, it is very easy to fly, no Military experience or CAF dues required A guy has to start somewhere. I was a crew chief on the L-19 and L-20 in the Military
Glad you asked.

[Tony B]

Thank you, There is a Harvard and Yak based at Headcorn Maidstone UK where we keep some kit. It was a grass fighter field with Mustangs and Thunderbolts. Now an active civil field and war museum. Also has a piloted V1.

[RANGER]

I grew up during the 40s-50s at the Main Gate to a WWII-Airfield, plenty of AT-6 Texans, P-47, P-51 Aircraft into the 50s, and early Jets such as F-80, F-84, and F-86. All lot of good memories.

[Tony B]

You would love Duxford then. We do military vehicle shows there, plus the Imperial War Museum aircraft, private owned plus the land warfare hall and the USAAF museum Europe. Now that is worth seeing. web site is Imperial war museum link to Duxford (mind you probaly know it)

[RANGER]

I am an avid Warbird enthusiast, haver supplied many rare warbird parts and have provided my vehicles for use by aviation notables. Wish I could get to Duxford, but cannot.

[kenj]

Hi:

Thanks for the great info- too bad the old head bolts had lockwashers, and that I didn't look at the manual closely enough. I suppose I will remove each bolt one-at-a-time and remove the lockwasher, and re-seal and torque.

When I wrote "re-machined" I meant that the head was milled (had a low spot), and the block deck was also milled for the same reason. All the cylinders were re-bored .060" over due to bad taper. All the holes were chased with various taps, but the main bearing and cam bores did not need to be re-bored.

On a positive note, the oil pressure at idle and warm was about 45 psi, but on a negative note the new rear main seal leaks. Maybe it will seal a little better after some break-in time???

[RANGER]

Rear main seal leaks do not normally go away. Permatex #3 should be available in the UK. It would be a good idea to drain your block whill re sealing the bolts.

[Tony B]

There is also STP Oil seal treatment, if the leack isn't to bad. I have developed a habit of sticking it in after any new seal cures many problems.

[kenj]

Sorry, I forgot:

I rebuilt the carburetor with the standard kit, but it seems the throttle butterfly shaft is rather loose and may be a vacuum leak; it sounds like leaks will be the thing to investigate, although with all new gaskets and Permatext high-temp gasket sealer, I had hoped not.