Ok, The Mystery Continues

[dabtl]

I have been posting on my problems for the past few weeks.

To recap:

I had AF in the oil. We pulled the heads and found the number five cylinder had the gasket blown INTO the cylinder area. We pulled the head, decked them looked for cracks, found none and put new head gaskets on. After a bit of driving, the engine ran strong, the head gasket blew out on the number six cylinder at the rear of the head.

Thought that perhaps we had not torqued the head properly, put new gaskets on with the proper torque and sequence just like in the manual. The motor seemed funny sounding on a brief start up. Pulled the number six fuel injector, turned the engine with the fuel cut off all the way out and AF blew out in some quantity. I do not know how much because we all ducked. The gasket was intact when the head was removed.

We find no cracks in the head. I suspect a bad cylinder liner and piston as the block shows no signs of being cracked.

Your thoughts on this would be appreciated.

 

[Oilleaker1]

I had deuceman51 tell me to watch the short hoses on the inboard side of the intake up top. He said if they are bad, you can get antifreeze into the engine. Is this a possible thing to look at for you???? I'm no expert. PM deuceman51 and ask him. He is a fulltime Nat. Guard mechanic and knows his way around a deuce. Just a thought. Good luck with your leak. John

 

[dabtl]

They are all new and were tightly installed during the reassembly both times.

 

[hoop]

As these are Dry Liners it would have to be the Block or the Head. Do a pressure test on your head.
Thats my bet.

 

[gringeltaube]

............ as the block shows no signs of being cracked.

I would pull out liner #6 and inspect the block to be completely sure...

G.

 

[scoutmanadam]

how long were you able to drive it between replacing the gasket the first time and when it blew out the second one

 

[gimpyrobb]

What about the oil cooler between the oil filters and the fuel filters

 

[dabtl]

how long were you able to drive it between replacing the gasket the first time and when it blew out the second one

A couple of hours. Maybe drove it 30 miles.

 

[dabtl]

What about the oil cooler between the oil filters and the fuel filters

Changed out last Summer.

 

[PropDr]

It's easy to miss a small crack. Pull all of the valves and have the head magnafluxed. As an alternative if you machine shop doesn't have the magnaflux setup you could use Dye Penetrant instead. Don't forget to check in the ports and around the valve seats for cracks.

Could it be possible that the intake has developed an internal leak?

Did you check the deck of the block with a streight edge to make shure it's not warped?

Did you use a gasket dressing when you put the head on?

I would only pull the liner only as a last resort..

 

[hoop]

TM 9-2815-210-34-2-2 pages 4-213, 4-214.
This shows the proper testing of a Head.

 

[dabtl]

I had not seen that, but I probably will build a sealing plate later just to loan out.

 

[jimmcld]

The most likely cause is still the head gasket. After you shaved the head, did you check to make sure that none of the bolts are bottoming out?

 

[rlwm211]

The heads on a deuce are held in place by studs and nuts....kinda hard to bottom them out....

RL

 

[jimmcld]

The heads on a deuce are held in place by studs and nuts....kinda hard to bottom them out....

RL

OK Is it possible to run out of threads on the studs?

 

[oddshot]

OK Is it possible to run out of threads on the studs?

In a way ... yes. Actually two ways.

In ANY engine: If the studs were removed ... all the prep work done (the head cut, the surfaces cleaned etc) ... and the holes for the studs weren't blown or cleaned out before the studs were replaced ... it IS possible that the studs didn't thread fully down ... because of antifreeze or dirt in the holes. On some engines this could cause the threaded portion of the stud to stick too far up ... and not allow a good clamp on the head.

Also ...

Studs, just like all bolts, can stretch .... causing the same as above.

Many years ago I had a similar problem with a customers TR6. It came in with a blown head gasket blowing coolant into one cylinder ...

I pulled the head off ... sent it out for a valve job ... and to take a couple thousandths off the surface to check for true.

I was VERY young at the time, and had not learned YET that studs can stretch. So I didn't check them.

I put the engine together ... and sure enough ... a different cylinder filled with coolant.

A careful (re) teardown and careful measurement revealed the cause.

New studs ... new head gasket ... re-assembly ...

The thing is probably still running ... some 30 years hence.

oddshot

 

[dabtl]

The bolts have not stretched and the thread is sufficient to hold the head in place.

 

[Wildchild467]

need some ARP head studs! haha. they dont make them, just saying though it would be nice to replace that hardware too. im not saying that is the problem at all, but I hate fixing stuff twice.

 

[rlwm211]

I appreciate the knowledge that surfaces when a member has an issue and other members start brainstorming the problem with them. I hope that DABTL gets things all straightened out and I am learning a lot from this discussion....Thanks all!

RL

 

[jimmcld]

The bolts have not stretched and the thread is sufficient to hold the head in place.

OK, then I have it........Steve took a wizz in your number 6 cylinder.