55mph detonation post mortum. . .

[FMJ]

Negative, it's shiney because of the unburnt diesel injected into the cylinder after the big boom. I always crank the motor with the stop pulled for a sec or 2 to make sure I don't have a hydrostatic lock situation.

Also, I wiped the oil off the top of the piston before I took the pic!

 

[stumps]

Have you tried wiping another piston off with a diesel wetted rag? Your engine only ran a very short time after it crashed. I am curious if a quick wipe down would shine things up like that.

There have been several crashed engines recently, and I forget which is which. Was this one new to you, or was it a trusted old friend?

-Chuck

 

[G-Force]

FMJ,
Would you post a some pictures of the rod and rod cap from the end so you can see the mating surfaces. Also can you post a picture of the rest of the rods and crank in the block?
I eould say the rod looks like it developed a crack on the side that is the bolt is still intact.

 

[FMJ]

Have you tried wiping another piston off with a diesel wetted rag? Your engine only ran a very short time after it crashed. I am curious if a quick wipe down would shine things up like that.

There have been several crashed engines recently, and I forget which is which. Was this one new to you, or was it a trusted old friend?

-Chuck

Old friend. . .

 

[OPCOM]

From what I have read on these boards, the gaskets with the tabs that stick out past the head are the new style.

-Chuck

no no no..

The new style is the black one, no tabs. the old style is the red one, yes tabs.

 

[stumps]

no no no..

The new style is the black one, no tabs. the old style is the red one, yes tabs.

Geeze! Every time this subject comes up someone says the gaskets with the vents are the new style.

Pink, black, vents, no vents, rings, no rings???

Which is it?

Here is a thread where Marti claims the pink gaskets with the vents and separate fire rings is
the new gasket: http://www.steelsoldiers.com/deuce/40801-blown-head-gasket.html?highlight=head+gasket+vents

I think it is time for some official documentation.

-Chuck

 

[Srjeeper]

Thank You

FMJ,

As mentioned much earlier in this thread I'm sorry Mr. Murphy chose to ride along with you on that day. It's certainly kept you much busier than I'm sure you'd like. Yet throught it all you have seen fit to take the time to photograph everything and answer the many questions/speculations that I'm sure you'd rather not deal with.

Thank you for the additional effort you've put forth for the good of the SS site and it's members.

 

[FMJ]

no no no..

The new style is the black one, no tabs. the old style is the red one, yes tabs.

Anyone know what year they started insatlling the new gaskets in new construction LDT motors, I have a 1987 USAF truck with a 1987 motor that has the tabs. . .

 

[FMJ]

FMJ,
Would you post a some pictures of the rod and rod cap from the end so you can see the mating surfaces. Also can you post a picture of the rest of the rods and crank in the block?
I eould say the rod looks like it developed a crack on the side that is the bolt is still intact.

Actually the broken rod bolt in the picture, had a crack all the way around right where the threads start, I know this because the area that was cracked prior to the engine letting go was coated with oil, the center of the bolt that finally broke all the way through was oil free, the threaded portion in the connectiong rod exited the motor and ended up on the side of the road.

I'll take more pics of the bolts today. I want to pull the intact rod bolt and send it along with the one that broke to be hardness tested somewhere.

 

[stumps]

Actually the broken rod bolt in the picture, had a crack all the way around right where the threads start, I know this because the area that was cracked prior to the engine letting go was coated with oil, the center of the bolt that finally broke all the way through was oil free, the threaded portion in the connectiong rod exited the motor and ended up on the side of the road.

I'll take more pics of the bolts today. I want to pull the intact rod bolt and send it along with the one that broke to be hardness tested somewhere.

I'd say that you found the smoking gun!

Stress breaks almost always start on the thread roots, as that forms a stress riser. That is why the old lathe cut "V" bolt standard was abandoned in favor of the UNS thread pattern. In addition to being easier to machine, the UNS pattern has a curved root that eliminates the stress riser at the thread root.

Here's an experiment you might want to try on one of the rods you haven't broken down yet:

Using a 6 point socket, take a sharpie marker, and draw line on the socket that goes down to the rod. .. (Or, you could take a long enough piece of tape and make a tape flag on the socket...) This is to give you an exact reference to the final angle to which the the nut was tightened. Set your torque wrench to the highest torque spec, from the TM, for the rod bolt. Loosen the rod nut 1/2T, and then torque it until the sharpie lines line up. If the wrench doesn't click before you reach the original angle, the nut was over torqued.

Thanks for all of your investigative work.

-Chuck

 

[Nonotagain]

Actually the broken rod bolt in the picture, had a crack all the way around right where the threads start, I know this because the area that was cracked prior to the engine letting go was coated with oil, the center of the bolt that finally broke all the way through was oil free, the threaded portion in the connectiong rod exited the motor and ended up on the side of the road.

I'll take more pics of the bolts today. I want to pull the intact rod bolt and send it along with the one that broke to be hardness tested somewhere.

I can perform the micro hardness of the intact bolt as well as the broken one.

At issue is that the numbers would be meaningless if both bolts turn out to be the same hardness.

What is needed is a new bolt that has not been used for comparatory purposes.

 

[tmbrwolf]

Geeze! Every time this subject comes up someone says the gaskets with the vents are the new style.

Pink, black, vents, no vents, rings, no rings???

Which is it?

Here is a thread where Marti claims the pink gaskets with the vents and separate fire rings is
the new gasket: http://www.steelsoldiers.com/deuce/40801-blown-head-gasket.html?highlight=head+gasket+vents

I think it is time for some official documentation.

-Chuck

OK Chuck here it is the only gasket available to me from DLA (Defense Logistics Agency) is the one piece gasket, the "black one" shown earlier, the "tabbed" 2 piece gasket has not been available from DLA more than the 10 years that I have been able to order from them, allmost every head gasket that I have had blow out or start leaking has been the old style.

 

[tmbrwolf]

Anyone know what year they started insatlling the new gaskets in new construction LDT motors, I have a 1987 USAF truck with a 1987 motor that has the tabs. . .

Were those the last contract trucks? If yours has the tabbed gaskets than they used them until then on new builds, I know we were using the new style to repair engines in the early 90's to repair blown / leaking gaskets, IIRC the style was changed to seal the cylinders better and the oil & coolant passages better, the gaskets are a little thicker to tolerate slightly more head warpage and the torque values were revised (TD block went to 157 LB FT )

 

[FMJ]

Were those the last contract trucks? If yours has the tabbed gaskets than they used them until then on new builds, I know we were using the new style to repair engines in the early 90's to repair blown / leaking gaskets, IIRC the style was changed to seal the cylinders better and the oil & coolant passages better, the gaskets are a little thicker to tolerate slightly more head warpage and the torque values were revised (TD block went to 157 LB FT )

This grenaded motor was a 92 TEAD rebuild, with the tabbed gaskets. The 87 USAF was a last contract M35A2C Also, the motor I just swapped into the truck was/is a 1988 motor. . . with the tabs, go figure. . .

 

[FMJ]

Is there a special torque wrench used to torque the shrouded nuts on the heads?, the ones directly below the injectors?

 

[baxter]

Yes it is a special head bolt wrench. I just did my gaskets and used a snap on 7/8 o2 sensor wrench on an extension, a little grinding on the wrench and it fit perfect past the oil cooler.

Vaughn

 

[stumps]

Wow! Someone, Marti I think, claimed there were three types: Black with loose rings, black with pressed in rings, and pink with vents and loose rings. The claim was that the pink with vents were the latest revision, and they have become all used up in the supply chain, so the older black type that was left over is what is currently easily available...

This is kind of a crucial problem. It would sure be nice if someone that has access to the change orders that detail the real story could post them, and if we could get the authors of the scuttlebutt to edit their posts.

-Chuck

 

[FMJ]

Yes it is a special head bolt wrench. I just did my gaskets and used a snap on 7/8 o2 sensor wrench on an extension, a little grinding on the wrench and it fit perfect past the oil cooler.

Vaughn

Do you have a part number for the "tool"

 

[det45]

According to "Trouble Shooting Manual LDS-465-1 Multifuel Engine" published by Continental Aviation and Engineering Corp. in June 1968, there were 3 designs, one black unvented, one red unvented, and one red vented (with "tabs"). The "multi-piece, vented head gasket" is the new design. This is for the LDS, but it seems to me that it would also apply to the LDT.

I have attached a copy of the page from the publication.

The entire publication can be found at http://old.steelsoldiers.com/index.php?module=pagesetter&type=file&func=get&tid=1&fid=file&pid=57

The discussion on head gasket is on page 49.

 

[tmbrwolf]

According to "Trouble Shooting Manual LDS-465-1 Multifuel Engine" published by Continental Aviation and Engineering Corp. in June 1968, there were 3 designs, one black unvented, one red unvented, and one red vented (with "tabs"). The "multi-piece, vented head gasket" is the new design. This is for the LDS, but it seems to me that it would also apply to the LDT.

Thats interesting I order them from DLA and the only one available is the "black unvented" and all have new manufacturing dates. From my experiance the tabbed gaskets are the most problematic and the ones I replace the most often in our shop.