55Mph Detonation. . .

[stumps]

I guess the counterfeit bolts were just a precursor to the pork dumplings made with pork fat and cardboard, the milk laced with melamine powder, the lead paint in toys, the melamine powder in pet food, fake heprin and who knows how many other frauds that they got away with!

The aerospace industry had to literally tear down and rebuild fleets of airplanes because they had counterfeit bolts in some parts bins.

Of course, whether this relates to deuce engines blowing up is entirely speculation on my part. There are more than a few of us on this board that have the capability of testing the remains of the connecting rod bolts for Rockwell C hardness. I think it would be well worth doing.

-Chuck

 

[USAFSS-ColdWarrior]

Of course, whether this relates to deuce engines blowing up is entirely speculation on my part. There are more than a few of us on this board that have the capability of testing the remains of the connecting rod bolts for Rockwell C hardness. I think it would be well worth doing.

 

[badgmc56]

FMJ, When you disassemble your motor, check the torque on the rod bolts just for ha ha's before you take it apart. See if they are all the same or if there is some variance between different rods. Set up a dial indicator, on a flat surface of course, to measure the length of the rod bolts to see if any are really stretched. I would be curious to know the results.

 

[stumps]

Checking the torque on a long ago torqued bolt can be a problem. Basically, any oil that was applied to the bolt for assembly has been squished out of the bolt/nut and a metal to metal joint has replaced it. Generally, it will take a whole lot more torque to start such a bolt moving than what was used to tighten it in the first place.

Measuring the bolts for stretch is a good idea... if you can be sure that they were all the same length before they were tightened. A 6 inch dial caliper should do the trick for that measurement.

-Chuck

 

[Nonotagain]

Checking the torque on a long ago torqued bolt can be a problem. Basically, any oil that was applied to the bolt for assembly has been squished out of the bolt/nut and a metal to metal joint has replaced it. Generally, it will take a whole lot more torque to start such a bolt moving than what was used to tighten it in the first place.

Measuring the bolts for stretch is a good idea... if you can be sure that they were all the same length before they were tightened. A 6 inch dial caliper should do the trick for that measurement.

-Chuck

I would also suggest measuring the diameter of the threaded portion of the rod bolts.

Typically when a rod bolt stretches, it's within the threaded portion due to the threads being rolled and deforming the metal.

FMJ should be able to use the caliper jaws and measure/sight down the length of the threads to see if there is/was an issue.

 

[stumps]

I would also suggest measuring the diameter of the threaded portion of the rod bolts.

Typically when a rod bolt stretches, it's within the threaded portion due to the threads being rolled and deforming the metal.

FMJ should be able to use the caliper jaws and measure/sight down the length of the threads to see if there is/was an issue.

My first line of attack would be to try and figure out how the cap came to be removed from the connecting rod.... which side released first is important to know.... that tells you which bolt broke first.

Next, I would put one of the failed bolts on my Vickers Micro hardness tester, and see if it meets the specs for a grade 8 bolt. That will tell us about incorrect application, and counterfeit bolt possibilities.

After that, the tests for shrink, thread rolling, or length would be worth trying. Unfortunately, the broken bolts won't yield much useful information in that quest.... and the unbroken connecting rod bolts will only be revealing if the assembly mechanic was using a bad technique, or a mis-calibrated wrench.

-Chuck

 

[sandcobra164]

As a manager over rebuilds at MCLB Albany, I can honestly say, torque wrench's are calibrated to a schedule, bolts are of the highest quality and trend analysis of failure's are tracked extensively. If there is a problem, we notice it quickly and I know of a few rebuilt trucks that slipped out, were almost shipped and came right back for another frame down rebuild to make sure we did everything possible to support the Warfighter. I can't speak to all of DOD or for how things were run in the 80's when these trucks run through TEAD but I doubt it was any different back in the day.
My National Guard experience has been that if a truck needed a motor, it recieved an LDS 465 as they have more power, could run 2600 rpm all day, and pull the load at at least 55 mph. More or less the same prime mover but could handle the stress of moving trucks across state. Of course, we still have alot of LDT 465 powered trucks getting the job done.

Test the bolts!!!

WO1

Formerly SSG

Carson

Army Strong!!!!v

 

[sandcobra164]

Also, I forgot to mention, Not saying Murphy was the one provided with all he should have needed tightening those bolts. He lives amongst this community.

 

[G-Force]

Ok, a crazy theory. is it possible for the rods to be installed in the engine backwards? In other words, the big end of the rod cap is cut at an angle on the connecting rod. This is generally done for clearance issues for removing the piston and rod out of the liner (in other words the big end of the rod wouldn't fit through the bore of the liner when removing the piston from the liner). If the rod was installed on the piston but turned 180 degrees and then the piston was installed in the liner and connected to the crank, there would be more stress on the cap bolts.
However, this would orient the locking tangs of the rod bearing shells in the wrong direction of rotation. This would eventually cause the bearing shell to spin in the rod cap thus causing a spun rod bearing. Unless there are tangs cut on both sides of the bearing which would then prevent the shell from turning in either direction. This might have been done to prevent spun rod bearings in the event the engine were to run backwards.
I don't really know if there would be clearance issues in the block if the rods are installed backwards. This is just a theory, we're all looking at whether the bolts were defective or the rebuilder over torqued the bolts. maybe the bolts are ok and the rebuilder torqued them properly.....its just that he installed the rods backwards. This would be a credit to the design of the engine to run that long before failure. I would be interested in seeing which way the rest of the rods are installed on the cranks of the engines that failed. Just a crazy theory........

 

[jollyroger]

I have ventilated more blocks than I want to admit. Mostly on race cars and things that I wanted to be race cars that had no business being thought of as such. I have had oil related failures, parts failures and fastner failures. IMO looking at the pictures I see it this way. The crank journal is clean. No groves. More importantly no discoloration. Oiling problems would result in groves and discoloration on the journal. Yellowing for lower temp overheating and blueing for the high temp overheating. The rod bearing did not spin or degrade on that journal. The rod also shows no blueing at the surface around the journal. It does not appear as a high temp/oil related failure. Because the rod and cap are mostly intact it would appear to be a rod bolt/nut failure. Then the question is why did the bolt fail? Inferior quality? improper instalation? Abuse/overstressing? A combination thereof? It is probably a perfect storm of all of these things. I think it will be very difficult to forensically figure out the exact thing that caused the failure. However I agree with investigating as there may be an obvious answer that can lead to improvements in the 465- LDT.

That being said I wonder if in a rebuild situation it would work better for the LDT-465 to be precision ballanced like we do on our high revving race car stuff. Taking this step in our flathead Dodge rebuilds for the M-37's has vastly improved the reliability and longevity over the factory rebuilds.

Through the forum I have been trying to absorb all the differences between the LDT snd LDS motors. Obviosly the LDS makes more power than the LDT. Are the blocks and bottom end the same between the two? If so I would not expect that we could overstress the LDT based on the LDS being able to run at 2600rpm and higher power with reliability. Please advise as to my theories. Thanks guys.

 

[bgekky3]

I saw the carnage of the block and rod. FMJ is going to send the remaining bolts out to be analyzed. He is away on business for the week. The rod bolt looked like it failed. There seemed to be an old break in the rod bolt (a dirty section) and the remaining clean part of the break. It looked like my broken cam. It was broken for a while and finally let go. We won't know for sure until the tests are in. I hope this helps until the tests are back.

 

[Maverick1701]

It doesn't take a rocket scientist to figure this out. The first time I drove my deuce at maximum said speed and heard the engine just about jumping out of the hood, I said forget this. I only run at 2200 rpm and no more than 48 to 50 miles per hour. You have to use a little common sense when driving a vehicle that was built for off road down the freeway.

that is where I urually run...
2000-2200rpm and between 45-50mph....I want to make sure my 6cyl stays a 6cyl

 

[TexAndy]

so... postmortem on the OP's engine? What was the culprit?

 

[mattg2448]

Now that's a hole!

 

[Ord22]

where do you think you can get another engine from?

 

[Katahdin]

Here you go:

http://www.steelsoldiers.com/deuce/45917-55mph-detonation-post-mortum.html

 

[velociT]

that is where I urually run...
2000-2200rpm and between 45-50mph....I want to make sure my 6cyl stays a 6cyl

I won't go over 2k on the highway.

That means 40ish MPH. Slow going but my motor is more important.

 

[TexAndy]

Hm. Ok, sounds like defective rod bolts from the other thread.

I wonder if it would be feasible to go into a not-yet-grenaded engine and replace them with new, known quality rod bolts?

 

[stumps]

Hm. Ok, sounds like defective rod bolts from the other thread.

I wonder if it would be feasible to go into a not-yet-grenaded engine and replace them with new, known quality rod bolts?

Of course! But then you would have to pull all of the piston/rods, press out the bolts, press in new bolts, check the rods for alignment, and possibly size them, scuff (hone) the cylinder walls, put in new rings, bearing shells, gaskets.... Sounds like a bottom end rebuild.

In an ideal world, we should all have our trucks entirely rebuilt, to protect them. But that just isn't going to happen until they become rare and expensive.

-Chuck

 

[TexAndy]

eh, guess I'll just take my chances.