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Crank journal dent, Now what?

809 Views 5 Replies 2 Participants Last post by  CJDave, 
1
Yes, I know your suposed to cover the rod bolts when inserting them into the block but Guess what I didn't and my last rod hit the crank leaving a nice ding on the bearing surface. After throwing stuff all over the garage I examined the spot and was able to champer the ding. I then installed the bearing cap and rotated the engine a few times. The bearing wasn't damaged. Now my feelings are the ding is really only like the oil hole on the other side of the crank and since it's not doing any damage let it be. My second thought is take the crank out have it welded and reground.
If I don't spend the money now will I be spending a lot more later?
Thanks,
Pigpen

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C
8
/wwwthreads_images/icons/tongue.gif Chances are, you'll be OK....that isn't the first time that has happened./wwwthreads_images/icons/tongue.gif Speaking of putting in/taking out rod bearings....some guys out here who have a few trucks were rolling in some rod bearings in an 8V-71 Detroit Diesel. The guy under the truck could not quite get clearance for a rod end so he asks the guy topside to "jog" the starter. The guys does, and the engine roared to life....the cab is tilted forward so they can't get to the air cut-off cable control....the engine...with the pan off, and a rod completely loose....runs wild...like those Jimmys CAN do just when you least expect it.....the guys run for cover....the engine revved into never-never land and blew, seting the truck afire, which also burned down the shop/wwwthreads_images/icons/frown.gif Lesson: NEVER work on a Jimmy unless you have checked the air cut-off and know it works and that you can reach it. You only have a couple of seconds/wwwthreads_images/icons/crazy.gifto react. Aren't you glad you are just a Jeep guy?/wwwthreads_images/icons/smile.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
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G
the dent should not be a problem on a stock or slightly modified engine. lots of engines have grooved bearings that only use the outer edges of the journal. Hey CJdave, I still have the pleasure? of working on 2 cycle detroits, I always tie the rack back to the no fuel position, never can be to cautious, but if it starts any way you bet i am getting out of there! I had one loose a cracked manifold, thought I sh*t myself, never heard anything that loud before, not even the jet engines I worked on for uncle sam can compete.
good luck, jjc

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C
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/wwwthreads_images/icons/tongue.gif Before I touch the starter I make darn sure that the little trip pawl for the air cut-off is free and I try it to be sure that the gate comes down. One of our buddies out here was dozing with his early model D8 and ripped through a natural gas line. The engine ran wild and the guy jumped off just before the clutch came up through the floor plates. He did not have the presence of mind to grab the compression release. If you have to spend any time whatsoever thinking, then it's usually to late to do anything but......run/wwwthreads_images/icons/crazy.gifWe even had a neighbor blow a small diesel tractor because the driver parked near the fuel trailer at noon and on the very hot CA valley day the gasoline vapors were all around the trailer. The engine sucked them up, ran wild and blew./wwwthreads_images/icons/crazy.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
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Its a shame cat did away with the compression release when the pony motors went away, Its damn near criminal negligence that detroit dropped the air shut off on the turbo motors, they should have moved it to the turbo compressor inlet, seals in a turbo are a lot cheaper than a blown motor. I never had a runaway from gas fumes, but seems like I have bad luck with 71 series injectors locking up. It took me 6 injectors to find 4 good ones on the last motor I tuned up, the only thing that saved that (old style non breakaway fuel rack)motor was the air shut down.
nuff said, jjc

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5
/wwwthreads_images/icons/smile.gif We converted a 17A D-7 to direct start and I thought we would have to use the compression release to get it rolling but we didn't. Rewound the generator to 24V and changed the flywheel gear to go with the starter. Had a nice battery box made for the LH sponson. Everybody wanted to run that seven after that./wwwthreads_images/icons/smile.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
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