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Cummins small cam Flywheel installation

Posted By RobertMoen Sunday, March 27, 2022 8:04 AM
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RobertMoen
 Posted Sunday, March 27, 2022 8:04 AM
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Recently had 2 flywheel bolts come loose and break, the hardened washers for them got chewed up when they went through the clutch. Cummins doesn't stock them and I cannot find anything hardened that's not way thicker locally. Would it be acceptable to install those 2 without washers? Trying to get this truck back up by Monday.
Geoff Weeks
 Posted Sunday, March 27, 2022 1:30 PM
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IIRC the damper bolts on the bull nose crank are the same as the flywheel bolts. Check if you can rob one from the damper and replace with a thicker washer and bolt on the damper until you can fix it right.
I am concerned why the failure in the 1st place? Crank bolts just don't snap.
Double check the length of the damper bolts to make sure they are the same as the flywheel, I think they are, but might not be.
Sunday, March 27, 2022 1:34 PM by Geoff Weeks
RobertMoen
 Posted Sunday, March 27, 2022 3:33 PM
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I'll check it out to see if the same washers are used, thanks. I found it odd the cummins dealer had the bolts but doesn't stock the washers. Not really sure why they broke, looked to me like the had come loose and backed out against the clutch disc and got snapped off. Maybe they didn't get torqued properly. I've only had the truck a year and don't have a lot of history on it.
Geoff Weeks
 Posted Monday, March 28, 2022 1:17 AM
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Be careful, you don't want a flywheel coming through the cab, you'll not likely live to tell about it. The bellhousing will not contain it. It has happened.
RobertMoen
 Posted Monday, March 28, 2022 5:58 AM
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It's going together with all new bolts torqued to spec with blue threadlocker. Flywheel and crank cleaned to bare metal and runout has been checked. I just may have to put 2 bolts in without washers, I figure no washer is better than the wrong washer and having the bolt lose torque. My book mentions 2 different bolts, one with washers and one with lockwire holes using no washer, assuming a clearance issue if used with a washer due to a thicker head. Just a guess.
Geoff Weeks
 Posted Monday, March 28, 2022 7:27 AM
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I've never had one come loose when clean/dry torqued to spec. When I worked in a truck shop, the flywheels got exchanged on every clutch job, We had one for each of the common engines, and would get the one we pulled cut and ready for the next clutch job. So they came off every time.
Working on my own stuff, I have had the engines apart many times, and would know if a bolt came loose. Never has.
Two main causes are: 1) not being torqued properly, and 2) being rattled on with an impact gun and stretched in the process. Once they get stretched they will continue to "neck down" and come loose.
RobertMoen
 Posted Monday, March 28, 2022 4:45 PM
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I was finally able to find some of the correct washers today. Should get it all buttoned up tomorrow. The only thing I'm a little concerned with is the way the new intermediate plate fits on the drive lugs in the flywheel, its a little tight but it felt the same as the old one I took out. I was able to slide it all the way on by hand so I think I got the lugs in straight. I didn't have a feeler gauge but could see a slight gap between the lugs and plate but I couldn't seem to rock it to one side at all. Hoping if they're a hair off they'll wear in or straighten themselves slightly.

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