rpm wobble?

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rpm wobble?

Postby ahale2772 » Wed Dec 23, 2009 8:07 am

i was cruisin around yesterday and took my truck out on the highway seems like anywhere over 2 grand there is a constant vibration that comes in goes at a constant interval, it also happens when i just rev the engine at a stop , one second on one second off, i dont really know what a cummins has for a harmonic dampener of if they ever have any common problems with vibrations, anyhelp? thanks
84 CCLB W350 project
94' W350 Dually, Diesel, Auto 1080HP/1980FTlbs
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Postby KTA » Wed Dec 23, 2009 8:48 am

They have a rubber ring mounted dampner. I have seen them deteriorate and that could be your problem. You can take a look and see if there is anything obvious. If there isn't put a white paint mark on the 2 halves and run it for awhile. If the marks don't line up anymore the dampner is junk.
Fleet of Junk: 1989 D350 627rwhp 1300 tq B-1/Hx60 twins, KTA pump/injectors, ported head, BIG fuel supply. 13.75@ 109.5mph 1/4: 1992 W350 Cab-chasis, 1993 W350 ext cab cust.370 inj Hx40/16cm 290rwhp hydroboost brakes,1984 D350 crew-cab another project.
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Postby ahale2772 » Wed Dec 23, 2009 1:42 pm

ok thanks ill look into it anyone make a hi-po replacemt one like a fluid dampner?
84 CCLB W350 project
94' W350 Dually, Diesel, Auto 1080HP/1980FTlbs
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14mm rotor
 
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Postby KTA » Wed Dec 23, 2009 2:42 pm

Fleet of Junk: 1989 D350 627rwhp 1300 tq B-1/Hx60 twins, KTA pump/injectors, ported head, BIG fuel supply. 13.75@ 109.5mph 1/4: 1992 W350 Cab-chasis, 1993 W350 ext cab cust.370 inj Hx40/16cm 290rwhp hydroboost brakes,1984 D350 crew-cab another project.
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Postby skilletky » Fri Dec 25, 2009 6:45 pm

do ya gotta modify anything for it to work? i am having the same problem with my truck.
92 d350, arp's, orings, 150lb springs, 4200 gsk ,ground pin ,64/71/14 ,ddp inj's, ats manifold, tim's tubez, ats trans, FASS, locker, timing + a tooth, bcdd intake

2001 2wd rclb dually 5sp, smarty, Bluechip FMS, TS MVP, 57/75 twins, stainless diesel pipe kit, valair clutch, airdog 150, DFI SAC 7x.014's, cheap a$$ intake, ARP studs, oringed head, CPP 115# springs
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