Front crank dampener for a 8070

I decided to give it a try, so I purchased a Vibratech dampener for a Detroit 71 series. As far as I can tell, it's a perfect match. Attached are a couple photos of the old and new, plus one photo of the old one cut open in case anyone was wondering how much space there is between the inner ring and the outside. Not much room for fluid, but then again, this isn't exactly fluid any longer.

Share the part number please.....

Got it painted yesterday, and installed tonight. What a difference! Before I could run at 1/2 throttle or above and the top of the exhaust stack would vibrate what seemed like 1/8” side to side from center, although that’s just a guess and it may not have been that exact. After installing this new dampener, I ran it all the way to full throttle and I couldn’t tell any movement in the exhaust pipe now. I’ll note that I don’t have any other warning signs of a bad dampener like broken alternator or A/C compressor brackets. I just did this as a preventive measure given that I’m sure the old one was original with the yellow primer and maroon paint on it, and I’m glad I did it.

Edited by CrestonM - 14 Sep 2023 at 8:34pm

You are correct, it did not have any gel-like fluid left. But I wouldn’t have known had I not cut it open, so it would’ve been rendered bad at that point, too, regardless. Just glad I did it. A lot cheaper than a broken crankshaft.

Also the actual part number for those who asked is Vibratech viscous damper 713398-000.

Edited by CrestonM - 15 Sep 2023 at 2:59pm

price on the link says 498

I started this threadbecause ive got a 8070 that I thought I i had rod knock in. Pulled the pan to checj the bearings. They looked new. After much talking to different people I figured out it must be the damper. Bought a new old stock damper and installed it. Its better but not right
Im going to get a new vibratech damper and put on it

The consistency of the silicone originally would have been about like 30 weight oil....Dale

Its cheap insurance
Better than losing a counterbalanced crank
I dont thimk a good one would be that easy to find

The silicone definitely goes bad over time with use. Some engine manufacturers (Cat, Detroit, etc) even say to replace them at Ohaul time or at a certain hour interval because of that possibility. Go bad over 20 years of sitting on a shelf ?? Can't answer that.

Itll probably be a month or so before i get the new damper but ill surely post the results

I put a new Vibratech one on last spring and it fit perfectly and runs nice.

I purchased 2 of these and replaced on both 8070's. Exact fit/replacement. So yes! The 4-71 Detroit balancer is what you need for your Allis. I've at least got peace of mind. Someday I'll cut open the old ones to see how they were...even the $1400 NOS AGCO one! I won't use it and wouldn't expect anyone to buy it. Will be interesting to see what father time did or didn't do to It.

I called vibratec and they gave me the name of a local dealer. He ordered it. It was around 650.00. Fit perfectly. Itvwas for a 4-71 or 6-71 detroit

P.S. They were very helpful at vibratec

Yes