The Stovebolt Site Forums The Shop Area Engine Shop VIBRATION DAMPER

Has anyone used a 250/292 vibration damper on a 270/302 GMC? i just read somewhere were someone said they work, give me scoop on this. I'm after a 2 groove pully. THANKS!!!
Jay D.

If the crankshaft snout is 1 1/4" diameter like a Chevy six, it should work. You might have to fine tune the length of the snout to make the belts line up with the water pump and charging system. On a Chevy, the 250 damper snout needs to be shortened about 1/4", and the OD where the seal rides needs to be moved back the same amount. I've done that several times.
Jerry

jay d I have a 292 down in the shed with the 2-groove balancer,it is pretty thick front to back looks like 3/8 belts would ride kinda hi. Need to hunt down a 250 for compactness I think it would be best. You might check aftermarket race balancers like jegs and summit we used one of those to handle high rpm,stock ones can blow off of there. There degree marked too.

I would say, if it's the same weight or heavier, it could work, not sure I would put a lighter weight balancer on any engine not designed for it.

An inline six cylinder is inherently balanced. It would run just as well with only a pulley on the front of the crankshaft. Even changing the weight of pistons, connecting rods, and the flywheel/clutch assembly won't make a measureable difference in how smooth it runs. Can anyone show me a crankshaft that has failed because of a different balancer being installed, or even an objectionable vibration developing? Nope- - - -I didn't think so. Real world experience- - - -not theoretical bovine effluent- - - -I've run stovebolts with balancers for a small block V8, and a 250/292 six, and swapped Chevy balancers onto GMC engines with no noticeable ill effects. Go ahead and pontificate- - - -the words are worth exactly what it costs to read them.
Jerry

PS- - - -Joe, how many 235's and 261's are out there running 216 balancers? Mostly so the belt width is correct when one of those engines is swapped into an early model truck with a wide belt. There's a huge weight difference.

There's rubber inside a balancer right? All the original rubber on these trucks is hard as a rock anyway.

Maybe true, there are lot out there, but GM put a heavier balancer on bigger engines for a reason. I pulled a balancer off a 9.0L cummins inline six, probably weighed 50 pounds, it too was there for a reason. https://www.damperdudes.net/harmonic-balancers/chevy/

About the only thing I can remember for Chevy V8's is that the 400 small block needs to use the damper designed for it due to being externally balanced. I have never had a truck with a straight six so I ain't much help.

I thought that as well until I drilled out the rivets holding a 1953 235 damper together. The rubber appeared and felt like it was brand new. I don't know what they used in 1953, but it held up surprisingly well.
That particular damper somehow developed a bad wobble. Maybe I dropped it during the rebuild. Once you drop one on the concrete in a very particular way, the rivets shift, causing the rubber to compress on one side, causing it to wobble.
I drilled out all of the rivets and installed 10mm bolts and nuts though all of the parts and carefully tightened them progressively to a specific final torque value. The holes which I drilled just happened to make for a very snug fit for the 10mm bolts. I then installed it to the engine and started it up and the wobble was gone.

thanks for all the replies, i found one on Ebay for 75.00 new made in the USA! 67-74 chevy 250 inline six should work ??? my crank snout is 1 1/4" and the short one. the back pully groove looks like its going to be real close i can make fit if i have to the other pully groove is going to be for the alternator or power steering pump which ever one works out the best. THANKS
Jay D.

I have always wondered about balancer design and weight.

I know some 283’s came with a common balancer design, and some just had a hub with a pulley bolted on it.

I can say I installed 216 balancers on many many 235’s and never saw a problem in the 30 years I did it.

I understand Panic’s point though.

Who knows?

A good theoretical argument trumps hands-on experience every time, right? At least the guys who don't turn wrenches any more can get lots of exercise pounding a keyboard.
Jerry

Come on guys. Lets keep things informational and polite.

terminology has clouded the subject. its really a harmonic balancer it cancels or dampens harmonics of the crank shaft. but the word balancer is confusing here.it doesn't actually balance anything, yes i know some do! but most just dampen harmonics.
Jay D.