The Stovebolt Site Forums The Shop Area Engine Shop GMC 228 Harmonic Balancer

Rough day in the shop today. The harmonic balancer on my 228 does not slide onto the end of the crankshaft far enough, resulting in it being at least a fan belt width too far forward. I'm sure it will throw the belt when I start it up. How can I tell if this is the correct balancer for my truck? An alternate question is this: is it possible that the timing gear is incorrect? When I install the balancer it hits the timing gear. Any suggestions would be appreciated.

Update: I had our machine shop at work take off 7/16" of the rear sleeve on the balancer. That seems to have done the trick, as it now goes on just enough for the pulley to line up with the pulleys on the water pump and the generator. Still not sure why it was the way it was. And hopefully I didn't just screw the pooch by shortening the rear sleeve.

Has the engine been assembled for a while, or has it been rebuilt recently? I think I would have investigated things a little further by dropping the oil pan and looking at the position of the timing gear before doing a butcher job on the balancer.
Jerry

Yeah I agree with Hotrod on the further inspection before modifying anything. The timing gear could have easily walked forward, and now if there is a gap between it and the crank, it can always move back, or worse yet come off completely. This could have been one of those red flag moments that needs further investigation.

Rebuilt about 5 years ago but hasn't been started yet. Trying to get things together to start it up and get the truck on the road. So no, it's not been run since rebuild. Looks like I'll take my chances at this point. Funny how I post a question before I do anything and get no responses in over a week. Lots of looks, though. Then as soon as I give an update on what's already been done I get all kinds of great advice.

There wasn't much info given in the beginning post to offer much of a response. Seeing now that your saying its a newly rebuilt engine, I would say your crank gear is either on backwards and not allowing the gear to seat flushly against the main journal(that would be about the same amount you had to cut off of the balancer), or the gear simply wasn't all the way on, even if it was not on backwards. Check that first.

If that damper is the correct factory part, it was a huge mistake, machining it off. The problem is with something else, like others here have mentioned. You should have asked here first for some dimensions.

Well, what's done is done I guess. I apologize if I came across a little short yesterday (no pun intended). Just frustrated. Thanks for the input guys. I'll have to do some work to find out what really happened. In the meantime, anyone have a harmonic balancer for a 228?

If you've got the ability to cut it off, you can also make a spacer to correct the problem. Just be sure to drill and tap the end of the crankshaft and use a Grade 8 bolt to secure the spaced-out balancer, because you've lost part of the press fit that would normally be holding it on. Machine a ring the same thickness as the cut you just made, and once the timing gear is on right, sandwich the spacer between the timing gear and the balancer. Use some blue Loctite on the center bolt and torque it to 55-60 ft/lbs. if it's a 7/16" diameter bolt.
Jerry

Sounds like a plan Jerry. Thanks for the advice.