Rough running after headgasket replacement.

Mike Puckett

SCCoA Member
One of the local guys in our group blew a headgasket the other week. It was the usual scenerio where white smoke pours out the tailpipe and it starts running rough. He pulled it into a parking lot, shut it off and had it towed home. The headgasket replacement went smoothly and the heads got a valve job and resurfacing. It also got new plugs and wires. Although it cranked right up, it ran really rough with lots of clatter on the left side. We ran it to warm it up but it got no better, running rough and popping out the exhaust occasionally. Fearing an overlooked motor problem and having a spare headgasket he went ahead and pulled the left side head off and checked everything we could. Piston heights were the same and it made no noise spinning over with the starter. The valve train worked fine, everything was torqued properly, and turned smoothly with the starter running. Back together the rest of it went with the original wires and another new set of plugs but when it started up, we had the same problem still???? So, we swapped the DIS, Coil pack, TPS, and no change. We went ahead and let it warm up since it would run without stalling and kept hearing a zing-zing-ziiiinnnnggg-clunk every so often. Then it hit me. I had him shut it off and jack it back up. I crawled underneath and put a screwdriver blade between the crank pulley and the balancer weight and sure enough the weight moved back and forth. It ain't supposed to do that! I could even wiggle it with my fingers. The hub isn't broken and looks fine but the elastomer is shot. That's the 2nd balancer I've found like this in the last year. The elastomer is wearing out before the hub breaks. He's ordered one of these Dorman replacement units from an ebay store. Hopefully, that's all that was wrong.
 
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