Senior Tech Team
Join Date: Mar 2004
Location: Shippensburg, PA
Need help with a vibration issue (Muncie)
I already think I know the answer, but I need a reality check.
Just got done converting my '65 Nova 327 from a PG to a Muncie 4-speed. I used a Hays Billet Flywheel (12-3/4"), and a Hays Street clutch. I've driven it < 100 miles. Transmission and clutch are working great, but I have a major problem.
I get a real noticeable vibration above 2000 rpm, and it gets really bad at 2500 rpm - enough to blur the rear view mirror and rattle the dash. It is not as noticable above 3000 rpm, but still there (just a higher frequency). I never had this problem with the PG. I replaced u-joints while it was apart. I can go ~50mph where the vibration is the worst. If push the clutch in to let the engine idle and the car coast at that speed, it is smooth as glass. Same is true at 70 mph. I can duplicate the vibes running the engine at those speeds in the garage.
At this point, I am pretty convinced that it can only be flywheel and/or pressure plate imbalance. Not real happy about this, as I used "quality" parts ($$) that were brand new - not Autozone China junk. Before I pull it apart, I wanted to see if anyone else has any other suggestions.
If it wasn't for this issue, I'd be really happy with the whole project. Clutch engagement is very smooth, and trans shifts perfect, whether under load or just cruising around.
So am I pulling the pressure plate and flywheel and visiting a machine shop for balancing, or does someone have other ideas? Thanks!