When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Unfortunately, the reality of match balancing flywheels (and possibly harmonic balancers) on LT1/LT4 engines is real. I had to do this on my 93 LT1 MN6 when I replaced the clutch/flywheel. I was able to do it after the flywheel was installed by using rare earth magnets to get the proper mass and placement of the weight. Then I cut and welded a piece of steel to the flywheel. It worked perfectly but was a total pain in the ***. I believe the weight I added to the outer edge of the flywheel was around 25 grams. Not a lot of weight but enough to cause noticeable vibration.
On my SMFW there is an inner lip, like a dryer drum, where I could temporarily place rare earth magnets and move them around to find the proper mass and placement to eliminate the vibration. Centrifugal force held the magnets in place while I revved the engine. Once I got the proper mass and location, I cut a piece of steel and welded it to the FW. I cut the steel a few grams light to compensate for the weight of the weld bead.
I never heard an explanation as to why GM resorted to individually weighting the FW (and possibly the HB) on the LT1/4 engines when they never resorted to something like this on the L98 engines (which also require a weighted flywheel). Even the SBC400s and the BBC454s required external weighting. But there was always an EXACT spec for the offset weight. Why did GM decide to weight the LT1 individually? It seems like a complete hack job. Like it was too much work/cost to balance the crank and rods during assembly so they just assembled the engine (without checking and adjusting the weight of the parts) and then got the motors in balance through "fine tuning" of the FW and HB.
Correct me if I'm off base. But I would really like to understand what the logic was there.
If you look at a Two-Piece rear Seal SBC Crank you will see a Pork Chop looking affair where the Flywheel bolts on. This is for balance. When You re design it for a One-Piece real Seal you need to machine the Pork Chop off to allow the Seal to go on. To make up for it being gone You need to add the weight to the Flywheel.
Is it possible to replace the clutch disk only and perhaps sand/emery cloth the DMF and PP? Would this work or would I be wasting my time.
My current set up, which I assume is stock (86K miles) chatters like crazy, especially when backing up. The clutch engages at the upper 1/3 or 1/4 of pedal travel.
