bbain

Big Block People Help!!!!!

Ordered the 5spd TKX conversion to take my '68 fastback from an auto to a manual (for the purists, my Highland Green Fastback started life as a straight 6 car with a C-4. I bought it with the 390 already in place). We made all the necessary changes and got everything installed as it should be.This is where the problems began. For history sake my 390 ran great mated to the C-6, pulled hard at WOT, did excellent twin strip burnouts (posi), but I wanted more highway drive-ability that the C-6 didn't allow. After install of the TKX we did the first test drive and the engine had a bad vibration at 2000 rpm, in neutral, parked on the side of the road. We removed everything and I took the fly wheel and clutch to have them balanced together even though the McLeod fly wheel is neutral balanced which is needed for the internally balanced 390. Got the assembly back and the a little material was removed from the fly wheel and the shops lead tech said I was good to go. We reinstalled everything and with fingers crossed went for another test drive. Damn It!!!! Same vibration any time the engine reaches 2000 rpm whether driving or sitting still. The TKX shifts smooth and the hydraulic clutch works good as well. The company I bought the kit from is scratching their heads along with me.

It has been suggested that I remove everything except the fly wheel, put the bell housing back on and start the engine and bring the rpm's up to 2000. If there is a vibration then I will know that my engine does not like the 40lb fly wheel. If there is no vibration then I should mount the clutch to the fly wheel and test again. If the vibration returns then I know its the clutch. If there is no vibration with the fly wheel and clutch by themselves then what could possibly be the culprit? Has anyone had any issue similar to mine? Super frustrated after having installed and removed the entire assembly more times than I care to count.

I'm hoping some wise souls on here have some thoughts, ideas or suggestions.

Super Frustrated!!!!
Brian

bbain

finally figured it out.......the new, supplied, transmission mount was touching the TKX, resulting in the vibration at 2000 rpm. After some grinding, and created separation, the vibration is gone and the car drives great. New life as a 5 spd from a C-6 resulting in big smiles every time it hit the gas or make a shift.

proeagles

Glad you figured it out. First rule of hot rodding is nothing is ever as simple as it seems.