Vibration after open track with FFR

JCoop · #1 (**permalink**) 10-24-2007, 09:45 AM

Motor mounts cracked or broken...just a thought...

RICK LAKE · #2 (**permalink**) 10-24-2007, 11:49 AM

Carmine What dampener is on the motor? Stock, ATI, Any markings? I will still go with the clutch assembly. Pulling the trans and clutch itself would be the first place to try and locate the vibration. It could be a bad bearing in the water pump, pulley not spinning true on the crank, If this problem just started I would stay with the clutch and flywheel first. Rick L.

JCoop · #3 (**permalink**) 10-24-2007, 12:26 PM

The reason I thought motor mounts is because for the longest time, my SPF BB would break the RH sidepipe mounts and vibrate at around that same RPM; whether driving in gear or in neutral at rest. The 3rd time I welded the mounts, I decided to change the motor mounts to poly (from Dennis O.) and haven't had a problem since. Didn't even realize it but the original rubber mounts were cracked from "spirited" revving and driving.

Worth a check, anyway. Cheers and good luck!

carmine · #4 (**permalink**) 10-24-2007, 12:44 PM

Interesting what you mention about the mounts, had that same problem with the right side, then changed to poly mounts from Olthoffs but vibration still there. What do you mean by you ( welded the mounts ). regards Carmine

JCoop · #5 (**permalink**) 10-25-2007, 06:07 AM

Quote:

Originally Posted by carmine

Interesting what you mention about the mounts, had that same problem with the right side, then changed to poly mounts from Olthoffs but vibration still there. What do you mean by you ( welded the mounts ). regards Carmine

I welded the broken piece on the sidepipe mount, then I bent a cut piece of .5" round steel rod to the same angle as the sidepipe mount, then welded that to the underside of the mount to reinforce it. Ground it down to finish it and painted it hi temp black. Make sure you use a welding blanket to protect the door and sill paint...

Actually, the new mounts transmit more of the engine resonance now than it did before. It's throughout the entire range, however. I feel it more on the seatback and can get annoying on a long drive. It got rid of a drone I had between 2400 and 3500, though. I suspect that was the broken motor mount. I guess it's a trade off for the crispier feel and seemingly more immediate response I get.