Nominal Clearances to frame

Brian · 06-23-06, 06:57 AM

I'm using a combo of Prothane and Energy suspension poly mounts for the driveline in our car. As the transaxle mounts are thinner than the stock GTD rubber ones and Roy's engine mounts are adjustable, I can drop the motor to some extent. What do the GTD boys recommend for nominal clearance between the transaxle and frame? In particular the center seam and the rear most frame rail of my R-21. Both the motor mounts and transaxle mounts are significantly stiffer than the standard items.

Many Thanks
Brian

Howard Jones · 06-23-06, 03:46 PM

Brian, I know just what you are talking about. I have used shorter rear gearbox mount "pads" also. I have shimmed them upward until the gearbox stopped rubbing on the same cross brace you refer to. In the end MY CAR requires a little more than 1/8" clearance at that same point. Over all I was able to lower the rear of the gearbox by about 3/4".

I established the point that the gearbox was rubbing by cleaning the spot on the gearbox at the point that was nearest the chassis and painting it black again. At the same time I would repaint the chassis red. I would then drive the car for a few hours over a couple of days and inspect the spot again. When I could not find ANY paint rubbed off either the chassis or gearbox I gave it another 1/8" for good measure. This did take a couple of trys.

I would say from your description of your mounts that yours are stiffer than mine. I have a "stock GTD" front motor mount system with Ford truck mounts. These are the ones with the big rivet through the middle of the rubber tying them together. I think they are for off-road and high performance use. At the rear I think the gearbox mounts are off some kind of Pontiac. Body mounts I think.

Could you forward your mount information. Supplier, part numbers etc.?

Brian · 06-23-06, 07:15 PM

Thanks Howard, that's what I was hoping for. I have not installed the parts as of yet, but I don't see that I'll have any issues.

The Transaxle mounts are Energy Suspension part number 9.4101G, they come as a pair and are listed as a universal mount for harsh conditions. The hole in the frame has to be opened up to allow the insertion of a bushing and the lower poly bush and washer have to be trimmed to nestle into the lower part of the angle underneath.

The Motor mount is a Prothane Part number 6-503-BL, listed as a Mustang Motor Mount v-8, 65-73. They are a little wider than the Autozone inexpensive plain jobs that I have, but I don't see any issues with trimming my frame mounts (Roy Smart items) in a bit and re-drilling for bolts.