Custom trans mount

[73Sedan]

OK, so I have a new Don Hardy mount kit...I say I love the headers and the engine mounts seem to be sweet, BUT THE TRANS MOUNT??? Man did they fall short. I did not trust it to hold over 400lb/ft of torque to save anyone's life! So, having seen a few member's mounts and some on eBuy, I decided to fabricate my own from the original "cups" and scrap mild steel laying around the workplace. It actually weighs in about the same as the factory 4-cyl original mount. Note: I AM NOT THE WELDER - I simply did all the mock up and cutting of all the parts (amazing what drill bits and a jigsaw can do). I am fortunate to have a couple of welders with over 45 years of combined metal experience helping me out. The notch in the rear is for the Energy Suspension poly mount relief, as well for quick visual inspection.

[Caveman]

Nice fab job!

[gerbsinmd]

That is a really sweet cross member

[v8astregt]

Very nice! That's one of the things on my eventual "to do" list. I didn't like that mount from the start, so I'll build one like yours soon. I just wanted to get mine on the road first.


The only thing I was wondering about is the fact that since it kicks back a couple inches, will the floor mount support the twisting motion of the weight of the engine? It's hard to explain, but before it held the weight of the trans straight down. Now it holds the weight, but a few inches out which will add a shear force on the bolt/mount. Do you know what I'm saying? (I guess this stuff I learn about in engineering classes does come back!)

[73Sedan]

Thanks. What I love the most is the lowest part on profile is the trans pan!! Not a big glob of steel under the car.

Josh, I agree that it will add some stress to the "knuckles", but one observation is that a 7/16" bolt will fit in the knuckles...would only need to bore the "cups" to the 7/16" size. This will add LESS ability for the whole assembly to put sheer force on the bolts themselves. Plus I will be replacing the original bolts with gr8's.

If I get some time, I'll export my drafted plans (to PDF), and document the order of cut and assembly.

[SOHCracer]

I'd like a diagram or "plan" of your mount when you have it finished. PM me or email me when you have time. Looks perfect!

[NixVegaGT]

What trans are you using? I will likely have to do something similar because I'm planning on moving the engine back a few inches. THat plus the T5 will put the trans mount back about 5 inches.

Thanks for the ideas!

[res0o7eb]

Robert,

That is a sleek design! I like the use of factory parts with the standard, heavy duty steel channel and plate material. The welding quality looks superb.
Utilize your experienced welding sub-contractors (they probably cost some bucks, though) to produce a few of those and sell them on ebay - they look real good.

Can you post a couple of close up images of those awesome welds?

[73Sedan]

I wound up losing my drafting plan file, but I do have the details:

This is based on the cup and hanger design (71-73 for sure - I don't remember if 74 or 75 is similar)

Also note: Use as large of a diameter bit to drill out any inside angle instead of having mitered corners - miters encourage areas for stress cracks to form - the smooth curves spread stress over a longer lateral (cut) surface...in other words - no "v" shapes on any inner angles - I used a 7/16 drill bit to round all inner corners, and did all finish cuts with a jigsaw. Yes the plasma is fun but messy on this scale.

mid fab photo will shed light (after text)

First, plan your mount cross section - note that the actual mount is offset (i.e. NOT centered between the sub frame factory mounts). I began by cutting my "plan" on a piece of cardboard bolted to the trans mount - giving enough room to clear ALL of the pan bolts. Make sure that this piece is at least 13.75 inches in overall length when cut. Actual measure of my finished cross plate is 13 and 11/16ths inch.

Second, mount the cross section as well as the "cups" that are cut off from the original bracket.

I chose to use a short piece of scrap the same thickness as the "sidewalls" to hold up on the "cups" to mark EXACTLY where I was to cut the cross piece.

Now the cross section can be cut to exact width.

Weld a large plate of sidewall to each cup.

Tack weld a bit of angle flush with the edge of the cross member.

Assemble cups and cross section. Clamp sidewalls to cross section at angle tabs.

Weld up, finish, and enjoy.

Serves 1 Vega

[73Sedan]

What trans are you using?

TCI StreetFighter - TH350 auto valve.
If you're moving 5" back I'd use even heavier plate for sidewall and DEFINITELY up the bolt size through the cups (mentioned in above post)

Can you post a couple of close up images of those awesome welds?

Thanks Tom, I'll have to print this out and show my welders. They love compliments. And It's a wonderful thing to have them on staff. And depending on their moods, I can get welds that look better than machine done.

Enjoy the visuals!

[1973vegasandiego]

nice work