In the next few weeks I'm going to be removing my 3.4 to swap in a Getrag and do a new cam and some top end work.
It occurs to me that the 2.8 with a Getrag has a history of cracking the cradle at the front tranny mount. Or so I've heard.
That being the case, I'm not sure that the cradle is up to the task of withstanding the abuse that the 3.4 can throw at it.
(I'm not going to be doing a lot of dragstrip launches, but I'm certainly not going to be babying it, either.)

I know that someone used to sell reinforcement plates, but he hasn't posted in... forever.
I'm thinking about a flat piece of steel, maybe 3/16"-1/4" thick, maybe a foot long, to fit inside the front cradle rail, where the front tranny mount attaches. The tranny mount studs will pass through this, as well.
My thinking is that this will help distribute the load a bit, and will prevent cracking and other nastiness.
It will just be held in place by the tranny mount studs/bolts. Not welded (since I don't know how to weld.)

Any thoughts or suggestions would be appreciated.

------------------
Raydar
88 4.9 Formula IMSA Fasback..........................88 3.4 coupe................................................

Read Nealz Nuze! Praise the Lowered!

That might work.
Just be careful to make the insert narrow enough and bevel the top edges so there's no chance of the insert edges cutting into the inside of the cradle when you tighten the mount bolts.

I saw a "c" shaped sleve that went around the cradle where the front mount bolted, I just boxed mine lower rail in.

quote Originally posted by HarryG: That might work. Just be careful to make the insert narrow enough and bevel the top edges so there's no chance of the insert edges cutting into the inside of the cradle when you tighten the mount bolts.

Good point. Thanks!

quote Originally posted by darkhorizon: I saw a "c" shaped sleve that went around the cradle where the front mount bolted, I just boxed mine lower rail in.

I think the "C" shaped sleeve is the one that I was talking about, that the builder disappeared off the face of the earth.

Boxing the lower rail is great for torsional strength, but is that going to stop the top from tearing out?
I think that's usually where they fail.

Edit - I just looked at your 3800 thread. Excellent! Nice work.

[This message has been edited by Raydar (edited 07-20-2006).]

Boxing the rail would make the whole rail stiffer, subject to less bending under load, reducing metal fatigue, and related cracking. It's the little bit of flexing that leads to cracks.

I banged my 3.4 on 30% of my shifts for 4 years and never had a problem with it. You know my power #s. Now then the V8 came in and that's when problems arised in the first 500 miles. But with 344lbs rwTQ what can you expect? Here is what I did. Has worked perfectly for 6000 miles in my V8. You can get some local shop to weld it for you for cheap. Nothing fancy but strong.




Here you can see the cracks I had at the top. Those were welded too.


Finished product;

welded some angle to the frame then welded the tranny mount to more angle.
Here is the front tranny mount. It wont win an award but it should hold up.

Here is the email address of a friend who makes reinforced front mounts.

briangeyer@hotmail.com

I might know someone that can weld up a brace for you in exchange for maybe some adult beverages or some help with an 88 coupe..... If you give me a drawing of everything with the dimensions on it, I can make it and then you could bring the cradle to me and I will weld it on. PM me or email. Scott