Holy crap---deja vu

I'd say the bell will snap first because of the way the bell is designed, the cracks always start in that lower corner and the vette tail piece is the short one with the mount very close to the 4 bolts. This makes that a meaty sections which is sturdier than the bell according to the pics :D It's also not a sudden failure, the crack develops over time and suddenly lets go when it reaches it's threshold. If AJ had inspected this earlier on he would have spotted a big crack.

If you spot it before you split it in half it can be fixed
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Stroker-427 said:
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It looks like your transmission was the only thing keeping your Vette toghether.

I asked for educated opinions, not random slander of a car you've never seen!! I take great pride in my work and I went over the frame of this car thoroughly before putting it together. I have also checked for stress evidence on a regular basis. I've been a fabricator and mechanic for 40 years. If you would read the entire thread instead of jumping in with random BS, you might see that this isn't some wet behind the ears kid asking daddy for critiscism!!! If you haven't guessed, yea, I am offended by your remarks! I will find out what the cause of this is without your help, thank you very much.
TT you're right. If I had inspected it I probably would have found the start of a crack. Ony problem is. It's a PITA to remove all parts that might stress like this on a regular basis to inspect. I had no indication there was a problem. No vibration or anything. It happened within about a 10 second timespan.
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I think you're taking Pier Paolo's message the wrong way, he didn't intend for it to be mean spirited. What he meant is, from the failure mode it seems that the trans case was acting as the backbone of your car, instead of the frame and that this caused the failure you experienced for the 2nd time now.
 
Twin_Turbo said:
I'd say the bell will snap first because of the way the bell is designed, the cracks always start in that lower corner and the vette tail piece is the short one with the mount very close to the 4 bolts. This makes that a meaty sections which is sturdier than the bell according to the pics :D It's also not a sudden failure, the crack develops over time and suddenly lets go when it reaches it's threshold. If AJ had inspected this earlier on he would have spotted a big crack.

If you spot it before you split it in half it can be fixed
24b9ec5d286080.jpg
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SO the crack starts at the pass side as shown by the weld, I presume??

any ideas what to do to make it all grenade proof??? before the issue arrives??

:fishing:
 
Twin_Turbo said:
I think you're taking Pier Paolo's message the wrong way, he didn't intend for it to be mean spirited. What he meant is, from the failure mode it seems that the trans case was acting as the backbone of your car, instead of the frame and that this caused the failure you experienced for the 2nd time now.
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Yeah, lighten up, if you ask for opinions you will probably get them!

Looking at your broken case, that doesn't look like a torsional failure it looks like a failure started by bending perpendicular to the drive axis. That might be your mounts, your crossmember or your frame (or all combined)?
 
I can tell you I inspected my BTO crossmember this past weekend. The new rubber mount had crushed just enough that the tranny itself was touching the crossmember. My tranny guy felt it was a poor design, as the "gusset" area should have been underneath, not above, where it interfers with the mount.
 
AJ77 said:
Stroker-427 said:
.
It looks like your transmission was the only thing keeping your Vette toghether.

I asked for educated opinions, not random slander of a car you've never seen!! I take great pride in my work and I went over the frame of this car thoroughly before putting it together. I have also checked for stress evidence on a regular basis. I've been a fabricator and mechanic for 40 years. If you would read the entire thread instead of jumping in with random BS, you might see that this isn't some wet behind the ears kid asking daddy for critiscism!!! If you haven't guessed, yea, I am offended by your remarks! I will find out what the cause of this is without your help, thank you very much.
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IMO: this is a prime example of how a message on a internet forum can be taken the wrong way.
I agree with the previous comments about something flexing: the frame or the crossmember - the poly trans mount would add to the problem and add more stress on the trans case than a rubber mount would have a lot more flex....
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I apologize. To me, it just stands to reason that if a person goes to all the trouble to build a (I think) nice looking and running car with a lot of well thought out mods, that he wouldn't go to all that trouble and then put it on a rotten frame! I'm sure it is a flexing problem also but the comment abnout the trans being the only thing holding the car together seriously rubbed me the wrong way. :surrender:Art
 
Hey man, don't sweat it - I'll bet that you're stressing a bit about this whole thing, who needs that crap. This is supposed to be a relaxing hobby......
Frank
 
I found a crossmember made by G-Force on the web today. It looks like a stock one on the ends, 2" x 3" tubing, but where the exhaust runs on both sides, it has an elongated "U" made from 1/2" plate steel about 3 1/2" wide welded in for clearance. No way that thing is going to flex. Might just have to go for it.
 
Here you go.
G-ForceCrossmember.jpg
 
Looks like stock, on each side the 2 bolts up into the frame and then the cross bolt. Do realize that the 80??-82 crossmember with the single hump (not the 2 holes) has a different location for the through bolt (why on earth they changed that is beyond me)
 
Of course I'm sorry about that!

May my english is very bad...... but for shure I have no reason to think that your car is a piece of rotten iron!

I assume that any enthusiast like me will take care of the Vette like I did.

May with the wrong words, but I was only trying to help you with my modest opinion. The bellhousing of a transmission can't be cracked in two parts only by the vibrations neither by any kind of abuse of the car.

I think (and I hope that you will try to understand that may I have some problem to be more accurate explaining my opinion) that only some very big force can do that.

Again, belive me, there is no reason to be offended..... first of all because it wasn't in my mind to do that.

Anyway I'm ok with me!
 
The only thing I can think of that might cause such a problem is maybe the trans is out of alignment with the engine. Check your alignment pins to be sure there is no binding and things line up correctly.
 
SHAKERATTLEROLL said:
The only thing I can think of that might cause such a problem is maybe the trans is out of alignment with the engine. Check your alignment pins to be sure there is no binding and things line up correctly.
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No problem there. The trans slipped right on the locator pins and the boss on the converter also in the crankshaft.
And to Stroker 427--- I'm sorry for my outburst. I probably would have jumped on my wife's or kid's asses if they would have said anything. I was and am so careful to think out everything I do to this car that when (not if) something goes wrong, I feel like I failed to think it through enough. I had it in my shop looking it over and planning for 3 1/2 years before I even touched a bolt on it. I'll be a good boy. Art
 
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AJ77 said:
SHAKERATTLEROLL said:
The only thing I can think of that might cause such a problem is maybe the trans is out of alignment with the engine. Check your alignment pins to be sure there is no binding and things line up correctly.
Click to expand...
No problem there. The trans slipped right on the locator pins and the boss on the converter also in the crankshaft.
And to Imo--- I'm sorry for my outburst. I probably would have jumped on my wife's or kid's asses if they would have said anything. I was and am so careful to think out everything I do to this car that when (not if) something goes wrong, I feel like I failed to think it through enough. I had it in my shop looking it over and planning for 3 1/2 years before I even touched a bolt on it. I'll be a good boy. Art
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Mice, Men, and Plans, and then Shit Happens....it all sounds very familiar....so you ain't alone.....:amazed::cussing::clap:
 
I have been helping a friend for years with automotive stuff of which he is BIG into. But the problem is that he is a GENIUS lol. No really he is a genius. And I think that is where lies the problem. It took a long time to help him to understand even if he does purchase the most expensive and best parts available that does not mean they all just bolt up lol. It would be nice but this just does not happen all that often when doing mods. The other problem is designing things to fit in the way of fabrication. If things go like the book he is a very happy guy but if not things go out the window lol. The other downside of which for him I do consider a downside is he does have funds to use however he wishes which can get him into trouble lol. Right now he has a Factory Five Type 65 Coupe kit with all of the upgrades one can have. The problem was at first he did not feel a SB Ford would be enough get up and go so he was going to get a Ford Big Block 557 CI lol. So I talked him back down to a good SB Ford 351W with some goodies and Webbers.

He also has a 67 Corvette that is very nice and built well with a 421CI Small Block with a Dart Block that is a bit over 525 HP with out the N2O backed by a TKO-600 RR and 3.73 Gears. He even has two fuel systems on board lol. The main tank for normal messing around and a sub 5 Gal tank that holds only race gas so when he does go to the 250HP N2O he just flicks a couple of switches and is on the Race Gas for the N2O. So many mods it would take up the entire page to talk about them all lol. That car has been a pain in my Rump lol.

The other car he has which almost killed him a couple of times is a Beck Spider it looks like the 1955 Porsche Spider that James Dean died in. I built the car for him oh by gosh that long lol. 20 years ago. Darn nice little car. As it only weighs 1250 Lbs so the engine I built after I told him not to use the darn Porsche Super 90 engine was a mild 2110 CC VW with about 140HP which is more than the factory HP rating of the Original race version of this car. Well this last year he decided that he needed more HP so thus since he knew I would not agree lol. He did not tell me till he had problems to make parts fit lol. When I got there and finished up all the fab aluminum mounts and such for things like the crank trigger ignition and fuel system mounts I was informed that he had more to go such as the Turbo lol. This thing is Electronic fuel injection with an intercooler turbo with 400HP on tap. With luck the system will let you control Boost and other stuff from the cockpit of the car. I did cheat a bit with the install and used a bit weaker clutch then what I felt was needed to maybe help keep him alive for a bit while he got used to the car along with turning the engine down to about 200 HP lol. But as said plans and mice and men lol. That night he took it for a drive and did notice the change and changed it back lol. I found this out when he informed me there might be a problem with the car lol. I asked what is the problem he said well I was on the highway next to a ZO6 Corvette at about 100 mph and they took off and he informed me that after he went into high gear and was going a bit over 140MPH his little Porsche changed lanes and I said ok and he told me he did not move his steering wheel lol. I said well you were in the air lol. He said WHAT lol. I had to inform him the car is not aerodynamically set up for those kinds of speeds like I told him before to keep it to a max of 120 or so MPH lol. There is lots of other stuff but that is just the jest of it lol.
 
I know all us olde pharts here and some maybe not SO olde can recall stories of past hotrod related kraziness.....and the stories need not be embellished one bit...but somehow we survived, ....

:thumbs::surrender:
 
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