M200 breakage
 

Well I finally got my stocker out after a year and a half of work, sweat and money. Booked in for the friday test day before the first bracket race of the year. Did some driving on the return roads and set the lash etc. Went down when the lanes opened and made my first pass ever in a class car. All was good, the launch felt excellent, pulled hard in first, second pulled hard, shifted into 3rd gear and BANG!! felt a thump on the floor after the BANG. Motor kept running, shut it off and pulled over to the side. Found the driveshaft in 2 pieces, twisted in the middle. The u-joints were both intact as well. The tranny case is busted all the way around and the trans pump and converter is busted up good. So my question is, the chicken or the egg scenario, did the trans case bust, push the trans backwards and bottom out the shaft and break it? Or did the shaft break, causing the destructive forces to break the trans case. I have read about the weak bell housing area of the 200, and the braces available, but I would have thought that a 305 would be easier on them, as I know guys run them behind big blocks. After I pulled everything apart, I think the trans case went first. Any thoughts on this? Also where can I get some of the bell housing braces? thanks in advance.

Dave

Re: M200 breakage
 

Thats why McClays come with a case brace.
I'm not sure if he will sell you one if you are not a trans customer.
How hard did it leave?

Re: M200 breakage
 

My car did the exact same thing . I believe it was caused by the stock driveshaft whipping. I installed a transmission brace and a larger diameter custom driveshaft and never had the problem again,

Re: M200 breakage
 

Bill,

It left good, felt good and looked good on video. It was 1.64, it was just ok.

Re: M200 breakage
 

What type of rear trans. mount do you have, should be stock rubber mount. Most guys with 200's (non Mclay) don't have a brace. There is a guy in B.C. Jim Mantle who does 200's I don't have his number, maybe somebody on the forum has . Sounds like there might be other issues. GSA 612

Re: M200 breakage
 

I spoke with Jim this weekend, he was at the track and he freshened that trans not long ago. He suggested the brace. He will be building me a new one.

The rear mount was one of the urethane energy suspension models, which came in the car, with the same trans, shaft rearend etc. It was working for years that way. thanks

Re: M200 breakage
 

I have a T200 without any bracing, but I do use a rubber trans mount. TurboAction 200 and never have had any problem. I was thinking you might have had a driveshaft problem, and it worked its way up stream. Mine isnt fast , by any means, but it goes 1.56-58, with a 1.54 best ever, at 50 over L weight.

Re: M200 breakage
 

We have never had a brace on a T 200 and have never cracked a bellhousing .
In fact , I always cut the ears off with a skillsaw and a carbide tip blade and de- burr the edges., Factory type engine mounts with a good, solid torque strap ,and a poly type mount.
I suspect your problem started with the driveshaft. Not sure why though.
On my Omega, (350 Buick stump puller), I shortened the original 2 and 3/4 ,thin wall shaft to accommodate the 12 bolt rear, and never had a problem with that either.

Re: M200 breakage
 

We use a stock rear mount on our Malibu M200 and the same trans has over 1000 runs without any breakage. We have a Mark Williams driveshaft with about 1 degree pinion angle. Smooth as anything.

Re: M200 breakage
 

Thinking about it more I would agree with what Bob and Mark both said. With the 60 foot you had the trans and drive shaft did not see a huge amount of torque. And I assume from what you said it did not shake or shudder on launch. It didn’t happen until the trans was in drive and starting to get up in RPM.
So probably something driveshaft related. The one thing I would check on the remnants of your transmission is the tail shaft bushing to make sure the yoke was not super sloppy in it. Could your drive shaft have been bent or dented? or overall length or yoke length a little short? Or touching drive shaft loop?
When Jim works on it you may want to also consider a roller bearing in the tail shaft.
Is that Peter Legg’s old car?
Are you going to have it back together for Bosie?

Re: M200 breakage
 

Dave,
I had several case failures with my TH-200, fortunately caught before catastrophe struck. I tried to buy a brace from McClay, but he only supports his own transmission customers, or at least did at that time. I built my own brace connecting the two "eyes" on the passenger side of the trans with 1/2" thick by about 1" wide aluminum. I tried to upload a photo but the file is too big. Email me at grant4060@yahoo.com if you'd like a few photos. I also bought an aluminum deep pan from Turbo-Action to act as a girdle and give more strength to the case. I run this behind a big block stocker, 3570 lbs. with best of 1.41 60' and since the changes have had no further troubles. The transmission is a reverse pattern unit built by Jim Mantle, who is the greatest guy to deal with, and his units have always performed perfectly. Ditto on using the stock rear mount, also would suggest the left front torque strap from earlier posts. Make sure there is enough spline depth in your driveshaft yolk so that it cannot bottom out when the car launches and the rear end pushes it ahead. Hope this helps,
Grant

Re: M200 breakage
 

Bill, it was smooth with no shake. The driveshaft was perfect length for sure, u-joints were good with fresh grease. The tailshaft looks ok, other than the seal has a slight bend when the yolk came flying out. The shaft looked good with no dents or any other signs of damage. Not touching the loop either. Could the shaft just have failed? seems rare to me that a shaft would twist and break like that.

It is Peter's old car, its not going to be back together for Boise now, all plans have changed, hoping to be ready for Mission.

also guys, I am using solid motor mounts along with the poly trans mount. so strap is not gonna do anything. Are the solid mounts not a good idea?

Grant,
I will e-mail you, thanks

Re: M200 breakage
 

Dave, I'll try to do these photos again....
Grant
P.S. No one will confuse these with the McClay brace, but so far so good...lol

Re: M200 breakage
 

call frank lupo or shawn at dynamic he can get you a professionally made brace

Re: M200 breakage
 

Leon Mirainian also builds a Tubular brace with heim joints. Great looking piece. I have had one on all of my metrics since I've been racing them. he also builds a great 200...

Re: M200 breakage
 

Todd, do you have a number for Leon?

thanks to all the guys who have replied. I really appreciate the help.

Dave

Re: M200 breakage
 

I raced an Olds with a 455/th400 and put many passes on the stock driveshaft that had a rubber slip connection close to the rear u-joint. Genius that I am, I figured that a solid shaft would be this huge improvement. On the first pass at 100+ it roused me out of my slumber by reconfiguring the floor contours. Found half of the shaft and the slip yoke was still in the back of the trans. The bellhousing was busted almost all the way around, plus lots more damage.
So, my wager would be the driveshaft failed for whatever reason. I don't think TH 400's have a reputation for weak bellhousings.

BTW, for Olds freaks, that was a "W" code tagged trans.

Re: M200 breakage
 

Leon Miranian's
Turbo-Flite Racing Transmissions
(443) 995-3945

Re: M200 breakage
 

We use McClay, with a rubber mount also. I might add that McClay not only uses
a brace but he adds a gusset or two on the case. The failure you described is the
common 200 breakage area, but without the driveshaft failure thats a new one.
If you did have everything mounted solid its possible you might have some pinion
angle issues that added to the driveshaft failure. just a thought..

Bob Aceves
#746 E/SA
A&M motorsports