Great, thanks for the info!

Related to this (possibly crazy) idea is the C4 IRS. I have read some bad things about the Dana 36 IRS and higher Hp engines (I am thinking something in the 350 – 400hp range). So, here’s a question likely to stir debate (sorry), what’s the best / strongest IRS out there? Heidts? Corvette? Jag? Something else?

Thanks for the help and quick replies!

Well................ I've just re-read all 12 pages of this thread and I still haven't seen that anyone has come up with the real info on this accident. Where did the original pictures come from? Can I go to that source for more information? It's too bad because there has been a lot of speculation as to what happened and a lot of criticism on these IFS designs and we still do not have any proof that this failure wasn't due to something as simple as a cheap ball joint failure or something of that sort. If I have missed that post in this thread, I apologies and would thank you for that information. I've been watching this very closely because I too do this work for a living. So it's imperative that I am up-to-date on these issues.
Thanks, Walt

Check post 41 and 42 in this thread, Deuce posted the photos from an email he got from a fellow 32 owner, and you are right, so far there is no further info on the original accident.

Later, mikey

__________________
BE different....ACT normal.

No one is completely useless..They can always be used as a bad example

I agree with you Walt, far too much speculation and theory. There are thousands of these IFS out there running around. Just look under any rod at any gathering, chances are it's got a Mustang II geometry IFS. If these things were faulty as in design we would be hearing a lot more about it.

We just do not know the circumstances around this accident and all the comments are just conjecture IMO.

Vince

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Here's to you DoC, you will always be here.
My project 34
http://www.hotrodders.com/forum/34-...ght=34+progress

I posted this ... before



I emailed my friend ... and he has no updates ... on the wreck. His information has it that the insurance company totalled the 32, paid the claim ... and took the car. It was going to be sold @ a insurance auction ... just like all the other vehicles that the insurance company totals.
May already be sold by now ...

All of this is now ... second and third hand information.

From what I can see ... in the photos ... it looks like the crossmember failed. ... I have seen some fairly weak looking crossmembers and add in a poor weld, no strut support or a installation error and you could have a problem.

I have junked ( to the scrap yard for weight ) at least 30 to 40 Pinto/Mustang II's ... a few were totaled by the insurance company for front end collisions ... and I never saw a stock Pinto/Mustang II front suspension fold up like the aftermarket one ...

I do not start this thread to cause HATE/DISCONTENT ... But to open lines of communication on this subject by rodders. Hopefully some good will come from all these views of this thread.

Deuce ...

Vince and Walt,I couldn't have put it any better.I know what you mean about alot of people running these set ups in there rods.This is the first time I have ever see one fail.If that's even what caused this problem. And the new front ends today are by far more better then the stock mustang II.

I've seen at least half a dozen such failures on the web (you can find pics of 3 or 4 on this board if you look), all showing definite signs of X-member failure. A couple show pics of X-members that have cracks (from the stress riser bottom plate on Heidt's econo design especially) but haven't totally failed, confirming the fatigue failure you would expect. ALL of these are on typical X-members w/ strut rod eliminator lower A-arms. I have never seen a failed stock MII X-member. I would almost say that about the after market ones that use strut rods except I have seen a LOT of weld on strut rod mounts cracked off frames, heading the car toward disaster.

"Thousands" of them cruising around and not failed yet is NO endorsement if the failure rate is 1/1,000 or even 1/10,000. This item should be in the 1/100,000,000 failure rate area.

And how many of those failures were due to owner installed components with shoddy welds....we don't know do we? As I said before, looking at a picture without first hand knowledge of the failure scenario and coming up with a conclusion is pure speculation.

Vince

__________________
Here's to you DoC, you will always be here.
My project 34
http://www.hotrodders.com/forum/34-...ght=34+progress

I would say the relatively small amount of failures I have read about is surprising considering the following --

It is installed by the end user who - in most cases is untrained; in many cases is untrained AND not skilled; and in some cases is untrained, not skilled, careless and ignores simple directions.

A relatively complex unit like an IFS is designed to fit under fairly strict guidelines and as we know many people will modify this unit to his own needs whether it is something simple like welding a bracket on to it, to widening it to suit the chassis or attempting to strengthen the unit and inadvertently causing stress in other parts.

I would suspect that many IFS units are not designed for the large engines and the masses of horsepower that many people like to install in their cars.

Ask any mechanical engineer who designs a relatively complex part like this to be installed by the end user and he will tell you the installation is a crucial part of the whole unit and he has absolutely NO control over it. For these reasons it is very difficult to sue unless you can prove systematic type failure of the exact same type.

Exactly, Nobody wants to see anybody hurt but I am with ya'll on this. Even if the failure rate is 1 in 10,000, that is not bad considering how many are improperly installed. I would bet This is a rare failure and caused by either a cheap kit or poor workmanship on the installers part.We all have different skills and skill levels and should realize our own limits.A good welder, fabricator should even be able to install an economy kit and repair its short comings during installation.So don't blame it on the suspension until you have proof of what caused it.

That would be true if there weren't good photos of the defect and some pretty simple mechanical engineering design principles that stress rod eliminators violate. Fortunately on most of the faiures there are good photos and the failures are in the body of the X-member, no where near the user affected areas. Installation skill has nothing to do with the failure.

This photo shows where a Heidt's (and probably most others) X-member is GUARANTEED to eventually fail if you use strut rod eliminators. The intersection of the bottom plate and side plates is a sharp corner (ultimate stress riser) and is in a spot where flex is greatest w/o strut rods. A fatigue crack forms from the plate intersection to the bolt hole and the bottom part of the X-member rips off. My educated opinion is that looks like what happened in the initial photos on this thread and what happended to ALL of the failures I have seen.

Key word!!!! ''Look's like'' Plus the cross member is not like the one you posted.

Touche'! That's the beauty fo America, you have the fredom to run what you like (mostly- can't run carbs, good exhaust, decent compression ratio, blowers, proper torque converters, good cam etc., etc., etc.,) but it's all for the collectivist good after all!!

Hello, my name is Trees and I had a M II failure and started a post about 3 years ago. This post is going to live a long life and imagine Jon will roll the two together so the info sharing will continue on this great site. Thanks to Deuce, he took the time to pass on info to us so we could "watch and learn". I was gone Nov and some of Dec and did not see this thread until this AM and have spent the last couple of hours plowing through each response to see what new ideals I could come up with. Not a whole lot new other than the need for a routine inspection of our strut-less kits can not be overlooked, ignored or neglected.

Unfortunately there is no way to determine the failure rates of the different components of kits, much less determining the causes and which manufacturer is to be shunned. We could possibly start a special Topic to post known incidents, what caused the problem and what the fix(es) was/were. I was pleased to see some people have implemented some of the ideals that came about from the original M II kit failure thread. In the meantime, if you have a MII kit installed, make sure your seat belts are in good shape and worn at all times!!!

Trees

Here is the thread started by Trees ... on June the 27th 2003 ...

http://www.hotrodders.com/forum/mus...lure-18601.html

It is fairly well documented here that I am NOT a fan of the Pinto/Mustang II IFS under Fords before 1933 and after 1948. To be completely FAIR ... ... How about seeing some failures of the straight axle front ends ... I only know of two in my 30 years of rodding ... a tube axle end broke off ... on a split wishbone front end under a 40 Ford ... and a Model A with a Super Bell axle ... that had been drilled and welded on by the owner ... failed where he had weakened the end by drilling and welding .