Here's the shock mount on my car (I realize this is the front....). I like the design - it's a continuous piece, both in length from left side of the car to the right side, and is a boxed design without welds (not open on any side). It may not look it from the pic but it is very thick walled stainless steel...it's BEEFY! Not going to win any awards for lightness. Just thought it might be interesting to see this type of mount.
Failed Shock Mount
- Thread starter Jim Craik
- Start date
Jim Craik
Lifetime Supporter
Very scary. Now I know why they call you lucky Jim! I would not be too chuffed to have that happen to me.
Interesting now it's become a "British Design" :laugh:
If I was lucky enough to own one, I would now perform a thorough eyes-on, hands-on, "nut and bolt check" of the entire vehicle. If there's one problem, there may be others. I think you are a test mule mate!
Is yours still in warranty Jim?
Keith1,
No she is well out of warranty, I've had P2264 for three wonderful years and 28,000 miles. I've been nothing but happy with the whole experience!
I am working on a couple of things, I'll let you know, when I know more.
FWIW, from reading only 'most' of the posts in this thread, there is a danger replicating what was done for racing in the 60's and applying that to cars driven on the open roads for many miles.
Granted, 100 miles on the track is supposedly equivilent to a 1000 miles on the road, but most of these cars suffered DNF's in their races at sometime and usually from breakages. But these cars were designed for one purpose only and driver safety was not even on the list of requirments.
The sway bar connected to the top shck bolt may be neat and light, but to my untrained eye, it's fundamentally flawed from a safety point of view in the modern world.
We ought not to get carried away with authenticly repreducing stuff we now know to be wrong.
Granted, 100 miles on the track is supposedly equivilent to a 1000 miles on the road, but most of these cars suffered DNF's in their races at sometime and usually from breakages. But these cars were designed for one purpose only and driver safety was not even on the list of requirments.
The sway bar connected to the top shck bolt may be neat and light, but to my untrained eye, it's fundamentally flawed from a safety point of view in the modern world.
We ought not to get carried away with authenticly repreducing stuff we now know to be wrong.
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FWIW, here's how the sway bars were mounted properly:
This is P/1080, a late Gulf-spec car. I deliberately shot closeup photos of the sway bar mounting because I was highly dubious of the SPF scheme, which seemed decidedly amateurish in comparison, and in the someday-faraway-future when I do finally get my GT40, I was going to have my car converted to follow the factory specification before it ever turned a wheel on the road.
Note that there is a sturdy and reinforced inverted U-shaped chingus which is captured by the shock mounting bolt; the sway bar is then contained in sturdy aluminum blocks which are bolted to said chingus.
One picture is the original and the other is a modified spf mk 1
Attachments
Seymour Snerd
Lifetime Supporter
There's an even worse danger, which is to implement something that superficially resembles what was done in the 60's, but implemented worse.
In the context of fatique and this particular failure, your "supposedly" is exactly backwards. Road miles are much harder on the equipment.
Reading 'most' of the posts is also dangerous in its own way.
Where specifically do you see someone being "carried away?"
And what specifically is wrong with mounting the anti-roll bar on top?
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Jim Craik
Lifetime Supporter
Alan,
I see a potential problem, as this design still places leveraged, side forces against this relatively light bracket, designed to take only vertical loads.
The top bolt that holds the removable Transmistion brace appears to be a better choice to me.
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Alan,
'supposedly' refers to the fact that much in racing car design is experimental and therefore conjecture is by necessity, par for the course.
I agree that only reading 'most' of the posts is dangerous to any comment made thereafter, but having said that, the admission was designed to express my comments as only 'offered' as a guide and not a proven argument against anyparticular opinion. My thoughts were offered as my perspective to various comments within the post, not all.
Frankly, if an untrained eye such as mine, can immediately spot an over-stressed componenet, then what are the 'supposedly' qualified car designers thinking by replicating such an obviously flawed element of a design?
I maintain that road miles are in no way less wear inducing than race miles. Show me a race car, fully maintained that has covered 20K miles and that is not a wreck when compared to a similar road car with similar miles.
Nothing is 'wrong' per se with mounting the roll bar mounts on top, just be darned sure that you haven't done a 'Chapman'. After all his cars killed people!
I did not expect my 'carried away' comment to be taken quite so literally with regard to any specific post in this thread. I merely suggested that 'we', all of us (including myself in my own endeavours to create an acurate replica of a sixties race car), should be careful to not blindly follow authenticity to the point of re-creating dangerous componenets. Mount your sway bar brackets where ever you ike, but for goodness' sake, factor in some strength to your designs.
All said with only the goodliest wishes for all in mind.
Just realised, I didn't infer that mounting the sway bar bracket on top was 'wrong'. I said, "The sway bar connected to the top shock bolt may be neat and light, but to my untrained eye, it's fundamentally flawed"
That bolt is stressed in to many directions and the sway bar forces are focused on theend (unsupported part of the bolt), which if not causing the bolt to break or bend, is surely going to induce the twisting force that others have mentioned. Therefore, stressing the bracket across its axis, when the bracket itself is clearly designed to brace against vertical forces.
That bolt is stressed in to many directions and the sway bar forces are focused on theend (unsupported part of the bolt), which if not causing the bolt to break or bend, is surely going to induce the twisting force that others have mentioned. Therefore, stressing the bracket across its axis, when the bracket itself is clearly designed to brace against vertical forces.
Howard Jones
Supporter
I think that Mark has hit right on the head. By moving the mount to the top and using both sides of the shock mount bolt the roll bar load becomes a vertical one that is feed straight down into the mount instead of hanging it out on the end of a lever and feeding the load in there. That is what the shock mount is at least designed for and I bet this is why the orginal cars seam to have been modified in this way.
Cliffs pictures are what I am talking about when I say I would fully box in the mount.
Cliffs pictures are what I am talking about when I say I would fully box in the mount.
Seymour Snerd
Lifetime Supporter
What design are you referring to when you say "this?"
Seymour Snerd
Lifetime Supporter
Howard and Mark: you're both agreeing to things that have already been agreed to by almost everyone way earlier in the thread. I'm having a really hard time figuring out what you're trying to communicate, unless it's merely agreement. And there are much shorter and simpler ways to communicate agreement.
Seymour Snerd
Lifetime Supporter
1. It's not clear the part is "overstressed" (meaning taken beyond it's elastic limits in normal operation). I think it is subject to fatique (which is different from overstress, and seems to be a point lost on several people here). But that is perhaps a matter only of terminology. Clearly the design isn't "correct" because it failed in normal use. (Unless of course someone wants to argue that Jim's use of his car is not "normal".)
2. It isn't clear that what Hi-tech/Superformance did is a replication of anything. I haven't seen a photo of an original GT-40 that is particularly close to the shock mount on my car, SPF P2160. Read the earlier posts and look at the pictures.
3. Even so, your question, although rhetorical I think, would be better adddressed to Hi-Tech and Superformance. I don't think anyone here knows "what they were thinking". I'm also not sure that is an interesting question except to a corporate historian.
4. But if I use the rhetorical interpretation of your question, you are asserting that Hi-Tech/Superformance should not have replicated an obviously flawed element of a design even if it was historically accurate. You sure about that? Where do you draw the line? You can argue that from either a modern or street-car perspective any 50-year old race car is "obviously flawed" in almost every respect. So where do you draw the line? If you "fixed" all the "obviously flawed" elements the result wouldn't resemble a GT40 in any way except maybe overall shape so what would be the point in building it? Ford already did that, and it's called the Ford GT.
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Seymour Snerd
Lifetime Supporter
1. I think you meant to say "road mile are in no way more wear inducing..."
2. You started with an assertion about road and race miles and then tried to defend with an assertion about road and race cars. Let's do one subject at a time.
3. I'm not talking about "wear", and Jim's car did not "wear out", it broke. I'm talking about fatigue and once again, a single street mile can easily produce more fatigue than a single track mile. As Rick Muck said earlier, race tracks are smooth and tend not to produce the frequency of cyclic loading that occur on the street.
For reference, the first line in the wikipedia article on "metal fatigue":
"In materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate stress limit, and may be below the yield stress limit of the material. Fatigue occurs when a material is subjected to repeated loading and unloading. If the loads are above a certain threshold, microscopic cracks will begin to form at the surface."
Hi
Ive been following this thread with great intrest from the start...
Unfortunatly, I cannot see the pic, Mike Drew posted, can Mike or someone else please re-post the pic
Thanks
mick
Ive been following this thread with great intrest from the start...
Unfortunatly, I cannot see the pic, Mike Drew posted, can Mike or someone else please re-post the pic
Thanks
mick
Seymour Snerd
Lifetime Supporter
I'd rather fix your machine. Here's the URL:
http://i692.photobucket.com/albums/vv288/576103/IMG_1179.jpg
What happens when you try to open that URL?
Alan,
I tried to open the URL, but I cant find it....
I tried to open the URL, but I cant find it....
Seymour Snerd
Lifetime Supporter
This is being hit on the head lessons in here.
Seymour Snerd
Lifetime Supporter
What happens when you click on the link in my previous message, the line that starts with "http..."?
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