AL Bushings

[TimZ]

Originally posted by Bob Gervais:
Well, the engineering data is in the form of common sense. In example, the stock bushing is held in compression, and the ring bushing puts the bolt in shear load.

Sorry, but this is simply not true. I went over this in detail the last time it came up and as I recall you were involved in the thread. BOTH the ring style and the cup style put the bolt in tension (not shear), just as the stock bushing did. BOTH the ring and cup styles hold the ring/cup in compression.

The only condition that presents shear loading to the bolt is when there is insufficient clamping load applied to keep the bushing from moving laterally. Both (actually all three) designs have this shortcoming.

<small>[ March 15, 2004, 01:02 AM: Message edited by: TimZ ]</small>

 

[SHODWN]

.185 and that is twice as thinc as the uni body is made from. there presently is not need to look at the Cup style for deformation, because it can cause any.

Do you understand what that pic is showing? it is showing the support that he unibody has when both bushings are installed.. The Ring has MUCH MUCH less, also MUCH less contact with the unibody, when the unibody is stretched into the gap the ONLY section left of the ring is the inner edge. See other pic for contact.

 

[munkee]

They sure look exactly like the rear gen3 mounts I just installed. Is it possible to get a pic of the insides?

 

[Lance Cheney]

I wanted to make a few points here, even though this thread is ridiculous. I think anyone who posted on the last thread about 'getting rid of the gap' should automatically be banned from this discussion because they obviously didn't understand how these work.

My points:

First, what does the inside of the FRONT subframe support look like. IIRC, these are not covered by the recall and have the factory support (not the 3/16" new hardened plate nut). These would be in more danger of deforming.

Secondly, does anyone have a statics book handy. Torquing the bolts up to 90lb-ft should apply a preload of somewhere between 7500 and 10000 lb to the bolt/nut plate/subframe combination per corner. I'd like to see how much this would deform the nut plate -- this would answer Tim Z's question directly -- but I don't have a ton of experience doing this and do not have the textbook I borrowed the last time I needed to. It would also be interesting to see how much it would deform the FRONT support area, since I think it would be more likely to be a problem since I don't believe it is as sturdy.


The last point is that even if you do deform the subframe I would not consider it dangerous as long as it did not result in loss of clamping force on the subframe. There is no way 10000 lbs is going to stress the reinforced nut plate to ultimate failure, but it may bend it enough to close up the gap on a bushing and cause it to go solid.

Oh yes, my last point. The aluminum in the cup-style is not immune to deformation as well. If you can deform a 3/16" hardened steel plate then the aluminum is going with it (I think it's what, 5/8" thick or so at in the middle -- probably around the total strength of the steel as far as deformability is concerned). This presents a dangerous situation since the amount of deformation required to 'go solid' is a lot lower than on the ring style -- the set of cup style ones I got are pretty close already (20-30 thousands of gap, if that). If you deform the nut plate/frame/bushing combination eough to close that small gap then you're in trouble. The ring-style ones have a huge gap and are immune to this concern.

Unfortunately, or luckily, I had to retain the lower half of the Delrin ones I had because I can't get them out of the subframe (I was replacing them because the top half is tweaking). They have a significantly shorter extension up into the subframe than the aluminum ones, so I have a lot of extra space there (my preferred design would have just enough material going through to center the subframe hole on the bushing and no more).

Of course, if the nut plate doesn't deform then this isn't an issue. But then in that case it isn't an issue for the ring-style either.

-Lance

<small>[ March 15, 2004, 12:20 PM: Message edited by: Lance Cheney ]</small>

 

[Lance Cheney]

SHODWN:
.185 and that is twice as thinc as the uni body is made from. there presently is not need to look at the Cup style for deformation, because it can cause any.

Do you understand what that pic is showing? it is showing the support that he unibody has when both bushings are installed.. The Ring has MUCH MUCH less, also MUCH less contact with the unibody, when the unibody is stretched into the gap the ONLY section left of the ring is the inner edge. See other pic for contact.

Contact area is irrelevant. I know the old thread had posts and posts about 'more contact area that OEM' and all that (mostly from Bruce), but the plain fact is that it just doesn't matter unless it is so small that the clamping force is concentrated so much that it causes failure of the source material.

As far as holding the subframe in place, the clamping force is what matters. For the ring-style bushings this clamp force is going to be loaded somewhere along the ring. This may involve deforming the aluminum, deforming the steel in the frame mount, or both. But it's not going to lower the clamping force and it won't have any effect on whether the subframe moves around.

In fact, if you really think about it you'd think it would be better for the subframe to deform, since if it does the ring has to go 'over' the volcano, so to speak, in order for it to shift around. The only time that's interesting is when you don't torque the bolt properly though, and then you're in trouble no matter which bushings you are using.

-Lance

 

[Bob Gervais]

Well, I'm done. I've wasted enough time on this. The spacers will be made to correct the design flaw, those who don't think they need them will not get them, and that's fine with me. My only intent was to offer some help where it's needed, not get into a ******* match about engineering basics. I paid attention in engineering school, enough to know what the difference is between tension and shear loads. When the spacers are available, a post will be made on appropriate forums/lists on where to get them, how to install them, etc. I don't plan on getting into why they're needed, just on posting the basic information so the Taurus community can use it as they see fit.

 

[Mike Kopstain]

I missed this thread and really don't want to involve myself that much, but I want to add a couple points. I am not an engineer first off, so when a potential problem was initially brought to light, I was at first relucatant to beleive it, but then assembled some parts together and brought them into an independant tester to have them tested.

Before I had them tested, I described the tests that would be done and more importantly also noted that I would not make the results public, unless a promblem was indeed found. The end result is that there is no concern here. I realize that I will catch a lot of heat for not posting the findings, but in all honesty, I will take the word of an engineer that's been in this field his whole life over the speculation of a bunch of backyard mechanics.

I sold these style bushings for the better part of a year and only pulled them off the shelf because I wanted to be able to voice my opinion on this subject truthfully, without people accusing me of trying to push my products.

Have people pulled ring style bushings off their car and found a deformed unibody? Yes. Have people pulled stock bushings off of their car and found a deformed unibody? Yes. Are all 3 types of aluminum bushings overkill? Yes. Will they result in a failure on your car? No.

If the spacers were necessary, we would have covered it out of pocket to get our customer's cars fixed. It is the finding of a professional however, that the spacers are not needed.

That's really all I can add on this subject.

Regards,

Mike

 

[Lance Cheney]

Bob Gervais:
I paid attention in engineering school, enough to know what the difference is between tension and shear loads.

headbang There's a lot of good information on this page, and it's organized in such a way that it's easy to understand. The writer has a graduate degree in mechanical engineering and knows his stuff. The content also happens to be extremely relevant to your continued belief that you know what you are taking about.

A good tutorial explaining fastener preload, shear and tension forces, etc.

In particular:

"The other type of joint is loaded by shear force (Fs). In a joint loaded in shear, the friction between the parts keep them from moving when subject to a shear force. The friction between the parts carries the load, not the fastener." and "With a properly designed and tightened joint, the bolt will not experience a direct shear load."

I can't believe you still think that this bolt is in shear during normal operation.

The only time this bolt is in shear is during an accident, and it's INTENDED to break then.

I'm trying to think of a bolt on the suspension that is designed to be in shear or double-shear and I can't think of ANY. Can anyone else?

You're definitely right about it being a waste of time though.

-Lance

<small>[ March 15, 2004, 03:20 PM: Message edited by: Lance Cheney ]</small>

 

[shojuan]

Lance Cheney:

A good tutorial explaining fastener preload, shear and tension forces, etc.

Thanks for the link Lance. That should be a good read for just about everyone here.

I'll see you at dyno day on Saturday.

 

[91taurisho]

Mikey, Was this test conducted with the recall kits or without??? If you don't feel comfortable saying then you can pm me. I would like to know but if not that's ok too...

I've been thinking this entire thread that all of you are argueing over nothing! All of you have brought up very relevant points. Yes they(ring style) can deform a unibody. Yes the stockers can deform a unibody. ****, A curb can deform a unibody... Anything CAN deform a unibody but will it **** you or your car is the question that should be asked(I know, it was.) As most of you have clearly stated, it is possible. But on the other hand wasn't it Ford who had a recall because they're subframe nuts and bolts were killing people??? My point is this: You can only say it is terrible if A)there is a death because of someone using the product, B)the car is ruined by the product as proven by an engineer(as Mikey has just stated that they will not ruin your car as proven by an engineer), Or C)the maker of the product feels that they are unfit and they should be traded for a newer, better product(Bruce has not done this! He has said he will stand by the usage of the ring style and he will still use it in his cars.). Niether one of these things has happened and all of you argue over this pointless issue!

I also noticed how none of you that were argueing posted after Mikey said that...

I know I might be flamed for this but I don't care... This is just my $0.02

 

[Dr. Tweak]

I'm behind you on that one. Mikey's SFBs are staying on my car. ****

 

[TimZ]

Bob Gervais:
The spacers will be made to correct the design flaw, those who don't think they need them will not get them, and that's fine with me.

Just want to mention one more thing on this thread...

If I read the posts from this thread correctly, the spacers mentioned above were intended to make the gap smaller by sitting inside the ring and taking up the additional space. For reasons that should be clear by now, this is not a good idea. At all.

By tightening up the gap you will run a greatly increased risk of bottoming out the bushing, decreasing the available clamping load, and causing the very failures that you were trying to prevent.

Hopefully these just won't be offered at this point, but I fear there are still a few people hanging on to superstition...

<small>[ March 18, 2004, 12:18 AM: Message edited by: TimZ ]</small>

 

[Bob Gervais]

TimZ:

Bob Gervais:
The spacers will be made to correct the design flaw, those who don't think they need them will not get them, and that's fine with me.

Just want to mention one more thing on this thread...

If I read the posts from this thread correctly, the spacers mentioned above were intended to make the gap smaller by sitting inside the ring and taking up the additional space. For reasons that should be clear by now, this is not a good idea. At all.

By tightening up the gap you will run a greatly increased risk of bottoming out the bushing, decreasing the available clamping load, and causing the very failures that you were trying to prevent.

Hopefully these just won't be offered at this point, but I fear there are still a few people hanging on to superstition...

They'll still be offered. The design of the shims allows the ring to be clamped with the same force it had initially.

 

[SHODWN]

Great link Lance..

In the situation that the diagram presents its correct. But now take the top pf the clamp (unibody) and make it thinkker then the lower section. Also make the unibody concave to the center of the bushing. Then calmping force as pict'd in that diagram if different.

The piont here is that with the ring bushing you WILL suck the unibody into the center of the bushing, Both weakening the unibody and forceing less contact of the ring because over time it will concave more making only the ID edge of the ring make contact to the now deformed unibody.

Also lets say you install the bushing with 100ft, and over the next few weeks the unibody has flexed into the bushing and now what seems like a loose bolt is realy the distance from the unibody to the top of the snout has shrunk. You re tq and re stretch, and repeat. Over time you will either pull the unibody all the way into the center, or the steel of the unibody will hold. But because it has stretched its all ready weakened, it can not support the same amount to load force that it was designed to hold. It can and WILL shear much easier under certain conditions. Track racing under heave throttle "could" cause a failure.

The Cup style useing a full 3" flat surface that supports the underside of the mounting point of the unibody will not let this happen. Once its compressed into place its there and nothing can stretch and deform. This is why FPS sells this same bushing (the original) with shims to stop this from happening.

The ring bushing is the worst style for support of any bushing, all versions of bushings but the ring supports the unibody under the nut. Mikey the stock Gen 1-2 bushign support the nut, there is a washer directly on top of the pedalstal that supports it.

If you look at the pic above (somewhere) you will see the support that the nut has with the two different types of bushings. One has alot more and one has alot less, I know when Im making corners at 60-100 MPH I want all teh support I can get, you cant argue that 2 thin peices of sheet metal that makes up the unibody will hold up for ever when you have a 3500 LB car making turns like that.

No one is screaming that the SKY is falling, My points are very basic. If you live in the salt belt you run a MUCH hiigher risk of pulling the nut through, you also have MUCH less clamping force which could affect you in a frontal impact because the subframe is MADE to shear away under certain circumstances. By stretching the unibody and not having the proper amount of clamping force you may run into alot of unknowns.

Should you run out and take them off, No not at all, But you should keep an eye on them and make sure that if you do take this car to a track you fully trust that they are ok. If they were the only ones out there , well then I would contact FPS for bushings or somehow find a washer to take up the space or shorten the amount of it up. But then again if you wanted a "better" product you would use a Gen 3 or a cup style AL bushing. They are both cheapier than the ring and will fully support the subframe correctly.

If a Ring style bushing was ok Ford would have made one as it would have taken alot less material to make. Take a look at any bushing and show me a 2-5/8 gap in the center and call me a liar. If you dont have a solid surface to calmp to then the link showing clamping force does not apply to this. Because the Pic did not show a huge gap in the pic, it showed very tight tollerances, and you do not get that with the ring bushing with out a washer or shim as provided by the OEM manufactuer.

Plain and simple they were not copied correctly to support your subframe correctly as it was designed to.

 

[revhardSHO]

the simple fact is that over 150 cars have the ring style SFBs and I have yet to hear of any real problems. Basically, what your doing Kirk, is almost pure speculation based on 3-4 pics. Until I hear of subframes dropping and unibodies bending i will not be worried. And if you are, your too parinoid. While i agree that the cup style is superior in design; I see no need for the flaming put-downs against the ring style, it makes me think you want to put someone out of business squint

 

[Yamaha V6]

I really don't want to get dragged into the middle of this, but in response to the last post:

Did the Firestones start exploding & rolling over Explorers right after they left the showroom floor, or did it take a while for these things to show (time after initial installation / environmental & use changes)? Then, did people even really know they had a problem on their particular car (info not widely known)? Then, when things started showing up, was it all of the tires, or only certain production runs (manufacturer denial)? Then in the end, when there was a mass hystery & lawsuits up the butt, it became a case of everyone climbing on board. I think (correct me if I'm wrong), that Firestone had a few more installations that Bruce's Ring Style Bushings, so please stop referring to how there "CAN'T" be a problem with a design because everyone's using it, and nobody's died (yet).

I never heard a case of the original people who tried to champion the cause to bring knowledge to the public's attention thanked in any way either.

I'm not saying either party is right or wrong, I have my own opinions about the products, etc. - I'm saying the way this whole thing was approached, rebutted, claimed as a witchhunt, pursued, dropped, pursued again, yadda yadda yadda was wrong. My opinion, not aimed at anybody or anything except the post about 4 pics vs. mass installations.

You are free to walk about the Cabin. Ding!

 

[Bizzy]

Yamaha V6:
so please stop referring to how there "CAN'T" be a problem with a design because everyone's using it, and nobody's died (yet).

Fred, this is a very good point.

As with pretty much every product out there, even the subframe platenut recall kit, if they are installed incorrectly they can cause damage. From what I'm reading, 9 out of 10 people who are installing subframe bushings, whether cup or ring styles are incorrectly installing them by over torquing the bolts! I don't give a rip if the new bushings are made of aluminum or lead for that matter...the torque specs are set forth not just for the part being installed but also for what the parts are being installed on.....

Classic example of an incorrect installation was my subframe recall done by a Ford dealer. Long story that I'll keep short....They installed the plate nut upside down with the nut side facing down. What happened 6 months down the road? The nut portion pulled out of the plate, pulled through my unibody and allowed the subframe to drop on the driver's rear. It wasn't fun...not only did it cost me money to have my car fixed but I had to buy a new pair of pants to boot! (poor attempt at humor here)

The whole point I'm making here is that we have aftermarket parts, all of which carry a certain degree of risk when installed. If installed correctly, they may be just fine and maybe not.

Subframe connectors are another classic example. Some make them with a beveled front end and some not. While the functioning of both are basically the same during normal operation. (That's another can of worms I won't open...but define: Normal operation. In my eyes, that's every day street driving, not track driving.) You guys do the research to find out what happens to the non-beveled ended connectors. The point is are there many documented cases of what happens to them? Nope. Has it happened? Yep.

All these parts are untested for use. Meaning that Ford Motor Company has not taken the cars through crash tests, etc. So the results of use are undocumented in that respect. But since when were aftermarket parts ever tested in an 11 year old car by them? In that respect the old style bushing nut was fine...****, everything was new! It wasn't until many years down the road that the problem was discovered and subsequently "fixed".

Each and every owner assumes a certain degree of risk when installing ANY aftermarket part. Now that the information has been presented, it is entirely up to each individual which product they choose to buy and install on their cars. You have some information, now go for what you know and use your OWN best judgement on what's right or wrong and what makes YOU happy as the owner. The choice is entirely your own.

In my eyes, there's nothing more to argue about as both sides have been presented.

<small>[ March 18, 2004, 09:49 AM: Message edited by: Bizzy ]</small>

 

[PaulRuffo]

Would it be a good idea to put a washer between the nut and unibody on the rear bolts to give the unibody more strength and distribute the forces over a larger area than just under the nut?

Paul

 

[revhardSHO]

The ring style is flawed in its design, but not to the extent that Kirk and others are making it out to be. And the ring style is not a "new" product, its been around for quite some time now without incident, as we ALL know.

 

[Bizzy]

Paul, see Bob G's responses for what he thinks will help with the issue. I think the suggestion of putting a washer on top has been covered on a previous page as was deemed that it would not be a good idea because it would lower the subframe. But take a look back on the other pages to verify that.

The ring style bushings have been around for some time, however this version of them is new...only just over a year or thereabouts.

Like I said before, there's nothing left here to bicker about, points have been made for both sides both good and bad. Everybody has had their fair share of say in this so I don't see what is left to debate.