Torsion Bar Retention Plate Improvement?

[LordFly]

I'm a little curious about why this hasn't been done yet. Maybe it's a bad idea for a reason I don't know of (since I've never even had my T-panel off). Why are there 2 separate retention plates, rather than 1 long one that spans across both? I can only imagine the forces put on the sheet metal roof box must be tremendous. The retention plates themselves look fairly thick, maybe about 3/8". If it were one solid 3/8" bar all the way across, I would think it would take a lot of the stress off the roof box, which I understand (and can see in the picture) can bend/warp over time.

Obviously it would make the door adjustments a little trickier, but I would prefer to fight with that for a few hours rather than constantly think about how my doors are trying to destroy the roof of the car.

http://i821.photobucket.com/albums/zz135/alex-akos/delo%20resto/DSC00062_zps13b3e2e6.jpg

[Delorean Industries]

The bars tension in two different directions. Not sure how it would work with a solid bar.

[Rich]

It's a good question.

We may never know why the retainer plates are the size they are.

Another way they could have reduced the roof delam tendency would have been to just increase the length of both of the brackets and moved the mounting holes apart to match. For example, doubling the length (width, if you like) of the brackets would have reduced the roof delam force by 50%. And still allowed the same ease of torsion bar installation/adjustment on either door as with the current design.

Maybe you were suggesting that somebody could supply a new full-width 2-bar bracket that uses the existing holes. That would also solve the delam problem but at the cost of perhaps being very difficult to install, as you say. To do it would call for some interesting forging or machining of the splines.

[LordFly]

The bars tension in two different directions. Not sure how it would work with a solid bar.

That's exactly my point :) They opposite forces would essentially cancel each other out.


Maybe you were suggesting that somebody could supply a new full-width 2-bar bracket that uses the existing holes. ... To do it would call for some interesting forging or machining of the splines.

That's pretty much what I was suggesting. Well, a full-width 1-bar bracket, like below (but done better than my 30 second photoshop job). I'm sure the splines wouldn't be that hard. The hardest part of it for sure, but they get made all the time for thousands of our applications.

25205

[Delorean Industries]

That's exactly my point :) They opposite forces would essentially cancel each other out.



That's pretty much what I was suggesting. Well, a full-width 1-bar bracket, like below (but done better than my 30 second photoshop job). I'm sure the splines wouldn't be that hard. The hardest part of it for sure, but they get made all the time for thousands of our applications.

25205

I was getting at he point that the bars would need to be tensioned at the same time. In two different directions.

[DMCMW Dave]

It would sure make adjusting the doors a bitch.

[dustybarn]

I agree that it would reduce the tendency of the roof to delaminate and the roof box to deform, but it would also make torsion bar installation much more difficult because both bars would have to be preloaded simultaneously, rather than one-at-a-time.

Edit: Heh. Josh and Dave replied to say the same thing while I was typing.

[LordFly]

I was getting at he point that the bars would need to be tensioned at the same time. In two different directions.

Oh, I see what you mean. Yeah, like I said, it would be tricky for sure. But once it was done, no more roof stress :) I would think that even a 3/8" piece of flat bar would have enough flex that you could bend it out just far enough to clear the torsion rods. And if not, well then I guess door adjustments would become a 3 person operation where both doors get done at the same time.

Really mostly what I was concerned about, having never played with anything in that general area, was would there be any clearance issues? Would the T-panel still fit? Looks like you'd lose a mounting location for the plastic cover piece, but perhaps it would be incorporated into the the 1-piece retaining plate.

[LordFly]

I agree that it would reduce the tendency of the roof to delaminate and the roof box to deform, but it would also make torsion bar installation much more difficult because both bars would have to be preloaded simultaneously, rather than one-at-a-time.

Edit: Heh. Josh and Dave replied to say the same thing while I was typing.

Haha, yes I definitely agree, door adjustments would suck. Which for Dave and Josh is a legit concern because they frequently have to make the adjustments. But for someone like me, who intents to adjust their doors practically never, it's a one time hassle that could potentially save having to someday replace the roof box or the fiberglass body.

[Delorean Industries]

The biggest issue I would be concerned with is the opposing torsional stress. With the two directly tied together there is nothing isolating the bars from each other. Bad things happen when a bar is twisted in the direction it was not initially twisted in. scenario: Left door closed (maximum load on bar) right door open (minimum load on bar). All of the stress from the left bar would be transferred to the right bar and vice versa.

I wouldn't expect it to shear off the other bar. But The roof box/fiber glass absorbs a lot of flex and stress. Watch the bar opening and closing. The movement is in many directions.

[JohnZ]

Little OT: what is the purpose of the black "hook" between the 2 torsion bar brackets? Holding the Tpanel or something?

[Bitsyncmaster]

It would take the load off the top plate but you would never be able to get it removed (maybe a 4 man job). As it is the brackets get stuck on very often with one door until all the torque is removed from the bar. My car the bracket could not be removed at a tech session with many experienced helpers. It was only when I was able to remove all the torque (door open past vertical) then release the bracket, then it would slide off.

Your idea would work if the connection between the two brackets was removable.

[LordFly]

The biggest issue I would be concerned with is the opposing torsional stress. With the two directly tied together there is nothing isolating the bars from each other. Bad things happen when a bar is twisted in the direction it was not initially twisted in. scenario: Left door closed (maximum load on bar) right door open (minimum load on bar). All of the stress from the left bar would be transferred to the right bar and vice versa.

:hmm: How would stress be transferred from one torsion bar to the other? The same mounting holes would still be used to bolt the 1-piece retainer in place. The only real difference would be that when the door is closed, instead of having 200ft.lbs of torque spread across 2 bolts that are 4 inches apart, you'd have 200ft.lbs spread across 4 bolts that are 2 feet apart.

[Kerichbe]

Little OT: what is the purpose of the black "hook" between the 2 torsion bar brackets? Holding the Tpanel or something?

The screw holding the rear screen upper finisher (Black plastic trim panel) attaches to that point, I believe.

[JohnZ]

The screw holding the rear screen upper finisher (Black plastic trim panel) attaches to that point, I believe.

You are probably right there, I don't really recall precisely how I removed / refitted the finisher last time I did it...

[Mark D]

Combining the two plates into one wouldn't be the best idea as others have already mentioned... it would probably take 3 people to install/adjust a set of torsion bars. One person each side to hold the pretorsion on the two torsion bars and another to secure the retention plate bolts and steady all the large socket extensions. Adjusting one torsion bar is difficult enough without requiring you to also maintain the pretorsion on both bars while attempting to adjust one door.

I can see the justification for wanting to make the the retention plates longer to distribute the load better across the roof bracket, but combining them into one plate would make things much more complicated.

If I had to guess why they were originally designed as short as they are it would be so they wouldn't smash into the rear window glass if they ever rusted in place and had to be rotated with the torsion bar as it was unloaded.

[David T]

Combining the two plates into one wouldn't be the best idea as others have already mentioned... it would probably take 3 people to install/adjust a set of torsion bars. One person each side to hold the pretorsion on the two torsion bars and another to secure the retention plate bolts and steady all the large socket extensions. Adjusting one torsion bar is difficult enough without requiring you to also maintain the pretorsion on both bars while attempting to adjust one door.

I can see the justification for wanting to make the the retention plates longer to distribute the load better across the roof bracket, but combining them into one plate would make things much more complicated.

If I had to guess why they were originally designed as short as they are it would be so they wouldn't smash into the rear window glass if they ever rusted in place and had to be rotated with the torsion bar as it was unloaded.

Your idea has merit but you would not make the removable plates into one piece. The way to do it would be to somehow form a single anchor piece into the Tee roof section that the 2 separate anchor plates screw into. You really do need to be able to do the torsion bars one-at-a-time to make it a manageable job.

[DMCMW Dave]

If I had to guess why they were originally designed as short as they are it would be so they wouldn't smash into the rear window glass if they ever rusted in place and had to be rotated with the torsion bar as it was unloaded.

Apparently you've never seen one get loose. They will turn far and long enough to poke holes in the T-panel AND break the rear glass if you're extremely unlucky.

[ALEXAKOS]

Apparently you've never seen one get loose. They will turn far and long enough to poke holes in the T-panel AND break the rear glass if you're extremely unlucky.
Oh don't remind me! My bar kicked out the tool while I was removing them and fortunately the two bracket screws were totally loose that just sliced off a bit of my rear glass.....:notworthy::notworthy::notworthy:

Hey Lord... that image is of my poor 5992! hahahah
That fault has been picked up! :)

[LordFly]

Combining the two plates into one wouldn't be the best idea as others have already mentioned... it would probably take 3 people to install/adjust a set of torsion bars. One person each side to hold the pretorsion on the two torsion bars and another to secure the retention plate bolts and steady all the large socket extensions. Adjusting one torsion bar is difficult enough without requiring you to also maintain the pretorsion on both bars while attempting to adjust one door.

Yes yes, I completely understand that it will make door adjustments much more challenging, especially IF you would have to do both at the same time (although I have a feeling that one solid plate could still be bend out an inch to allow the doors to be done one at a time). Even if it is much harder, the end result still seems like it would be a huge improvement. I'm pretty sure heart transplants are quite difficult, but you don't see people going "oh that's too difficult, just let the person die".


Hey Lord... that image is of my poor 5992! hahahah
That fault has been picked up! :)

Haha, I know, I figured you'd see it eventually! It was the best picture I could find showing the retaining plates :cool1:

[ALEXAKOS]

Haha, I know, I figured you'd see it eventually! It was the best picture I could find showing the retaining plates :cool1:
...and the awful result to their construction fail :(

[LordFly]

...and the awful result to their construction fail :(

A 1-piece design could fix that :D

[SS Spoiler]

What about permanently adapting a heavy-duty ratchet to the ends of the bar. To adjust the doors a simple click or two with a breaker bar and your done! Went too far, flip the reversing knob and back it off. This would work on either door and either direction. If anyone wants to run with this idea, have at it. Remember you saw it here first.



Paul Cerny #2691
Kalispell, MT

[David T]

What about permanently adapting a heavy-duty ratchet to the ends of the bar. To adjust the doors a simple click or two with a breaker bar and your done! Went too far, flip the reversing knob and back it off. This would work on either door and either direction. If anyone wants to run with this idea, have at it. Remember you saw it here first



Paul Cerny #2691
Kalispell, MT

A lot of work to avoid doing and adjustment that is done very infrequently. Once the torsion bars are properly set they don't need to be adjusted. What happens is the strut gets weak so the first idea is to overdo the torsion bar adjustment to compensate. Bad idea because now you have to keep tightening the torsion bar to keep compensating for the dying strut OR when you do break down and spend for the new struts the torsion bar has to be loosened. If you set the torsion bar with new struts you are good for about 5 years. Now when the doors start to droop, instead of adjusting the torsion bars just get a new set of door struts.

[LordFly]

A lot of work to avoid doing and adjustment that is done very infrequently. Once the torsion bars are properly set they don't need to be adjusted. What happens is the strut gets weak so the first idea is to overdo the torsion bar adjustment to compensate. Bad idea because now you have to keep tightening the torsion bar to keep compensating for the dying strut

That wouldn't happen nearly as often if adjusting the torsion bars was a 4 person operation :biggrin:

[Patrick C]

A lot of work to avoid doing and adjustment that is done very infrequently. Once the torsion bars are properly set they don't need to be adjusted. What happens is the strut gets weak so the first idea is to overdo the torsion bar adjustment to compensate. Bad idea because now you have to keep tightening the torsion bar to keep compensating for the dying strut OR when you do break down and spend for the new struts the torsion bar has to be loosened. If you set the torsion bar with new struts you are good for about 5 years. Now when the doors start to droop, instead of adjusting the torsion bars just get a new set of door struts.

I agree, however some brand-new struts have more "oomph" than others and require the bar to be kicked down a notch (or maybe up a notch).

[Rich]

A lot of work to avoid doing and adjustment that is done very infrequently. Once the torsion bars are properly set they don't need to be adjusted. What happens is the strut gets weak so the first idea is to overdo the torsion bar adjustment to compensate. Bad idea because now you have to keep tightening the torsion bar to keep compensating for the dying strut OR when you do break down and spend for the new struts the torsion bar has to be loosened. If you set the torsion bar with new struts you are good for about 5 years. Now when the doors start to droop, instead of adjusting the torsion bars just get a new set of door struts.

++1 on that post and esp. on the part in boldface.

There will likely never be data to prove the last part of this sequence but like David says, the first part is all too common - the struts lose their charge (as designed or at least as expected with a wear item like struts), then instead of renewing them an owner gets the doors up-torqued (not as designed) to compensate. This puts an increased pre-load on the torsion bar retention system (not as designed, asking the torsion bar and retention system to do what the blown strut was supposed to do before it blew). That increased pre-load cannot do anything good for the roof box, which may delaminate and deform when it can no longer withstand the torque.

Whether roof boxes can delaminate with correctly-set torsion bars isn't worth going into. Sure, that's possible. Not every roof box was perfect, I'm sure.

The message is that if your doors are over-torqued with good struts then de-torque them.

And you get a bonus if you do that: the doors become very easy to close....just like when they were when they were new.

[304stls]

I think you all may be looking at this from the wrong angle...

What about installing a thick piece of flat stock behind the roof box in lieu of those pesky nuts which are tack welded in place and tend to break loose when you are trying to remove the retaining plates.
A single piece spanning the two plates, behind the stamped steel "box" could be tapped for the bolts and the retaining plates could be bolted thru the "box" to the backer plate.
I'm pretty sure there is enough room in there...

-Carl

[PJ Grady Inc.]

I think you all may be looking at this from the wrong angle...

What about installing a thick piece of flat stock behind the roof box in lieu of those pesky nuts which are tack welded in place and tend to break loose when you are trying to remove the retaining plates.
A single piece spanning the two plates, behind the stamped steel "box" could be tapped for the bolts and the retaining plates could be bolted thru the "box" to the backer plate.
I'm pretty sure there is enough room in there...

-Carl
No Carl unfortunatey there isn't. It may appear that way if your roof has broken free of the epoxy bond to the fiberglass and started to bend with the twisting forces present but that's not the way the car was delivered and the gaps will vary with the amount of damage present. A thicker stronger box is the easiest solution but that is not really easy nor will it be inexpensive or a fast install. I am looking into it however it will take some time to scratch this one off my bucket list.
Rob

[PJ Grady Inc.]

I'm a little curious about why this hasn't been done yet. Maybe it's a bad idea for a reason I don't know of (since I've never even had my T-panel off). Why are there 2 separate retention plates, rather than 1 long one that spans across both? I can only imagine the forces put on the sheet metal roof box must be tremendous. The retention plates themselves look fairly thick, maybe about 3/8". If it were one solid 3/8" bar all the way across, I would think it would take a lot of the stress off the roof box, which I understand (and can see in the picture) can bend/warp over time.

Obviously it would make the door adjustments a little trickier, but I would prefer to fight with that for a few hours rather than constantly think about how my doors are trying to destroy the roof of the car.

http://i821.photobucket.com/albums/zz135/alex-akos/delo%20resto/DSC00062_zps13b3e2e6.jpg

I think that a one piece plate is a physical impossibility due to the need for movement of the plates in opposite directions to adjust or even install them. Anyone who's gone through the adjustment process just needs to think how they would accomplish that task with the two plates made as one will realize it can't be done.

It reminds me of those sheets of ethnic jokes that used to get passed around by the salesmen in my Dad's new car showroom back when I was a kid in the politicaly incorrect sixties.
How many (insert your favorite ethnic slur here) does it take to change a light bulb on a pole? Answer....Three. One to hold the bulb and two to turn the latter!
Even if it could be done you'd look mighty silly doing it. Never stop thinking however and you'll find a better solution.
Rob

[PJ Grady Inc.]

A lot of work to avoid doing and adjustment that is done very infrequently. Once the torsion bars are properly set they don't need to be adjusted. What happens is the strut gets weak so the first idea is to overdo the torsion bar adjustment to compensate. Bad idea because now you have to keep tightening the torsion bar to keep compensating for the dying strut OR when you do break down and spend for the new struts the torsion bar has to be loosened. If you set the torsion bar with new struts you are good for about 5 years. Now when the doors start to droop, instead of adjusting the torsion bars just get a new set of door struts.

"Once the torsion bars are properly set they don't need to be adjusted."(Quote Dave)

Dave you live in New Jersey. Just because your car never feels the frozen breezes of your home state doesn't mean other people with fewer transportation options don't need to use their cars in the winter months. The T bar adjustment exists for temperature as well as gas spring pressure drops. That need for seasonal adjustments is something I'm trying to eliminate or minimize with the introduction of our "Northern Winter" gas springs but that will be another thread in due course.
Dave your "pampered pooch" of a car will never need those as it hibernates peacefully in the winter months ;)!
Rob

[304stls]

My apologies,

I forgot that the "box" dips in between the plates.
Why not produce a replacement that straightens out these curves and integrates a stiffener?

-Carl

36974

[David T]

"Once the torsion bars are properly set they don't need to be adjusted."(Quote Dave)

Dave you live in New Jersey. Just because your car never feels the frozen breezes of your home state doesn't mean other people with fewer transportation options don't need to use their cars in the winter months. The T bar adjustment exists for temperature as well as gas spring pressure drops. That need for seasonal adjustments is something I'm trying to eliminate or minimize with the introduction of our "Northern Winter" gas springs but that will be another thread in due course.
Dave your "pampered pooch" of a car will never need those as it hibernates peacefully in the winter months ;)!
Rob

Actually we take the car out in the Winter for the annual parade on Long Beach Island that Gary Gore organizes. If you replace the struts when they start to go weak it's not too bad. About every 5 years or so, depends on that particular batch and which vendor (some overpresserize them WAY too much!) Anyway I would not recommend adjusting the torsion bars twice a year for the winter and the summer. I set on the low side where the doors don't bounce hard when you open them in the summer and in the winter I have to push them open fully to get it all the way open but it will stay all the way up when I let go. Toby was selling temperature compensated ones but I haven't tried them yet. As for "pampered pooch" it gets out almost every week for a car show, cruise night or club event. Weather permitting it will be at the Trump National Golf Course this Sunday (I prefer not to go if it's raining).

[PJ Grady Inc.]

Actually we take the car out in the Winter for the annual parade on Long Beach Island that Gary Gore organizes. If you replace the struts when they start to go weak it's not too bad. About every 5 years or so, depends on that particular batch and which vendor (some overpresserize them WAY too much!) Anyway I would not recommend adjusting the torsion bars twice a year for the winter and the summer. I set on the low side where the doors don't bounce hard when you open them in the summer and in the winter I have to push them open fully to get it all the way open but it will stay all the way up when I let go. Toby was selling temperature compensated ones but I haven't tried them yet. As for "pampered pooch" it gets out almost every week for a car show, cruise night or club event. Weather permitting it will be at the Trump National Golf Course this Sunday (I prefer not to go if it's raining).

Perhaps you would like to try my new door gas springs (standard version) which work well from summer temps down to near freezing. The winter version should work well from below zero up to around 60 degrees with the bar set at the normal summer rating. In either case no rocking at the top extension regardless of temperature due to a special dampening feature.

That is the old JZD estate right? What's going on there this weekend?
Rob

[David T]

Perhaps you would like to try my new door gas springs (standard version) which work well from summer temps down to near freezing. The winter version should work well from below zero up to around 60 degrees with the bar set at the normal summer rating. In either case no rocking at the top extension regardless of temperature due to a special dampening feature.

That is the old JZD estate right? What's going on there this weekend?
Rob

It IS the old Delorean estate. Go to the other thread I opened about the event. It is being hosted by Hudson Mod. Next set of struts I will try from you.