got a replacement window motor with no mounting hardware
Oh, Hi... first post here. 97 Z28 just purchased.
Had a 94 TA (gt 6spd) - 20 years ago... lol. miss that car.
Anyway, help appreciated. Thanks. -d
Using them to connect the regulator to the door (metal to composite) is not good and leads to this: https://ls1tech.com/forums/general-m...-included.html
Just be sure to use nylock nuts or lock washers.
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The problem is movement and bearing of the fastener on the composite. (That amplifies the fatigue on the composite.) The stock rivets could still tear, but the chances of them being loose and moving are much much less than a bolt. If we all keep the cars long enough, these doors will probably all tear out. Personally, I'm counting my days...
The stock rivets have an aluminum jacket, which deforms to fill the entire hole. A bolt (or even a steel jacket rivet) won't do that and will increase those bad fatigue stresses on the composite because they can move in the hole.
A nylock nut will help cut that movement over a normal nut or regular lockwasher, but one would still be relying on the clamping force of that bolt/nut/washer to relieve the bearing stresses on the composite.
A long time ago, I had a paper that talked about the steel mandrel and aluminum jacket rivets and their application here, but I don't know where that went. I suspect this paper below would have a lot of good information on using bolts in this application and their limits, but I'm not up for springing the money for it.
http://papers.sae.org/940623/
I have seen guidelines for SMC that bolt holes should be less than the thickness of the material and using bolts here would exceed that guideline.
If you are talking about not having any issues with bolts securing the regulator the door, then you don't have issues until you do. If you are talking about bolts securing the motor to the regulator, they are fine and nylocks are the way to go since normal nuts can vibrate loose and cause the window skipping.
* Use a bolt the size of the hole (to limit potential movement).
* Use wide washers to spread the load to prevent pull-out.
* Use nylocks / locknuts / lock washers
* Use thread locker.
---(Alternatively, use double nuts).
That will hold sufficiently and not pull through or loosen up.
The real reason rivets were used here is for speed on the assembly line.
It still comes down to load & fatigue and how to spread the load and mitigate/limit the fatigue.
I didn't see where in that article it said that a rivet was better than a bolt. It sounds like your argument/concern is regarding the bolt loosening up and not the method of mechanical fastening. If the bolt is sufficiently tightened and has an additional mechanical (lock washer/nylock/etc) or chemical (thread locker) means then that should be fine. As for spreading the load to prevent pull-out, having a wide washer would have helped the rivet as well.
If the holes are slotted, then you'll have to make new ones. My holes were beginning to slot so I drilled new holes and made a reinforcement plate to sandwich it all together.
https://ls1tech.com/forums/appearanc...ml#post4147168
Something like this mspaint drawing:
(the solid white bit is roughly what I made out of flat aluminum 1/8" thick -- probably less, I forget -- bar from Home Depot).
Last edited by VIP1; Feb 13, 2015 at 04:20 PM.
I'm not an expert in composite fastening, but I understand there are general guidelines on hole size to panel thickness, etc. I did see one guideline that said that, if using bolts, the diameter of the hole should not be wider than the panel thickness. In this case, we'd be outside of that envelope.
If the bolts are clamped down with enough torque to limit movement, they should be fine. I'm not sure what that torque value would be, though. The nice feature about the stock rivets is that they are steel mandrel with an aluminum jacket and the aluminum will fill up the void of the hole to keep the thing from moving. (In addition to any clamping forces it would develop.)








