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SOLVED! BETTER WINDOW MOTOR 3RD & 4TH Gen F-bodies
The following is from countless hours of testing and research over my last 2 years. This is a quick and dirty background on this project
This modification is compatible with all 3rd and 4th gen F-bodies.
This modification will not work with bent or excessively worn window regulators. Regulator replacement might be needed for those people
Window Motors-
3rd gen F-bodies use a stock window motor from a 87-96 Chevy Beretta (Driver’s front) that has 12 teeth on the motor. Works on both sides
4th gen F-bodies use a stock window motor from an 86-96 Corvette (Driver’s front), that has 9 teeth on the motor. Works on both sides (84-85 Corvettes come from the factory with the same crappy motors found in the F-bodies. GM changed to the better style in 86)
Window motor Modification-
Both these new window motors need to be modified. I tried like hell to just have an adapter plate, but the motor will fail over time if this is not completed.
The shaft that the motor’s external gear turns on, needs to be extended. I completed this by drilling and tapping the end of the shaft. I then installed a cap head hex bolt to the end of the shaft. This bolt has a round head and is the same diameter as the shaft, making the shaft longer with the head of the bolt (see pictures below)
This shaft is CASE HARDENED and tricky to tap. I suggest making a counter sink hole so it’s easier to tap.
Window Motor Buyer’s Guide-
Tested were OEM style motors only. Dorman makes a plastic universal motor that has not been tested with this set up.
To the best of my knowledge, a majority of NEW window motors are manufactured by a company called ACI. If you order Cardone, ACdelco, GM or ACI, they are all the same. My ACdelco motor was cast with ACI on it. These are slightly different than OEM motors but for a better reason. The gear shaft it molded into the motor when it’s made.
Cardone seems to be the least expensive.
I use Cardone #82905(with pigtails) or #82105 for 3rd Gens
I use Cardone #82910(with pigtails) or #82131 for 4th Gens
There are several aftermarket motors and OEM motors that I have not tested. This is just what I found works for this project.
Wiring-
Both these motors use the same factory wiring plug as the 3rd and 4th gens. The only thing that needs to happen, extra wiring for the motor pigtail needs to be pulled from the wire loom in the door. Approx 1-2 inches.
No splicing, no cutting, plug and play
Adapter Plate-
The adapter plate fits between the regulator, and the new style motor. I took a ton of measurements and had mine laser cut off a CAD file. Although I think people could just make their own.
The adapter plate I made is universal between both driver’s and passenger’s side. So that means one motor and one adapter plate with fit either side.
Adapter plate to motor mounting-
The plate is .060in thick cold rolled steel. I used “self clinching” studs because they are flat on the side they are pressed in. This is a requirement or the stud will interfere with the adapter plate laying flat on the regulator. The studs I used require a .060in thickness plate for proper securing, so that’s why I used .060in
Adapter plate to regulator mounting-
The last thing is the small holes need to be drilled to mount the adapter plate, to the regulator
Moderators- If I violated any of the rules for posts I apologize. I mean no harm, and really needed to post this info given the impact it will have on our F-body community. I really wanted to link my facebook page, but can’t afford the $300 a month to do so.
Special thanks to Michael (Need4Camaro) for being super patient with me as we worked out some bugs.
Adapter plate only, and secured to motor. Note these motors do NOT have extended shaft for the external gear.
Shaft extension installed.
Extension meeting the support hole that it's made for
Awsome. Thanks Kyle, your inspiration and help with this has gone a long way to making this successful. I am curious, do the other ACI motors have removable gears? If so, would it be possible to swap them between an F-Body window motor (longer gear) to make them more forgiving the to damaged Window Regulators?
How is it solved if you haven't had these on the car for a couple of years?
I've had a cheap ebay one in my camaro for over 7 years now and it just recently started getting slow and needing help to get to the top.
My passengers side is still original, worked flawlessly since getting its own power supply. I forget what the mod was called, but the passengers side gets its own dedicated power source instead of running back off of the drivers switch
How is it solved if you haven't had these on the car for a couple of years?
I've had a cheap ebay one in my camaro for over 7 years now and it just recently started getting slow and needing help to get to the top.
My passengers side is still original, worked flawlessly since getting its own power supply. I forget what the mod was called, but the passengers side gets its own dedicated power source instead of running back off of the drivers switch
I understand what you are saying, and yes I do agree that that they should be installed and tested on the vehicle for a period of time. I will note that for myself... I didn't install the motors just to get rid of the thermal resistor issue, I could have just soldered a wire and bypassed the thermal resistor and had a permanent working motor.. I did this because these motors are much faster than the stock motors, even with the "AutoTrix" kit you are speaking of. Note that the Autotrix kit is not an actual fix, it only masks a factory GM flaw by providing enough voltage to overcome the worn thermal resistor issue...this isn't fixing the issue, only masking it.
I don't believe that the Gen 4 Corvette motors fall prone to the same thermal resistor wear that the F-Body motors are known for, but I guess time will tell.
Obviously this isn't for you. The 90% of others that hate their window motors, and complain about them, it's for them
I don't think this comment is fair at all.
You indicated in the initial post that two years of work went into these results. With all due respect for the ingenuity and commitment, many stock 4th gen F-body motors have lasted exponentially longer than that, so I don't think two years is conclusive proof of this concern being "solved"/better....at least not in terms of longevity (though improved speed would be easier to prove, at least in the short term.) For example, the driver's side motor on my daily driver '02 Z28 lasted for ~10 years/95k miles and the original passenger side one was still doing fine at 12 years and 105k+ miles when I sold the car.
I'm pretty familiar with C4 window sizing, I would suspect that the glass on these is smaller than 4th gen F-body windows. If the motors are know to last longer on the C4s, part of this may be due to lighter/smaller glass (thus reduced load.) I wonder if these motors will prove as durable under the weight of 4th gen F-body glass? Or perhaps you have weighed the glass and found the difference to be marginal? Can't say that I'm as familiar with glass size on the Beretta, so I'm not sure if the difference there would be favorable or not.
Overall, again, I certainly respect the ingenuity and commitment, but I don't think it's fair to call "hate" on those who would accurately point out that many original F-body motors have lasted far longer than this, so there really is no conclusive proof that this "solution" will prove significantly more durable over the long term in an F-body application. If you have further supporting evidence, such as a weight comparison of the C4 glass showing no appreciable difference between it and the F-body, then it might be fair to directly compare general longevity of these motors in their original application against the original F-body piece and draw a conclusion from there.
Sorry, hate is a strong word. I should of edited that
I did this project for myself because of my past experiences-
- Owning two 4th gens, with a combined 7 window motor replacements-
- Being a mechanic at a Chevy and Pontiac dealer in the 2000s, and replacing countless window motors UNDER WARRANTY
Lots of other cars use the same motor found in F-Bodies, and they fail just as much
The fact that you have not needed to replace them is great.
This project was something I did for myself and judging by the 14,000 views on the "window motor myths" Sticky, a lot of others are looking for answers as well.
I have had this updated window motor project installed in my daily driver 1996 Grand Am for over a year. It has been working just fine for me. During this time, it was discovered that the motor MUST HAVE the gear shaft extended, or the motor will fail. As far as longevity, these updated motor’s style is used in a lot of current GM cars. The motors look a little different and are made for a cable driven regulator, but the design is still close.
I do not have years and years of testing. If there’s an issue, swap back in the original motor. The regulator is unmodified.
I find it very ironic that the C4 corvette started life with the same motors as the F-bodies. Mid production 1986 the window motors and regulators were changed by GM and they used the "better" style motor for the rest of the C4 production. My guess is Corvette owners were not happy and there were a lot of failures. GM could have redesigned the regulator and kept the original motor, but they chose to use the “better” motor.
Here's the article- or google C4corvette window upgrade http://www.corvettemagazine.com/tech...grade-install/
So, for every post on LS1tech that states they buy new window motors every year, tired of the window taking 12 seconds to go up and down and the guy who carries extra window motors and tools to install in his car - THIS THREAD IS FOR YOU!!
I don't think two years is conclusive proof of this concern being "solved"/better....at least not in terms of longevity
This would be my concern, as well. Particularly after my failed experiment with a smaller motor unit. ^
I don't think this needs to last perpetually to be a success. For me a success would be:
- Generally lasting longer than a stock motor
- Experiencing different failure modes than "Oh crap, I'm in a blizzard at a tool booth and my window won't go up!"
I find it very ironic that the C4 corvette started life with the same motors as the F-bodies. Mid production 1986 the window motors and regulators were changed by GM and they used the "better" style motor for the rest of the C4 production. My guess is Corvette owners were not happy and there were a lot of failures.
We've said a lot here about the F-Body motors being relics from the '60's... because they are. They are REALLY old parts and came out during that decade!
The Corvette motors are newer, as would be expected for the top Chevy model, but even when the part we are talking about here was designed - motor technology (mainly the magnets inside) was improving with leaps and bounds. The motors going in to electronics today are much smaller and stronger than what we had access to in the '80's and '90's.
^ This is why I am cautiously optimistic that this mod will be successful. Hopefully the leap from 1960/70 to 1985 in motor technology will have made the smaller motor an equivalent in durability in strength. For some reason, the OEM's hide the specs on these units :Z - otherwise we could calculate all that out.
I would still call this "in test" vs. "solved".
My only concern would be the point that RPM WS6 brought up with regard to the Corvette windows being smaller. It looks like the Corvette motor has a smaller gear than the F-Body motor. Assuming the motors are equal, this would account for the faster motion of the glass, but it also translates to more stress on the Corvette motor for a given load.
So, for every post on LS1tech that states they buy new window motors every year, tired of the window taking 12 seconds to go up and down and the guy who carries extra window motors and tools to install in his car - THIS THREAD IS FOR YOU!!
There is a missing link here though, specifically the fact that not all of us experience such rapid failure. The question there is....why? Is it due to poor quality of the replacement motors (meaning quality issues beyond just an "inferior" design?) This is an important consideration, as the C4 motors may also have quality control issues since they are aftermarket pieces at this point (vs. assembly line originals.) Or is the issue gummed up regulators that are in need of replacement/re-lubing? Excessive drag might be the reason why some folks only get a year or two out of a new motor, vs. the many years that the OEM original may have lasted. Re-lubing of various points during a motor swap might have gotten them many more years of service from the replacement.
Both of these points might be concerns even with the C4 motor conversion. Overall, I think it would take many more users over a period of several years to draw a conclusion. Again, it's great that you've put the time into this, I certainly hope it proves to be a solid upgrade, but...
Originally Posted by wssix99
I would still call this "in test" vs. "solved".
...I agree. "Solved" is a bit premature at this point, IMO.
There is a missing link here though, specifically the fact that not all of us experience such rapid failure. The question there is....why? Is it due to poor quality of the replacement motors (meaning quality issues beyond just an "inferior" design?) This is an important consideration, as the C4 motors may also have quality control issues since they are aftermarket pieces at this point (vs. assembly line originals.) Or is the issue gummed up regulators that are in need of replacement/re-lubing? Excessive drag might be the reason why some folks only get a year or two out of a new motor, vs. the many years that the OEM original may have lasted. Re-lubing of various points during a motor swap might have gotten them many more years of service from the replacement.
Both of these points might be concerns even with the C4 motor conversion. Overall, I think it would take many more users over a period of several years to draw a conclusion. Again, it's great that you've put the time into this, I certainly hope it proves to be a solid upgrade, but...
I get what you're saying.
My completely factory window motor on my passenger side lasted from the date of production (probably in 1998 since its a 99 car) to the end of 2016. That is a fairly long time for any Window motor in my opinion...but the thing is, it still fell prone to the thermal resistor issue. Even though there may be another catalyst (and if there is I do agree it definitely warrants just as much attention) .. is that F-Body cars are the only cars that I know that experience this issue of the thermal resistor wear on an otherwise fairly decent motor design... So it brings me to wondering why is it almost always the thermal resistor that goes bad (at varying lengths of time and sometimes, not at all but in almost all cases of window motor failure it starts here...) I get what you mean about the resistance of the regulator, but why is it only happening in F-Cars, because technically other vehicles driven by less mechanically concerned individuals than ourselves will undoubtedly have their regulators dried up and Im sure it does cause problems..but ours are the ones that fail at the thermal resistor.. which leads me to believe there is a weak spot in this area, even though a dried regulator is definitely not optimum or recommended ... ours actually failing here where others survive similar conditions in other vehicles to me shows there is a weak link in our motors.
Neither of you guys let your cars be touched by water that falls from the sky, right?
#MostCarsLiveARoughLife
You're thinking of my '98 car. It's not even allowed to see humidity. The motors on that one are original and quite fast (almost shockingly so), but I didn't think it was a fair example as the car is most definitely a garage queen. On the other hand....
Originally Posted by RPM WS6
For example, the driver's side motor on my daily driver '02 Z28 lasted for ~10 years/95k miles and the original passenger side one was still doing fine at 12 years and 105k+ miles when I sold the car.
My '02 car lived a life closer to that of a taxi cab. The only time it had a roof over its head is when I'd drive under a bridge.
02-16-2017, 04:06 PM
Solved!! Better window motors 3rd,4th gen 
They are REALLY old parts and came out during that decade!
