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Borg Warner M12 for performance

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WesternRed View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Jul/12/2012 at 12:07pm
On closer inspection the piston in the front band servo of the M12 is much larger in diameter and the servo arm is a little different. Seems like the changes are all about improving the effectiveness of the front band servo.
 
Did a bit of measuring and counting, the clutches are more or less the same as those in the Ford FMX.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote madmax Quote  Post ReplyReply Direct Link To This Post Posted: Jul/12/2012 at 12:59pm
main difference between 11 and 12 are the band servos.

be carefull when buying clutches, there are many different thicknesses of the clutch and steel plates.
bw 11/12, fmx, cast iron med case ford are all basically same,they will all fit in the drum but you need to make sure they stack to the correct clearance. also some have cushion steels and some are flat.
also not all the gasket sets are the same. make sure you get a bw12 kit.

you can use the fmx front band with a different strut kit.

not any valve body kits that i know of, i usually set my clutch packs at the bottom side of tolerance and the shift very well.

on race ones i change out the cushion steels for flat ones and use appropriate thickness clutches to get the right clearance.
if they are still availible they used to sell brass clutches for the med case ford. only use these in the forward drum.

i have had a bw 12 in my old street strip amx, ran low 12s and used nitrous a lot in the mid low 11s.
drove it all the time for 5 years no problems.

hope this helps.
if you need help with getting the correct parts shoot me a pm and i will be glad to help.

thanx  rick

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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Jul/12/2012 at 10:40pm
Thanks for the great info Rick.
 
Seems like parts for the FMX are even getting hard to find these days.
 
This is about all I could find in the way of clutch frictions and steel plates.
 
 
I haven't seen any rebuild kits specifically listed for the M12, they all have the application as M11/11B/12 so one would hope there are extra bits in there to cover any differences between them.
 
In my case what I have is a M11 that has toasted the front band and scored the drum and a M12 that has been laying around in somebody's paddock for years and has a bit of water damage in a few places. Plan of attack would be to do a rebuild using the case, servos and front drum from the M12 and probably everything else from the M11 if that would work? The M11 is from a console shift car and the M12 has the shift lever pointing down so I'm assuming it's from a column shift car. I believe the valve body from the floor shift car would be the one to use because it allows more manual control of the shifting aka the "Shift Command" feature. I don’t know if there are and differences between the M11 and M12 valve bodies that would work against this?
 
Hopefully when I get the engine and diff sorted I can crack into the 12’s that would be the plan.
 
Going a little bit of the rebuild side of things the only other thing on my mind is if I can use something other than the factory dipstick tube, which is a real pain with headers? Maybe drill the case to take a Lokar setup of some sort?
 


Edited by WesternRed - Jul/12/2012 at 10:54pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Jul/16/2012 at 4:21pm
I deleted my long comment to save space on AMC Forum

one easy hop up tip is to adjust the throttle cable or vacuum modulator to raise the mph shift points (the throttle valve inside the valve body has a direct effect upon main line pressure; 'raising the shift point' also raises the MLP)

the next easiest hop up tip is to adjust both bands '1/4 turn tight' (I learned this from a 'Trans Go' info pak that came with some parts I bought to rebuild an AMC 904)

the way to do this is to simply follow the directions in the AMC TSM or rebuild manual on how to adjust the band (snug up the set screw then back it off to the specs quoted in the book) then turn the set screw 90 degrees tighter from there > what this does is it reduces the time it takes for the band to apply and release during a shift change (reduces 'slip time' on the band) -this'll make the trans shift quality feel more firm...

...and along with the raised main line pressure caused by re-adjusting the throttle valve mechanism (cable or vacuum type) making both these adjustments work together to make the trans have a more firm shift quality/'feel' -performance wise- this reduces the time it takes to make a gear change and it reduces the amount of slip (on the clutches and the bands) for better durability

*best thing about it is you don't have to buy anything -just make the adjustments & that 'firms up' the transmission


Edited by amcenthusiast - Sep/29/2018 at 7:10am
Link to XRV8 Race Parts website: www.amcramblermarlin.1colony.com
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jackdk Quote  Post ReplyReply Direct Link To This Post Posted: Jul/16/2012 at 4:35pm
That's some good info AMCFAN! I'll have to keep all this stuff in mind, and the next time at the shop, have them tighten the bans 1/4, and boost the preasure. I like hard shifts!  Beer
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Jul/16/2012 at 5:55pm
Good, BUT there are some errors. I've got an article about the BW/Ford/Studebaker connections somewhere... dated around 1952. Detroit Gear was either a subsidiary of Borg-Warner or BW bought DG in the early 50s. Not sure on that part, but the DG auto became the BW. Studebaker started having financial problems in the early 50s and Ford joined the fray, probably through connections with BW (they had been buying BW T-85s with ODs, and a few other manual trannys). Don't know what the deal worked out between Ford and BW was, only that they shared some development. Ford has always cast their own main cases and valve bodies, and they don't interchange with BW counterparts, but the main rotating assembly DOES interchange... mostly. Might be some minor differences, such as splines on the output shaft (or even internal splines), but most internal parts will interchange.

I was going to mention changing the main regulator spring, but I see that's in the posted article. That's a great PDF file to have on hand!


Edited by farna - Jul/16/2012 at 5:57pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Jul/16/2012 at 10:12pm
I deleted this comment, to remain polite, but also to save space on AMC Forum.


Edited by amcenthusiast - Sep/29/2018 at 7:12am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Jul/17/2012 at 1:13am
Since I think there is too much repetition in the former long comments I posted here in this thread, I deleted my other extra long comments because I don't want to hog too much space on AMC Forum.

Perhaps I can contribute to this AMC community by adding another perspective.

Studebaker and Jaguar used the Detroit Gear automatic trans for a certain period of time.
 
They look like this:



'61 Jaguar DG-250

Tag looks like this:




(teal colored tags indicate BW LTD = made in England)

Here's a Stude DG 250:



Here' the tag (red indicates made in USA... this tag must be faded?):



Here's a Jag DG 150 (aircooled):



Here's the tag:



here's a quick pic of the 'three band' DG-250 internals:



for comparison, here's a pic of my '65 AMC Warner Gear 10B:



here's the tag (red indicates made in USA, but I owned one Marlin which had teal tag AM WG 10b saying 'LTD made in England')



Here is my '65 AM WG 10b, complete, but no torque converter, on a simple scale:


close up, same pile of parts (including all bolts washers etc) to read the scale:


only 135 lbs -mainly because AMC bell & tailshaft housings die cast aluminum instead of cast iron

  





Edited by amcenthusiast - Mar/16/2016 at 1:27am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Jul/17/2012 at 6:46am
Great info guys. The only thing with the pressure regulator spring is that the old Hotrod article I posted doesn't give any specifics as the idea would have been to buy the B&M bits back in the day:
 
Quote The main-line pressure regulator valve spring is replaced by a heavier spring; shorter, but with a larger diameter wire. This change works with valve body modifications to boost line pressure.
 
Would be a bit of trial and error to get something that gives the desired effect I reckon. Those FMX shift improver kits are pretty cheap might just grab one on the off chance that some of the bits work.
 
I did find someone over in Sydney who can re-line the bands for me, so that a little bit closer to home than sending them to the US. They suggested I might want to use Kevlar linings if I am planning a bit of abuse, don't know if there is any downside to this. The guy did say that it was very important to deglaze the drums otherwise the new bands would tend to slip and would not last very long.
 
 
 
Amcenthusiast, you might have to work on your links and pictures, try the little tree symbol at the top of the window to insert a picture. Not sure what is going on with the amccf website from Finland, seems you can only link up the main page.  
 


Edited by WesternRed - Jul/17/2012 at 6:47am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Jul/17/2012 at 7:49am
BW was the major developer, I don't know if Ford just fed them money or had an active part in development. As far as patents go yes, BW holds many (if not all) the patents, but I'm sure they used some from the by then expired Hydramatic (first appeared in 1939, preproduction pilots tested 35-36, so patents would have been late 20s/early 30s).  As to Ford manufacturing, it would all depend on what kind of agreement they had with BW. It looks to me like they had some sort of license manufacturing deal where Ford made their own cases and valve bodies (at least later made the VBs) but purchased some internal parts from BW. A few of the internal parts of pre FMX Ford models have BW on them, according to some tranny people I've talked to.  The FMX was the last BW based trans Ford made and appears to be mostly Ford produced, even though many components still interchange with later BW models. 
Frank Swygert
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