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FMX valve body info.


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Thanks for sharing! 

That is GREAT info. I've rebuilt mine (don't think I would want to do it again). 

Rod

Edited by machattack
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That's a really good source for everyone who's planning to service his FMX by himself. 

Thank you very much for sharing. 

Frank

1972 Mach 1, 351C-2V, wimbledon white, blue all vinyl luxury

born in Dearborn, grown in the district of San José, spent a lifetime in California, moved to Germany in 2010

Mustang_Mach1_wallpaper_300_150.jpg proud member of clublogozusammen.JPG.59fb4a10d15cfff9ec756235059135b8.JPG

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Is there a list in the book that gives the dimensions of each spring, i.e. length, diameter, wire gauge and spring rate?

If so, I would be pleased if you could also copy and display this list.

Frank

1972 Mach 1, 351C-2V, wimbledon white, blue all vinyl luxury

born in Dearborn, grown in the district of San José, spent a lifetime in California, moved to Germany in 2010

Mustang_Mach1_wallpaper_300_150.jpg proud member of clublogozusammen.JPG.59fb4a10d15cfff9ec756235059135b8.JPG

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Today I swapped my vacuum modulator / throttle control valve.  

Learned some things along the way.

1) Color (blue / green / etc) is a general indicator of how the vacuum servo will function, there still seems to be a lot of variability between manufactures.

2) A more radical camshaft / lower engine vacuum works better with a green vacuum modulator / throttle control valve.

3) The adjustment (in the adjustable ones) moves the stationary spring inside.  It does not change the input to the throttle valve during WOT.  All the adjustment does is alter the point where the servo starts to move.  IE- If you took a green servo (vacuum modulator / throttle control valve) out of the box that started to move at 6" and was all in by 15" you could turn the adjuster in clockwise by a couple turns and alter it to start to move at 6" and be all in by 17"...                             

4) The green servos start to move at 6-7" of vacuum, and are all in by 15-16" vacuum.

5) The blue servos start to move around 10-11" of vacuum and are all in by 19-21" vacuum.

6) The distance from tip of the pin that interfaces with the throttle valve in the transmission to the face of the vacuum modulator/ throttle control valve seems to vary a bit.  All the ones I had had the pin pocket in the movable diaphragm about .445" deeper than the machined face of the 3/4" hex where it seals up against the transmission case with a small round gasket.  There was one exception where the distance was about .100" less, and I was too chicken to run it as It shifts plenty hard at WOT.  This distance will alter how it interfaces with the throttle valve under WOT when there is very little engine vacuum.  There is no adjustment for this, other than making a longer or shorter pin, or possibly using thicker gasket / copper washer.

 

With my blue servo low engine vacuum it was running around with higher pressures most of the time.  That resulted in me feeling downshifts as I was rolling to a stop.  With a green servo that all went away and it feels perfect.  Nice light low throttle shifts, not discernable jerk as it is slowing to a stop but still rock hard shifts when I have the pedal flat to the floor.  Feels pretty frisky now.  Anyway if you have lower vacuum at idle (10" ish I highly suggest a green)

 

 

A9321FC1-AB05-41D3-878F-D9F849606E58.jpeg

Edited by Bentworker
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Still on the quest to make my FMX shift later I put the Governor on a diet.  Took it from 16 grams down to 11.

Standard on the right- high RPM on the left…

Weather is too wet to take it out for a drive - hopefully next weekend I can test it out and report back.

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ED88CB26-1D7A-45CA-BECF-DB0296D773C2.jpeg

E15D4A56-1147-4437-B52F-0AC96EA51546.jpeg

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Please post before and after WOT shift RPM after you get a chance to drive it. Thanks, Chuck

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Will do.

So far I have a Transgo 37-1 shift kit in it.  With that alone it shits 1-2 and 2-3 at 5000 RPM WOT.

I installed a Governor anti-stick spring (aftermarket) and drilled a 3/16” hole in the end that may have removed one gram.  That got me up to about 5150 RPM WOT.  
 

Below is a pic of what got me to 5150 RPM.  I am hoping the one I just machined gets me somewhere in the 5500-6000 RPM range.

 

D835B28A-8D1A-4F1C-A425-A924CD8C3DC2.jpeg

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Great post and good info.  I might try the governor trick. Where did you pick up the anti stick spring  from?  In regards to the modulators the green strip has a bigger diaphram in it and responds better to low vacuum.  I spoke to tech support at Rostra Powertrain Controls earlier in the year in regards to my C6 and was given that information from them.  I also attached a  pdf on their modulators for trans type and year. 

rostra-modulator-application-guide.pdf

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Kilgon

 

 

"The only dumb question is the one not asked"

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Governor anti-stick spring was from Cobra transmission parts.

https://cobratransmission.com/a404-a670-spring-governor-anti-stick-200129-1

The captured governor spring I used was the stronger black spring (there are two that look similar, see circled spring in pic) out of a Transgo SK 700-Jr kit.  The application is a 700R4 (cut the spring in half where the coils are touching each other, use the shorter half).  It had a seat pressure of about 2.25 pounds while the stock spring was about 1.5 pounds.  I think you could also use the anti-stick spring out of the Transgo kit (in Liew of buying one from Cobra), but the wire gauge is thicker, and may require machining the governor a bit to make up for the added thickness of the collapsed spring.  

The AOD's use a stiffer spring along with a lighter governor to raise WOT shifts.  Unfortunately the AOD governor guts are different enough that they don't interchange with the FMX.  I bought the high RPM kit for an AOD and reverse engineered it to apply to an FMX.  Don't go buying a Transgo AOD- HIRev kit and expect it to be of any use on an FMX.

Machining the governor itself to lighten it is a bear.  It is case hardened and requires carbide tooling.  I machined a recess into the outward end of the gov with a 17/64" carbide ball mill after I drilled it with a .110" drill (drilled all the way to the center "spool"  I also used a parting tool on the lathe to cut a groove in it.  The 6 holes around the perimeter of the spool were cut with a 9/64" carbide endmill.  I may be talked into doing some for folks on the forum, but the tooling and time is not cheap.

With mine at full weight (about 16 grams) it shifted at 5K, with the weight reduction to about 11 grams it shifts at 6K.  These numbers are with a Transgo 37-1 kit installed in the transmission and a lightly spicy converter.

 

Transgo700jr.PNG

Edited by Bentworker
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