Where can I get a stiffer spring for the 1-2 shift valve?

Current shifts to 2nd at 30mph (about 3000 rpm) vs the 70mph 2-3 shift (about 4000 rpm).

Still have 1bbl, so the 4000 rpm is fine (don't need governor) as I'm running out of breath there anyway, but I'd like to raise the 1-2 shift point with a stiffer spring to get 4000 rpm there to.

Either I'd

1. Buy spring from known source (can't seem to find one anywhere)
2. Improvise.

Improvising would be easy if I knew the original spring's specs (OD, length, spring rate), and if the spring coil binds with the shift valve (or how much can I shim the spring to increase the pressure and raise shift point.

Valve body is in car, so don't have any specs on the spring

Anybody have a valve body lying around?


Thanks

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

...shim it. Or simply adjust the kickdown rod.

D/W

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If it ain't broke, fix it!

Kickdown is adjusted correctly.


What I don't understand is why don't shift improver kits allow you to change shift rpm when in automatic mode.....................

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Call Pat Blais 206-365-1966
He is the formost expert on 904's and 727's
He is a super nice guy and will answer all of your questions and supply you with any parts you might need.

Correctly? Within reason (max travel), kickdown can be adjusted to suit taste. Of course (as you know) this will raise the 2-3 shift also. Picky, picky!

D/W

_________________

If it ain't broke, fix it!

The problem is the difference between the 1-2 shift (3000rpm) and the 2-3 shift (4000rpm) at WOT.............

At WOT, the throttle linkage physically bottoms out the throttle valve and without going into all the workings of shifting, you're left with the governor, the 1-2 shift valve spring, and the 2-3 shift valve spring as adjustments.

With the governor you'll raise or lower both the 1-2 shift and 2-3 shift points.

With the 1-2 shift valve spring you only adjust the the 1-2 shift point, and the 2-3 shift valve spring only adjusts the 2-3 shift.


I want the 1-2 shift point to change without affecting the 2-3 shift point, so the spring needs to be changed. (of course changing the governor to raise the 1-2 shift point, and then the 2-3 shift valve spring to lower the 2-3 shift point back down is another way )


And I don't want to even go into part throttle where various hydraulics pressures are applied to components to vary the shift points..................

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

...yeah, I got all that. That's why I said you were picky!

I think if it's shifting 1-2 WOT @ 3000 RPM and your kickdown is adjusted for max travel, you have some kind of valve body malfunction, either an internal leak or a weak spring. Perhaps even renewing the 1-2 shift spring would help.

D/W

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If it ain't broke, fix it!

Only 17000 miles on tranny (and car btw), so it probably was new that way.

It is within spec according to the manual as the shift points at WOT are:

1-2 28-45mph. (2800-4500rpm)
2-3 62-76mph. (3500-4500rpm)


But those are awfully large ranges for manufactures tolerance.



And yes, I am picky.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

I'll also throw out that adjusting the shift point(s) rpm will have MUCH more of an effect on accleration than the shift quality which is what the so-called shift-improvers only do....

So it shouldn't be such a pain-in-the-neck to change the shift points.........

_________________
Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes