Sourcing TV Limit Spring

[BEATAV8]

Looking for some stiffer TV limit springs to try. Please let me know if you have any available or where to find.

 

[RmvBfrFlght]

Not sure how much higher you want to increase the TV pressure, but if the current spring won't coil bind can shim it some.

McMaster-Carr carries a variety of springs and is a good company to deal with. Measure the length and wire diameter and see if anything they carry will work.

RemoveBeforeFlight

 

[BEATAV8]

Right now I have 2 springs and a shim and could use some "more". Instead of using such a contraption I'm wanting to experiment with stiffer single springs. Currently not experiencing any unwanted WOT downshifts the way it is.

 

[INEEDAGN]

Looking for some stiffer TV limit springs to try. Please let me know if you have any available or where to find.

You still looking for a valve body? I got a lead on a BQ...

 

[BEATAV8]

You still looking for a valve body? I got a lead on a BQ...

Nah I got a BRF recently. That's the one I'm messing with now. Thanks though!

 

[INEEDAGN]

So what was your kc setup doing that made you go back to the br?
Reason I ask is I got a kc here that I'm planning to upgrade a buddies trans with.

 

[BEATAV8]

The spread is too high. 1-2 at 6400 and 2-3 at 6000. Supposedly only factory hot rod VBs have flat shift points. Supposedly....

 

[INEEDAGN]

So what you're saying, the kc gave you high enough shifts but not flat enough, and the br is flat enough but not high enough. And it's easier to up the br than flatten the kc.

Did the kc with the gn gov feel like it had any quirks at part throttle? Stacked shifts etc.

 

[BEATAV8]

Lol well I'm learning as I go. I'll experiment with the BRF and see what it does. Who knows maybe I will go back to the KC, or even try swapping parts between the two. Will see how it goes. Maybe the solution is to use the KC with a heavier gov or a softer TV limit spring.

The KC has perfectly good street manners. No odd mannerisms.

 

[INEEDAGN]

I wouldn't go softer on tv limit. That would limit the max available signal pressure to the main boost valve and the accumulator valve.

Maybe could get away with it with a .555 boost valve and a larger than stock accumulator valve (or blocked accumulators). I'd probably mod the shit out of the governor before going weaker on tv limit.

 

[BEATAV8]

Thanks I was wondering about that.

 

[TurboBuRick]

Any problems with 2-3 shift hunt with the kc? Sometimes my trans just cannot seem to choose what gear it wants to be in. I shimmed the spring and it initially seemed to help but after some miles it came back.

 

[BEATAV8]

No, the KC never did the 2-3 shift business thing. But I have experienced that in the past with a BR.

 

[77 cruiser]

Kinda sounds like the same issue I had with the OG vb, I managed to get the 1-2 62-6300 & 2-3 5800.
I couldn't use the GN gov it would just go too high on the 1-2 like over 7000.
I'd always thought of trying a heavier gov. spring & lighten the weight more, but never got to it.
Ended up finding CQ, but I have to raise the shifts up on that on, they're at about 53-5400 now.

 

[RmvBfrFlght]

Interesting thread. I've been studying the operations manual and the 1-2, 2-3, and 3-4 shift valve springs can be changed to change the shift RPM. This will affect both WOT and part throttle up & down shifts. But looks to be what is required to get the shift RPMs where they need to be.

All three of these line ups are fed the same governor oil. So any change to the governor will affect all three shift points. To affect each individually, change that valve lineup spring.

These springs are likely a major difference between the various low & high perf valve bodies. Which is why swapping governors around doesn't always give the expected results. Just some theory but to me it seems the way to go.

RemoveBeforeFlight

 

[BEATAV8]

Some on here posted that the individual shift valve springs affected part throttle shifts but had little effect on WOT. I am wondering if the entire shift valve assembly could be swapped?

 

[VIN7]

I had the opposite in my CZ the 1-2 was about 400 rpm lower than the 2-3 at wot. I stretched the 1-2 shift valve spring and the only change was a higher part throttle 1-2 shift, no change in wot.

 

[BEATAV8]

I had the opposite in my CZ the 1-2 was about 400 rpm lower than the 2-3 at wot. I stretched the 1-2 shift valve spring and the only change was a higher part throttle 1-2 shift, no change in wot.

Interesting! How much difference between the two?

 

[VIN7]

It was the same spring, but I pulled the ends to stretch it. Maybe a half inch difference in length after I was done. It went from about 15 mph part throttle 1-2 to about 25 mph. I think if you stretch a spring you change the mean diameter which changes rate (raises it). I could tell it was stiffer by stroking the valve assembly, by how much I don't know. But it made zero difference in wot 1-2.

Maybe a much higher spring rate is needed to affect wot since gov and tv pressures raised at that condition. Also, the CZ 3-4 spring was lighter than the BR 3-4 spring. I swapped those and got a part throttle 3-4 at 40 mph vs 50 mph with the BR spring (I'm using the CZ spring in the BR valvebody).

 

[INEEDAGN]

Yeah there was a thread awhile back about changing springs. Its a battle of governor oil vs tv oil, and since the spring rate is constant, it becomes a smaller and smaller relative force in the battle as throttle gets heavier.