another shift point question

[SBNova]

Ive searched and read about 100 posts, but I would just like some clarity.

Ive got a non-GN governor in a non-GN tranny that Ive been running in my Nova for years. Its always shifted early, and I understand that its probably due to the valve body not just the governor. I have tweaked the gov. every time ive had the pan down, whittling away the the weights in search of higher shift points. This time the trans broke (2nd gear band), so I didnt have time to jot down the shift points before the catastrophe. I have 3:50 rear gears, and it shifts very early in part throttle(1-2 at under 15mph, 2-3 and under 30), somewhat early at WOT- not real sure here as I usually shift manually at WOT.

My weights are getting pretty small. The small weight is barely big enough to retain the spring. I had a picture a long time ago of a GN governor and tried to replicate it, and it got even smaller after that. Ive still got whatever factory springs were in it. Ive got the TV cable adjusted correctly, and its as tight as it will gowithout losing a click at WOT.

1) Ive read some people run no spring on the big weight, what does this do (rpm wise) and to which shift point does this affect?

2) Is there a relationship between any certain weight and any certain shift point or does the assembly affect both shift points?

3) Am I correct in thinking less weight= higher shift points?

4) Am I correct that lighter spring weight will increase shoft points?

5) I read in a few posts that people are shimming a spring to raise shift points, which spring is that? Are there different springs for 1-2 and 2-3? Someone said they used a short piece of 1/4 copper tubing, and someone else said washers so I know its not a governor spring. Is there a reference as to how much shim = a certain rpm increase?

Thanks so much, Ive learned a ton on this board.

 

[SBNova]

Nobody???

Can I just shorten the stiff spring on the small weight some, will that make a part throttle difference??

This is the last step I need to do before I button up the trans and put it back in. Somebody please shed some expertise on me.

 

[77 cruiser]

So about what RPM will it go to now?

Removing the spring from the big wt. will raise the 1-2 p/t shift as will lightening the big wt. It will raise the 2-3 slightly too.

If you shim the TV limit valve it will raise all shifts but it also allows the trans to shift down at a higher speed.

http://webpages.charter.net/77cruiser/Gov/

A pic of mine it shifts at 6200 1-2 & 5800 2-3

Do a search on code OG.

 

[SBNova]

I just buttoned up the pan, and without any further info I decided to just trim 1 1/2 coils off the stiff spring on the small weight. I plan to install the trans tonight, or Thursday eve at the latest. Unfortunately, I dont have exact shift points before this to know if Ive changed anything, but I hope it helps a little. My weights are so small that I was afraid to make big spring changes of trim any more weight off. My small weight is only big enough (barely) to hold the spring, and my large weight has 1/8 more than the spring pad and thats it. I wish I wouldve snapped a pic, they are small.

 

[77 cruiser]

With trimming the coils like that you might see a quite a bit of raising of the 1-2 but not as much on the 2-3.

What VB do you have?

 

[SBNova]

Ive never looked for a code on it. I got it from a junk yard about 10 years ago, I pulled it from an Olds with a diesel. I cant even remember what year the car was. It was long before I knew of this or any web site for that matter.

 

[Syclone0044]

If you shim the TV limit valve it will raise all shifts but it also allows the trans to shift down at a higher speed.

Will shimming the TV limit valve also raise WOT shifts, or just part throttle? Thanks for your help,

 

[Lee Thompson]

shimming TV valve

I thought that if you shimmed the TV TOO MUCH that you could raise the min. line pressure so high that the trans won't downshift back into 1 st gear @ a stop.

 

[chris718]

the tv limit feeds the plunger 90 psi and the plunger regulates this pressure from it into the modulated tv upshift circuit .itll feed 0 psi at no tv closed throttle and 90 psi at max tv wide open throttle into the modulated tv upshift circuit .raising the tv limit feed psi to 92 0r 94 will raise all of the shift points very very slightly.start with an .020 shim betww=een the sping and valve and experiment.A GN GOVERNOR (TYPE 3 LIGHTWEIGHT ACCORDING TO MY MANUAL)WITH A STOCK NON HIGH PERFORMANCE VALVE BODY(USED IN A GN WITH A 3.42 AXLE RATIO) WILL RESULT IN LATER SHIFTS THAN YOU WILL GET WITH THE GN VALVE BODY BUT THE CAR WILL BOUNCE OFF THE REV LIMITER WITHOUT SHIFTING AT WOT UNLESS YOU LIFT THE THROTTLE BECAUSE THE ENGINE IS OUT OF AIR AND CANT TURN THE DRIVE SHAFT FAST ENOUGH TO PRODUCE ENOUGH GOVEROR PRESSURE TO UPSHIFT THE SHIFT VALVES AGAINST MODULATED TV UPSHIFT OIL AND SPRING WEIGHT.