Governor weights and shift RPM?

[Clay Thompson]

I have a rebuilt 200 4R, D-5 torque converter, CZF valve body and servo (092), 10-vane pump and Art Carr modifications to the VB and pump. I installed a stock 87 BRF governor. Shifts were coming at RPMs that are too high at WOT--second required letting off the gas momentarily to force the shift.

I have extra governors and the BRF governor for comparison and want to "adjust" my shift RPM. Where and how is it best to start to keep from pulling the oil pan dozens of times?

Can someone explain how the heavy weight, light weight and single spring interact to control the shift RPM? If I understood how they interact I would have some idea how to alter the weights.

I actually have two BRF governors--I am assuming that governors with a single spring and an orange speedo gear are BRFs--but they are not identical. One has N2 on the light weight and H1 on the heavy weight and the other has D5 on the light weight and B3 on the heavy weight--both have a single blue spring and an orange speedo gear. The two governors look nearly identical. Is anyone familar with this level of detail to know if one governor is a 1987--that is what it is supposed to be--and the other a BRF but another year?

 

[MeanBuicks]

Originally posted by Clay Thompson
Can someone explain how the heavy weight, light weight and single spring interact to control the shift RPM? If I understood how they interact I would have some idea how to alter the weights.

The idea behind the two weights is to provide a wide range of governor pressure change vs. road speed. The governor is a centrifugal device so, as its rpm increases, so does the propensity for the weights to sling outward.

The heavy weight will move out first at low road speeds sealing its checkball against the governor shaft. The light weight and spring control shift points at higher road speeds.

That being said, depending on how much you need to move the WOT shift points down, you will need to either find a stiffer spring or add weight to the light weight.

I've no doubt that Bruce has more experience than I do at modifying 200-4R governors so I'll turn over the microphone to him for additional guideance.

Bruce?

 

[WE4]

heheheh

Use the d5 and b3 gov. Also set screw the spring in which will give you about 3-400 rpm(drop) Try taking the green tv spring out of the tv valve. (the big tight wound green Art Carr spring)
also you want to ADD weight to reduce not take weight off by modifing. Try leaving the govenor alone other than set screw and try the spring thing first. Then add weight to small weight only. If you mess with the big one , part throttle shifts will also be affected..

 

[Fred 86 GN]

Cool!

Add some weight to the small weight to decrease the WOT shift point. Set screw the spring in place. Then add something like 5 grams on top of that if no shift is occurring at WOT and I would like it to shift at 5300rpm?

Add some weight to the large weight to decrease the part throttle shift point. If the part throttle shifts are 500rpm to high, how much weight to add start with?

Is putting weld bead on the edge of the weights a good way to add weight?

Thanks for your advice

 

[Fred 86 GN]

Some pressure information.

Tranmission line pressures (cold and hot) to help diagnose if my WOT no-shift problem can be fixed with governor modification:

cold at 850rpm:

park = 90psi
reverse = 240psi
neutral = 230
overdrive = 260
drive = 260
second = 260
first = 260psi


hot (175F engine) at 775rpm

park = 50psi
reverse = 160
neutral = 150
overdrive = 120
drive = 120
second = 130
first = 130psi

When in park, if i blip the throttle, the pressure jumps immediately from 50psi to 140psi. Looks like that boost valve from PTS is doing its job

These pressures seem OK?

 

[MeanBuicks]

If you're saying that both of your charts represent WOT pressures at different temperatures, you have got a problem there. The 'hot' pressures are way low. If those pressures are at idle with minimum TV, it's ok.

The pressure shouldn't vary a whole lot due to temp. Your 'cold' pressures are right on the money.

 

[WE4]

Yes, as Greg said

If those are done at min tv you are ok. If they are at WOT yes they are low.

 

[Fred 86 GN]

The pressures are at idle, with minimum TV (factory adjustent, no gas pedal movement). How do I get the WOT TV pressures?

Do I disconnect the TV cable and pull it out to max TV then move the gear selector and record the pressure values?

Any suggestions on the magnitude of governor mass addition to either the small or large weights to lower shift points?

Thanks,

 

[WE4]

Make sure....

You need to MAKE SURE that nobody has SCREWED with the TV LIMIT valve or spring. If they have you will chase a ghost forever. I dont quite understand why you have such a drop hot. Or another way to look at is why they are so high cold. With WOT hot they should have the values you show cold, at wot tv.
Tv is cked by kicking up idle to 1500 and pull tv cable out to full, yes. We ck at 1/2 WOT too, to insure we are having a smooth and consistant Pressure Rise. I can fax you a worksheet from work tommorrow if you so desire. Just print and insert your values in the spaces provided. Just email me and request one.
Good Luck