Drilling C6 Governor to increase WOT shift.

[HOWDY69]

So what actually happens at stall? I understand the C6 torque converter does not "lockup". So is there still a little slip in the converter after stall?

[68F250]

Stall IS slippage. That's what allows the engine to run when you're stopped. When starting up (stall), the impeller is rotating at engine speed while the stator remains stationary which redirects fluid to the impeller and multiplies the torque to the turbine, somewhere around a 2:1 ratio. When you're at speed, the stator inside the converter is rotating so there's no torque multiplication and releases the one-way clutch so the whole thing rotates together as a fluid coupling (almost). Yes, there's still a little slippage at speed, that's why the engine revs up a little when you gas it. A lock-up converter is nice for mileage but makes the engine feel a little doggy.

Here's a good little write-up on converters:
http://www.bankspower.com/Tech_understa ... conver.cfm

[DuckRyder]

Here is another good info page:

http://www.tciauto.com/tech_info/torque ... lained.htm

I would not recommend one of their converters though the tech info is good.

[71-F-250SC-72-F-250C]

Hey Duckryder,
Can you post pics of what you are doing to the governer after you are done?

Thanks, Stephen

[DuckRyder]

I'll make every effort to write a how to, If I can remember.

I am seriously pretty forgetful

[DuckRyder]

Reference:

http://www.network54.com/Forum/74182/thread/1139487212/

http://www.network54.com/Forum/74182/thread/1152993361/

and

http://www.network54.com/Forum/74182/thread/1055869825/

Today I finally got a chance to mess with this a bit more.

Following Werby’s TSB I drilled the secondary governor piston to a total depth of .80. (.05 More than the TSB) and restored the governor otherwise to stock configuration (other than the extra weight found in the truck transmission)

Now at WOT throttle the up shift 1>2 and 2>3 occurs at 5900-6100 RPM. There was a slight rise in part throttle shift RPM that was a welcome result as well.

Drilling the secondary piston absolutely does work!!!

Now, should you decide to try, no drill bit I tried would produce more than a mild scratch in whatever the piston is made of. Cobalt, Titanium, Hi Speed Steel, they all looked like a used pencil eraser in short order.

I ordered a TiAln Coated End mill from McMaster-Carr. This is clearly the right tool for the job. The only hard part of this process was centering up the bit without a pilot tip or proper mill. I ended up using a drill press and a small bit to position the part, and then changed the bit prior to starting the drill press. The end mill was 25.00 or so shipped so if a machine shop will do it for you that could be the way to go. I should also mention that in order to go to .75-.80 inch total depth, you have to pass through a section of the secondary piston that is only 19/64, so there is little room for error in centering…

Thanks for all that helped, I am quite pleased I can stop worrying about this, now on to the next issue…


Postscript:

This thing is stupid fast... If you can stand to hold it on the floor when it shifts to second it covers the rear of the truck in tire smoke. The whole thing is absurd, I love it!!!

[DuckRyder]

Oh, and I forgot to take pictures of the secondary valve. It is the small one with a big end and a small end. You are drilling from the big end to a total depth measured from the upper edge. A truck governor will probably have an extra small weight in it which you will remove. Thats the end that you are drilling from.



This is the weight that you will remove, the valve is also visible.

The text of the TSB is as follows:

GOVERNOR SECONDARY VALVE

The governor secondary valve differs from that used with the conventional C-6 in having less mass, which has the effect of raising the shift points at any given throttle setting. It can be identified by a 13/64 inch diameter hole drilled to a depth of ¾ inch from the inner end of the valve. (Fig. 3).

[Jake11]

Like working on autos? http://www.transgo.com/jointech.php

If you want to build ones that last/ hold up to anything.

If yer just making a toy one, ok. Look at the freebie on line stuff. As you
may know, you get what you pays for. I looked at that sight, and they
are just great if thats good enough for you. Good luck.