Re: i have no clue? Jamie, We are talking about one small passageway inside the case/front pump. Fluid must be restricted in that one passageway in order for the switch pitch feature to work. It is part of the conversion process. Overall fluid flow for cooling and operation of the trans is unaffected. There are several types of stall speed. Brake stall is how much RPM you can attain with your foot on the brake and gas. With an efficient converter, you should not be able to reach the rated stall speed of a converter. It should spin street tires right through the brakes well before that speed. Actual stall speed is defined as the maximum RPM you can turn the impeller(front half of the converter), with the turbine(rear half of the converter) held stationary. When you let go of the brakes and launch the car, the RPM can flash anywhere from 500-2000 RPM above the actual stall speed. This is flash stall. A high stall converter does not suddenly grab. It is gradual. There is a speed where the converter transmits torque in almost a 1:1 ratio. That is stall speed. There are so many factors that effect stall and converter efficiency. Converter building is an art. The more a builder knows about your engine and driveline, the better his chance of building the converter you need. You get what you pay for with converters.
once again,thanks Larry:TU:your awesome with your help:eek2: i kinda get it,but wont know untill i actually drive it:Brow: darn cold weather is keeping me from working on it!!!:rant:
Thanks, Larry for the help, but if it doesn't work i guess i will be pulling it apart again. Also the stall coverter multiply's the torque up to 2.5x, until the turbine rotates.(car moves).
Oh, it seems a lifetime ago, back in the early 80's when I got a complete built TH400 switch pitch trans w/convertor and adapter plate for it as it was a BOP trans and this was for my BB Chevy LS6 at the time. fficeffice" /><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:af: <o></o> <o></o> I ended up selling the SP parts and getting a Chevy TH375 medium tail trans core of which my trans guy made in to a built short tail TH400 for me. The trans guy (a Buick GS owner <?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" /><v:shapetype id=_x0000_t75 stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" oreferrelative="t" o:spt="75" coordsize="21600,21600"><v:stroke joinstyle="miter"></v:stroke><v:formulas><v:f eqn="if lineDrawn pixelLineWidth 0"></v:f><v:f eqn="sum @0 1 0"></v:f><v:f eqn="sum 0 0 @1"></v:f><v:f eqn="prod @2 1 2"></v:f><v:f eqn="prod @3 21600 pixelWidth"></v:f><v:f eqn="prod @3 21600 pixelHeight"></v:f><v:f eqn="sum @0 0 1"></v:f><v:f eqn="prod @6 1 2"></v:f><v:f eqn="prod @7 21600 pixelWidth"></v:f><v:f eqn="sum @8 21600 0"></v:f><v:f eqn="prod @7 21600 pixelHeight"></v:f><v:f eqn="sum @10 21600 0"></v:f></v:formulas><vath o:connecttype="rect" gradientshapeok="t" o:extrusionok="f"></vath><o:lock aspectratio="t" v:ext="edit"></o:lock></v:shapetype>) said they (KB) never installed that small plug...<o></o> <o></o> I later worked for Borg-Warner trans rebuilding division and the guys came across an odd Rolls-Royce TH400, I informed them it was a SP vintage 1967! Yes Rolls had GM TH400s in them back in those days. The trans had to be rebuilt to BW specs, so rather than see the parts go in the trash, I took the pump trans and input shaft stuff and sold it, now of course I wish I had it, but I did not expect to own another TH400 equipped car again, now I have 2 <v:shape id=_x0000_i1026 style="WIDTH: 27.6pt; HEIGHT: 11.4pt" type="#_x0000_t75" alt="0"><v:imagedata src="file:///C:\DOCUME~1\Owner\LOCALS~1\Temp\msohtml1\01\clip_image002.gif" o:href="http://v8buick.com/images/smilies/confused4.gif"></v:imagedata></v:shape><o></o> <o></o> What is the link for this TSP place?, PM or email me please.<o></o> And does anyone sell conversion kits anymore like KB did back then?<o></o> <o></o>
yes, thanks i figured out already that TSP mean Tri Shield Performance, was just reading their site info.
I had good luck putting the restrictor in the pump body. Locate the hole in the pump that aligns with the normal restrictor location in the case. Tap the hole to 10/24 and use a short 10/24 allen head set screw for the restrictor. Make the restrictor hole in the set screw before installing it. The smaller the hole, the quicker the 'switch' to high stall. At part throttle, a bit less than .020" hole feels like a firm gear change. On the other side, it takes a little longer to switch back to high stall. Over about .030" and the switch pitch quits working.
Terry, that is good info, i may pull it apart and try that route. I have not put fluild in it yet. I guess i have to source out to get a .020 drill bit? What would happen if the restrictor gets plugged by my backwards installation?
Actually, I cheat a little. I hold the set screw with an allen wrench and 'kiss' the end on a grinder (fine stone) until it just turns blue. The end will be thin enough to poke a hole through. The screws are cheap so you can do a few practice ones until you get the size you want. I do have a pin vise assortment of drills to use but have made many using a small needle. The trick is accurately gauging the hole so it isn't too big. Hint: it is hard to make it too small.
Anyon know why after .030 hole the switch stops working, seems very odd a few thousands of an inch would have such a dramatic effect?
The switch pitch pump has a fluid circuit to control the stator position. The circuit has a solenoid, the orifice and a spool valve with a spring. When the solenoid is energized, pressurized fluid is dumped and the spool moved to high stall. Close the solenoid and the spool moves back and routes the fluid for low stall. The orifice acts like a timer or hourglass effect between the two positions. A few thousands can make a big difference. Larger than about .030 the timer action is lost. Picture an hourglass without the necked down part ,,,,,,,,,, the sand would simply dump to the other end when you turned it over.
Thanks, just looking for the quickest way to switch from high to low stall as i will be launching off the transbrake then will have the high to low stall set by a certain mph with a electronic controller used for a lockup converter. Hope it all works!
