TCC question on a THM-350C...

[Freddie's Buick]

Does anyone know when is it proper to 'lock-up' the converter?

For example, the OEM manuel suggest that for passing and de-celleration the trainy is in the 'un-lock' stage.

De-celleration I could understand this is good, but passing?

I thought that 'locking' up the converter gives it that extra jolt when you open up on the throttle.....

Any ideas fellas?

 

[fc227]

I believe it is designed that way to:

1. Save the clutch from wearing out quicker

2. Too allow the engine to get up to a rpm quicker. So it can pull better.


That's my opinion.

 

[Freddie's Buick]

I kinda figured that Fred. But my question is aimed at the fact that I am thinking of installing a manual switch. And I wanna know at what point it would be good to 'lock' it, or 'unlock' it.

Do you know? Any suggestions?

 

[b4black]

Yeah, it only is locked when your crusing at constant speed. It can put a considerable amount of extra load when lightly accelerating (causing knock). Whenever the TPS moved up or down the ECM unlocked the TCC.

You would only want to lock it in third gear. It should still unlock itself when the brake is applied assuming you haven't undone the brake swict in the 12V feed.

Did you poke around on www.montecarloss.com ? In the tech section there are several ways to address this. I think there is a way to get it to lock whenever it's in third gear using the pressure switches in the transmission. This might be good enough (instead of constantly flipping a swicth).

 

[fc227]

What RPM does your engine pull best at? I would try at that RPM.

 

[Freddie's Buick]

Jeez Fred...... I wish I knew the terminology. What does 'pull' mean. Although I've read about this many times before. I don't have a clue as to what it means. You think you can school me?

What's up Rich,

Yep I did check that out, (www.montecarloss.com), but most of it pertains to that other transmission, (you know which one). The brake toggle switch will remain.

It's article goes into detail on the later 12 pin ECM/ALDL and how to bypass and modify the TCC system. This leaves me at a loss since there is no info on the earlier 6 pin ALDL.

Anyway, my goal is to remove ECM control and have it lock up according to the manuel. It locks up at 25 MPH, unlocks at about 30-35, then locks up again at 45, to unlock again at 50-55 MPH.

This seems O.K. to me and this is the way my car runs currently. But I am working on an experiment to retro the car. I'm almost finished with the Non-CCC Q-jet. And Bruce out in the transmission forum was kind enough to send me a schematic on wiring the THM-350C up.

http://members.telocity.com/~familiadiaz/Bruce.jpg

I really don't know what I am going to achieve with this schematic. He has'nt gotten around to answering that question. I do know that I don't want to be constantly flipping a switch all the time and especially not while I am driving long distance. (I don't mind an occasional switch).

The schematic is quite simple and easy to execute. It's the end result I'm worried about. The ECM system will be 'unplugged'. I'll just pull out the ECM fuse. The sensors will remain intact. The distributor, carburetor, ISC will be removed. What do you guys think of this idea?

 

[fc227]

Buy Pull, I mean where does the engine make it best power or "pull" the car the best.

EX. My car likes 3000 to 5500 RPM range.

 

[Freddie's Buick]

2000-3000 RPM

 

[RCI2990]

heck freddie just pull the tranny out and get a older th-350.that way you can put a shift kit in it while the old ones out.

 

[Freddie's Buick]

Hey Marc!

It's an experiment. Besides, I had posted an earlier thread about a timing problem. I resolved it by lowering the stock OEM 15 degrees BTDC to 8. Now the car runs great.


By the way I just finished with a '80 non-electronic Q-jet from a Pontiac. Way too many mods had to be done to it. Hopefully she'll work great when I implement the experiment. Check out the pic:

http://members.telocity.com/~familiadiaz/80Carb.jpg

 

[RCI2990]

boy that's ironic,the q-jet i'm using came off of a 80 toronado but the numbers on the carb show that it's a pontiac carb. what for mods did you do to it? mine i just rebuilt it and used the secondary rods and hanger off my ccc q-jet because there a little richer than the ones that came with it.when i get some time this weekend i'll borrow my friends dig. cam. to upload some pics of it.

 

[Freddie's Buick]

Mods: Had to use the primary throttle linkage off of my '82 Q-jet. Had to re-drill PCV port. Had to drill open the rear booster vacuum port on the throttle plate.

Re-drill secoundary discharge ports below the throttle blade. Drill open upper primary discharge ports. Cut the secoundary adjustment tang so the blade opens full for 850 CFM operation.

Drill open front port for proper canister operation. Drill open rear port for secoundary diapraghm operation. Open up accelerator pump arm to fit '82 throttle linkage.

Boy I hope this works........