Turbo 400 trouble

[Robbie Welch]

Thanks Tom & Henry, this is a customers engine that came to us with a the trans side of the trust bearing burnt and the bearing welded to the crank.The crank was useable and everything else rebuilt and checked out good. The customer checked the converter clearance and drive shaft clearance all said to be good. Well 2 races later and its back again with the same problem converter side of the trust bearing burnt. Since then the converter has been checked by the (manufacturer) and was good and the trans is bring checked. Both times after the run when he lifted the engine shut off when this occurred (I believe it was going on during the run and just locked up after the run). Also he had a less powerful engine in the same car with out a problem. With that engine he had motor mounts and a rear engine plate but I heard he cut the rear plate loose to gain header clearance after the first engine. He also checked engine movement in the car and said there was none. When checking cooler pressure do you just put a gauge in the line or do you use a port on the trans. Thanks Robbie

[Tom Goldman]

Robbie ,the side port is the line pressure port......Line pressure depends on many factors ,but should be between 165 -200#
Tee into the cooler line to read the pressure on the bottom cooler out line from the trans.
Does the customer do his own transmissions ? ...He may know if the pressure regulator spring was replaced or if any horse shoe shims were added.
If the cooler pressure is high , remove the cooler from the circuit , and measure the pressure on the loop to see if there is a restriction in the cooler raising the pressure.

[Alan Roehrich]

Did he take the plate loose from the frame, or did he take the plate out completely? If the mid plate was removed completely, that is the problem, unless the converter was also altered. The converter should be made to compensate for the thickness of the mid plate. When you then remove the mid plate, the converter is "too long", and you have a thrust problem.

Also, it is possible for the pump itself to develop a leak internally, and have line pressure leak into the converter charge/cooler circuit, that will create excessive pressure and burn the thrust bearing.

I've also seen people block off the cooler passages and create this problem. I just don't like blocking the cooler, if I'm not going to run a cooler, I make a small loop from steel tubing to run between the two cooler fittings, I find that to cause no problems at all, where I've seen various methods of blocking off the cooler cause all sorts of problems.

[Robbie Welch]

No, he doesn't build his own trans. The plate is still between the engine & trans I believe just cut off. Tom I'll get with him and find out about cooler & line size. Can ATI check pump pressure (they didn't build the trans). He'd like to find the problem before putting the engine back in the car.Thanks again Tom & Alan

[Tom Goldman]

I'm sure ATI could dyno the trans and moniter pressure.

[Alan Roehrich]

Tom is correct, ATI can dyno the transmission. I can't say what the cost would be, probably not inexpensive, considering they did not build or sell it.

[Robbie Welch]

Tom & Alan thanks for the info, I'll let you know what we find.