aeolus
Mechanical
- Mar 11, 2004
- 1
We are an aftermarket engine remanufacturer and specialty machine shop on the east coast. Recently we have run into a problem with a 4.2 ford engine thrust bearing failure, two engines, two failures within 500kms of installation.
After hours of trial and error we have determined that with the vehicle in park engine running there is a force of over 150lbs being applied to the back of the crankshaft by the transmission which is trying to shove the crank out the front of the block. Thrust bearings are designed to handle intermittent loads up to 200lbs but not constant loads, from any research I have done I have been led to believe that a vehicle in park engine running with no load should apply minimal force on the trust bearing (back of the crank) so my question is where is this force coming from.
We have replaced tourque converters (twice) had the tranny out for service (nothing found to be wrong except for some wore out bushings in the input shaft, so where is the force coming from, fluid pressure of some kind on the converter which is trying to push the converter off the input shaft and into the back of the motor, but what is the cause. Flow rates appear to be normal, .2 - .5 gpm and main line pressures of around 65, cooler line pressures of between 5 and 15 lbs. Is there something in the tranny that could be causing this pressure? There is very little info on the net concerning this problem.
The engine we have in the truck now has .250 end play and when the truck is started the crank snaps out the front of the engine .250 and requires 150+ pounds of force to push it back in. Help.
After hours of trial and error we have determined that with the vehicle in park engine running there is a force of over 150lbs being applied to the back of the crankshaft by the transmission which is trying to shove the crank out the front of the block. Thrust bearings are designed to handle intermittent loads up to 200lbs but not constant loads, from any research I have done I have been led to believe that a vehicle in park engine running with no load should apply minimal force on the trust bearing (back of the crank) so my question is where is this force coming from.
We have replaced tourque converters (twice) had the tranny out for service (nothing found to be wrong except for some wore out bushings in the input shaft, so where is the force coming from, fluid pressure of some kind on the converter which is trying to push the converter off the input shaft and into the back of the motor, but what is the cause. Flow rates appear to be normal, .2 - .5 gpm and main line pressures of around 65, cooler line pressures of between 5 and 15 lbs. Is there something in the tranny that could be causing this pressure? There is very little info on the net concerning this problem.
The engine we have in the truck now has .250 end play and when the truck is started the crank snaps out the front of the engine .250 and requires 150+ pounds of force to push it back in. Help.