CRANK THRUST FAILURE! $2500.00 in damages

[turbolou]

I need some input on Precision Industries single disc lock up converters as I had a thrust bearing failure caused by one of their converters & would like to know of any others possible experience with this. The air gap between converter turned out to be only 040 thousands instead of the recommended .125 causing pressure against the crank. The converter was manufactured wrong & out of spec. Just want to make you people aware of this. Two other converter combinations were tried in this car with no issues & both had the required minimum distances. I am now about to find out how good the company stands behind their product.It gets shipped back today.Any B.S. or excuses I don't want to hear & wont be taken lightly. More on this story later depending on what develops from here.

 

[Lee Thompson]

I feel for you

Good luck !!!
I have run their multi disc (rattler) but it had enough clearance.
I assume this is in a 2004R.

 

[turbolou]

Reply

Good luck !!!
I have run their multi disc (rattler) but it had enough clearance.
I assume this is in a 2004R.

Yes it's a 200 & in your case the rattle is considered normal. I'm trying to determine if there is a failure pattern involved with the single disc version. I having a difficult time trying to pin down the cause for sure.

 

[Nick Micale]

No chance in hell............?

Lou, I fought this battle with 2 different GN's using Precision converters when they destroyed thrust bearings. We were told by Precision that .040" was enough clearance?

Even when opened up to over that, it STILL took out a thrust bearing, or at least started too as we keep checking crankshaft play and removed it.

Look at the flexplate and see if there is contact mid-way between crank flange and converter bolts. These converters also push off the input shaft and you can see the mark on the flexplate.

We will NOT warranty any engine thrust problem with flexplate marks or distortion. :frown:

 

[turbolou]

Reply

Lou, I fought this battle with 2 different GN's using Precision converters when they destroyed thrust bearings. We were told by Precision that .040" was enough clearance?

Even when opened up to over that, it STILL took out a thrust bearing, or at least started too as we keep checking crankshaft play and removed it.

Look at the flexplate and see if there is contact mid-way between crank flange and converter bolts. These converters also push off the input shaft and you can see the mark on the flexplate.

We will NOT warranty any engine thrust problem with flexplate marks or distortion. :frown:

Thanks Nick! I value your input. I have checked all that throughly. The standard in the industry is to have min .125 thousands clearence.I too was told the same story by Precision & am not buying it. I was told by a trans builder that the convertor may be manufactured with a stator that has a restricted orifice to prevent surge & pissing fluid out the vent & dipstick. This increases line pressure & hydraulics the convertor forward into the crank with a lot of force. Since I'm not a trans specialist I may not be stating this right. What I understand needs to be done is to check line pressure coming out of the convertor to not exceed 110 psi. There again If somebody in the know could jump in here & explain this better I would appreciate it. Also I was told an engine ground problem could eat up the bearings. Since I have tried two other convertors with no issues I highly suspect a bad unit. My problem is & as you know it no one ever owes up to being wrong.Once I ship it back to the manufacturer you just know that they will deny any fault & piss me off even more. Its the end user/installer that gets it up the butt & quite frankly I'm tired of it. I'm hot enough to drive down to Precision & air mail the piece of sh""t through their front window. Lou

 

[3.8TransAM]

Look at the flexplate and see if there is contact mid-way between crank flange and converter bolts. These converters also push off the input shaft and you can see the mark on the flexplate.

:frown:

U mean the flywheel flange or where the flywheel bolts to crank?

 

[49-blues]

There was just another thread on this and i think chris from CK said line pressure should only be 40-55 psi or thrust could go out.The thread was on T-400s and thrust bearings. in this segment.

 

[ijames]

There was just another thread on this and i think chris from CK said line pressure should only be 40-55 psi or thrust could go out.The thread was on T-400s and thrust bearings. in this segment.

That was on T400's which have a much bigger input shaft diameter and so need to have much lower cooler line pressure to keep from taking out the thrust.

 

[Alky V6]

There are other factors to explore in the trans itself. Was converter feed modified in the transmission pump? Different converters will handle internal flow differently and may have different limits as to how much flow volume they can handle before an excessive back pressure is experienced. For this reason, if crank thrust problems are the main concern, any modifications to the pump that might increase flow volume to the torque converter should be avoided. Are there any cooler system restrictions? Take those restricted cooler line fittings and throw them in the trash. They restrict flow after the torque converter which can cause a dangerous buildup of pressure. Bottom line, if you have any concern for the crank thrust, do not mess around with converter charge pressure.

 

[JC'sGN]

There are other factors to explore in the trans itself. Was converter feed modified in the transmission pump? Different converters will handle internal flow differently and may have different limits as to how much flow volume they can handle before an excessive back pressure is experienced. For this reason, if crank thrust problems are the main concern, any modifications to the pump that might increase flow volume to the torque converter should be avoided. Are there any cooler system restrictions? Take those restricted cooler line fittings and throw them in the trash. They restrict flow after the torque converter which can cause a dangerous buildup of pressure. Bottom line, if you have any concern for the crank thrust, do not mess around with converter charge pressure.

Precision sends a restricted cooler fitting with their converter and claim it is needed to retain pressure in the converter . Is this what you refer to?

 

[turbolou]

Reply

There are other factors to explore in the trans itself. Was converter feed modified in the transmission pump? Different converters will handle internal flow differently and may have different limits as to how much flow volume they can handle before an excessive back pressure is experienced. For this reason, if crank thrust problems are the main concern, any modifications to the pump that might increase flow volume to the torque converter should be avoided. Are there any cooler system restrictions? Take those restricted cooler line fittings and throw them in the trash. They restrict flow after the torque converter which can cause a dangerous buildup of pressure. Bottom line, if you have any concern for the crank thrust, do not mess around with converter charge pressure.

Thanks Don! I have a 16 row Setrab cooler routed through the stock cooler doing what I guess to be a sano installation job. Frankly It's probably time to get more scientific & start double checking things like trans pressures. I have had too many trans tragedies through the years.Problem is I keep so busy with building engines,Trying to keep up with tuning & keeping these cars running & now working alone .I didn't ever want to become a trans expert also.As far as whats done in the trans.My builder who I trusted,supported & praised
has decided to play dead, blocks my calls & refuses to comunicate. So I haven't a clue what he may or may not have done? I think that bothers me the most. So I have a broken motor,questionable convertor problem,lost a friend, & a bunch of time, money & no support. Wish I had the balls to treat people that way. This sucks!

 

[turbolou]

Reply

Precision sends a restricted cooler fitting with their converter and claim it is needed to retain pressure in the converter . Is this what you refer to?

Not in my case it isn't unless something was done in that respect inside the trans?

 

[Alky V6]

Precision sends a restricted cooler fitting with their converter and claim it is needed to retain pressure in the converter . Is this what you refer to?

Yes.