Worn crankshaft @thrust surface

[RDavis]

The Crankshaft is trash. Worn from thrust of torque converter. Bruce or someone can you tell me a fix?
I will pull pressures when I get the engine back in.
Any suggestions?

 

[FJM568]

Ballooned torque converter...

 

[KEVINS]

I agree...

 

[WE4]

well.....................

Not to be negative but I would look for another problem . Do converters balloon? Well, yes , but at a rate 7/8ths smaller than what is talked about. I have been racing and building trannys for over 20 years and I have only seen 4 that I can document as "ballooned" ( and they were sitting on the brake at 6500 rpm with a 700 hp motor. Driver screw up. ) . This is a term that one guy has happen to him, and they all think it happened to them. Yes it does occur but at a rate of 1000 to 1. Not as common as some people lead you to believe.
Look elsewhere for a problem. Did converter stall extremely high? Was performance effected before you had the motor problem?
If you do see a converter ballooned, 9.5 times out of 10 it is a cheap no name brand converter with crap parts. Converter ballooning is one of the most common engine builder excuses there is. They need to blame any other reason than , the motor itself. It is very easy to point the finger..............

 

[FJM568]

Heheh...Whoops...okay, here comes the hearsay part of my answer...ballooned converter is what I've always heard was the most likely cause of wasted thrust bearings...I guess also it would depend on who machined the block or crank, or if the thrust clearances were out of tolerance and such...

But I will say, I would probably not put that torque converter back in with the new motor...But that's just me

I will now just sit back and soak up every little slice of knowledge that you would post here Bruce....You da man!!!

 

[6PacktoGo]

ballooned converters are not the only

thing related to the transmission that will kill a thrust bearing.


You can also have a problem with converter charge pressure. If the converter charge pressure is too great, it will force the converter out of the pump. Common problem with the 400 and with others to a lesser degree. At one time, Don Wang posted on the GNTType digest about this. He had a cure for it (you there Don?). I see BOTH sides, as a builder of both engines and transmissions. Honestly, I've rarely seen a thrust flange or bearing worn without an external source of pressure, be it converter ballooning, excessive charge pressure, or high static pressure on a stick car.

 

[Alky V6]

What trans are you running? What is the line pressure at idle and stall? Has the pressure regulator valve been modified (second land ground away)? Converter charge pressure could be the problem, if it is at all related to the trans. The circumstance that Bruce described could certainly cause it too. I have known of bad cranks also causing this problem. I once troubleshot a C4 for a customer that was tearing up the crank thrust on a 302 engine. I have never heard of this type of problem with a ford. I restricted converter feed until there was close to nothing as far as cooler line pressure which is a good indicator of converter charge pressure and the crank still went bad. It turned out that his crank supplier finally admitted to him that he started noticing other customers having problems with these particular cranks also. Probably offshore stuff.

 

[Scott231]

RDavis - are you certain you do not have a detonation problem that is tearing up the crankshaft/bearing? Did the #2 and #3 main caps come out of the block registers real easily?

I pulled my motor apart last month and also found a trashed thrust bearing (crank is OK). The #2 and #3 were obvioulsy tweaked...but the converter and trans were operating at 100%. As such, I wouldn't immediately jump on the ballooned converter bandwagon.

My $0.02

 

[6PacktoGo]

Originally posted by DonWG
What trans are you running? What is the line pressure at idle and stall? Has the pressure regulator valve been modified (second land ground away)? Converter charge pressure could be the problem, if it is at all related to the trans. The circumstance that Bruce described could certainly cause it too. I have known of bad cranks also causing this problem. I once troubleshot a C4 for a customer that was tearing up the crank thrust on a 302 engine. I have never heard of this type of problem with a ford. I restricted converter feed until there was close to nothing as far as cooler line pressure which is a good indicator of converter charge pressure and the crank still went bad. It turned out that his crank supplier finally admitted to him that he started noticing other customers having problems with these particular cranks also. Probably offshore stuff.

It's a 200 4R Don. He did lose both a cam lobe and a couple head gaskets. I'm not sure what has been done to his transmission, I never looked at it. His converter looked stock, still had the sticker on it. He also told me they had tremendous detonation. I'm out of this project now, but I told him I'd try to help.

 

[Alky V6]

Mmmm, that explains a little bit. Blown head gaskets = water in oil. Worn cam lobe = metal floating around in oil. Water and floating metal hit thrust surface = not a good thing.

 

[RDavis]

trashed thrust bearings

Don
The 200r4 is stock. The Doctor inherited it from his Dad after he passed away. The thrust bearing was polished smooth with ripples indicating to me it had taken a while to do this. The other
Bearing surfaces that saw the cam lobe failure were clearly fresh
scratches.
The first indication of this was a rear main oil leak and upon inspection of the main bearings one was worn excessively
rough into the babbit.I think it was the last or next to it. He has a GNX which had a main bearing out from the oil journal area also and sometimes I confuse the two.
I will have the block checked.The crank is comming back Standard bearings hard chromed, cross drilled, indexed, and lead in grooved in the mains. I will check all the pressures as soon as it is running.
I really appreciate the help and I do believe it is possibly the charge pressure on the converter. But it shifted so well.
I will repost as soon as it is running.
Thanks
Rod

 

[RDavis]

Worn Thrust on crankshaft

Something that comes to mind on this car is that time to time it would die at idle spme times a surge or lack of acceleration,
but not often enough to track down. I FEAR IT IS THE DREADED TCC LOCKUP SOLENOID SYNDROME. It would make sense on the worn thrust surface also. When running I will replace it and run it with a meter on the wiring to make sure the chip is not sending lock up at the wrong time.