Thrust bearing

G

gene

New member
Sep 29, 1999
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About a year ago, there was a discussion here about rebuilt engines.. At
that time someone said (I thought it was Tom) that the end of the crank had
to be ground down to keep the Torque conv. from pressing on the crank or to
get proper clearance.....

Did I get this wrong?? It sticks in my mind that it was said this is
something Mondello does as a part of his rebuild. Is there such a thing?
Should we be monitoring the play in our cranks'?? Is there a tolerance here
that we need to monitor for the new Allison converters ?? Is ballooning of
the torque converter a part of this problem?

How can this failure happen? Is it a tranny problem? What would have made
Mr.C's engine fail in this way? Do the engines push on the tranny? or does
the tranny push on the engine? or is there any reason to suspect a problem
here?

enquiring minds want to know.
gene

Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
>
> About a year ago, there was a discussion here about rebuilt
> engines.. At that time someone said (I thought it was Tom)
> that the end of the crank had to be ground down to keep the
> Torque conv. from pressing on the crank or to get proper
> clearance.....

Gene, that's got a little bell going off in my head. First I remember a
conversation with Dick Paterson at Marion where he recommended milling a
groove across the thrust bearing to aid in lubrication. Second, I don't
remember exactly(might have been Chuck Stoddards seminar at Myrtle Beach)
where, someone talked about improper finishing of the crank thrust bearing
surface by machinists when cranks were reground. This turns the thrust
bearing surface into an inefficient flycutter, eventually machining the
bearing away.

> Did I get this wrong?? It sticks in my mind that it was
> said this is something Mondello does as a part of his
> rebuild. Is there such a thing? Should we be monitoring
> the play in our cranks'?? Is there a tolerance here that
> we need to monitor for the new Allison converters ?? Is
> ballooning of the torque converter a part of this problem?

I recall that in the second forum above that this problem only arose after
an engine rebuild - seldom or never after replacing the trans or torque
converter, which pointed to an improper job finishing the crank.

> How can this failure happen? Is it a tranny problem? What
> would have made Mr.C's engine fail in this way? Do the
> engines push on the tranny? or does the tranny push on the
> engine?

Well, the thrust bearing is there for a reason - somethings pushing
somewhere. Maybe calls to Paterson, Mondello and Stoddard are in order.

Patrick
 
>About a year ago, there was a discussion here about rebuilt engines.. At
>that time someone said (I thought it was Tom) that the end of the crank had
>to be ground down to keep the Torque conv. from pressing on the crank or to
>get proper clearance.....

Gene - there was an article about this in the Tech Center #27 from
the Western States GMC. http://www.gmcws.org/techcenter/99-12tc27.html

This seems to come up every once in a while and there seems to be two
distinct schools of thought on this. One side says it cannot happen
and the fault is improper machining of the thrust surface on the
crankshaft and the other says it is the fault of the torque converter.

Dick Paterson, in his presentation on engine rebuilding at Rayne, is
of the first school and says special care must be done to get the
proper surface on the crank.

The engine rebuilders for the most part though, seem to blame the
transmission folks and vise versa. It seems to be hard to get anyone
to take responsibility when it happens to a fairly new rebuilt
engine. In Mr.C's case his engine bebuild by Stakus of Albuquerque
is really not that old and apparently Stakus feels that it is the
fault of the converter. We'll have to wait and see what comes of
this for Mr. C. He had the GMC hauled back from California on a
flatbed truck back to Stakus' shop (you don't want to ask the cost of
the trip!).

Emery Stora
77 Kingsley
Santa Fe, NM
 
great articles, but how do we find the correct answer ??

gene

>>About a year ago, there was a discussion here about rebuilt engines.. At
>>that time someone said (I thought it was Tom) that the end of the crank had
>>to be ground down to keep the Torque conv. from pressing on the crank or to
>>get proper clearance.....
>
>Gene - there was an article about this in the Tech Center #27 from
>the Western States GMC. http://www.gmcws.org/techcenter/99-12tc27.html
>
>This seems to come up every once in a while and there seems to be two
>distinct schools of thought on this. One side says it cannot happen
>and the fault is improper machining of the thrust surface on the
>crankshaft and the other says it is the fault of the torque converter.
>
>Dick Paterson, in his presentation on engine rebuilding at Rayne, is
>of the first school and says special care must be done to get the
>proper surface on the crank.
>
>The engine rebuilders for the most part though, seem to blame the
>transmission folks and vise versa. It seems to be hard to get anyone
>to take responsibility when it happens to a fairly new rebuilt
>engine. In Mr.C's case his engine bebuild by Stakus of Albuquerque
>is really not that old and apparently Stakus feels that it is the
>fault of the converter. We'll have to wait and see what comes of
>this for Mr. C. He had the GMC hauled back from California on a
>flatbed truck back to Stakus' shop (you don't want to ask the cost of
>the trip!).
>
>Emery Stora
>77 Kingsley
>Santa Fe, NM
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
Gene wrote;

Should we be monitoring the play in our cranks'??

A definite resounding YES to this!!!!!!
(hope the censor police doesn't catch this)
Jerry
 
>About a year ago, there was a discussion here about rebuilt engines.. At
>that time someone said (I thought it was Tom) that the end of the crank had
>to be ground down to keep the Torque conv. from pressing on the crank or to
>get proper clearance.....
>
> Did I get this wrong?? It sticks in my mind that it was said this is
>something Mondello does as a part of his rebuild. Is there such a thing?
>Should we be monitoring the play in our cranks'?? Is there a tolerance here
>that we need to monitor for the new Allison converters ?? Is ballooning of
>the torque converter a part of this problem?
>
>How can this failure happen? Is it a tranny problem? What would have made
>Mr.C's engine fail in this way? Do the engines push on the tranny? or does
>the tranny push on the engine? or is there any reason to suspect a problem
>here?
>
>enquiring minds want to know.
>gene
>
COUNT ME IN ON ENQUIRING MINDS WANT TO KNOW
al
 
Jerry

I am not sure you are into the spirit of this inquiry ;>)
I am not sure we are on the same page here!!!
sounds like you are warming up for your Rally, wish I could be there.
gene

>Gene wrote;
>
>Should we be monitoring the play in our cranks'??
>
>A definite resounding YES to this!!!!!!
>(hope the censor police doesn't catch this)
>Jerry
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
>Just for information sake, I did have a new transmission and a new
>torque converter put in by Darrell Winterfeld.

Al

>I think you guys may be confusing thrust bearing clearance (.004"-.010")
>(which is checked when torquing rod journals) with balloning of the torque
>converter. Any competent engine builder should know how to set crankshaft
>end play but they do not check the torque converter which is normally the
>culprit for premature engine failure. The original torque converter balloons
>pushing the crank shaft forward and ruining the engine. If I were going to
>spend all of this money on a new engine i would postively change the torque
>converter to a heavy duty unit. It should be brazed and have torrington
>bearings.
>
>
>

> >
>>
 
- ----- Original Message -----
From:
To:
Sent: Wednesday, June 28, 2000 9:44 AM
Subject: Re: GMC: Thrust bearing

Al,

Sorry to hear about your engine trouble.
How did you first notice the problem - was there a noise, vibration,
anything? If this is a common problem, it would be good to know what the
early symptoms are.

Thanks,

Peter
77 Eleganza II
Colorado

> COUNT ME IN ON ENQUIRING MINDS WANT TO KNOW
> al
>
 
>----- Original Message -----
>From:
>To:
>Sent: Wednesday, June 28, 2000 9:44 AM
>Subject: Re: GMC: Thrust bearing
>
>
>Al,
>
>Sorry to hear about your engine trouble.
>How did you first notice the problem - was there a noise, vibration,
>anything? If this is a common problem, it would be good to know what the
>early symptoms are.
>
>Thanks,
>
>Peter
>77 Eleganza II
>Colorado
>I was nothing that just occured. It seemed that as I was driving I
>heard a little thump, and at first it sounded like what you might
>consider as a ping or so on the engine. I listened as I have the
>Caspro Knock Sensor, and it seemed to go away if I lowered my speed
>to like 55 to 60 and if I drove under this magic speed the noise
>went away. At first I thought I was getting knocking as the
>pinging(thump) went away. then when I raised the rpm it came back.
>I then decided to pull over and see if something simple was causing
>the problem..ie, a belt, an alternator, water pump etc Something
>simple. But when I stopped and opened the hatch, the thumping did
>not go away, although the sound was coming from the front of the
>engine. It did not sound like a rod, and the thumping was now
>evident when it idled. That's when I stopped and had it towed to
>Bob Lamy's. He crawled under the front and coul dsee the crank
>moving. I did not think to look there as I am not familiar with a
>thrust bearing going out.

Hope that helps.
al
 
Thanks, Al
Peter
- ----- Original Message -----
From:
To:
Sent: Thursday, June 29, 2000 12:35 AM
Subject: Re: GMC: Thrust bearing

> >I was nothing that just occured. It seemed that as I was driving I
> >heard a little thump, and at first it sounded like what you might
> >consider as a ping or so on the engine. I listened as I have the
> >Caspro Knock Sensor, and it seemed to go away if I lowered my speed
> >to like 55 to 60 and if I drove under this magic speed the noise
> >went away. At first I thought I was getting knocking as the
> >pinging(thump) went away. then when I raised the rpm it came back.
> >I then decided to pull over and see if something simple was causing
> >the problem..ie, a belt, an alternator, water pump etc Something
> >simple. But when I stopped and opened the hatch, the thumping did
> >not go away, although the sound was coming from the front of the
> >engine. It did not sound like a rod, and the thumping was now
> >evident when it idled. That's when I stopped and had it towed to
> >Bob Lamy's. He crawled under the front and coul dsee the crank
> >moving. I did not think to look there as I am not familiar with a
> >thrust bearing going out.
>
> Hope that helps.
> al
>
>
>
 
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