Engine Rebuild

[gene]

Well I for sure like this finally a number to check from the outside, and I
think I will try some oil analysis to look for metal also. I guess if you
start to see metal, you might want to change the torque converter.

>He thinks we are just getting sloppy work. But then I knew he would say
>that. Well, I dont know if this helps or not. He said to tell all of you to
>grab the front of the crank shaft and pull then push. If you can feel about
>.005 of play you should be fine. He also thinks I worry to much. As he
>puts it "you have got one of the best hunks of engine iron GMC ever
>built."

As to worrying too much, Al had a new engine, new tranny, new torque
converter, and exquisite maintenance.......

Some people get the elevator some get the shaft.

gene

Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/ http://www.california.com/~eagle/

 

[patrick flowers]

>
> Well I for sure like this finally a number to check from the outside, and I
> think I will try some oil analysis to look for metal also. I guess if you
> start to see metal, you might want to change the torque converter.

No absolutely not!! I was going to wait until later tonight to do this
because I've got to run out for a while, but this makes me want to speak
out now. I've got three separate opinions today that I feel are well
qualified stating that torque converter "ballooning" is a rare
occurrence and then only at high rpm applications. This is not a factor
in the GMC motorhomes. This ballooning BS has been smelling to me ever
since the Marion NC GMCMI rally when it came up during a Tech session.
I didn't like what I heard then and it hasn't smelled any better since.

If converter ballooning were a problem, then the original converter
would be the worst offender, being the lowest cost alternative that GM
had. If it could eat a thrust bearing in 25,000 miles, then GM would
have been faced with a recall situation. My suspicion at Marion that
"ballooning" was being used as an excuse to cover sloppy engine building
technique has pretty much been confirmed.

Torque converter ballooning in the GMC application is a MYTH!

As for the forward force applied by hydraulic action of the torque
converter, I'm sure the GM engineers were well aware of that.

> >He thinks we are just getting sloppy work. But then I knew he would say
> >that. Well, I dont know if this helps or not. He said to tell all of you to
> >grab the front of the crank shaft and pull then push. If you can feel about
> >.005 of play you should be fine. He also thinks I worry to much. As he
> >puts it "you have got one of the best hunks of engine iron GMC ever
> >built."
>
> As to worrying too much, Al had a new engine, new tranny, new torque
> converter, and exquisite maintenance.......

Was his engine "new" or "rebuilt" - there is a difference.

> Some people get the elevator some get the shaft.

C'est la vie!
Patrick
--
Patrick Flowers
Mailtoatrick

The GMC Motorhome Page
http://www.gmcmotorhome.com

 

[patrick flowers]

>
> Be careful when you start comparing opinions such as the one from Archs
> friend.

I'm not talking about one person with three opinions. This came from
three different highly qualified individuals in different areas of the
U.S. Only one of them was Arch's mechanic.

> Remember that most serious builders or racers(and I am sure he is in
> this category) use the best parts and that means they do not use OEM torque
> converters. Get a JEGS or Summit catalog and check and see. When you talk
> racing you use torrington bearings, furnance brazed fins and anti ballooning
> plates.

That's right, they buy these parts because ballooning is a problem at
10,000 rpm - not 3,000. Just use a little common sense. The torque
converter is bolted to the flex plate - it can't move forward. If it
expands, which way will it go? It can only expand outward and back.
There's over an inch of room behind it. If it expanded that far, the
metal would fail and the converter would burst. As Rick Staples pointed
out earlier(thanks Rick! this was one of the final pieces of the
puzzle), ballooning is due to rotational(centrifugal) forces, not
internal pump pressure. This force exceeds the modulus of elasticity(I
hope that's right - it's been a long time since Mat.E.) of the steel.
The case(stator?) is permanently deformed. When a torque converter
balloons, it doesn't damage the crank, it damages itself.

I'll say it once again. If a torque converter could damage the crank,
the OEM unit would be the worst. Al C's crank failed in 25,000 miles.
If this had occurred in 1973, GM would have been forced into a recall.
It didn't happen - why not? And why is it happening now?

I don't know the real problem(at least not yet) and it may not be just
one thing. But I'm pretty sure now what it is not.

> I hope all of you guys to do not think that MONdello is offering
> these Heavy duty torque converters for MHs just for fun.

Make no mistake about it. Joe Mondello is a good businessman. He sells
things because there's a market for them - even if the market was
created by someone exploiting either our fears or our tendency to "gold
plate".

> Ballooning of the converter happens believe it.

Oh, it happens. Just not at 3,000 rpm.

My $.02,
Patrick
--
Patrick Flowers
Mailtoatrick

The GMC Motorhome Page
http://www.gmcmotorhome.com