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Discussion Starter · #1 ·
Before going into the details, here is my basic setup:
86 Mustang
331ci sbf
76mm turbo
PTC 9.5" Converter
th400 trans

After taking the engine out to refresh everything I found that the crank has been pushed forward enough to eat the #3 bearing and score the block. The crank will move about 1/4" front to back. The motor ran great, and I had no idea there was a problem.

The #1 thing that comes to mind causing this is the converter ballooning and putting pressure on the crank. The converter is being shipped out to be tested regardless.

A couple people have suggested that the transbrake was not properly adjusted, and when activated could have pushed the converter towards the engine, putting a lot of pressure on the crank, and causing this problem. I can't see how this is possible, so it would be nice if the experts can chime in. I cannot identify the manufacturer of the brake.
 

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I kill parts
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It would either be converter ballooning our converter feed pressure vs available return passages/flow from the converter. - I don't know glides to help you in that aspect.

Usually when you have a converter ballooning issue the trans pump will show wear just as the thrust mains in the engine.
 

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Its not the "tranbsbrake" portion of the trans causing the problem as much as system pressure or converter to flexplate clearance. What is the clearance between the converter cover and flexplate bolts? Converter pilot adapter and converter? What system did you use to adapt? Was the trans made knowing it was going to be used in a turbo car?


Hutch
 

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Discussion Starter · #4 · (Edited)
Its not the "tranbsbrake" portion of the trans causing the problem as much as system pressure or converter to flexplate clearance.

What is the clearance between the converter cover and flexplate bolts?
Looks to be about 1/8" to 3/8"
Converter pilot adapter and converter? What system did you use to adapt?
Used a J.W bellhousing to convert, and the converter has a ring pressed on to adapt to the Ford crank. The converter uses the GM style bolts where they bolt into the converter.

Was the trans made knowing it was going to be used in a turbo car?
Yes, the trans was rebuilt mid season with new clutches by a reputable local guy. The trans builder could not identify the make of the transbrake.


Hutch

Thank you for the reply.
 

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from across the pond...
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You need to do a search for this as there are various threads that address those type of problems.
Hutch is referring to turbo mods in the trans. If your builder only changed the clutches then you need to get a trans built by someone who knows how a turbo engine effects the transmission,and vice versa. There is a difference between an N/A trans and a turbo one.
 

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When you installed the converter , how much play between the converter and the crankshaft did the spacer have?

The charge circuit has to be changed for a turbo combination where you may get away with it on an N/A combination.


Hutch
 

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HUTCH.
I THINK YOU NEED TO MAKE A STICKY ON THE CONVERTER BALLOONING NOT THE REASON WHY OR THE ANSWER BUT TO SHOW WHAT IT LOOKS LIKE,
ESPECIALLY THE U TUBE LINK,TO THE ORANGE P/G GROWING SO MUCH. TOTALLY UNBELIEVABLE TO WATCH.
SHOWED MANY A CUSTOMER.
GOOD TO SEE EYES DROP ON THE GROUND.
 

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Discussion Starter · #10 ·
When you installed the converter , how much play between the converter and the crankshaft did the spacer have?
The converter itself had room to slide back to the trans maybe !/4" by eye. When the converter was seated against the flexplate I remember the spacer being really close to the crank, but I don't remember exactly. I will check it out when I get the converter back.

The charge circuit has to be changed for a turbo combination where you may get away with it on an N/A combination.


Hutch
That video is crazy... looks like that can cause a lot of damage.
 

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wow, that video...... man. so was it a pressure problem forcing the crank forward? causing the thrust bearing to go out?
 
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