Torque Converter To Flex Plate Space

[69 GeeTeeX]

Today I received my new 9.5” torque converter built by PTC. Engine has a new Eagle crankshaft with new B&M flex plate. When I checked the converter hub fit into crankshaft it was good. After installing the flex plate I rechecked the converter hub to crankshaft and noticed with the hub engaged all the way into the crankshaft there’s about .100” - .150” gap between the converter lugs and flex plate.

Am I supposed to use a washer between converter and flex plate with the 7/16 bolt?
Should the converter hub bottom out in crankshaft or have some space?

505 engine with 727 transmission.

 

[440Coronet500]

No washers, do you have the flex plate installed properly? 440'

 

[69 GeeTeeX]

Yes, the flex plate is stamped “engine side” and that’s how I installed it.

 

[69 GeeTeeX]

It’s a 8 bolt flex plate to fit the Eagle stroker crankshaft.

 

[440Coronet500]

The converter bolt standoffs should be flush against the flex plate when installed. That should ensure the converter snout will be engaged in the crankshaft pilot. If the converter snout bottoms out in the crankshaft pilot before their mated together something is wrong. 440'

 

[69 GeeTeeX]

I’ll call PTC tomorrow. I think they made the hub to long to fit the Eagle crank. Or the crankshaft wasn’t machined deep enough. Either way you’re right, definitely a problem.

 

[440Coronet500]

Good idea, I have had similar issues with aftermarket parts. Hope you get it figured out. 440'

 

[493 Mike]

Could the flex plate be mismarked?
Mike

 

[chtampa]

Perhaps a pilot bushing? I seem to remember having to cut mine out.

 

[beanhead]

Doubtful it's a converter issue. Maybe you get lucky and it's as 'chtampa' said, and they put a bushing in the hole for a 4-speed....otherwise she gotta come back out
Now, I don't remember about 8-bolt flexplates, but 6-bolters have a bolt offset and can only go on one way. Maybe 8s can go on backasswards? If the flexplate is "wrapped around" the crank and not "standing off" of it, it's on correctly regardless of how it's marked..

 

[Dipstick]

8-bolt flexplates also have an asymmetric bolt pattern, can only go on one way.
Even if the flexplate was on backwards the problem would be the opposite, no gap.

 

[69 GeeTeeX]

So I’m still working on this problem. I took my stock torque converter and checked again found the same problem. I finally figured out the flex plate is the difference. New torque converter and Eagle crankshaft all measure the same as the stock 440 crankshaft and torque converter. I need an 8 bolt flex plate and only found the B&M #10231. After fitting the PTC converter and centering it up I have .090” between the flex plate and converter lug. Do I just tighten up the bolts and draw the two together bottoming out the converter hub and crankshaft. I always thought there was a small space between the two but maybe not.

 

[wyrmrider]

gap looks good to me but converter should not "bottom out" in crank
will it push up flush to the flexplate or is this what you've been saying?

 

[Fran Blacker]

When you tighten the bolts are you bending the flex plate or drawing the converter out of trans to meet flex plate?

 

[Dipstick]

I finally figured out the flex plate is the difference.

Measure from the mating surface at the back of the block to the converter lug mating surface of the flex plate. Should be .375"-.400".

 

[69 GeeTeeX]

The photo is with the converter hub bottomed out in the crankshaft. If I tighten the bolts it’ll bend the flex plate.

 

[69 GeeTeeX]

Measure from the mating surface at the back of the block to the converter lug mating surface of the flex plate. Should be .375"-.400".

Just checked block near cam plug and bottom of block both to backside of flex plate where converter lug would touch. .400” in both locations.

 

[493 Mike]

So, is it a defective/improperly stamped flex plate? Do you have a stocker to compare the offset with?
Mike

 

[wyrmrider]

wait he says .4oo which is within spec givev
he's bottoming converter nose into the crank
pull the trns
measure converter nose on severl converters
and measure depth n the crank
check for MT bushing
pics

 

[Dipstick]

Yeah, I'm thinking the aftermarket crank flange isn't bored deep enough or the converter pilot hub is too long. I've heard of converter hubs intentionally being made long to compensate for motor plates.