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Discussion Starter · #1 ·
Hello all,
I’m in need of some help. 72 nova with a completely fresh rebuilt Chevy 383 stroker. Freshly rebuilt TH350. And a brand new 9.5 inch Freakshow converter with billet hub. Used to be a 307 on this same transmission.

Im trying to get it all together and the converter pads were pushing up against the flexplate. Thinking it was a seating issue I reseated get converter like ten times and it’s in. I called Freakshow and they said the splines are tight and to tap it in with a rubber mallet. It’s in all the way becauseI put a small drop of red grease on the tip of the input shaft, installed the converter, and pulled it off. The grease was gone. It had been pressed against the inside of the hub. I looked in the converter with a flashlight and saw the grease spread against the hub so I know it seated.

i measured the converter pads relative to the face of the bell housing and am only getting one 8th short of an inch. So 7/8. I think it should be 1-1/8.

Freakshow had me measure the output shaft and it appears to be 1/4 inch too long. Could this be a bad rebuild?

I ended up switching the flexplates. Put on the smaller one off the 307. The new one on the 383 was a larger SFI approved unit. I noticed the factory 307 flex plate was more shallow. This solved the issue as far as the converter pushing on the flexplate. I can spin the converter now. I’m just not getting the clearance I need. Only a couple thousands of an inch.

bad rebuild? Bad converter? Could this be a 6cyl trans With an odd ball input shaft?

Any advice?
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Discussion Starter · #3 ·
Three clicks every time. That’s not the issue. Plus check out my post where I wrote that the input shaft bottoms out inside the converter so it’s in all the way.
 

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Mike - 74 Nova Baltimore, MD
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Is the flywheel mounted to the crank so that the mounting pads on the flywheel (for the converter) are protruding out towards the torque converter/transmission (red arrow below)?
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Freakshow had me measure the output shaft and it appears to be 1/4 inch too long.
I have a spare turbo 350 trans and I measured the distance from the flat surface of the bell housing (using a straight edge held against the bottom/flat portion of the bell housing) to the tip of the transmission input shaft = 1 3/16" .
What is your measurement?
 

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Discussion Starter · #5 ·
Thank you so much for this. Yes, bell housing surfaces facing out towards transmission.

my measurement is 1 2/16.

from what I’m seeing is the input shaft is bottoming out on the front billet hub of the converter. I put grease in the pump tabs and they are only engaging about 1/8th. This is with the converter directly against the flywheel with no play. My converter guy told me to run a 1/8 trans to engine spacer, but that will disengage the pump.

i measure the depth of the converter and it’s 2 8ths shy of 6 inches. My factory converter is 6 inches. Seems the converter is not deep enough. The converter builder is saying the input shaft is sticking out too far. My trans rebuilder is closed for the weekend.


Not sure what to do or where to start.
 

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Mike - 74 Nova Baltimore, MD
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Yes, bell housing surfaces facing out towards transmission.
What is a "bell housing surfaces"?... did you mean the flywheel mounting pad surface?

If the tip of your trans input is 1 2/16" to the flat surface of the bell housing, I do not think that your input shaft is sticking out too far... in fact, it is only sticking out 1/16" more then my turbo 350 (and I never had an issue with torque converter to flywheel spacing when this trans was installed in my Nova).

I beginning to wonder if the machining to the billet hub of the Freakshow converter might be a little "freaked-up".
 

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Discussion Starter · #7 ·
Yes sir, my mistake. I meant “ flywheel mounting pad surface”. This whole situation has me all screwed up.

Thats exactly what it seems like. Billet hub not deep enough. I’m thinking 2 8ths.
 

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if you get the converter all the way in to the trans then mate the trans and engine together you want to then pull the converter out of the trans 1/8"-3/16". if the converter comes out more than 3/16" before it touches the flex plate than you need to shim between the converter and flex plate. if you can't pull the converter out at least 1/8" then the converter is not going into the trans far enough and you need to figure out why.
 

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Discussion Starter · #9 ·
if you get the converter all the way in to the trans then mate the trans and engine together you want to then pull the converter out of the trans 1/8"-3/16". if the converter comes out more than 3/16" before it touches the flex plate than you need to shim between the converter and flex plate. if you can't pull the converter out at least 1/8" then the converter is not going into the trans far enough and you need to figure out why.
 

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Discussion Starter · #10 ·
That’s the issue. There is no gap. Converter is fully seated in the transmission and fully up against the flex plate. The input shaft is bottomed out inside the converter. Even if I could pull out the converter, the pump is only engaged with about 1/8th of the sbout tabs. That means I can only pull out the converter less than an 8th of an inch just to barely engage the pump. Either the input shaft is too long, which does not seem likely, or the converter hub is not deep enough. The converter is 2/8th shy of 6 inches deep.
 

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1969 Nova . . 2dr . . Chino Valley,Az USA
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I don't know . . . your answer . . . .

Have you looked at the "end of your crank" ............................ No pilot bushing , is there . . . ?

jim
 

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Asks Freakshow if there is a chance the converter was mistakenly made for a combination using a midmount plate between the block and the transmission.
They are typically .090"- .159" thick.

You could still be right about the depth though, if you haven't got enough pump drive contact.

Verify you don't be chance have a TH-350C input shaft in it by mistake??....it is slightly longer with an unsplined tip section on it, with a small o-ring on it also.

There isn't 1/4" of adjustment in endplay shim to the TH-350 trans(not even 1/8"), so it can't be a wrongly assembled Th350....just make sure it isn't mistakenly the 350C
 

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Discussion Starter · #13 ·
Nah, it’s not a TH350C. It’s got the regular shaft. Freakshow recommended running a midplate spacer of 1/8 to resolve the issue, but it would leave 1/16 contact to run the pump. It’s like the input shaft is too long or the converter is not deep enough.

If any of you have any th350 converters laying around, could you measure the depth from the tip of the snout down to the hub through the center. The Freakshow is 2/8 short of 6 inches. The factory is 6 inches. 2/8ths seems to be what I’m missing.

The converter is basically not deep enough in the transmission because the input shaft is bottoming out on the billet hub.
 

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Discussion Starter · #15 ·
What are your thought in the input shaft being too long? Is that a thing? Can that happen on a rebuild?
 

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Discussion Starter · #17 ·
My local trans builder told me to grind the taper off the tip of the input shaft. It will give me almost 2 8ths that I need
 

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My local trans builder told me to grind the taper off the tip of the input shaft. It will give me almost 2 8ths that I need
...and why would you need to do that for a new custom billet torque converter that I'm sure cost well over $1k... Grinding an input shaft?!? News to me...
 

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Good point brother. Gona send it back for inspection.
I mean, ya paid hard-earned CASH MONEY for this thing and you have to grind your input shaft to make it fit? F-THAT!! thinking most here would agree too. while grinding the tapered end would possibly give you the clearance needed for spline engagement and pump operation, it's not what I would consider an orthodox method of installation considering a new converter... Sounds to me like either there's something wrong with the input shaft and basket alignment in the trans or the converter is totally FUBAR inside either in the stator or one of the converter halves was milled too short... no telling without a complete forensics team eval :p Sorry, brother! That sucks either way.
 
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