Oh no, not another torque converter thread

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grjammer

grjammer

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I have looked through everything I can find, and I can find nothing to help me with this question. I have a 77 440 with a forged crank, internally balanced. I am mating this to a 77 727, ID PK3681056 4017 8246. I had received a torque converter but more than likely just something thrown at the parts package. no numbers on it. I had the trans and TC rebuilt. The engine is about 8.5 compression, with a HP replacement cam. Stealth heads, Tri-Y's, performer intake, TQ "super-quad".
The torque converter is fully set back and gives very minimum measurements of 1.25 inch to ring gear and 1/2 inch to pad. My flex plate is an OEM cheapie and measures 3/8 from back of block. Is 1/8" enough "flex"? Is there a different TC/Flex plate combination for a forged crank? I have found in my "travels" that there is a thin or thick mounting pad on different 440 TC's. I have filled out a tech data sheet and submitted to Hughes just this morning, I will probably buy a new converter and flex plate, If I can determine the eng/trans are not a total mismatch.
I figure a medium stall is probably best, as the cam runs out of power around 5500.

My main question is the clearance of what I have, I put it together and did not have to use the bolts to pull the trans in, but when I went to put in the TC bolts the plate was contacting the pads enough to inhibit the rotation of the TC, but only barely so. I could rotate the crank 360° if I locked the converter. I pulled the trans back out of the car and visually verified the pump still has it's lugs intact. I did several placements of the TC in the trans and can never get any better set back than what I have measured. I just think its not quite enough.
Has anybody else seen this? I will post this diagram showing the measurements I did with the trans out.
car tc clearance measure.JPG
 
I have not personally seen that happen, but all I can think of is the converter is not fully engaged into the input shaft. Normally the TC pretty easily engages with a little twist as you work it in. As a test, do you have another TC that you can try to fit to see if that one fully engages?
 
It is fully engaged. verified many times. When the pump is not engaged, it sits out so far I wonder how people can use bolts to pull in a trans and damage something. My eng/trans mated up very easy with no bolts. Ordering a new converter and flex plate anyway, as the snout of this one has considerable wear on the slots, or somebody was grinding on it to make it easier to install. It looks like \__/. I have never run it. I will probably have better luck with clearance when I get the new units. I am going to give the vendor the tech data to ensure I have compatible parts. I also don't know the stall of this POS, so am going to be ahead in the long run. I was hoping someone could chime in and tell me I needed a converter with thin pads or a different flex plate. I didn't know they existed until all the research I have been doing. I guess I will find out when I start calling the shops on Monday. I will follow up with this if I find out anything unexpected.
On a positive note, I now know what it takes to remove the transmission from a RB with try-Y's and stock PS gear and starter lol. Going to get a mini starter too at a minimum. Installation was a breeze from underneath with everything assembled, though not so maintenance friendly after.
Thanks for input, any and all is appreciated.
 
It sounds like the "flexplate" is bent. Rotate the crank 120 degrees and check the depth again at the same spot on the block, then repeat (runout).
 
A simple test. If you can fit your fingers completely behind the converter when it's installed in the transmission, it's not fully seated.

What I would do for stall speed would be a modern version of the factory high stall and call it a day.
 
The only
grjammer said:
I have looked through everything I can find, and I can find nothing to help me with this question. I have a 77 440 with a forged crank, internally balanced. I am mating this to a 77 727, ID PK3681056 4017 8246. I had received a torque converter but more than likely just something thrown at the parts package. no numbers on it. I had the trans and TC rebuilt. The engine is about 8.5 compression, with a HP replacement cam. Stealth heads, Tri-Y's, performer intake, TQ "super-quad".
The torque converter is fully set back and gives very minimum measurements of 1.25 inch to ring gear and 1/2 inch to pad. My flex plate is an OEM cheapie and measures 3/8 from back of block. Is 1/8" enough "flex"? Is there a different TC/Flex plate combination for a forged crank? I have found in my "travels" that there is a thin or thick mounting pad on different 440 TC's. I have filled out a tech data sheet and submitted to Hughes just this morning, I will probably buy a new converter and flex plate, If I can determine the eng/trans are not a total mismatch.
I figure a medium stall is probably best, as the cam runs out of power around 5500.

My main question is the clearance of what I have, I put it together and did not have to use the bolts to pull the trans in, but when I went to put in the TC bolts the plate was contacting the pads enough to inhibit the rotation of the TC, but only barely so. I could rotate the crank 360° if I locked the converter. I pulled the trans back out of the car and visually verified the pump still has it's lugs intact. I did several placements of the TC in the trans and can never get any better set back than what I have measured. I just think its not quite enough.
Has anybody else seen this? I will post this diagram showing the measurements I did with the trans out.
View attachment 1716328099
Click to expand...
The only mention I can see for a thinner mounting pad for the 727 is a 77 and up 225/318 application. It seems to me, that I read somewhere that it is possible to install the OEM flex plate backwards. Perhaps Rusty or Kim can help with this.
 
Last edited:
Can't install backwards as one hole is offset. I did put it all together today and had my 1/8" wiggle room and was able to rotate the converter. I just had the converter rebuilt, so I am going to run it and see how it does. Trans is under warranty anyway lol.
Thanks for help.
 
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