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th400 converter question

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Old Jun 30, 2016 | 06:47 PM
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Default th400 converter question

I have a 10.5 converter for a sbc at the moment I have an TCI pn399753 I had with my ptc converter. I installed the trans and converter with spacer to see if it would have the .050-.075 spacing needed (assuming that the 399754 is the one I need and is the same minus the mounting holes) the converter is bottomed out on the trans and not touching the flexplate and i cant get the trans seated before it makes the converter bind. It is a rossler th400 with a ultra bell on a lq4 block. The ptc converter fit with no spacer needed and had plenty of room for me to shim. I have since sold that and had this converter built by sinister racing. wondering if anyone has info on the different flex plates in relation to different converters and or the height of an ls based converter so I can measure this one.

Last edited by ghost-1; Jul 5, 2016 at 12:10 PM.
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Old Jul 4, 2016 | 12:37 PM
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From: Deland, FL
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Originally Posted by ghost-1
I have a 10.5 converter for a sbc at the moment I have an ati pn399753 I had with my ptc converter. I installed the trans and converter with spacer to see if it would have the .050-.075 spacing needed (assuming that the 399754 is the one I need and is the same minus the mounting holes) the converter is bottomed out on the trans and not touching the flexplate and i cant get the trans seated before it makes the converter bind. It is a rossler th400 with a ultra bell on a lq4 block. The ptc converter fit with no spacer needed and had plenty of room for me to shim. I have since sold that and had this converter built by sinister racing. wondering if anyone has info on the different flex plates in relation to different converters and or the height of an ls based converter so I can measure this one.
I think you meant TCI flexplate? If so then I believe you have the dished LS1 flexplate. Sounds like your LQ4 has the long crank that requires the flat LT1 style flexplate OR it has a flexplate spacer that needs to be taking off to work with the dished flexplate and then all you need is the pilot adaptor extension for the converter.

-Dalton
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Old Jul 5, 2016 | 12:09 PM
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From: ft rucker
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Originally Posted by FTICONVERTERS
I think you meant TCI flexplate? If so then I believe you have the dished LS1 flexplate. Sounds like your LQ4 has the long crank that requires the flat LT1 style flexplate OR it has a flexplate spacer that needs to be taking off to work with the dished flexplate and then all you need is the pilot adaptor extension for the converter.

-Dalton
I sure did mean TCI lol. I did not install the flexplate so I am not sure if it has a spacer installed in between the crank and flexplate. I do not have the extended crank and it worked just fine with the ptc converter I had installed before I switched.
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Old Jul 5, 2016 | 02:27 PM
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Originally Posted by ghost-1
I sure did mean TCI lol. I did not install the flexplate so I am not sure if it has a spacer installed in between the crank and flexplate. I do not have the extended crank and it worked just fine with the ptc converter I had installed before I switched.
Being as the PTC converter worked im betting you don't have the spacer.

You NEED a stock height TH400 converter with a LS1 bolt circle and the LS pilot. Since I'm not sure what you're working with converter wise I would double check to make sure the converter is all the way in the transmission(you should feel 3 solid steps going in) and check the converter depth in the bellhousing. You should have approx. 1.050-1.150 of clearance from the pad of the converter to the bellhousing surface that goes up against the block.
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Old Jul 5, 2016 | 07:48 PM
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I was told to go with the TCI 399753 flywheel since this converter is also 10.5 instead of 9.5. But I used the spacer that was supplied and the converter was seated all the way into the transmission. I am not sure if the converter is stock th400 height or not I will find out today.
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Old Jul 18, 2016 | 06:31 PM
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Got a huges flex-plate which is the correct bolt pattern but the converter with the spacer used seems to be hitting the balloon plate. The trans cant be tightened down because the converter is touching the flex-plate and the trans.
I was told to have the balloon plate machined I have never ran into this before so not sure what the correct solution would be.
th400 converter question-13662458_1316811168333815_1797549295_o.jpg

th400 converter question-13663454_1316812468333685_1132432242_o.jpg

th400 converter question-13702473_1316811088333823_1810084078_o.jpg
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Old Jul 19, 2016 | 07:37 AM
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Easiest way to check the height of the converter is to stand it up on its hub(snout that goes in the trans) on a flat surface and measure the distance from the flat surface to the pad of the converter where it bolts to the fly wheel. If it is stock height it should be very close to 6.150"
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Old Jul 19, 2016 | 01:32 PM
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Originally Posted by FTICONVERTERS
Easiest way to check the height of the converter is to stand it up on its hub(snout that goes in the trans) on a flat surface and measure the distance from the flat surface to the pad of the converter where it bolts to the fly wheel. If it is stock height it should be very close to 6.150"
It was 6.148 so that is pretty close to what u have. It seems as if it is not going all the way into the trans due to the balloon plate being flat.
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Old Jul 19, 2016 | 04:24 PM
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Check the balloon plate for markings. that'll tell you if its hitting the bell housing. I don't see any reason why it would be....

edit: 6.148 is spot on so that's not the issue
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Old Jul 19, 2016 | 06:15 PM
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From: ft rucker
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Originally Posted by FTICONVERTERS
Check the balloon plate for markings. that'll tell you if its hitting the bell housing. I don't see any reason why it would be....

edit: 6.148 is spot on so that's not the issue
If you look at the second pic you can see it looks like there are marks where its hitting
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Old Jul 20, 2016 | 07:22 AM
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Originally Posted by ghost-1
If you look at the second pic you can see it looks like there are marks where its hitting
Before calling Hughes to get that fixed, lets check the clearance of the converter in the bell housing. from the surface of the bellhousing that bolts to the motor to the pad of a converter should be between 1.050-1.150
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Old Jul 20, 2016 | 09:18 AM
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Originally Posted by FTICONVERTERS
Before calling Hughes to get that fixed, lets check the clearance of the converter in the bell housing. from the surface of the bellhousing that bolts to the motor to the pad of a converter should be between 1.050-1.150
Thanks for the info I will get that measurement today
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Old Jul 25, 2016 | 03:21 PM
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So got to measure it today it is 3/4 of an inch in the locations you mentioned.
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Old Jul 26, 2016 | 07:46 AM
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Originally Posted by ghost-1
So got to measure it today it is 3/4 of an inch in the locations you mentioned.
Converter isn't all the way in the unit. Time to call Hughes or send it in to us and we'll take a look at it.
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