TCI SFI Flexplate TC Bolt Holes Too Large!?
08-01-2005, 05:33 AM
#1
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TCI SFI Flexplate TC Bolt Holes Too Large!? Those of you with the TCI LS1 SFI Flexplate - did you notice when you did the install the amount of slop in the bolt holes used to attach the verter?!?
They measure 12.5mm, while the bolts are 10mm - I am used to (and would be more comfortable with) the holes being a lot tighter tolerance so that the stress is carried by the bolt diameter + the head torque instead of just the head torqe and some locktight. I could see the bolts loosening over time and allowing the converter to shift back and forth in the flexplate mounting holes and ovalling them out. Plus, not one of the tapped holes in my new Yank verter line up with the center of the flexplate holes - they are all located to the outer edge of each hole - as if the flexplate verter mounting holes are on the wrong bolt circle?
I called TCI and they pretty much 'poo-pooed' the whole idea and stated that as long as you torque them properly, and use locktite - there will be no problem. Reasoning behind the larger bolt holes was that 'some' LS1 owners are using other non-lockup verters/trannies and they use the larger 7/16" bolts. Well as far as I'm concerned, if you state that the product is for an LS1, then it should be mfg. for what the MAJORITY of owners will be using - the 4L60E with lockup verter. I don't have a real warm fuzzy feeling about this flexplate at all - I only hope the rest of their LS1 line of products is not so shabby...
Has anyone running one of these behind 400+ rwhp/rwtq had any problems? And are there any other SFI flexplates out there for the LS1 that actually utilize tighter machining tolerances in their product?
TIA,
-Jay-
They measure 12.5mm, while the bolts are 10mm - I am used to (and would be more comfortable with) the holes being a lot tighter tolerance so that the stress is carried by the bolt diameter + the head torque instead of just the head torqe and some locktight. I could see the bolts loosening over time and allowing the converter to shift back and forth in the flexplate mounting holes and ovalling them out. Plus, not one of the tapped holes in my new Yank verter line up with the center of the flexplate holes - they are all located to the outer edge of each hole - as if the flexplate verter mounting holes are on the wrong bolt circle?
I called TCI and they pretty much 'poo-pooed' the whole idea and stated that as long as you torque them properly, and use locktite - there will be no problem. Reasoning behind the larger bolt holes was that 'some' LS1 owners are using other non-lockup verters/trannies and they use the larger 7/16" bolts. Well as far as I'm concerned, if you state that the product is for an LS1, then it should be mfg. for what the MAJORITY of owners will be using - the 4L60E with lockup verter. I don't have a real warm fuzzy feeling about this flexplate at all - I only hope the rest of their LS1 line of products is not so shabby...
Has anyone running one of these behind 400+ rwhp/rwtq had any problems? And are there any other SFI flexplates out there for the LS1 that actually utilize tighter machining tolerances in their product?
TIA,
-Jay-
08-01-2005, 06:55 AM
#2
Man, Im glad your not the only one who has noticed that!! Im in the middle of tryin to get my th400 back in the car with the new flexplate and converter. The holes on the flexplates are huge compared to the converter holes!! Being that my setup is completely freaking weird I have ended up with about 1/2" gap between the converter and the flexplate so Im going to use the biggest grade 8 bolt and washers I can and tighten the crap out of it and cross my fingers.
08-01-2005, 08:03 AM
#3
You will also want to buff or grind that powdercoating bullshit off of it where it bolts to the crank. 
It stops the bolts and the crank from facing up to the flexplate. I had my flexplate come loose. It was properly torqued. I believe the coating was the issue 
It stops the bolts and the crank from facing up to the flexplate. I had my flexplate come loose. It was properly torqued. I believe the coating was the issue
08-02-2005, 03:25 PM
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Anyone have any success? Do I just tell the tranny shop to lock tight it and use some washers or should I find another company? Does anyone know how much H.P the stock Flexplate (flywheel) is good for?
08-02-2005, 03:48 PM
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I didn't see any problem with the holes for the converter/flexplate, but there is way too much play in the bolt holes for flexplate/crank!!! I had them torqued to spec and loctited and they backed out! This time they're impacted in and loctited, hopefully it'll make a difference and they'll stay in!!!
08-03-2005, 05:49 AM
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I think the answer to the problem for me is just to return this TCI POS 
I'm a Mechanical Design Engineer and have never seen such sloppy tolerances in a mfg. part that is supposed to support high HP - apparently no one @ TCI gives a rat's *** - just another reason I would NEVER buy a torque converter from them - many tighter tolerances are needed internally.
I haven't even realized the slop in the crank-flexplate bolt holes yet
Anyone want a new, never used TCI Flexplate?
I'm with mustgofasster - are there any other companies that sell SFI flexplates for LS1?
I'm a Mechanical Design Engineer and have never seen such sloppy tolerances in a mfg. part that is supposed to support high HP - apparently no one @ TCI gives a rat's *** - just another reason I would NEVER buy a torque converter from them - many tighter tolerances are needed internally.
I haven't even realized the slop in the crank-flexplate bolt holes yet
Anyone want a new, never used TCI Flexplate?
I'm with mustgofasster - are there any other companies that sell SFI flexplates for LS1?
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08-03-2005, 07:13 AM
#8
Originally Posted by Loudmouth LS1
I didn't see any problem with the holes for the converter/flexplate, but there is way too much play in the bolt holes for flexplate/crank!!! I had them torqued to spec and loctited and they backed out! This time they're impacted in and loctited, hopefully it'll make a difference and they'll stay in!!!
08-03-2005, 09:32 AM
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Thats the damn powdercoating that caused that you have to grind/sand it off
I guess I could take the time to grind the powdercoat off of the side walls of the counterbores, but that would not yield an accurate 1" OD doing this by hand, and why should you have to **** with something that cost $189 anyway?
08-03-2005, 06:27 PM
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After doing some searching - I found that ATI Performance sells an LS1 SFI Flexplate and supposedly so does Hughes Performance.
I'll be calling ATI tomorrow to get the details (concentrating on hole tolerances) and hopefully ordering one from them.
I'll be calling ATI tomorrow to get the details (concentrating on hole tolerances) and hopefully ordering one from them.
08-03-2005, 06:35 PM
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Yeah, they went to a lot of trouble making a part that is NEVER seen very pretty
Too bad they didn't pay attention to some of the more important details
Too bad they didn't pay attention to some of the more important details
08-04-2005, 05:55 AM
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Meziere Also has a Ls1 Flexplate All Billet
http://www.meziere.com/2005_catalog/22.pdf
Reactor also has a Ls1 Flexplate All Billet with a bolt on steel starter ring, so you can replace it if you lose a tooth (This is the one I have)
http://www.reactorproducts.com/index.html
Madman sells Both
http://www.meziere.com/2005_catalog/22.pdf
Reactor also has a Ls1 Flexplate All Billet with a bolt on steel starter ring, so you can replace it if you lose a tooth (This is the one I have)
http://www.reactorproducts.com/index.html
Madman sells Both
08-04-2005, 12:33 PM
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Hey Guys,
I just wanted to let you know the details about the TCI flexplate design. I designed the flexplate a couple years ago because of all of requests that we were receiving from people with broken OE flexplates.
The bolt holes are the same size as OE. The OEs measure around .504". Our spec is .500". The only difference in the design between our bolt holes and the OE is that we don't utilize the one oval shaped hole...all of ours are round holes.
As a side note, we use Grade 8 7/16" bolts in most of our 10" and smaller diameter converters. This hole size will accomodate our converter bolts just fine.
The bolt pattern on ours is the same as the OE flexplate. Our machining tolerances are held extremely tight on our CNC mill...typically within .001".
I've read the concerns about the powdercoating as well. We use powdercoating on all of our flexplates. It's a good way to prevent rust and is asthetically pleasing as well. You certainly wouldn't want to open a box and and see that the flexplate that you just paid $200 for is rusty.
All of that being said, I'd certainly entertain constructive suggestions on improving the flexplate, whether they be changes to the design or coating. In the meantime, you could scratch the coating off in the bolt head areas and in the crankshaft mating area...if you have concerns about the bolts becoming loose.
Thanks,
Kevin W
I just wanted to let you know the details about the TCI flexplate design. I designed the flexplate a couple years ago because of all of requests that we were receiving from people with broken OE flexplates.
The bolt holes are the same size as OE. The OEs measure around .504". Our spec is .500". The only difference in the design between our bolt holes and the OE is that we don't utilize the one oval shaped hole...all of ours are round holes.
As a side note, we use Grade 8 7/16" bolts in most of our 10" and smaller diameter converters. This hole size will accomodate our converter bolts just fine.
The bolt pattern on ours is the same as the OE flexplate. Our machining tolerances are held extremely tight on our CNC mill...typically within .001".
I've read the concerns about the powdercoating as well. We use powdercoating on all of our flexplates. It's a good way to prevent rust and is asthetically pleasing as well. You certainly wouldn't want to open a box and and see that the flexplate that you just paid $200 for is rusty.
All of that being said, I'd certainly entertain constructive suggestions on improving the flexplate, whether they be changes to the design or coating. In the meantime, you could scratch the coating off in the bolt head areas and in the crankshaft mating area...if you have concerns about the bolts becoming loose.
Thanks,
Kevin W
08-04-2005, 02:14 PM
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Kevin-
Thanx for the reply post. I can't tell you that I actually know the diameter of the holes in the stock flexplate, as the guy that installed my tranny also installed my original Midwest verter.
When I received my TCI flexplate there was also a bag of 7/16 bolts included - they do indeed fit the holes very nicely. Unfortunately, the bolts used from factory are 10mm and the verter is drilled/tapped for these. I did talk with a tech @ TCI and asked him about this - he stated that the holes are drilled for the 7/16 bolts so that those who are using tranny's/verters other than the 4L60E (such as TH350 or TH400) will have the correct size bolts - I didn't just make that up. I wondered why the holes would have been drilled for a setup that was not the norm (most will be using the stock style components)? That is why I assumed (possibly mistakenly) that the holes were drilled too big on purpose.
So, are you saying that there will be no problems with flexplate shifting back-and-forth in a radial direction with relation to the verter under high HP/TQ within the enlarged hole dia? I find it hard to believe you can tighten the bolts (even using loctite) enough to prevent this from eventually happening. I personally haven't seen the problems with the powdercoating as I have not got to the install yet.
Any chance I can return this flexplate to you and have one custom drilled with tighter dia holes for both verter & crank bolts during your next production run?
Thanx for the reply post. I can't tell you that I actually know the diameter of the holes in the stock flexplate, as the guy that installed my tranny also installed my original Midwest verter.
When I received my TCI flexplate there was also a bag of 7/16 bolts included - they do indeed fit the holes very nicely. Unfortunately, the bolts used from factory are 10mm and the verter is drilled/tapped for these. I did talk with a tech @ TCI and asked him about this - he stated that the holes are drilled for the 7/16 bolts so that those who are using tranny's/verters other than the 4L60E (such as TH350 or TH400) will have the correct size bolts - I didn't just make that up. I wondered why the holes would have been drilled for a setup that was not the norm (most will be using the stock style components)? That is why I assumed (possibly mistakenly) that the holes were drilled too big on purpose.
So, are you saying that there will be no problems with flexplate shifting back-and-forth in a radial direction with relation to the verter under high HP/TQ within the enlarged hole dia? I find it hard to believe you can tighten the bolts (even using loctite) enough to prevent this from eventually happening. I personally haven't seen the problems with the powdercoating as I have not got to the install yet.
Any chance I can return this flexplate to you and have one custom drilled with tighter dia holes for both verter & crank bolts during your next production run?
08-06-2005, 01:09 AM
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We also use the 7/16" bolts in our 10" LS1 converters...so that is the norm for our performance converter. They provide an additional factor of safety over the factory 10mm bolts. We just need to get you upgraded from the Brand Y converter to a TCI converter
I haven't seen a problem with the bolts loosening, but if you wanted additional insurance, you could certainly remove the coating from the bolt areas and install some star lock washers or even some Wizlock bolts.
Kevin
I haven't seen a problem with the bolts loosening, but if you wanted additional insurance, you could certainly remove the coating from the bolt areas and install some star lock washers or even some Wizlock bolts.
Kevin
Originally Posted by 1QUIKWS6
Kevin-
Thanx for the reply post. I can't tell you that I actually know the diameter of the holes in the stock flexplate, as the guy that installed my tranny also installed my original Midwest verter.
When I received my TCI flexplate there was also a bag of 7/16 bolts included - they do indeed fit the holes very nicely. Unfortunately, the bolts used from factory are 10mm and the verter is drilled/tapped for these. I did talk with a tech @ TCI and asked him about this - he stated that the holes are drilled for the 7/16 bolts so that those who are using tranny's/verters other than the 4L60E (such as TH350 or TH400) will have the correct size bolts - I didn't just make that up. I wondered why the holes would have been drilled for a setup that was not the norm (most will be using the stock style components)? That is why I assumed (possibly mistakenly) that the holes were drilled too big on purpose.
So, are you saying that there will be no problems with flexplate shifting back-and-forth in a radial direction with relation to the verter under high HP/TQ within the enlarged hole dia? I find it hard to believe you can tighten the bolts (even using loctite) enough to prevent this from eventually happening. I personally haven't seen the problems with the powdercoating as I have not got to the install yet.
Any chance I can return this flexplate to you and have one custom drilled with tighter dia holes for both verter & crank bolts during your next production run?
Thanx for the reply post. I can't tell you that I actually know the diameter of the holes in the stock flexplate, as the guy that installed my tranny also installed my original Midwest verter.
When I received my TCI flexplate there was also a bag of 7/16 bolts included - they do indeed fit the holes very nicely. Unfortunately, the bolts used from factory are 10mm and the verter is drilled/tapped for these. I did talk with a tech @ TCI and asked him about this - he stated that the holes are drilled for the 7/16 bolts so that those who are using tranny's/verters other than the 4L60E (such as TH350 or TH400) will have the correct size bolts - I didn't just make that up. I wondered why the holes would have been drilled for a setup that was not the norm (most will be using the stock style components)? That is why I assumed (possibly mistakenly) that the holes were drilled too big on purpose.
So, are you saying that there will be no problems with flexplate shifting back-and-forth in a radial direction with relation to the verter under high HP/TQ within the enlarged hole dia? I find it hard to believe you can tighten the bolts (even using loctite) enough to prevent this from eventually happening. I personally haven't seen the problems with the powdercoating as I have not got to the install yet.
Any chance I can return this flexplate to you and have one custom drilled with tighter dia holes for both verter & crank bolts during your next production run?
08-06-2005, 01:45 AM
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I have a TCI Flexplate and I also have a TCI Converter... Hell, everything thats goin in my trans is TCI. (clutches, steels, billet servos, hd drum, etc) Looks like I'm good to go!
Oh yeah, I got the flexplate for $75 brand new...
Can't beat that with a stick!
Oh yeah, I got the flexplate for $75 brand new...
Can't beat that with a stick!