How do I make my T56 NHRA legal to 10.00 E/T??
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Joined: Dec 1998
Posts: 2,161
From: Haslett, Michigan
How do I make my T56 NHRA legal to 10.00 E/T??
I've converted my thirdgen to a T56 6-speed, and have dynoed 400 RWHP, plus a 150-shot of nitrous on top. There's a Moser 12-bolt in there, and a Chromoly driveshaft, plus a new rear suspension. There's some M/T ET streets sitting ready for track day. I've got the 8-point roll bar and the requisite safety harnesses.
There's technically enough beef there for a low 11, possibly high 10-second E/T in the quarter mile. What do I need to do with the bell housing to make it pass tech? I've got a gen1 SBC with 2-piece rear main seal, and currently use a stock LT1 bell housing. Is anyone making an SFI certified steel bell housing that's compatable with LT1/Gen1 applications? I suspect that an automatic transmission's scatter blanket wont pass tech. Is this true?
What's our 10-second and 9-second 6-speed users doing?
There's technically enough beef there for a low 11, possibly high 10-second E/T in the quarter mile. What do I need to do with the bell housing to make it pass tech? I've got a gen1 SBC with 2-piece rear main seal, and currently use a stock LT1 bell housing. Is anyone making an SFI certified steel bell housing that's compatable with LT1/Gen1 applications? I suspect that an automatic transmission's scatter blanket wont pass tech. Is this true?
What's our 10-second and 9-second 6-speed users doing?
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Joined: Dec 1969
Posts: 10,745
From: Buffalo, New York
I think McLeod has a bell housing that is SFI approved. http://www.mcleodind.com/faq.html#bellhousings
Rich
Rich
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Joined: Dec 1998
Posts: 2,161
From: Haslett, Michigan
Oh, Thanks for the tip.
Some quick reading says Mcleod makes an assembly, p/n 8710-15 that will bolt the LT1 T56 into the 1955-1997 GM V8 application, but notes 1,2,5, and 7 apply:
So it looks as if I'd need some sort of bell housing that would require a different set of hydraulics at the clutch to switch from the pull-type throwout to a push-type throwout bearing. Now I have to wonder, does this also mean I must convert to a different clutch assembly?? I'm using the LT1 SPEC stage III, but it's new, never started at this point.
1. LT1 CAMARO COMES WITH EXTENDED PILOT BUSHING. BELLHOUSING HAS NO PLACE FOR STOCK SLAVE CYL. W/PULL CLUTCH. WITH THIS BELLHOUSINGYOU CAN CONVERT YOUR PULL CLUTCH TO A PUSH WITH A HYD. T.O. BRG PART NUMBER 1400-22.
2. CONVERTING LT1 TO PUSH TYPE CLUTCH - USE OUR KIT NUMBER 74010-1A-07 WITH STEEL FLY, OR 73010-1A-07 WITH ALM. FLY.
5. SOME T56 TRANS MAY REQUIRE THE FRONT INTERMEDIATE PLATE CHANGED TO ACCOMMODATE MECHANICAL LINKAGE.
7. 1964-85 PONTIAC MOTORS USE BUSHING 8-1380-1, 8-1380-2, 8-1380-3, 8-1380-4, USE CORRECT ONE FOR PROPER ADAPTION.
Some quick reading says Mcleod makes an assembly, p/n 8710-15 that will bolt the LT1 T56 into the 1955-1997 GM V8 application, but notes 1,2,5, and 7 apply:
So it looks as if I'd need some sort of bell housing that would require a different set of hydraulics at the clutch to switch from the pull-type throwout to a push-type throwout bearing. Now I have to wonder, does this also mean I must convert to a different clutch assembly?? I'm using the LT1 SPEC stage III, but it's new, never started at this point.
1. LT1 CAMARO COMES WITH EXTENDED PILOT BUSHING. BELLHOUSING HAS NO PLACE FOR STOCK SLAVE CYL. W/PULL CLUTCH. WITH THIS BELLHOUSINGYOU CAN CONVERT YOUR PULL CLUTCH TO A PUSH WITH A HYD. T.O. BRG PART NUMBER 1400-22.
2. CONVERTING LT1 TO PUSH TYPE CLUTCH - USE OUR KIT NUMBER 74010-1A-07 WITH STEEL FLY, OR 73010-1A-07 WITH ALM. FLY.
5. SOME T56 TRANS MAY REQUIRE THE FRONT INTERMEDIATE PLATE CHANGED TO ACCOMMODATE MECHANICAL LINKAGE.
7. 1964-85 PONTIAC MOTORS USE BUSHING 8-1380-1, 8-1380-2, 8-1380-3, 8-1380-4, USE CORRECT ONE FOR PROPER ADAPTION.
Thread Starter
Registered User
Joined: Dec 1998
Posts: 2,161
From: Haslett, Michigan
Okay, I did some more reading. Al Fox did some research and posted it on the Michigan Speed board at this thread:
http://www.michiganspeed.com/Speedfo...ad.php?t=10623
I guess the gist of this is that I need to examine the Mcleod system, then also look for some kind of motor plate to attach to the back of my engine block. Boy this sure sounds like a lot of work to stay safe. However I want to make sure it's 100% correct!
http://www.michiganspeed.com/Speedfo...ad.php?t=10623
Flwheel, clutch, and trans protection as per IHRA/NHRA
At 11.49 seconds ET or quicker a stick shift car must have.
SFI 1.1 or 1.2 flywheel, clutch and pressure plates mandatory.
The use of stock type cast iron flywheels or pressure plates is prohibited.
SFI 6.1 (single disc), 6.2, 6.3 (multi disc), or 9.1 flywheel shield.
Section 2.6 ..flywheel shield & motor plates word for word from the book.
Where an SFI 6.1, 6.3, or 9.1bellhousing is mandatory, a full, one-piece motor plate is also mandatory at the rear of the engine block.
The motor plate must be constructed of 6061-T6, 7075-T6, or 2024-T3 wrought heat-treated alumunum alloy plate, minimum 1/8" thick for 6.1 or 9.1 apps or 3/16" thick for 6.3 apps.
The flywheel shield must be fastened to the engine and motor plate (upper) with a minimum of 7, 3/8" grade 8 bolts or high strength studs at the top to the motor and 8, 3/8" grade 8 bolts or high strength studs at the bottom to the motor plate (lower). Allen bolts prohibited.
Nowhere in either book does it say that a trans blanket is ok in place of the required flywheel shield/motor plate on any app. requiring a clutch.
Nowhere does it say that just a flywheel shield is OK either. You must use a motor plate too.
At 11.49 seconds ET or quicker a stick shift car must have.
SFI 1.1 or 1.2 flywheel, clutch and pressure plates mandatory.
The use of stock type cast iron flywheels or pressure plates is prohibited.
SFI 6.1 (single disc), 6.2, 6.3 (multi disc), or 9.1 flywheel shield.
Section 2.6 ..flywheel shield & motor plates word for word from the book.
Where an SFI 6.1, 6.3, or 9.1bellhousing is mandatory, a full, one-piece motor plate is also mandatory at the rear of the engine block.
The motor plate must be constructed of 6061-T6, 7075-T6, or 2024-T3 wrought heat-treated alumunum alloy plate, minimum 1/8" thick for 6.1 or 9.1 apps or 3/16" thick for 6.3 apps.
The flywheel shield must be fastened to the engine and motor plate (upper) with a minimum of 7, 3/8" grade 8 bolts or high strength studs at the top to the motor and 8, 3/8" grade 8 bolts or high strength studs at the bottom to the motor plate (lower). Allen bolts prohibited.
Nowhere in either book does it say that a trans blanket is ok in place of the required flywheel shield/motor plate on any app. requiring a clutch.
Nowhere does it say that just a flywheel shield is OK either. You must use a motor plate too.
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Joined: Dec 2000
Posts: 766
From: GARDNERS,PA
I just received the 2007 rule book and I think your correct about the motor plate. I'm running a 6.1 bell housing and 1/4" thick flywheel shield on my T56 but there's no friggen way I'll ever get a motor plate in there arount the starter and headers. I doubt seriously I'll ever get checked on it but it's still not legal below 11.49 which I'm dangerously close to.
Steve
Steve
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Joined: Dec 1969
Posts: 10,745
From: Buffalo, New York
NHRA seems to be on a path to drive away all but the most hard core racers with dedicated track cars. Probably fear of liability is the reason. If a movement away from the track and back towards the street occurs it will decrease safety. Law of unintended consequences at work and another illustration of how pernicious the blame culture has become.
Rich
Rich
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Joined: Apr 2005
Posts: 957
From: Berkley, MI
NHRA seems to be on a path to drive away all but the most hard core racers with dedicated track cars. Probably fear of liability is the reason. If a movement away from the track and back towards the street occurs it will decrease safety. Law of unintended consequences at work and another illustration of how pernicious the blame culture has become.
Rich
Rich
Thread Starter
Registered User
Joined: Dec 1998
Posts: 2,161
From: Haslett, Michigan
It sure sounds like it. I'd like to know what kinds of real-world accidents have prompted these particular rule changes, and if it's one, two, or more mishaps that force the new rules. If there aren't any mishaps to report, then I wonder exactly what kinds of scientific engineering research they are using to justify the rule changes. There's got to be something--- just exactly what is it, and is there another way to address the problem?
---
So, it looks as if the Mcleod and the Weir bellhousings all require a pusher throwout bearing and a different clutch assembly. In my particular case that means discarding the NEW hydraulic slave cylinder assembly, along with the NEW Spec stage III clutch, and buying all new pusher throwout bearing & clutch hydraulics, plus a pusher-style clutch. I dont know if I could retain my aluminum flywheel or not.
All in all, it sounds tedious and expensive, and it cannot happen this year.
---
So, it looks as if the Mcleod and the Weir bellhousings all require a pusher throwout bearing and a different clutch assembly. In my particular case that means discarding the NEW hydraulic slave cylinder assembly, along with the NEW Spec stage III clutch, and buying all new pusher throwout bearing & clutch hydraulics, plus a pusher-style clutch. I dont know if I could retain my aluminum flywheel or not.
All in all, it sounds tedious and expensive, and it cannot happen this year.
Last edited by ws6transam; Dec 9, 2006 at 11:05 PM.
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