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skiboatm

Issues with LT1 harmonic balancer?

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Hey guys,

 

Having an issue with my 79 280zx/Carbed LT1/700R car assembly. I'm missing only a few parts to get this thing running, and can't seem to get any "definitive" answer on it. Everyone that I've asked has been 100% sure of their answer, but I've gotten so many conflicting answers I don't know what to think.

 

I'm using the JTR kit to install this motor, and I have the JTR guide for the S30 Datsuns. Here's what I think I know.

 

1> JTR kit specifies that a 7.25" or less balancer is required. Per JTR helpdesk, this is due to interference with the steering rack.

2> 1995 LT1 (and all other GenII Chevy V8s) are neutrally balanced on the front, and externally balanced on the flywheel. (This is jargon to me, prolly why I'm having trouble)

3> My LT1 motor does not seem to have a keyway on the crankshaft, so it appears a first gen 6.8" balancer will not attach to my motor. (Is this just because mounting hub is still attached?)

4> I do not feel like spending $350+ on a balancer.

 

I spent 3 hours the other day at Pep Boys trying to figure out what my options were. Per Summit Racing, here are my options...

 

Pioneer Race Balancer - http://www.summitracing.com/parts/PIO-872044/

ATI Super Damper - F Body - http://www.summitracing.com/parts/ATI-917271/

ATI Super Damper - B Body - http://www.summitracing.com/parts/ATI-917327/

 

They also have a specific Corvette balancer for the LT1/LT4, but that has a longer hub, so I don't think it would work with any of my accessory placement. It appears that the ATI balancers are the same except for the mounting hub. Both are 10% UD from OEM, both have the same shell (917071-44), both are 6 rib serpentine.

 

Questions:

1> Should I even be concerned about a 7.25" balancer, or is that only for S30 guys? Since I'm running the S130, is there enough room to not worry about it and run the factory balancer?

2> Do I need a balancer on the front, since they're internally balanced, so I can just run a pulley?

3> Will a first gen balancer work, or mount to my existing hub?

 

Thanks in advance guys, hopefully you'll be able to shed a little more light on this issue.

 

Matt

Edited by skiboatm

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2> Do I need a balancer on the front, since they're internally balanced, so I can just run a pulley?

 

YES!!! Definitely run a balancer. There is no advantage to NOT running one. Refer to the attached PDF on why you have to run a dampener:

BHJDynamics_Damper_Info.pdf

Edited by yellowoctupus

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On my S30 I'm running the stock balancer, as far as the S130 I'm not sure if you have power steering or a manual rack. That might be the big difference.

 

Yellow octopus, very interesting article! Thanks for posting it

 

GOTHLOSISM, I have the manual steering rack and intend to keep it manual steering. The B body LT1 hub kick the balancer out the furthest from the block, so it might just be safest to order a factory balancer and a performance ID balancer and just mock them both up with the motor in the car? I realllllly don't wanna Do that, but it is prolly my only option if no LT1/S130 guys comment on clearances

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An SBC (LT1) mounts further forward in an S130 than a JTR installation in an S30, very similar to whats called a Scarab mount, so the balancer is not going to interfere with the steering rack or crossmember.

You really shouldn't try to use the JTR S30 Chevy V8 swap book to determine how to mechanically mount an SBC into an S130, the chassis is very different from an S30 and the mount positions are not the same.

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I'm running the stock balancer on a LT1 in a s130.

Jtr s130 sbc kit, No clearance issues, tons of room, it's nothing like a scarab mount, I'm slammed against the firewall, with a t56

Hope that helps, also I have a power steering rack and I'm planning on making custom hydraulic lines for the stock lt1 pump, all my research I've done, I see no problem with running that pump with that rack.

Cheers

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