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LT1 Flywheel - Internally or externally balanced type?


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I'm getting conflicting answers to this question and perhaps grumpyvette or another engine expert can help answer. What type of flywheel can I use on a LT1 engine? Can I use a standard flywheel off an earlier model 350 engine with a one-piece rear main seal? Is this an internally or externally balanced engine and how should the new flywheel and pressure plate be balanced? I’m contemplating on going to a standard push type clutch and doing away with the pull version that I have now.

 

Thanks,

Danno74Z

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Guest ls1z4me

All Lt1 are internally balanced. With that said, I am not positive any flywheel is going to work. I would have thought that you could still purchase a push style clutch /pressure plate that fit on the LT1 flywheel. With a bell housing for the style of clutch set, you should be in business.

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http://www.flatlanderracing.com/flyflexgmsb.html

 

look carefully youll notice the flywheel hub changed in about 1986 so pre-1986 flywheels differ from 1986 and newer designs keep in mind that aproximately when they changed from two piece rear seals to one piece and the crank flange went from 3.58" to 3"

one piece rear seal 350 flywheels should interchange but I would get the assembly ballanced ANYTIME a NEW flywheel FROM ANY SOURCE was installed

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Thanks all for the help. Today I received this information from Centerforce.

 

Dear Danno,

 

Our sources and expertise have confirmed that the LT1 engine is an externally balanced engine. With that said, a replacement flywheel, ours or another, would have to have the factory counterbalance specification in order for the flywheel to be a bolt on part. The 700170 is a flywheel with a counterbalance which offsets or counteracts the engine's internal out-of-balance condition. A ZZ4 crate engine is also an externally balanced engine.

 

The reference to having your LT1s internal rotating assembly balanced and thus needed a zero or neutral balanced flywheel was to proide awareness to you that if you did have or planned on having your LT1s internal rotating assembly zero balanced, our 700170 and 700160 would NOT be appropriate. Our 700170 and 700160 flywheels are designed as direct bolt in replacements for factory (OE) original equipment engines with factory balance specifications. Also, if you are using an aftermarket crankshaft, you may have to obtain a zero balanced flywheel depending on the balance characteristics of the crankshaft itself.

 

If you have any more questions or need any more clarification, please feel free to give us a call. Thanks!

 

Rick Mard

Technical Representative

Centerforce Clutches,

A Div. of Midway Ind.

928/771-8422 x36

rickm@centerforce.com

 

Based on the above information I need a counterbalanced flywheel to do my conversion. Digging a little deeper into this I saw a picture of the CBF and on the back side is a place to add a weight. One side has a "A" and the other position is a "C". For the LT1 I need to put a 125.5 grams of CB weight at location "A" to properly balance the flywheel for the LT1 engine.

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