Flywheel Questions, BBC

[Sawtooth]

So I have been gathering parts here and there as I can afford them for my BBC build and was wondering about the flywheel. This motor is for my crusier so it will have a TH400 trans hooked to it and one of the presure plate/splined drive deals from Rex. So I have been looking at aluminum flywheels, new and used, most all the new ones through Summit and the like say that they have a steel center which is for a presure plate deal. So #1 does the deal from Rex spin like a normal presure plate/clutch set up or is it bolted solid to the flywheel, and #2 I found a used aluminum flywheel for a BBC that is "neutral balance" so this means it is not internal or external balanced (what's the difference) and #3 what is a good/average price for a used aluminum flywheel in good condition. Any info anybody in the know would care to share would be welcomed, thanks.

[obnoxious001]

The drive plates bolt up solid to the flywheel using six 3/8" bolts into the normal pressure plate bolt holes.

For a cruiser you might do just as well with a steel flywheel I think, unless you are drag racing it. The heavier flywheel may not accelerate as fast, but it should also keep the boat a little smoother if you are on and off the throttle in rough water.

Neutral balance is the same as "internal" balance. Depending on what you are building, most aftermarket cranks will be internal balance, but you do need to know before you buy a flywheel. The GM 454's and 502's are externally balanced.

[Sawtooth]

The drive plates bolt up solid to the flywheel using six 3/8" bolts into the normal pressure plate bolt holes.

For a cruiser you might do just as well with a steel flywheel I think, unless you are drag racing it. The heavier flywheel may not accelerate as fast, but it should also keep the boat a little smoother if you are on and off the throttle in rough water.

Neutral balance is the same as "internal" balance. Depending on what you are building, most aftermarket cranks will be internal balance, but you do need to know before you buy a flywheel. The GM 454's and 502's are externally balanced.

Hey Barry Chris here, the dummy that did not buy your Gentry turbo stuff a couple years back because I did not have enough money:smackhead:smackhead,thanks for the reply. Motor is going to be a 540CI TT (w/carbs). Let me ask you this, are the starter rings replaceable on an aluminum flywheels (press on/bolt on). Thank you.

[obnoxious001]

Hey Barry Chris here, the dummy that did not buy your Gentry turbo stuff a couple years back because I did not have enough money:smackhead:smackhead,thanks for the reply. Motor is going to be a 540CI TT (w/carbs). Let me ask you this, are the starter rings replaceable on an aluminum flywheels (press on/bolt on). Thank you.

Yes, you can replace starter rings on iron or aluminum flywheels. Been some years since I have had to do one, but heating with an acetylene torch, the ring should go on easily.

[racerden]

The drive plates bolt up solid to the flywheel using six 3/8" bolts into the normal pressure plate bolt holes.

For a cruiser you might do just as well with a steel flywheel I think, unless you are drag racing it. The heavier flywheel may not accelerate as fast, but it should also keep the boat a little smoother if you are on and off the throttle in rough water.

Neutral balance is the same as "internal" balance. Depending on what you are building, most aftermarket cranks will be internal balance, but you do need to know before you buy a flywheel. The GM 454's and 502's are externally balanced.

A neutral balanced ALF can be balanced either way. I just finished balancing one for Wheeler...it had provisions (tapped threads) for external the external balancing weights
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[Sawtooth]

Can an externally balanced alum. flywheel be rebalanced to make it usable on a internally balanced motor. Lets say I buy a aluminum flywheel that is for an internally balanced motor won't it have to be rebalanced with all the motor internals......I know I am missing something here:headscratch:. I just can't afford a new one so I am going to have buy used when I find one I can buy and don't want to end up with a paper weight for my desk. Can somebody shed some more light on this for me, thanks.

[BamBam]

Can an externally balanced alum. flywheel be rebalanced to make it usable on a internally balanced motor. Lets say I buy a aluminum flywheel that is for an internally balanced motor won't it have to be rebalanced with all the motor internals......I know I am missing something here:headscratch:. I just can't afford a new one so I am going to have buy used when I find one I can buy and don't want to end up with a paper weight for my desk. Can somebody shed some more light on this for me, thanks.

I'll try to shed light.
You could buy a "neutral/Internal balance" flywheel and adapt it to an External balance motor by adding a bunch of mallory (heavy metal). I would not recommend buying an "External balance" flywheel and trying to take the mallory out. Whichever flywheel you buy you will have to match balance to your internal components if you are building the motor correctly. You stated you are building a 540ci BBC that should be an Internal balance (neutral) rotating assembly. So if you are going to buy used pick up a neutral flywheel. I agree with Barry about the weight and would go Steel or cast iron. I have a neutral balance billet steel flywheel for a Mark IV brand new mounted and taken off my Gen VI (wrong backspacing) if you are interested PM me. I would recommend the same thing if I had one for sale or not. I have a neutral balance iron flywheel on my 540 in a 21' Schiada. BTW a 350 chevy is a neutral balance flywheel and will bolt up (has to be a two piece rear main on the 350 though)

How's progress on the boat? I like the stringers.

[obnoxious001]

Can an externally balanced alum. flywheel be rebalanced to make it usable on a internally balanced motor. Lets say I buy a aluminum flywheel that is for an internally balanced motor won't it have to be rebalanced with all the motor internals......I know I am missing something here:headscratch:. I just can't afford a new one so I am going to have buy used when I find one I can buy and don't want to end up with a paper weight for my desk. Can somebody shed some more light on this for me, thanks.

Yes, even an internally balanced flywheel should be checked when your assembly is balanced, even though it's theoretically "zero" balanced. Many times they will come back with very small adjustments from the balancer.

If you are trying to save money, makes no sense not to just look for a used internally balanced flywheel. I ran a steel flywheel on my engine with the turbo 400 trans, as was the practice with most of the ski race boats that GT Performance was building engines for at the time. (Guess I should know, I was doing their engine building at the time I put mine together). The thinking was that the boat speed would be a little smoother for the skier with the heavier flywheel, which probably makes sense for even a pleasure boat in rough water.

I do have a used aluminum internally balanced flywheel here, haven't advertised it since it needs a ring gear. I also have a variety of steel ones, including one new billet steel, so could probably figure one that fits your budget.

[Sawtooth]

Hey Barry and BamBam thanks for the information, it makes a little more sense now. I was under the impression that an aluminum flywheel was the way to go as the motor would RPM quicker and I have always heard that spinning weight was a total HP robber. I am not going to race the boat, it's just going to be a pleasure ride.......some day, hell at the rate I am going I may just put oars in it and use it for fishing:D. Barry I will have to send you a PM about what you got and what kinda $$$ were talking. Thanks for the compliment on the stringers BamBam, not much else done other than removing the deck so I could finish grinding and make it a little eaiser to install the stringers and what not. Right now I am just trying to keep my business going and paying the bills, not much "extra money" lately if you know what I am saying. Thanks again guys for the help.:thumbsup