Flywheel balancing- anyone tried one of these?

db · Post by db » Tue Feb 07, 12 12:16 am

http://www.kmjent.com/cart/product.php?productid=2077

I have a neutral balanced flywheel and i need an externally balanced one for a 360.
This seems like a good solution if it works?
Or i can get mine drilled like so...

db · Post by db » Tue Feb 07, 12 12:18 am

I've just read on Moparts that some use a B&M weighted flexplate sandwiched behind the flywheel & that works fine

Cannonball · Post by **Cannonball** » Tue Feb 07, 12 12:40 am

db wrote:I've just read on Moparts that some use a B&M weighted flexplate sandwiched behind the flywheel & that works fine

hey paul
get your engineering man to drill/mill yours it will be fine save you the cost of that flexplate,,

dont let anyone worry ya,

Pete · Post by **Pete** » Tue Feb 07, 12 6:33 am

I have a B&M Externally balanced flex plate....

db · Post by db » Tue Feb 07, 12 10:22 am

Pete wrote:I have a B&M Externally balanced flex plate....

...care to PM me a price Pete?

Dunc- Just weighing up the options mate,
It'll cost me a minimum £20 to get it drilled...

Anonymous · Post by **Anonymous** » Tue Feb 07, 12 11:57 am

Hi db,

The old balancing problem rears it ugly head once again.
All 360's are a problem especially with flywheels.
I have got a pukka 360 steel flywheel here if you need it?
All V8 balancing is an issue and late cast crank engines are a lottery.
If its really bad, you will know as soon as you run the engine.
If its fairly close then you will not know how good or bad.

Ask youself this?
Would you fit a tyre on your car and not bother balancing it?
Or would you then try and balance the wheel with guesswork, if the tyre fitter said it may be alright if we stick 10 grams opposite the valve and see how it goes?

Some folks still do not understand how the V8 balancing system works with external balancing and therefore trust to luck!
It can never be right if you just guess it?
It can only ever be right if you balance the whole rotating assembly with Flywheel and Damper as a UNIT!!!

Like a wheel on your car there are two vibration ranges and mostly we only feel the one when we drive.
An engine can experience both at low and high RPM.
One you will rev through, at low rpm, the other at higher rpm will shake your fillings out and wreck your rear/front mains!

Do you feel lucky?
Nuff said HH.

Dave-R · Post by **Dave-R** » Tue Feb 07, 12 12:00 pm

baccaruda wrote:It can only ever be right if you balance the whole rotating assembly with Flywheel and Damper as a UNIT!!!

Spot on Bacca.

Anonymous · Post by **Anonymous** » Tue Feb 07, 12 12:02 pm

Thanx Dave, you've made my day!!!
At last some sensiblity.

Bolting a flexplate on behind the Flywheel!!!
I have heard it all now L0L!!!

HH.

Went to a propshop recently and the guy was balancing the prop with a Jubilee-Clip/metal slithers and guesswork!

Old habits die hard?

Dave-R · Post by **Dave-R** » Tue Feb 07, 12 12:04 pm

baccaruda wrote:Bolting a flexplate on behind the Flywheel!!!
I have heard it all now L0L!!!

Yeah that had me scratching my head.

db · Post by db » Tue Feb 07, 12 1:17 pm

http://board.moparts.org/ubbthreads/sho ... ost5950521

Please understand Bacca and Dave- I have no experience of anything like this so I'm looking at it from a purely logical perspective.

Are we saying that those who have used the 'bolt-on' methods with success.. are simply lucky? (or b...s...ing?)

Why is bolting on the correctly calibrated KMJ weight, or a correctly weighted B&M flexplate any different to swapping to the correct flywheel?
If i need to get the rotating assembly balanced as a whole, surely that will still be the case if I fit the correct steel 360 flywheel anyway?

How much would you want for your flywheel Baccc and would you p-ex my neutral balanced one?

At the moment, I simply don't have the funds or time to, strip the motor, cart it half way around the country to get it balanced then rebuild it, etc, etc...

So, back in the real world... My only realistic options are- to try either drilling or one of the bolt-ons. It will at least be good enough to get me on the road and registered.
If it's awful I can get balancing done properly later.

db · Post by db » Tue Feb 07, 12 1:17 pm

Cannonball · Post by **Cannonball** » Tue Feb 07, 12 2:51 pm

Dave wrote:
baccaruda wrote:It can only ever be right if you balance the whole rotating assembly with Flywheel and Damper as a UNIT!!!
Spot on Bacca.

thats the exact point of it the whole shooting match would be balanced before the build, so paul is up against it now

option 1 buy baccas flywheel thats the best idea and i also think dave billy has one for sale
option 2 get the one you have machined to the spread sheet
either will certainly be good enough,

Dave-R · Post by **Dave-R** » Tue Feb 07, 12 3:28 pm

The factory could get away with it because they were using all standard parts and they could get ballpark enough for rpms up to 5500rpm.

If that engine has been built using new parts then chances are the balance is going to be way out.
If it was "balanced" without a flywheel then changing the balance on the flywheel could throw it out rather than bring it in.

So who built it and what did they do with regards to a balance?

I would want to know exactly how it was balanced in the first place before going any further. If that information was not available or from a trusted source then I would be pulling the crank out and paying £180 for a proper balance.

Unless the car is never going to be raced or thrashed that is.

Anonymous · Post by **Anonymous** » Tue Feb 07, 12 4:29 pm

Nice one Dave!!!

Explained to perfection as usual!
Where's D999, we need his wonderful input too.

Anyways db9, you are more than welcome to try my flywheel and if all goes well then its yours, we can work out an exchange plan?
I can re-balance your flywheel at leisure, as and when I need it.

I believe this is PeteW's old barracuda motor and think it had a auto on it, cos Pete hates Stick-banging!

Crank balancing is a minefield at the best of times.
Let this be a lesson to all future 360 owners.
Go on any US site and laugh at the problems Folks have had, and what has happened due to this Mopar Nightmare.
If its a grocery getter, then you is fine, if your gonna be hitting the High Notes then you is in for a shockaroo!

On a lesser note, you shoudn't be using cast flywheels on race type motors anyways. If you miss a gear then you is in the same boat as the 727 boys. Hand grenade time!

HH

db · Post by db » Tue Feb 07, 12 6:01 pm

Yes Bacc it's Pete's old Sox motor, however he did have a 4-speed behind it. I stupidly sold this, bought an auto off Andy Neal, then changed my mind and went back to 4-spd! Live 'n' learn eh?

The motor was put together by Alex, so has a good pedigree. Pete may be able to answer how it was originally balanced?

I do appreciate your comments guys and I'll do the best my finances will allow

Baccles- If we can deal on my flywheel that sounds like the best plan?