I bought a Fidanza aluminum flywheel for my Z/28, but it isn't balanced at the factory. The local machine shop says it has to be balanced With the crank. Now that I think about it makes sense...... without the weight on the crank to compensate for the fly weight on the flywheel there would be no way to truly get the package balanced. Is this true or false? Thanks for the help! Bob

 

No!! No!!! No!!! NO!!!!! DO NOT let them do that to you!!!!!!!!!!!!!

Th efactory balances them just fine to where as engines roll down the production line, FINSIHED COMPLETED ENGINES balanced TO SPEC, they simply take a flywheel off the shelf and bolt it up; and guess what? THEY'RE BALANCED!!!!!!!

There's no reason that the same thing can't be accomplished by anybody that can rub 2 neurons together and get them to fire. Hell I can't even do THAT, and EVEN I know better!!

There's a spec for that. I don't recall exactly what it is, but I've seen it and know that it can be found. If your shop DOESN'T know that, PICK UP YOUR PARTS ON THE SPOT AND GO SOMEWHERE ELSE!!!!!!!!

What will happen if you let the crank and the flywheel exist in their shop at the same time, is that they will do themselves the favor of "custom" balancing your crank and flywheel together. Think about that: that means that if you EVER have to replace EITHER of them, the engine has to come COMPLETELY back apart and be re-balanced, so the "custom" non-stock crank matches your specially sodomized "custom" non-stock flywheel, or vice-versa. Where if you get it done the RIGHT way, namely to the factory spec, then you can bolt up your UNMOLESTED STOCK SPEC flywheel to your STOCK SPEC motor, and if you ever have to change ANYTHING, you just go get another STOCK SPEC one and bolt it up, and you're down the road.

 

I just called the machine shop to see what there story would be. All parts are still in my shop.

There is a chance that in my smallish city the properly informed machine shop may not exist........................ I may need to ship it to one. Any suggestions?

Anyone just slap a new fidanza on the way it came and have a good/bad result?

 

Have them balance your motor to THE STOCK SPEC. If they understand that. They don't need to know, much less care, what flywheel you're using.

If you think the flywheel isn't balanced to THE STOCK SPEC, send that to them AFTER you pick the engine up; and have them balance it to THE STOCK SPEC.

If they say they can't, won't, or otherwise give you any lip, TAKE YOUR PARTS SOMEWHERE ELSE. I can't tell you about other shops, I don't even know where you live; but I can SURE tell you, you DO NOT want the mess they are trying to hand you. WHATEVER it takes to find a different shop, it's worth it. I'd suggest hanging around in the pits at your local circle track on money night and ask the guys that WIN where they get things like that done.

Oh... and did I mention, you want all of your parts INDIVIDUALLY balanced to THE STOCK SPEC?

 

Still looking for a shop to send my flywheel to........... Suggestions?

 

Am I missing something here? Why does the flywheel need to be balanced?

If you bought one that the manufacturer didn't bother to balance properly, why did you buy it?

 

It's just the way they do it. Not sure why. My guess is that alot of people do go ahead and have their "assembly" balanced as a unit to get the maximum result. Kind of like starting with a clean slate. I'm sure the flywheel is very close just as it is... probably close enough to work just fine. I would just like to get my flywheel, clutch, and pressure plate balanced as a unit. My old factory set up vibrated a little.

 

If anyone is following this.................
I have been looking into the balancing thing, and from what I have read.... other 87 and newer gen I small block owners with externally balanced motors who replace their flywheels have them "balanced matched" to the flywheel they took off as they are balanced to the crank as a "matched pair"

According to the factory manual if you have to replace a flywheel on a 91 Camaro you "re balance" the flywheel on the car by adding weights supplied by GM to holes in the flywheel. You start the car and see if there is any vibration felt. If you feel vibration you move the weights around in a trial and error method until you have a smooth result. This is straight from the factory manual.

My experience putting a "factory balanced" flywheel from one motor to another was some vibration, so I am inclined to believe they are a matched set.

 

lol

They arent matched. Go down to your local parts store and get a flexplate for a 91 Camaro, and they'll sell you one... and it will work fine as is. GM didnt do any matching of parts at the factory, way too time consuming. Bolt it on and go, thats the way its made.

 

Bolting my clutch to that flex plate might not work out so good..........
My documentation in the manual indicates that balancing of a replacement flywheel is necessary

Where is your documentation....... oh, you don't have any........ LOL

 

Well maybe you should look at your manual again, and what they're telling you to do, and how much you want to trust that. Do you balance your tires by putting on some weights, taking the car out and driving it, and putting more weight or adjusting them until you feel there's no vibration? Maybe while we're at it we should balance the rods by putting one in each hand and grinding off material until they feel like they're the same weight. I could really care less if I have any 'documentation' or not, with the kind of recommendation your "factory manual" is giving you.

Yea, a flexplate isnt a flywheel, glad you noticed. The balancing (or imbalance) of said item is the same, although a flexplate the weight is attached and you dont mess with it.

 

Without a doubt engines and flywheels (or flexplates) are not balanced together from the factory.

What the factory may or may not have done with replacement parts, I don't know. But, the aftermarket parts available are properly balanced to work with the engine without rebalancing.

To what gram level they're balanced - that's a different question. But, to rebalance a flywheel to balance and engine/flywheel is not a good idea - unless you're willing to rebalance with any component replacement.

 

Well I went to the Chevy dealer today looking for the elusive flywheel balancing spec that the three machine shops I called had no knowledge of. A service guy and I searched their data base for about 15 min. and the only thing we found was this quote. "replacement flywheels must be balanced to match the one being removed" That is exactly what the sticker on my Fidanza flywheel says. I may not be a smart man........... but I know what that means. If there is a "balancing spec" out there I challenge all who think there is to come up with it from a ligament source! ....

 

Since I'm DEFINITELY not a smart man, I didn't even resort to a "search"... I just typed in "centerforce" and hit CTRL+ENTER. Amazing. Took me less time to type that than it took you to issue your "challenge".

Then I clicked (!) on "Online Catalog", and (!!!!) Chevrolet; and lo and behold, this is what I observed.

http://www.centerforce.com/clutches....make=CHEVROLET

So there's your number, down in for example the 700160 (86-92 305). Now I don't know if they're a ligament (sic) source; but I'd say they're certainly a legitimate one. Which is probably better than that other kind anyway.

Keep in mind, you MAY not be a smart man, but I DEFINITELY am not; so I have to keep things simple.

I highly recommend you go to a vehicle assembly plant someday, and take the tour. The Corvette plant in Bowling Green is an awesome one. Once you see how cars are ACTUALLY built, you will have a much greater understanding of how to modify them.

 

I can't find that procedure anywhere in the factory manual. Where are you looking?

 

right next to the page on "speed holes" in the hoods

 

actually in bowling green the drivetrains are already assembled, i've been there

aside from that i would get the whole assembly balanced if you feel comfortable doing so, and you can find a shop to do it for you. granted another flywheel must be balanced if your old is replaced, your buying a quality flywheel and hopefully you won't have any problems.

I have replaced several flywheels and just ran down to the parts store and got one. Don't get me wrong, it works. But if your worried about it, yank the motor, pull the crank, bring the harmonic balancer, rods, pistons, crank, flywheel and pressure plate to your machine shop.

 

Right....

I'm well aware that it's a VEHICLE assembly plant.

Still very instructive: it shows the observer how MASS PRODUCTION works in the auto industry. Doesn't take a rocket scientist to watch that, and figure out how they do flex plates for engines.

 

I know times change but this sounds like a lot of BS to me. I had many engines, flywheels, drive shafts etc. balanced over the years, especially in the `60s and `70`s (anybody remember Henry`s Machine in Bellflower?) and I have never heard of balancing a flywheel on the crank. Sounds reasonable though. Is this something new? Sounds like the flywheel mfg. owns a chain of machine shops. I will follow these posts to see if I learn something new.

 

Page 10 of the index........ flywheel balancing V8, page 6A3-34

 

They don't do the flexplates for the engines there, its all a rolling chassis that is shipped in. It still wouldn't suprise me if at the place they assemble motors they have a pile of flywheels marks ~25.01g imbalance with a dot at a point on the flywheel. For example when ford used to build engines they didn't just have a bin of 302 pistons. They had if i remember right, blue and red coded pistons. The assembler miked the bore looked at the spec sheet and then grabbed the right piston. Same for bearings and rods.

 

I'm not sure I follow you. I'm not looking for a source for a flywheel.. got one. I'm looking for a balancing spec. Maybe I'm blind but I didn't see it on that link.

 

yeah and that link says rough balanced, not like finished balanced. That might just be a way of covering their behind though.

 

I think that says it............... It would be nothing for a manufacturer do a quick spin and put a "final balance" on the flywheel if there wasn't some variable involved.....

$693..................... I could have mine balanced ($50) eight times for the the extra that would cost me over the Fidanza

 

they specify their balance like 23.4in/oz and the rough balance stuff is for counter balnced flywheels for engines that are externally balanced not you internally balanced one...

 

My engine is externally balanced. They took the fly weight off the end of the crank when one piece rear main seal came into play. That weight is on the flywheel now. Counter balance flywheel.

 

what? the 1 piece RMS 350/305 is a internally balanced engine which means the flywheel would be a neutral balance as its weight isnt needed to balance the crank... unless you had tommy hackjob down in his garage balance your crank then you need a neutral flywheel period

 

The 1 piece RMS is no more externally balanced than the 2 piece RMS is. The mass that was on the 2 piece RMS crank flange outside the block has just been moved to the flywheel.

Terms like internally/externally balanced have become worse than meaningless.

 

I just got a call back from the Fidanza tech department...... according to them, and all other sources I've checked.... All standard transmission flywheels, from any manufacturer including the Chevy parts counter, have to be balanced to match the one that came with the motor. If that isn't possible it must be balanced with the crank.

 

I get the feeling this is one of those issues where 99% of the parts are going to be balanced to the same X value whatever that is

i mean you could have some mud stuck to your u-joint and cause an imbalance

i think the point is if they go to town on your entire assembly, you will be stuck using those parts forever, since you quite possibly might not even be able to balance another "factory correct" replacement flywheel in the future if they go nuts with yours now

does it have the holes in it like the factory one? the book method sounds nice and easy, and probably not even neccassary when its together and you arent feeling any vibration anyways :P

 

well they lied to you...
http://store.summitracing.com/egnsea...115+4294908216

there you will notice that each flywheel has a specified engine balance...external/internal... only the EXTERNAL balanced flywheels will need to be balanced with the crank...

but hey i you want to have your flywheel for an internally balanced engine hacked up go ahead

and why the hell would you ask a question about something you dont know then argue the answer?

oh you should read this
http://www.aa1car.com/library/2003/eb10330.htm

but here is the good part...

When rebuilding an engine that is internally balanced, the flywheel and damper have no effect on engine balance and can be balanced separately. But with externally balanced engines, the flywheel and damper must be mounted on the crank prior to balancing.

 

I had the T-56 in my car for a year with the flywheel, and a new factory clutch from the donor car, a 97 LT1. In neutral from 1500 to 2500 rpm it vibrated. I sold the 5.0 and freshened up a 91 Vette motor to go back in. I didn't get the flywheel with the Vette motor when I bought it. Unfortunately the Fidanza flywheel doesn't have any "balancing holes" like a factory piece.

 

I posted because I wasn't sure what the machine shop was telling my was correct. I was looking for someone with a reliable reference to back up or dispute what I had been told.

I got a bunch of "opinions" but nothing concrete, so I started doing research on my own and posting what I had found....... again more opinions came, but nothing to back it up. I'm just trying to provoke constructing discussion about something that isn't the usual... "what cam should I run, or which exhaust sounds better" topic.

Clearly there is a gray area when it comes to this topic, and the final chapter hasn't been written yet.

 

if you had bothered to actually read the links i had posted instead of just deciding that all those words wouldnt help...

you would have read

that it is possible to balance a flywheel for an internally balanced engine but the process is different than you were told... first the rotating assembly is balanced then and only then can the flywheel be attached and at that point they balance the flywheel... which would give the flywheel a "neutral" balance. so that its rotating mass doesnt affect the balance of the rotating ***... it should NOT be balance at the time of the assembly

which would be called the "stock spec"... for an internally balanced engine which is what your 91 1pc rms is...

and your so called vibration was from something else not the flywheel being out of balance... as it would have got worse by about 2900 then again around 3500 and again at say 4800
it wouldnt just go away...

 

I did read the link, and I thank you for it.

What you just said, ....."first the rotating assembly is balanced then and only then can the flywheel be attached and at that point they balance the flywheel.. which would give the flywheel a "neutral" balance".... completely backs up what I have been told. I cant just throw my flywheel on a balancer by it's self and balance it. The only way to get a neutral balance out of it is on the crank it is going to live with, and if the day should come that I need to change that flywheel for another the new flywheel will need to be balanced to match the one I take off. My motor still has the original pistons, and retains it's factory neutral balance. My flywheel is "ball park" or "rough" balanced at the factory, so to achieve an true nutral balance it will have to be bolted to the crank and spun as a unit.

As for my "so called vibration" I can assure you it was real, and wasn't there before I changed flywheels.

 

no it does not need to be balanced with the crank the neutral balance can be achieved with just the flywheel there is NO need to do balance it with the rotating assembly as the rotating assembly has to be done first which gives it the neutral balance... so then adding the flywheel would only be balancing the flywheel as its weight isnt needed to balance the crank at that point

do you know what neutral means?

 

I am very old and I loose brain cells by the million every day. I may totally be misunderstanding the term neutral balance, but here is a quote from the link you gave me.

""Externally balanced" engines, on the other hand, have additional counterweights on the flywheel and/or harmonic damper to assist the crankshaft in maintaining balance."

There is a counter weight on my flywheel.

 

and how is that counter weight attached? welds? fasteners?

they specify the inclusion of counter weights with that flywheel so that if it is used with a externally balanced engine you have weight to work with instead of drilling their flywheel

 

I know I am right on this....................... Every motor in f-bodys 87 to the introduction of the LS1 has a counter weight on the flywheel...... All of them.

Are you saying I don't need the counter weight?

 

nope i am saying that because it already has the counter weight then it is already neutrally balanced... which means that if you took just the flywheel and spun it by itself it would be balanced as in it wouldnt have any vibration where as if you took one that was for an externally balanced crank and did the same it would probably have a pretty good vibration do to its mass being used to balance the crank

___
fidanzas catalog specifies EXTRA weights along with the counter weight that is already attached... foot note (5) in thier catalog i believe

 

With all due respect sir, if you took a flywheel from a 87 and newer and spun it would be way out of balance. The weights offered by fidanza are to fine tune the mass that the fly wheel needs to balance the crank that no longer has the flyweight cast on it's tail.

 

I give up guy... have you noticed that no one else cares enough to tell you your right... they have already chimed in, told you how it is supposed to be done and you cant accept that why is that...

do what ever you want but how exactly do you plan on balancing a flywheel that weighs only 12lbs to begin with and is made of AL? those are gonna be some pretty big holes they drill

that is it i have argued enough with the old man in the hat sitting with the blue haired old lady....

 

Am i wrong in thinking this?

I thought by being "nuetral" the flywheel had no imbalances.

I could see in the world of production slight imperfections being slight imbalances, personally i've never had a problem with these on a flywheel. I just put them on and go, but i could see that possible.

I think of it this way... I understand tires and flywheels are two different things, but i think some of the same physics applies.

Very rarely do i mount a tire that is on balance right away. But generally it is fairly close. I would figure that a tire is designed to be as closely balanced as possible without adding weights, but most of the time I have to add weights.

However for the bookooo money you spent on that flywheel I would think it should be dead on... Like I said, they probably just say it is rough balanced to protect themselves with any chance of a warranty.

 

Why not install it and see how it works? How hard can it be to take the car out and see how it works. If it shimmies and shakes all over you will know it needs more attention, if it drives smooth, problem solved and over.

 

Well the way I see it, the link you provided makes your claims of neutral balance completely wrong. The flywheels in question are not neutral, they are part of crank balance.

As for insinuating that I am "less than" because I have been on the planet for a good long time............ well, that just sounds like a punk that realizes he is wrong and is trying to change the topic. I sir never insulted you.

I sent an email to Lingenfelter performance today........... lets see what they have to say.

 

Letter to Lingenfelter performance................................

Dear sirs,
I am going to the experts to get an answer to a question I just can't seem to get anywhere else.

I am working on a 91 Corvette 5.7 that now has one of your fine cams in it.... thank you very much.

I am going to run the Vette motor in a 91 Camaro with a T-56, and an aftermarket flywheel. I am uncertain about balancing the flywheel. One school of thought (on thirdgen.org) is that there is a factory spec that the counter weight flywheel must be balanced to. The supplier (Fidanza) says it needs to be matched to the flywheel that came off the motor or balanced "with the crank".

Please share with me any thoughts you might have on this topic.

Thank you very much, Bob

Hi Bob,

Thank you for inquiring with Lingenfelter. To my knowledge, they are internally balanced in the front, and externally balanced in the rear. Fidanza is correct in which the crank would have been balanced with the flywheel, so you will have to match the flywheel to what the stock flywheel is, unless you are building the engine, and balancing the crankshaft.
Jeff Myers
Lingenfelter Performance Engineering
1557 Winchester Rd
Decatur, IN 46733
260.724.2552 x 1004
260.724.8761 fax

 

Hey this is gonna be funny to see spitotrs305 argue with lingenfelter....

 

I don't mind good old fashioned give and take on a difference of opinion, or being wrong for that matter.....

Laughing at, and insulting people who don't share your view accomplishes very little.

 

sure i will argue with him... i mean god damn this is ridiculous

are you gonna spin this thing to 8500RPM?? NO then quit being stupid about it you have already been told i am right by other posts bolt the damn useless peice on and go.. and why the hell would you send a email? to lingenfelter about your FIDANZA flywheel...

this sounds like more of your sorta like throw some weights on it and drive it around.... then if it vibrates just move them around... yeah thats right out of a service manual...

like stated above... do you really think that GM took the time to individually balance every piece to match a specific set? NO! this is assembly line **** speed is the key..

if the weight is there like you say then it is ready to run...

and the "rough balance" statement was actually on the CENTERFORCE website refering to CENTERFORCE pieces
and you are telling me that lingenfelter isn't sure cant give you 100% definitive answers on a SBC...

what is this bull about internal in the front external in the rear... how does that make sense i mean think about it... the flywheel is intended to have a specific amount of weight in a specific position that is it...DONE it does NOT NEED TO BE BALANCED...

and if you really need your hand held and really need to make up a bunch of bull **** to oh i don't know seem smarter than some... then your are "less than"

 

and here i will do your homework for you it is called read the goddamn instructions!!

http://www.fidanza.com/Files/flywheelInstructions2.pdf