please, explain this to me.. ( about engine balance ).
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
please, explain this to me.. ( about engine balance ).
Our engines are neutral balanced at the front ( damper side ), but not at the rear ( FW/FP ) right?
Im looking at 383 stroker kits with cast crank, and they all say its external balanced ( 86 and later with 1 pc main seal ). Some companys offer to balance the kits. But thats not really going to help me is it, cause they dont have MY ZF dualmass FW. So unless I send them my FW the balance is just a waste of money, do i understand this right??
This must mean that if I whant to get a new FW som day. I must take out the internals and rebalanced it? IF I dont find a machin shop that can "transfer" the old FWs balance to my new FW? Or does the external balance fw and fp have the same offset all the time. Like i heard the 400 engines has?
Im having a hard time belive that GM balanced all the engines that came out, dident they just use the same offset on all the FW and FPs?
How do the shops use the FW to balance the rotating assambly? Do they drill holes in the FW? I know my ZF dual mass has tiny wights inserted. Are the ZF FW zero balanced without those tiny wieghts? Or are these wieghts only for "fine" adjusments?
Please help me understand this..
Im looking at 383 stroker kits with cast crank, and they all say its external balanced ( 86 and later with 1 pc main seal ). Some companys offer to balance the kits. But thats not really going to help me is it, cause they dont have MY ZF dualmass FW. So unless I send them my FW the balance is just a waste of money, do i understand this right??
This must mean that if I whant to get a new FW som day. I must take out the internals and rebalanced it? IF I dont find a machin shop that can "transfer" the old FWs balance to my new FW? Or does the external balance fw and fp have the same offset all the time. Like i heard the 400 engines has?
Im having a hard time belive that GM balanced all the engines that came out, dident they just use the same offset on all the FW and FPs?
How do the shops use the FW to balance the rotating assambly? Do they drill holes in the FW? I know my ZF dual mass has tiny wights inserted. Are the ZF FW zero balanced without those tiny wieghts? Or are these wieghts only for "fine" adjusments?
Please help me understand this..
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: please, explain this to me.. ( about engine balance ). (devilfish)
you about have it.
when GM balanced the motors, they did so with the dual mass flywheel. The tiny weights were used to bring the entire assembly into balance.
if it was me... I would have the motor internally balanced, then, get a single mass flywheel to zero balance. that way, you will never have to worry about the flywheel ever again!
Besides, the DM is HEAVY and EXPENSIVE. This is a great chance to get rid of both issues. All you will pick up is some tranny rattle at idle and low speed. Once over about 15mph or so, there will be no more noise than usual.
The DM weighs about 40lbs. Even if you use an F-body flywheel (93+ Camaro/Firebird) cast iron single mass, you will loose about 1/2 the weight!
You will need an Fbody friction disc to go with your existing Corvette pressure plate and throw out bearing. You might want an adjustable pivot, too.
It's the way I WILL do it when I rebuild my engine.
when GM balanced the motors, they did so with the dual mass flywheel. The tiny weights were used to bring the entire assembly into balance.
if it was me... I would have the motor internally balanced, then, get a single mass flywheel to zero balance. that way, you will never have to worry about the flywheel ever again!
Besides, the DM is HEAVY and EXPENSIVE. This is a great chance to get rid of both issues. All you will pick up is some tranny rattle at idle and low speed. Once over about 15mph or so, there will be no more noise than usual.
The DM weighs about 40lbs. Even if you use an F-body flywheel (93+ Camaro/Firebird) cast iron single mass, you will loose about 1/2 the weight!
You will need an Fbody friction disc to go with your existing Corvette pressure plate and throw out bearing. You might want an adjustable pivot, too.
It's the way I WILL do it when I rebuild my engine.
Burning Brakes
Joined: Dec 2000
Posts: 1,023
Likes: 0
From: Marietta, South Carolina, USA
Re: please, explain this to me.. (devilfish)
Why is it that its only "special" cranks that can be internal balanced and not cast cranks??
Jay
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 0
From: High Plains Drifter Fayetteville, AR
Re: please, explain this to me.. (devilfish)
ok thanks.
Why is it that its only "special" cranks that can be internal balanced and not cast cranks??
Why is it that its only "special" cranks that can be internal balanced and not cast cranks??
I will switch to internal balance when I build my 383. When you bring your rotating assembly to the machince shop, you always want to bring them your damper, flywheel or flexplate, rods and pistons.
Drifting
Joined: Jul 1999
Posts: 1,337
Likes: 0
From: Brighton, MI
Re: please, explain this to me.. ( about engine balance ). (devilfish)
There have been a lot of recent posts on this, many of which are mine.
You can neutral balance your rotating assembly (crank and internals), and then mate it up to a 0 balance flywheel as stated above. I have a cast Scat crank that is internally balanced in my 383. You will want to read this before you attempt to have a dual-mass neutral balanced:
http://forums.corvetteforum.com/zerothread?id=738670
Quite a bit of material needs to be removed from the dual-mass to get it neutral. The FW is not neutral balance with all the weight pellets removed. My theory is that they are for fine-tuning as you said.
More reading on the subject:
http://forums.corvetteforum.com/zerothread?id=750197 http://forums.corvetteforum.com/zerothread?id=749510
I've been told that GM did spin balance every engine - after it was assembled. Not something you can have done at the average machine shop.
You can neutral balance your rotating assembly (crank and internals), and then mate it up to a 0 balance flywheel as stated above. I have a cast Scat crank that is internally balanced in my 383. You will want to read this before you attempt to have a dual-mass neutral balanced:
http://forums.corvetteforum.com/zerothread?id=738670
Quite a bit of material needs to be removed from the dual-mass to get it neutral. The FW is not neutral balance with all the weight pellets removed. My theory is that they are for fine-tuning as you said.
More reading on the subject:
http://forums.corvetteforum.com/zerothread?id=750197 http://forums.corvetteforum.com/zerothread?id=749510
I've been told that GM did spin balance every engine - after it was assembled. Not something you can have done at the average machine shop.
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 0
From: High Plains Drifter Fayetteville, AR
Re: please, explain this to me.. (Jeff Hickman)
I've been told that GM did spin balance every engine - after it was assembled. Not something you can have done at the average machine shop.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Re: please, explain this to me.. (JCAIRE2)
if it is like you said, that means that all the FW to our cars have the same out of balance offset. And then you just use the tiny wieghts to fine tune it ( put on the same place on your new FW to your old one ).
If thats NOT the case then replacement FW should be inpossible.
If thats NOT the case then replacement FW should be inpossible.
Drifting
Joined: Jul 1999
Posts: 1,337
Likes: 0
From: Brighton, MI
Re: please, explain this to me.. (devilfish)
if it is like you said, that means that all the FW to our cars have the same out of balance offset. And then you just use the tiny wieghts to fine tune it ( put on the same place on your new FW to your old one ).
If thats NOT the case then replacement FW should be inpossible.
If thats NOT the case then replacement FW should be inpossible.
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Re: please, explain this to me.. (Jeff Hickman)
i see..
Has all the ( 86 and later ) chevy 350 fw and fp the same offset balance? Cause I can se in the summit catalog on fw that its printed external or internal balance? Mayby that mean that the internal FW has zero balance and the external has the "stock" cehvy offset?
Has all the ( 86 and later ) chevy 350 fw and fp the same offset balance? Cause I can se in the summit catalog on fw that its printed external or internal balance? Mayby that mean that the internal FW has zero balance and the external has the "stock" cehvy offset?
