Not really, every engine is neutrally balanced.

 

So i wouldnt have to have it rebalanced with that part? Just trying to make sure I understand.

 

lo-tec, the timing marks do line up

 

shaggy, yea i deff. seen that weight before.... but it dosnt bolt up to the 1 one piece rear main seal cranks

 

sorry, i got neutral balanced and imbalaced mixed up

 

If you're running a 400 flexplate, all should be good already (if it ain't broke don't fix it). The pic I posted is a band-aid to allow running a stock 350 flexplate on a 383 stroker.

 

I just wanted to upgrade balancers if possible. I just dont want any extra work, otherwise ill just leave it alone.

 

na shaggy, if u have that "bolt on weight" it will properly balance your engine as long as u have a 2 piece rear main seal

 

If you have a stock 400 balancer on there now, a replacment 400 balancer will not affect the balance at all.

 

if u want to upgrade balancers, just make sure its for a 400 s/b. and that a machine shop didnt "balance" the balancer that u have now

 

Im pretty sure from memory the original balancer was untouched the paint didnt look disturbed if I remember correctly. I was also curious why some balancers have some kind of material removed while some dont.

 

shaggy, if material is removed from the balancer than chances are that it was balanced as an assembly with the pistons, rods.. etc.

 

For instance I see balancers for sale with material already removed. Their are tons all over ebay with material removed. Is this normal? When I gave the machinist all the parts for balancing the flexplate and balancer still looked the same way I gave them to him. He didnt machine them at all.

 

Like this one has material removed already.

http://cgi.ebay.com/ebaymotors/SBC-C...15294493QQrdZ1

But then some dont.

http://cgi.ebay.com/ebaymotors/Chevy...15171958QQrdZ1

 

Read the add:

"It has a machined area on the back of the intertia ring that provides the proper amount of imbalance to be suitable for use on externally balanced small block Chevys. The stock 400 and most 383's require an externally balanced damper."

 

I see some balancers could have 3 areas drilled while some may have less. Are these balancers all interchangebale without having to get anything rebalanced? Their are so many different balancers I have no clue which ones are best suited for what. I mean you have stock, SFI approved, Fluid Dampeners or what have you. I mean if I go insane on buying a balancer is it even worth the money you spend? I asked a buddy he told me that the better dampeners will make your engine last longer but just trying to verify how true this is or is it a waste of money for a street engine.

 

Let's clarify a few points:
Early 350 with 2 piece seal: no balancing on flexplate/flywheel.
Late 350 with 1 piece seal: small balancing weight on flexplate/flywheel.
400 motor only made with 2 piece seal: large balancing weight on flexplate/flywheel.

Stroker rotating assembly:
Externally balanced without harmonic balancer and flexplate: about $700
Externally balanced with harmonic balancer and flexplate: about $900
Internally balanced: with harmonic balancer and flexplate:about $1900

REW's problem is chevy never made the 400 with a one piece seal so there is no stock flywheel that has both the big weight for the 400 crank AND will work with a one piece seal.
This would be a great thread to have the source where this aftermarket flywheel can be found. and it ain't Summit.
Anyone who has built an externally balanced 383 with a one piece rear seal AND a manual transmission has solved this problem. So SPEAK UP!

 

Jegs also has the hays one listed for an automatic. Another possible source-check out GM's ZZ383 stroker crate motor, it's a one piece RMS and comes with an auto flexplate. However, I believe it is a 3.80" stroke crank. I can post a part # for it on monday.

As far as a manual trans goes, all you would need to do is have a balance shop balance one to stock 400 specs. The aftermarket steel one's I've used for 350 one piece RMS engines just have a bunch of holes drilled in one section 180 degrees out of where an auto flexplate would have the extra weight.

Supervisor42 , nice summary on all of the possible balance combinations!!

 

Flywheel!! as in "not a flexplate", as in "not for an automatic transmission", as in for a manual transmission.
They cannot drill enough holes to make it simulate the big weight on the 400 flywheel only the small weight of the one piece RMS 350 flexplate.

 

Take an aftermarket flywheel to the machine shop and have them balance it to the same specs as a 400.

I.E. drill more holes in the back of it.

 

What kind of flywheel? The hays one I had (30 lbs) had a lot of meat on the back. If they can't drill enough, have you looked into an aluminum one? Mine for a 350 has a small weight bolted to the backside (engine side). There might be room in there to bolt a bigger weight. Might want to give SPEC or Fidenza a call.

P.S. when you edit your post to reply to mine, I would type in EDIT to show you changed it to answer my question or respond with a new post.

 

If you're not stupid and you know what you're doing, then why are you

a.) asking this question in the first place

b.) taking 4 weeks to figure it out?

 

well because the place that i bought the kit from gave me all the claimed it was a balanced assembly and as to come find out once the engine was assembled and dyno'd it isnt the engine is out of balance

 

It very well could be balanced, you just didn't buy all the parts you needed to go with it.

 

its not that i didnt buy all the parts...... i bought a"KIT" and it was supposed to be "assemble and go"

 

it's that the wrong parts are on both ends of your engine...

...if you had bought all the right parts you wouldn't be here posting. However, you now know what is wrong and what to do to fix it, and that is what matters in the end.

 

I just got my assembly from the machinist Friday. I watched him do his deal. He used my balancer and flexplate only for references. Machining was not done to either piece. This Scat crank was designed for use of a regular balancer and a weighted flexplate. I know it sounds crazy, but a call to Scat confirms it.

As far as balancing a rotating assembly inside an engine