GrossPolluter

iTrader: (1)

I was curious about rotor balancing in case I would not have matching letters or 1 letter off for a future engine build. I was looking at a few websites and it looks like people add weight. I was really hoping they would remove material to match.

So do they add or remove at the rotor or the counterweight?

I'm curious also on how much weight diference there is between an "a" rotor vs a "d". If someone were to get their rotors balanced, couldn't they also get them both lightened at the same time, or would it not be significant enough?

fendamonky

iTrader: (6)

I have had my rotating assembly balanced by Chip Ursu (Chips Motorsports). Balancing is good even if you have same letter rotors, honestly after having it done I can't imagine NOT balancing my engines rotating assy..

Who said they add weight to the rotors??? Mine had already been lightened/clearanced, but I can't imagine a shop trying to add additional weight, verses just shaving some off the rotor.

GrossPolluter

iTrader: (1)

What diference did you feel in the balancing? The adding weight thing I saw looked like welding material to the counterweight

so lightening is the same as clearancing the side, or is there another area they remove material to lighten?

What application is clearancing the side recommended, or is it even good to do on any application depending on budget?

fendamonky

iTrader: (6)

I changed significantly more than just the rotors for that rebuild (brand new engine, different ports, changed rotor series, etc., etc., etc) so I don't think I can give an accurate report on JUST lightening the rotors.

Lightening and clearancing are not the same thing. Lightening a rotor is just what it sounds like, you're removing material from the sides of the rotor to reduce its weight.

Clearancing a rotor is where you remove a small amount of material from the points of the rotor near the side seal. Clearancing is there to compensate for e-shaft flex at high rpms, that way your rotor tips won't brush the irons and jack them up.

Balancing is done to smooth out your rotation and minimize outward force during operation.


Somebody please correct me if my explanations are inaccurate.

GrossPolluter

iTrader: (1)

Cool, yeah, after I did a little more searching I saw they were creating more clearance off the sides.

I was always under the impression you want clearances tight from cyl engine rebuilds.

Now I am curious where they would take off material for lightening.

BLACK MAMBA

iTrader: (58)

Most of the times when they add weight it is added to the front counter weight, some people do it by drilling small holes on the CW and filling with lead.

fendamonky

iTrader: (6)

Tight (seal) clearances are good, clearancing the rotors won't/shouldn't effect seal clearances though.

Here is a pic of my rotor when we were building my engine last winter, you can see where it was lightened and sorta see the line from where it was clearanced.

GrossPolluter

iTrader: (1)

Oh cool, just lightened just under the side seals. Nice rotors! How much were they able to lighten it?

So i am still curious on the weight difference of rotors from a to b.

I am picking up someone's s4 na rotors that are "d" and "e". I'm really debating if i should get them balanced with the crank. I plan on traking the car, but not real racing

rwatson5651

iTrader: (5)

That rotor is a work of art!!!!!!!

fendamonky

iTrader: (6)

Yeah, all credit goes to Chip on them! I was half tempted to call off the build so I could mount them on my wall

GrossPolluter

iTrader: (1)

Anyone recommend in California for rotary machining, balancing, etc?

SPENT-IT

iTrader: (15)

California, Mazdatrix.

Mdessouki

iTrader: (7)

Racing Beat