2nd Gen Fl 'bird

iTrader: (13)

If you drop 1000.00 dollars(and up) on a complete clutch kit from the well known brands, don't you think they would ensure that it is balanced if spending that kind of money? Maybe I have missed something on why. Your el cheapo stock replacement kits I could understand.

BALLSS

every clutch company uses the same clone off shore made PP for the LT1 "pull" clutch. These are not the Valeo made ones that were "balanced" for "external" balance stock motors

Either way and whatever clutch even if it is an original valeo PP for a "internal" balanced motor you need to get the FW then the PP zero balanced.

S10xGN

iTrader: (11)

I got a new Fidenza 'wheel and a "lightly used" Spec stage II clutch/disc off E-Bay, so I won't feel right unless it's been properly balanced...

2QWK4RU 06 GOAT

iTrader: (1)

The two McLeod units I had were off by a ton. That's good advice from them.

BALLSS

My billet McLeod FW was 25 grms off. I always confirm balance. Clutch/FW swap is a big job so spending $50 to check your stuff, IMHO, is wise

I have the McLeod Street Twin ordered as the Neutral" balance kit. The FW did not have weight that screwed on but the FW did have the 4 holes taped to hold the weight on. That material = 25 grms. Shop just added short alan head screws in 3 of the holes

2QWK4RU 06 GOAT

iTrader: (1)

Don't feel bad, my street twin was almost 40 grams off. Then, I blew up 2 of them at half their hp rating on the street, in about 500 miles. One of their arguments was, "5th and 6th gear pulls will do that to any clutch." They were a pain to deal with when refund time came around. In the early days when Red was around, issues were few and fixed immediately, no questions asked. They use to be my exclusive go to clutch maker.

S10xGN

iTrader: (11)

Bringing this back up, I called our local balancing shop today and got some hinky info. He asked what it was for, I told him a neutral-balanced LS motor. He says he needs the crank (I have a spare) and bob-weights of the rotator. Does that sound right just for a flywheel and PP? The 'wheel was built to neutral-balance spec (just want it checked) and should already be good. He was surprised that I wanted the PP balanced. To my thinking, that's the only part that should actually need it since the 'wheel is new ? ? ?

Guess I'll have to box this up and send it off somewhere...

Kyle Reber

Hey folks I'm a balance tech in Lynchburg Va and I can balance flywheel assemblies . I kinda figured this on my own when I started putting my racer back together . We build balancers at American Hofmann for most everything. Dental drill rotors to 10.ooo lbs . Turbos , aerospace . 1st I static bal the f wheel . Down as low as I want . 1/4 Gm. I also want all bolts . They get weight marched . I then put the p plate on the f wheel. I then set the balancer up for 2 plane balance . Dynamic balance . Nothing worse then couple unbalance . That's unbalance 180 * apart but on separate planes . Top bottom. These amounts cancel each other out in static balance . Where if you did a spin test and used gravity it would appear balanced . But it is not . Couple unbalance is violent . Only only detected electronically . So I will make corrections on the p plate alone once the f wheel is done . In case you replace a clutch in a pinch at least your f wheel is good . I can index the p plate till I get lower readings and finish w maybe adding weight by weld or grinding . Mind you repeatability is not the greatest . Clearance holes for bolts , well , are clearance holes and they have wiggle room . I will re mount a few times and can determine if I should re correct . But I guarantee a good job. I saw my f wheel go from balanced to 8 and 9 grams out on each plane when I put the p plate on . Bal it . Then after dis assemble and re mount be 2 to 3 grams out . And stopped messing w it. I find it hard to believe folks are looking for this service . I can't get circle track racers to bite . Smh . The amount of force that 10 gm,s at a 6 inch radius at average 7k rpm equates to 100,s of lbs of force every rev . Hit me up . American Hofmann. Lynchburg Va.

Kyle Reber

Sounds like he wanted to use the crank as tooling to hold the clutch assembly . I have a lathe chuck that I can hold the flywheel with . Bal it then bolt the p plate to it then bal it dynamically . I modified a clutch alignment tool to slip in the chuck jaws so I can center the clutch disc and p plate . Yeah I need the disc too . Lol . Why not .

Kyle Reber

Sounds like he wanted to use the crank as tooling to hold the clutch assembly . I have a lathe chuck that I can hold the flywheel with . Bal it then bolt the p plate to it then bal it dynamically . I modified a clutch alignment tool to slip in the chuck jaws so I can center the clutch disc and p plate . Yeah I need the disc too . Lol . Why not .

Gen2-LT4

I just got a call from the Machine shop. My new SPEC clutch, flywheel, is ****, but the pressure plate, is up to 58 grams off depending on how its clocked!

Is there a known, "acceptable" amount or is it just, "as close to zero as possible"?

BALLSS

The machine shop should align the PP with the least amount of out of balance to the FW and put a paint dab or mark that lines up to the dowel pin hole on FW (like a stock PP would have). Then zero balance the PP to that orientation

58 grm is to much and it will vibrate

With that said I "think" I read the stock weighted FW can absorb about 2x grms (read twenty something)….but the machine shop should be able to zero out the PP by drilling one or more of the 3 ears of the PP

stevieturbo

I would be very surprised if it was actually so far out...a second opinion might be worth while ?

BALLSS

...well possible but this would be balance 101 for any machine shop. All the china clone PP the clutch companies use are not drilled/balanced like the original Valeo. Look at post #7 pic...those holes easily = (read more) than 58 grams. Each one would be different ….which is why the Valeo was neutral balanced and had a paint dab mark to line up with the dowel pin of the crank/FW

stevieturbo

It should be....but 58g is a hell of an amount for a precision manufacturer like Spec to get so badly wrong ?

Gen2-LT4

I had to call several times all morning long before I finally got someone on the phone. They are going to send a new plate today with a return label. In the mean time the flywheel was **** so at least the machine shop can finish the crank and come back and double check the new plate once it arrives.

This motor is jinxed or something, its already a month behind and this is my first SPEC clutch. I just put a Monster Triple disk in the Chevelle, but they don't make anything for the LT-4...