Tell Me Your Girth

[GTR1993]

Hey, this is for everyone using ATI balancers on rb series motors, specifically rb26

I have one going on my gtr, they say you want approx 0.02 mm interference fit (even a bit bigger is ok)

I measured up my std crank, 30.00, checked on another crank i have 30.00 as well, miced up the ati balancer and its 30.00 as well!, they say they are undersized and need to be honed, i have no material to hone, ita already too big!

Now, do i have a dud balancer, or is this the reason RB26 calls for over double the torque on the balancer bolt?

Cheers

[GTR1993]

anyone, DIRT??

[Swiper the Fox]

anyone, DIRT??

you called?

your measurements tell me if you hone it 0.02mm it will be perfect.

My ATI was fitted to my new RB26 crank without any modification and it fitted perfectly

Edited February 1, 2009 by DiRTgarage

[GTR1993]

I did What has been your interference fit on you ati balancer? Did you have to hone yours out?

[GTR1993]

nah that cant be right, i pulled the balancer on with just the crank bolt, and only the engine compression holding the crank in position. If i wanted a 0.02mm interference fit, my balancer would need to be 29.98 mm and crank being 30.00

[GTR1993]

I will check, ill be back, i think this is the reason for 460 Nm on a RB26 bolt.

[Swiper the Fox]

nah that cant be right, i pulled the balancer on with just the crank bolt, and only the engine compression holding the crank in position. If i wanted a 0.02mm interference fit, my balancer would need to be 29.98 mm and crank being 30.00

are you sure its an interference fit...i was sure it was a clearance on balancer (i.e.0.02mm clearance)...i can remove mine with a few taps with a rubber mallet. It and the woodruff key were in perfect order when it was removed on the last pulldown so it didn't move at all when locked on with the bolt. They are not supposed to be pressed on like a bearing onto a shaft i.e. interference. The way you have described it being fitted sounds like a perfect fit...remember to moly lube both sides of the washer and bolt thread...no loctite!

Edited February 1, 2009 by DiRTgarage

[Swiper the Fox]

I will check, ill be back, i think this is the reason for 460 Nm on a RB26 bolt.

just checked my documentation and you are correct...interference fit.

without this fit it also states that it "will not correctly transfer crankshaft vibration into the hub"

gee thats a worry.

[GTR1993]

So what do you think the answer is? I mean yours is ok still lol.

I measured up the std balancer, and its 30.00 to 30.01, so loose fit too.

Im thinking its using 460 Nm to apply pressure thought he face to the gear that drives the cam belt then to the crank, because it doesn't matter what friction surface it uses.

[Swiper the Fox]

So what do you think the answer is? I mean yours is ok still lol.

I measured up the std balancer, and its 30.00 to 30.01, so loose fit too.

Im thinking its using 460 Nm to apply pressure thought he face to the gear that drives the cam belt then to the crank, because it doesn't matter what friction surface it uses.

i use 150ft/lb (200Nm) and 1/2 a turn with a length of pipe over my biggest breaker bar to apply 'correct' torque.

haven't had one come loose yet.

touching wood as i type

Edited February 1, 2009 by DiRTgarage

[T04GTR]

well, does it slide over the crank? if it only get like a few mil on then stops its ok.

tension is 400nm~ odd. big bar and you can feel the bolt start to stretch its the right tension..(use grease on the bolt head/washer)

[Swiper the Fox]

well, does it slide over the crank? if it only get like a few mil on then stops its ok.

tension is 400nm~ odd. big bar and you can feel the bolt start to stretch its the right tension..(use grease on the bolt head/washer)

mines seems to come on and off a little easier than im comfortable with...it doesnt push all the way on by hand and is pulled up with the bolt. But as i said before i can remove it with a rubber mallett without too much effort and the balancer, key and crankshaft snout are in pristine order.

I hope it because i use a smear of 'silverslip' on the shaft and its a brand new crankshaft and balancer.

ARP moly lube is the stuff for the crankshaft bolt and washer.

Edited February 1, 2009 by DiRTgarage

[GTR1993]

It doesn't slide on by hand, it does stop, but it pulls on real easy with the crank bolt pulling it on. But its not the interference fit that its meant to be. Not sure if to just leave it and do bolt up to proper torque, i mean what else can i do, unless this balancer is wrong ID from factory.

[T04GTR]

sounds fine to me aslong as its not loose. (if it is to tight it will gall up and f**k the crank and the balancer)

and yes. molly lube is good for the bolt and the crank snout. dont use locktite on the thread!