GOSFAST

Adam, make that "under" or you'll need a new balancer!!

(Add) I'm guessing the crank will be somewhere between 1.246" and 1.247". I have seen some variations from these numbers but this generally what you find.

Thanks, Gary in N.Y.

P.S. On a side note I doubt the balancer could never get to some of the temps mentioned above, not going to happen. No matter how hot it gets you'd always be able to touch it w/o any burns?

REELAV8R

Not wanting to argue with you Gary as your experience far exceeds my own. But the balancer is exposed directly to the air from the radiator which is at or slightly below the temp of the water. the oil in the crankcase will be at or above 212* on any extended run period and will rise far above that without the benefit of an oil cooler on hot days when run hard, so the oil seal will see that temp as well. Extended and repeated exposures to high temps will eventually cause problems for sure. But 250* one time and by the time you got the balancer on it has dropped well below that temp. I guess I don’t see the problem.

NewbVetteGuy

Yes. Under. That's what I meant.
Thanks for the clarification.

Adam

NewbVetteGuy

It makes a difference if you don't want to burn your house down (I don't). -Open flames and engine oil seem like a bad combo.

What I was talking about doing was a "double boiler" where I heat up a pan full of water to boiling on the oven and then put a coffee can of oil down into the larger pan of boiling water to transfer the heat from the water to the oil -without having the risk of an open flame and engine oil. -I wasn't going to immerse the balancer hub in water, but the oil, which gets heated from the water bath. (Just makes me feel more comfortable with the risk of fire.)


Adam

CanadaGrant

I just use an ice pack on the crank snout and hot or boiling water on the balancer. That way there is no need to go overboard on either and it should slide right on.

3X2

We use 2.5-3.2 thousandths press fit.

REELAV8R

Yowza! Tight fit. Just goes to show there are many opinions on this subject. One thing is agreed though it’s gotta be a good interference fit.

3X2

That is what we strive for with an ATI balancer and a LS crank. I'm sure a sbc or bbc is no different. My best suggestion is ton follow ATI's directions.

Antz81

Do you have to heat the balancer and press that on for that interference? It does seen extremely tight.

3X2

I do on a hot plate. I heat just the hub then bolt on the balancer afterwards. And I use a quality balancer installer. My case a Snap-On. I'm sure a Mac. Matco. or OTC would do just as well. Remember, a normally aspirated LS has no keyway to help keep the balancer from spinning on the crank . I use this same spec when assembling dry sump engine with Dailey and A.R.E. set ups. It has been years since I did a balancer on my 69 427, but I would follow ATI's directions to the letter.

suprspooky

Interesting info folks, I've installed two fluidampr's ( sbc and bbc) and many oem type HB's and didn't need to heat or cool anything. I've always used a proper installer and hub bolt type puller and never had problems ( I will say the bbc fluidampr was tougher to seat though). Very good info on the hone fit for ATI, I almost went with the ATI until I decided to stay around 6200 for the rev limit.

Adam, glad to hear it wasn't a full disaster (I had several with my 460 build, just not the damper).

GOSFAST

Not sure how you're measuring the press but below is ATI's directions!

ATI damper fit

5. Press fit of the hub to the crankshaft is vital to transfer harmonics to the damper assembly.
Recommended press is as follows:

Crankshaft OD ----------------Interference
1.0000" - 1.2500"-------------.0009" to .0012"
1.6010" - 2.0000"-------------.0006" to .0008"
1.2510" - 1.3750"-------------.0008" to .0011"
2.0010" - 2.5000"-------------.0005" to .0007"
1.3750" - 1.6000"-------------.0007" to .0009"

GM cranks are typically to tolerance +/- .0001 (one ten thousandth). If you are using an OEM GM crank you
can hone the damper hub as follows:
Big Block:--------------------------hone to 1.5993" +/- .0001"
Small Block:----------- -----------hone to 1.2453" +/- .0001"

Thanks, Gary in N.Y.

P.S. In over 50 years of doing this stuff I've never seen the press fits you mentioned!

bmans vette

Why not put the engine in a walk-in freezer at your local restaurant overnight?
Then heat the balancer on the grill.
Mount with installer.
Do this before the lunch rush.....

Just kidding......

Glad to be warned about the steps to do an install with ATI.
Any install I ever did was pretty easy just s long as it was lubed, the keys lined up and a good installer was used.
Making sure it was a straight in shot and go slow.
Any resistance, back it off and find the issue.
A little dykem helps with that.
And remember to lube the timing cover seal before the install.

Thanks for the details from others using ATI dampers.

L88Plus

I watch most engine building shows on TV. They were in John Kasse's shop a while back and had what looked like a hydraulic rig that pressed the balancer on with ease. I'd never seen one before, haven't since.

derekderek

just wait until winter... JK. a friend used to work at Pratt and Whitney. he had helicopter rotor shafts in the deep freeze, hubs in the oven. he had about 4 seconds to get hub on to the seat. if it didn't make it, the whole assy was scrap metal.

jim2527

That was 4 Sundays ago....

3X2

Note I mentioned LS, which is 95% of the engines we do. That is the spec my engine builder strives for. I also said I'd follow ATI's instructions. Your results may vary. Always good to hear what other professionals do and to compare notes.

buns

These gel packs work well for cooling the crank snout. Also good for keeping your pilot bushing cold.

NewbVetteGuy

LoL!

I JUST dropped the balancer off at my machine shop. They're great- They looked at my caliper measurements and went "umm.. no!" -We'll machine it to SBC OEM spec because that's not right. (I didn't know to use the ratcheting screw on the end and made it too tight, apparently.)
-I'll re-measure it again tonight so when I go to pick it up tomorrow I can see if my technique improved based upon what they showed me and if I can get a more accurate #.


Adam

NewbVetteGuy

I was watching the PowerNation TV or something like that on YouTube last week where John Kasse was involved in the BigFoot 1 supercharged BBF engine build; magical machines everywhere. Floor looked like you could eat off of it in that place!


Adam