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ATI Harmonic Balancer (keyway question) #2564518
10/15/18 06:10 PM
10/15/18 06:10 PM
Joined: Mar 2005
Posts: 1,581
N/E, Michigan
RATTRAP Offline OP
pro stock
RATTRAP  Offline OP
pro stock

Joined: Mar 2005
Posts: 1,581
N/E, Michigan
The hub has a 3/16 key way, The crank has a 3/16 & 1/4 inch keyways, Broach the hub to 1/4 key or just run the 3/16 and not worry about it?

Re: ATI Harmonic Balancer (keyway question) [Re: RATTRAP] #2564522
10/15/18 06:16 PM
10/15/18 06:16 PM
Joined: Feb 2005
Posts: 20,116
PA.
pittsburghracer Offline
"Little"John
pittsburghracer  Offline
"Little"John

Joined: Feb 2005
Posts: 20,116
PA.
I had to get a 1/4 to 3/16 key from Summit. ATI offers it but Summit has it.


1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: ATI Harmonic Balancer (keyway question) [Re: RATTRAP] #2564596
10/15/18 09:23 PM
10/15/18 09:23 PM
Joined: Mar 2005
Posts: 1,581
N/E, Michigan
RATTRAP Offline OP
pro stock
RATTRAP  Offline OP
pro stock

Joined: Mar 2005
Posts: 1,581
N/E, Michigan
I have the choice as the crank has opposing keys, 3/16 & 1/4, I just have it in my head that the 1/4 key is stronger. I may have the hub broached to 1/4.

Re: ATI Harmonic Balancer (keyway question) [Re: RATTRAP] #2564634
10/15/18 10:58 PM
10/15/18 10:58 PM
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
T
TRENDZ Offline
master
TRENDZ  Offline
master
T

Joined: Jan 2005
Posts: 2,540
Milwaukee WI
Is this a blower application? If so, broach the hub. If not, run the single. The correct key slot to use in a single application is the one that lines up to the #1 cylinder rod journal.
#1 tdc, the key should be aimed at the #1 deck. This will assure balancer marks in the correct position to use OE timing mark location.


"use it 'till it breaks, replace as needed"
Re: ATI Harmonic Balancer (keyway question) [Re: RATTRAP] #2564729
10/16/18 07:01 AM
10/16/18 07:01 AM
Joined: Mar 2005
Posts: 1,581
N/E, Michigan
RATTRAP Offline OP
pro stock
RATTRAP  Offline OP
pro stock

Joined: Mar 2005
Posts: 1,581
N/E, Michigan
Thanks for the insight as to why there is two key-ways in the crank, I will run as is, So bigger is not always better,lol

Re: ATI Harmonic Balancer (keyway question) [Re: RATTRAP] #2565216
10/17/18 02:47 AM
10/17/18 02:47 AM
Joined: Jul 2003
Posts: 3,374
Rancho Cordova, CA
Exit1965 Offline
master
Exit1965  Offline
master

Joined: Jul 2003
Posts: 3,374
Rancho Cordova, CA
Here's something I read on a Ford forum, found through googling, when I was concerned about crank keyway when putting my engine (non blown) together. It gave me reassurance that the key didn't really matter!

----

We used to experience these types of failures years ago on Chevrolet small blocks when we would use GMC blowers on the engine. The solution at that time ended up to be using a Chrysler sized snout (1.530" Dia) on the chevy cranks. The solution usually came with a double keyway. The double keyway existed because those of us with the Chryslers wanted quick and easy way to remove our lower blower drive hubs. To effect the easy removal we would hone the ID of the hub to have a very light press fit on the crank snout. We would also use double keys but our keys were 1/4" hardened or for those of us with access to it, tool steel. Our lower blower drive hubs were made out of premium billet steel material so we had a lot of strength to start with.

The final touch was the fact that Chrysler used a 3/4 x 16 snout bolt that, in grade 8 form, reached proper bolt stretch at 380 ft/lbs of torque. Very few of us (that I knew) ever went that high. But and here is the important point, at anywhere between 150 and 200 ft/lbs of torque nothing but nothing moved. The clamp load was phenomenal and it was the friction from the clamping load that actually secured everything on the front of the crank.

from:
https://www.modularfords.com/threads/184...r-balancer-here







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