How Do You Break a S&S Gear Drive
Outstanding HDF Member
Joined: May 2007
Posts: 2,304
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From: Florida
RE: How Do You Break a S&S Gear Drive
There are two ways to break teeth of the gear drive, I take it you broke the pinion gearto rear cam gear.
#1 Not setting up the back lash correctly getting the gear mesh too tight on the pinion shaft then the run out of the pinion shaft closes the tolerance even tighter(up to .003)and snaps a tooth off, once one tooth goes it's dominoes from there.
#2 Setting up the back lash too lose letting the gears slap forward and aft from the open and close of the valves. This slapping becomes very violent the stronger spring pressures you run and it takes it's toll on the gears.
One other thought: Andrews makes 90% of S&S gear drives and their kits can be identified by a job number etched into the gear itself plus the gears have a (hardness) shine to them, S&S also has some other co. making gears that are dull in color that are not nearly the product or quality that the Andrews are. I seen many of the dull in colorgears break in the past.
In all my days of installing gear drive cams I only remember to times I actually used the standard gears that came in the kit....I always had to use over sized gears to get the back lash correct...one time I had to use a.0005 under sized cam gear.Point being istoo many people just take the gears out of the box and installthem into the engine without checking the back lash.....signs of problems are a loud ticking from being too loose or a whine from being too tight. Gear drives set up correctly will be very quiet.
Doc
#1 Not setting up the back lash correctly getting the gear mesh too tight on the pinion shaft then the run out of the pinion shaft closes the tolerance even tighter(up to .003)and snaps a tooth off, once one tooth goes it's dominoes from there.
#2 Setting up the back lash too lose letting the gears slap forward and aft from the open and close of the valves. This slapping becomes very violent the stronger spring pressures you run and it takes it's toll on the gears.
One other thought: Andrews makes 90% of S&S gear drives and their kits can be identified by a job number etched into the gear itself plus the gears have a (hardness) shine to them, S&S also has some other co. making gears that are dull in color that are not nearly the product or quality that the Andrews are. I seen many of the dull in colorgears break in the past.
In all my days of installing gear drive cams I only remember to times I actually used the standard gears that came in the kit....I always had to use over sized gears to get the back lash correct...one time I had to use a.0005 under sized cam gear.Point being istoo many people just take the gears out of the box and installthem into the engine without checking the back lash.....signs of problems are a loud ticking from being too loose or a whine from being too tight. Gear drives set up correctly will be very quiet.
Doc
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Cruiser
Joined: Feb 2007
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RE: How Do You Break a S&S Gear Drive
Well the motor was done by a Harley shop here in town. My worry Now is, do I have to go through the whole motor Top and Bottom now because of this?
Far as I know I only broke the (TOP) Gear Drive but I have not gone in any farther then that so I hope to find out today.
And off the top of my head it is the dull one.
Now I would guess this motor is Garbage now.
Far as I know I only broke the (TOP) Gear Drive but I have not gone in any farther then that so I hope to find out today.
And off the top of my head it is the dull one.
Now I would guess this motor is Garbage now.
Outstanding HDF Member
Joined: May 2007
Posts: 2,304
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From: Florida
RE: How Do You Break a S&S Gear Drive
I wouldn't say it was shot just yet. Did the valves hit the piston after the gear broke, can you find all the teeth that broke off, did anything enter the oil pump. Thats the questions I'd ask or find the answer too.
Good Luck
Good Luck
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Cruiser
Joined: Feb 2007
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RE: How Do You Break a S&S Gear Drive
How do I know for sure nothing went into the Motor? The motor was warming up and at idel when this happenned it shut right down and I pushed it home. I found 5 teeth but one of the spots it broke at is not a very clean break and also I took the front Rocker box cover off and the was a very small amount of meatal sitting in the fron right cornor not much but it was there. and for the oil pumpjust dont know how do I go find this out?
Thanks for the help Doc 1 I really need it. This has been a $6000 Nightmare.
Thanks for the help Doc 1 I really need it. This has been a $6000 Nightmare.
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Road Captain
Joined: Jun 2007
Posts: 512
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From: Washington
RE: How Do You Break a S&S Gear Drive
Is the shop an Indy or HD dealership? IF a dealership, then you should be covered as most warranty their work. Good luck if it's an Indy..
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Joined: Feb 2006
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From: TX
RE: How Do You Break a S&S Gear Drive
Doc ~
What about failure of the left (non-Timken, on 03 & later) crank bearing, or perhaps a twisted crank?
I would think sheared teeth would stem more from lateral forces...???...
What about failure of the left (non-Timken, on 03 & later) crank bearing, or perhaps a twisted crank?
I would think sheared teeth would stem more from lateral forces...???...
Outstanding HDF Member
Joined: May 2007
Posts: 2,304
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From: Florida
RE: How Do You Break a S&S Gear Drive
I'd take it back where it was done and have them look in the pump...if it's good and you have compression in both cylinders your probably good to go. Get a Andrews gear drive....all gear drives say S&S on the box but not all aremade byAndrews. Bobby Wood sells nothing but Andrews Gears http://www.woodcarbs.com/