Cam gear conversion: alignment of crank and cam gears
 

A question for you converts to gear drive cams...when you put the rear cam and crank pinion gears on, did the gears line up? When everything is torqued properly I only got about 3/4 overlap with the outside of the cam gear and the inside of the crank gear biting air. I also had no backlash, so suspecting that something isn't the way it should be I pulled the cam gear off and plan to re-install it tomorrow after I pick up a new gear key. (The one that came with it isn't reusable)

I can't tell from your post which gear is not lining up but it sounds like the rear cam gear is the offender and that you just haven't pulled it down all the way. It could be in a bind and torqued but not flush with the face of the cam.

Did you check crank runout? Did you check lash on the inner gears? You should have received instructions and they are clear that inner gear lash should be checked before proceeding with the installation. If I were in your shoes, I would back off, disassemble, inspect the parts, re-read the instructions and try again. You should have .0005"-.0001" lash at the outer gears.

This is why I keep telling guys that gears are not worth the trouble; the hydraulic tensioner, roller chain setup is the way to go. No outer bearings to press on, no inner gear lash to setup, no gears to press on, etc. The hydro setup is a piece of cake and it will tolerate some crank runout. Good luck.

That's what I think, too. The gear key was pretty boogered up when I took the gear off which leads me to believe that it wasn't in there right when I put the torque wrench to it.

Anybody know where I get find replacement gear keys? This isn't a half moon like a woodruff key, just a little rectangle. Can you get them at auto parts stores or do I have to go to a machine shop?

McMaster Carr might have one that is the correct size.

http://www.mcmaster.com/#machine-keys/=anq7ax

If not, take it to a local machine shop and if they don't have any, they should be able to tell you where to get them.

I usually take some fine emery cloth and work the gear keway and the key before installing the gears and I use a little WD40 or assembly lube, whatever, at the keyway. If one is particularly stubborn, I will stick it in the oven for 20-30 minutes. Hot to handle but once you get it on the shaft/keyway and tap it a couple of times, no problem. You should be able to tap the gear on enough to know it is aligned before you apply the torque wrench.

If you don't get the lash issue sorted out, the gears will be noisy; follow the installl instructions.

It is quite possible the key shifted as you installed the gear, then jammed on tightening things up. Was the key part of the kit, or is it a Harley part? For such a small item it would be better to contact the original source than shop around.

You have bumped into 'The Inverse Rule'. The smaller a thing is the greater the effort of sorting out the problems it causes. Try to take the shortest route to getting a replacement, otherwise you could spend a lot of time chasing shadows.

Great suggestions, and thank you both for taking the time to reply.

The key came with the S&S gears, and I hear you about the "inverse rule". I never seem to have a problem finding something I've dropped as long as it's as big as my fist. :-)

I'm also going to "dry-fit" it without the key to see if it lines up the way it should.

One question though...it seems like I would want to put the key in the freezer to shrink it, not the oven? Or is the idea to heat it enough to soften it?

Freezer could well help. I haven't fitted an S&S set-up to appreciate just how small this small thing is! :icon_sad:

I suggest phoning S&S themselves for a replacement. They may insist you go through a dealer, but for such a small part they might just send you one - in a big jiffy bag! Plead as much humility as you can muster, so they take pity on you.... :icon_redface:

Call Andrews; they make the gears for S&S. I was referring to the cam gear for the oven, not the key. I find McMaster Carr as the "go to" place when confronted with the inverse rule. A machine key is what you need and they have them, just need the right size. Measure yours with an accurate set of vernier callipers.

Questions answered
 

Just got off the phone with Andrews and they answered all my questions. The key is a "404", which he said is a standard "off the shelf" size and should be available at hardware stores, auto parts stores, etc.

He also told me that the gears do NOT run aligned, and an offset between the rear cam gear and the crank gear is correct.

Again, thanks.

Good information on the key but "gears do not run aligned" is a new one on me.