New product: cam gear adapter
Posted: Sat Jan 21, 2012 2:00 pm
Hey all, just want to let the engine builders here know about a new item I will make available soon that offers a solution to some common problems some of us deal with regularly in using aftermarket camshafts and properly fitting helical gears in Type1 and wbx crankcases.
What are the problems?:
1. Aftermarket camshafts are available in many fun grinds but are almost exclusively ground on early-style 3-bolt blanks, BUT...
2. Aftermarket aluminum helical gears are not available in the range of off-sizes that were originally made for setting gear lash properly. The aftermarket parts makers offer new alu gears, which they infer are std. but in my experience they have mostly been much smaller than a standard size. Gene Berg had some stock in off-sizes for a pretty penny, but it is drying up and they say there will be no more once a size is sold out. So, if the one you buy fits OK, you're good to go, but if it's way too big or too small, you're SOL, UNLESS...
3. You take a gear from an old Type1 cam, remove the rivets and modify it to allow room for bolt heads, which is easy and means you can conceivably have all the off-sizes you might need, BUT
4. The Type1 3-rivet gears were cast in soft magnesium. That's just fine until, despite being properly fitted, a mag gear does a number like this:
If you use the old mag gears and this hasn't happened to you, all you can say is that it hasn't happened yet. Can you afford a comeback when it does? And would you then go on and take the chance of it happening again?
5. Meanwhile, we have lots of old rusting 4-rivet cams lying around that have nice strong aluminum gears on them, in various sizes, but they're useless because the new cams we like to use are all 3-bolt sticks.
6. And finally, if you're someone who actually blueprints his builds, you already know by now that you rarely get an aftermarket cam that's actually timed on zero out of the box. I buy from several cam grinders, and mic up every single cam, and I don't think I've got one yet that is less than 2 degrees off; I've had them with over 5 degrees error. Plus I like to dial in my cam timing for particular applications, once I determine what the actual timing of the cam I have in hand actually is.
So, I'm having this piece made for myself and some other colleagues, and it will be available to any other builder whom it will help. It's a hub adapter for fitting the later 4-rivet aluminum cam gears to the early-style 3-rivet cams.
And, it is drilled and tapped in a pattern that allows you to attach the gear to the cam in one of nine different positions, straight-up zero, or 2, 4, 6 or 8 crankshaft-degrees advanced or retarded. That gives a wide range of positions for correcting base cam timing or modifying it to alter the torque curve.
These will be available about a month from now, as a complete kit including the fasteners needed to install, all 12.9-grade button-head bolts (not the hexbolts shown in the picture). And of course there will be clear instructions how to install.
If you open an engine and it has a correctly-sized 4-rivet gear in it, you could go on and use that same gear on any camshaft you like using this adapter.
It allows adjusting cam timing during the build but is not adjustable thru the oil pump hole once installed.
I will offer a price-per-kit including shipping, as well as reduced pricing for small quantities.
Please PM for pricing info (which won't be nailed down for a few weeks anyway), but feel free to discuss or ask questions here.
What are the problems?:
1. Aftermarket camshafts are available in many fun grinds but are almost exclusively ground on early-style 3-bolt blanks, BUT...
2. Aftermarket aluminum helical gears are not available in the range of off-sizes that were originally made for setting gear lash properly. The aftermarket parts makers offer new alu gears, which they infer are std. but in my experience they have mostly been much smaller than a standard size. Gene Berg had some stock in off-sizes for a pretty penny, but it is drying up and they say there will be no more once a size is sold out. So, if the one you buy fits OK, you're good to go, but if it's way too big or too small, you're SOL, UNLESS...
3. You take a gear from an old Type1 cam, remove the rivets and modify it to allow room for bolt heads, which is easy and means you can conceivably have all the off-sizes you might need, BUT
4. The Type1 3-rivet gears were cast in soft magnesium. That's just fine until, despite being properly fitted, a mag gear does a number like this:
If you use the old mag gears and this hasn't happened to you, all you can say is that it hasn't happened yet. Can you afford a comeback when it does? And would you then go on and take the chance of it happening again?
5. Meanwhile, we have lots of old rusting 4-rivet cams lying around that have nice strong aluminum gears on them, in various sizes, but they're useless because the new cams we like to use are all 3-bolt sticks.
6. And finally, if you're someone who actually blueprints his builds, you already know by now that you rarely get an aftermarket cam that's actually timed on zero out of the box. I buy from several cam grinders, and mic up every single cam, and I don't think I've got one yet that is less than 2 degrees off; I've had them with over 5 degrees error. Plus I like to dial in my cam timing for particular applications, once I determine what the actual timing of the cam I have in hand actually is.
So, I'm having this piece made for myself and some other colleagues, and it will be available to any other builder whom it will help. It's a hub adapter for fitting the later 4-rivet aluminum cam gears to the early-style 3-rivet cams.
And, it is drilled and tapped in a pattern that allows you to attach the gear to the cam in one of nine different positions, straight-up zero, or 2, 4, 6 or 8 crankshaft-degrees advanced or retarded. That gives a wide range of positions for correcting base cam timing or modifying it to alter the torque curve.
These will be available about a month from now, as a complete kit including the fasteners needed to install, all 12.9-grade button-head bolts (not the hexbolts shown in the picture). And of course there will be clear instructions how to install.
If you open an engine and it has a correctly-sized 4-rivet gear in it, you could go on and use that same gear on any camshaft you like using this adapter.
It allows adjusting cam timing during the build but is not adjustable thru the oil pump hole once installed.
I will offer a price-per-kit including shipping, as well as reduced pricing for small quantities.
Please PM for pricing info (which won't be nailed down for a few weeks anyway), but feel free to discuss or ask questions here.
