jeyjey

It appears 9products is aluminium/aluminium, LR is aluminium/steel and DRS is aluminium/titanium.

I've got a stock valve-train so the centre material probably doesn't make much difference?

The 9products is the sexiest, but the gearhead in me really likes how the DRS is indexed.

Noahs944

Hmmmm, the 9products one I bought was around $500 cdn and I think it was worth it but haven't fired up the engine yet. The only "fault" I detect is the embossed TDC mark isn't there.

wildcat077

I'm using the Lindsey Racing unit , which is now going in it's third race engine.Looking at the current price at $325.00 US , i would
say it's reasonable.Not sure a titanium gear would make any significant difference , it's hidden by a cover anyways ...

Cheers
Phil

Perry 951

928 Motorsports has a stepped key that will give you 2 or 4 degrees +/-. Excellent bang for the buck if you're not changing cams.
https://928motorsports.com/parts/off...aft_keyset.php

jeyjey

Yeah that stepped key falls prey to my inner engineer: no matter how well it works in practice, it's still a hack. I just can't do it.

Perry 951

Your inner engineer should tell you that a woodruff key should bear no load so in essence your more expensive adjustable timing gear does the same thing at +/- 2 or 4 degrees. Just sayin. If that makes you squeamish, you should know that the vast majority of modern engines don't have keyways on the cam or crank.

I run one at +4 and it had a noticeable bottom end gain.

Chalt

What holds the modern gears still with no key?

jeyjey

Friction at the shoulder.

A sky-scraper is not held up by the bolts in its steel frame, but by friction between the frame members. The bolts are just there to maintain the friction.

But none of that matters to my inner engineer. My inner engineer is into elegance, and for all the positives of the offset key solution, elegance isn't one of them.

Gage

+1 on that. The off set key also moves the ignition rotor relative to the cap which doesn't seem ideal.
jeyjey, have your inner engineer speak with your inner machinist about broaching a new keyway (or several) in the cam gear bore. This is easily referenced off the belt "teeth" for set up, 3 or 4 degrees advance works best according to the local seat of the pants dyno. I have mine done on an EDM.

jeyjey

Oh great, you've woken up my inner machinist. He's now yammering on about how we should have bought a set of duMont broaches years ago....

V2Rocket

im a huge fan of the offset keys. the best bang for buck you can get on a 944 engine.

would it help your inner engineer to know the 944/928 offset camshaft keys offered are in fact Genuine Mercedes-Benz parts that happen to fit the Porsche engines?

jeyjey

Anyone have a gear off the car handy that can measure the width of the keyway and the diameter of the bore?

jeyjey

PET calls the key a "4 X 4 feather key", so presumably that's a 4mm wide, 4mm high square key.

So I think I just need the diameter of the bore....

Noahs944

yup

Noahs944

keyway 3.86 mm wide, cam gear bore 22.86 mm