Fronkenstein

If anyone would be interested in committing to a set of new CNC machined cam gears please DM me. Feel free to post questions here but please send commits via DM. Target price is $400 a set unless I can get 21+ commitments. The commitments will require 50%. Yes you guessed it, we're all funding it. This would be for a straight stock replacement of square toothed gears. Roger set me straight that roundies are available for a little over $400 a pair.

Fronkenstein

The Forgotten On

What material are they? Steel or alloy?

Fronkenstein

They will be alloy likely 6061 and hard anodized. As I discuss more with the experts out here the consensus is not to waste time with square tooth gear sets since the round tooth pattern is superior. So unless there are a lot, meaning 21 of us, are too lazy to upgrade to round tooth it is sounding like this doesn't make sense. And that pursuing an adjustable round tooth gear set is the way to go.

Fronkenstein

SeanR

Aren't these still available for around $200.00 a piece from Porsche?

Mrmerlin

I would suggest to regear the engine and swap to over to the HTD gears ,
the square tooth gear drive is old school

M. Requin

I would strongly suggest you 7075 rather than 6061, it's a much harder alloy.

Fronkenstein

Yes! That's the intent. I forgot to update that. I will have a cost on building adjustable gears later today They will be similar to 9 Products.

Fronkenstein

hacker-pschorr

7075 won't last much longer than 6061 if the coating fails.

Hard anodized 6061 is commonly used in camshaft gears.
7075 is stronger, but when was the last time someone physically broke a camshaft gear? The issue is surface wear, which is 100% up to the coating to protect against.

Few years ago I was on the same path to make some gears, I sat down with a metallurgist who specializes in gear sets. 6061 was his recommendation. If you stress a 6061 gear to failure, the camshaft or belt will snap first.

Twin Turbo Todd (the metallurgist I talked to about this) is running arguably the tightest valve train known to the 928 world. His 100% stock gears are holding up just fine - and those are cast aluminum, much weaker than 6061 gears would be.

Fronkenstein

My guy uses 7075 and stage 3 hard anodizing so that's what we're going to use as a prototype. As you pointed out Eric what's really important is adjustability, being able to dial in the valve train. This will be a moot point if I can't get 30 16V lovers to commit to the $s necessary to make it happen. I am not going to tie up $12K on the if come of cam gear sales. And what's more as a group effort we get them at cost

hacker-pschorr

Oh come on, that's chump change. You cannot even buy a decent 928 for $12k anymore

Fronkenstein

Well having just purchased 2 more euro cars, for what reason I don't know,, I need that $12K just to fix one

Lizard928

I would strongly urge those needing new gears to just upgrade to the 83+ HTD gears instead.
I do like your thoughts about doing this, but the newer belt is a better belt, and the other parts are available.

Fronkenstein

Sorry not familiar with HTD term. If you are referring to round versus square, these will be round. I changed the direction as indicated above with input from Eric and Stan. Initially I was going for the lazy way out

Lizard928

HTD is the round tooth design.

Mrmerlin

HTD = Hi Torque Drive,
belt tooth designation for the round tooth belt
HTD® Timing Belts feature a curvilinear tooth profile, which is a design advancement over the standard trapezoidal shaped belts. The curvilinear profile allows the belts to have a much larger contact area with the pulley, which improve performance. Some of the advantages of HTD® belts are as follows:

Advantages of HTD® Belts

• Proportionally deeper tooth; tooth jumping or loss of relative position is less probable.
• Lighter construction, with correspondingly smaller centrifugal loss.
• Smaller unit pressure on the tooth since area of contact is larger.
• Greater shear strength due to larger tooth cross section.
• Lower cost, since a narrower belt will handle the same load.
• Small installation tension results in light bearing loads.

(HTD: High Torque Drive) offers especially good protection from timing belt ratcheting. This is thanks to the height of its teeth and their semi-rounded geometry. However, because of the larger timing belt teeth which require substantial clearance (generating backlash) to enter and exit the pulley groove cleanly. The HTD profile is typically used on applications that require minimal positional accuracy. The HTD profile or curvilinear profile is admirably suited to transmitting high torque.