Cam Gear Thread
#31
I'd be willing to take a chance on Carl's tooth profile, but I can't afford those prices. I'll have to rely on used cam sprockets and a 20k belt change interval instead.
If you are interested in such a program, PM me.
#32
Carl,
In the interest of healthy debate, could you take a new Gates or Porsche belt (NOT conti), and lay a new/good used Porsche gear on the belt (smooth part of belt on counter). Then do the same with your gear. Taking high quality macro photos from one side with a light shining on the back.
the same thing again but with 3/4" wrap around the gear itself.
This will help to show some of us how the teeth engage the gear, and will be able to better judge the possible weak areas.
My biggest concern right now is the tooth profile on the gear allowing/causing the tooth to slightly roll. I worry about this as it may stress the tooth causing it to separate from the belt.
In the interest of healthy debate, could you take a new Gates or Porsche belt (NOT conti), and lay a new/good used Porsche gear on the belt (smooth part of belt on counter). Then do the same with your gear. Taking high quality macro photos from one side with a light shining on the back.
the same thing again but with 3/4" wrap around the gear itself.
This will help to show some of us how the teeth engage the gear, and will be able to better judge the possible weak areas.
My biggest concern right now is the tooth profile on the gear allowing/causing the tooth to slightly roll. I worry about this as it may stress the tooth causing it to separate from the belt.
#34
I see the point Carl is making here, the Porsche gear in the pics he is showing for comparison is of the old Porsche cam gear not the revised one. Maybe Porsche changed the tooth profile slightly to help reduce wear?
Great work Carl, I know the R&D is costly on this, but any thoughts on a reduced price and going higher volume? I know the MSRP is $413 for the Porsche gear, but it is available through our venders here for the same price as yours. If you could whittle this down a bit you could sell a ton of these as they are a wear item.
Great work Carl, I know the R&D is costly on this, but any thoughts on a reduced price and going higher volume? I know the MSRP is $413 for the Porsche gear, but it is available through our venders here for the same price as yours. If you could whittle this down a bit you could sell a ton of these as they are a wear item.
#36
From just a pure theory standpoint, the hard-anodizing process should be a superior process to whatever Porsche is using at this time. 6061-T6 is also a very strong allow, with good machinability and corrosion resistant properties. Tooth profile differences aside, the materials used in Carl's gear should be better than the new Porsche part. That in no way is an endorsement, as I have no way of verifying the accuracy of the tooth pattern, keyway.... etc, but from pure materials standpoint, it would appear to me as though that portion of the project is well selected. It is the material and treatment process I would have used for the wear portion of the gears if I was making them.
#38
I've been running belt drives on my Harleys for over 40 years. Based on the information Carl has provided, I'll buy his gears before I'd buy from Porsche. Carl has INHO produced a superior product, that in the long run will be cheaper and less prone to stripping the teeth off of the belt. Plus the gears are beefer, and use a better alloy. I only want to have to replace the gears once.
I don't know if you guys re aware of this but detergent oil on Gates HTD belts will cause failures. On the old Harleys we had to block off the chain oilers. Gates found that the detergents in the oil caused the belts to delaminate, and shread, or break. Also they went from square teeth to round teeth, and heat was also a problem, in enclosed aluminum primarys, with electric start bikes. This was all harleys had dry clutches. A belt drive wasn't available for Sportsters till the 90's.
All new Harleys can be retrofitted with primary belt drives, but they must run in a special oil from gates, that is nondetergent, yet provides gripping power for the new style wet clutches.
I only added this comment about the belts because some of the cars have oil leaks, and if the high detergent oil gets on these belts it may be a cause for failure that most here don't know about. Our timing belts are made the same way primary, and final drive belts for Harley are made. Prolly have the same tooth profile. The cost is about the same also.
BTW, the final drive belts on Harleys, last almost forever.
I don't know if you guys re aware of this but detergent oil on Gates HTD belts will cause failures. On the old Harleys we had to block off the chain oilers. Gates found that the detergents in the oil caused the belts to delaminate, and shread, or break. Also they went from square teeth to round teeth, and heat was also a problem, in enclosed aluminum primarys, with electric start bikes. This was all harleys had dry clutches. A belt drive wasn't available for Sportsters till the 90's.
All new Harleys can be retrofitted with primary belt drives, but they must run in a special oil from gates, that is nondetergent, yet provides gripping power for the new style wet clutches.
I only added this comment about the belts because some of the cars have oil leaks, and if the high detergent oil gets on these belts it may be a cause for failure that most here don't know about. Our timing belts are made the same way primary, and final drive belts for Harley are made. Prolly have the same tooth profile. The cost is about the same also.
BTW, the final drive belts on Harleys, last almost forever.
#39
You have a new one in the garage, its from Docs GT with a broken piece of camshaft inside it. But the tooth is still brand new.
Its hanging on the wall next to the maroon sit seating on top of the red parts cleaner.
ALi
#41
These are new 01 Wheels bought in 2003. Porsche has not changed the tooth profile. The cogs in question have a different profile because the people involved cannot see the details of the change. Many people operate this way, and it just.... is. Whether or not this completely different profile is good or a bad thing will not be seen until testing, which we know didn't happen.
#43
If you look at the attached picture, the red would be the cam belt tooth.
On the factory gear you can see that the tooth is much more encased in the gear (arrows)
On Carl's gear, you can see where the tooth meets the belt is not fully cased, and this will cause the tooth to roll, causing the tooth to want to separate from the belt.
If you look at an older belt, this is how they begin to fail over time. If you are using high performance cams this will be further exaggerated due to the additional loading.
On the factory gear you can see that the tooth is much more encased in the gear (arrows)
On Carl's gear, you can see where the tooth meets the belt is not fully cased, and this will cause the tooth to roll, causing the tooth to want to separate from the belt.
If you look at an older belt, this is how they begin to fail over time. If you are using high performance cams this will be further exaggerated due to the additional loading.
#44
BC,
Thank you for those photos.
The latter shows what I am referring to.
I have added two arrow that show there is very little gap holding the tooth tight and preventing the tooth from trying to rotate.
Thank you for those photos.
The latter shows what I am referring to.
I have added two arrow that show there is very little gap holding the tooth tight and preventing the tooth from trying to rotate.
#45
If you look at the attached picture, the red would be the cam belt tooth.
On the factory gear you can see that the tooth is much more encased in the gear (arrows)
On Carl's gear, you can see where the tooth meets the belt is not fully cased, and this will cause the tooth to roll, causing the tooth to want to separate from the belt.
If you look at an older belt, this is how they begin to fail over time. If you are using high performance cams this will be further exaggerated due to the additional loading.
On the factory gear you can see that the tooth is much more encased in the gear (arrows)
On Carl's gear, you can see where the tooth meets the belt is not fully cased, and this will cause the tooth to roll, causing the tooth to want to separate from the belt.
If you look at an older belt, this is how they begin to fail over time. If you are using high performance cams this will be further exaggerated due to the additional loading.
Maybe the more parabolic shape of Carls gear allows the belt to depart from the pulley better without rubbing the shoulder of the gear tooth opening ... and maybe an old belt tooth fails because it does rub on the more closed profile standard pulley shoulder. Maybe the new pulley profile would wear less on the shoulder and cause less distress to the belt.
The only way you'd really know how a belt behaves dynamically under different loads and RPM, and whether the changed profile is a good or bad thing, would be to use high speed photography.