Cam Gear Thread
 

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It was probably requested to be closed. Since there was some personal bashing.....

I'm not surprised it got removed. Nevertheless, I would like to see results and test data to be comfortable enough to buy them. Have they been installed on any 928 and for how many miles have they been tested? Why would this product be a better buy from the current NEW design from Porsche, since the prices are the same? What will I gain by using these vs the NEW factory ones?

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missed the original thread.....who is making the alternate to Porsche?

Carl presented an alternative that he had build, but it seems he was not aware of the new parts from Porsche, the tooth profile was questioned, and some claims he made regarding advantages were bashed by the usual bashers. I did not look at his price, but I gather it was similar to the Porsche part.

The tooth profile did look different, a little bit. could have been the angle of the camera. A better comparison would be to put the gears on top of each other, Porsche vs Motorsports, to see if the profiles are the same. The link provided above has the pictures.

thx Roger et al........not taking sides as I didnt see the original thread but one of these days the usual suspects (doubting thomas) will piss off the small amount of excellent suppliers we have today leaving us with nothing but Camrys.

no offense to anyone named thomas unless of course theres also a john involved; Roger will know the rhyme.

I have a set I bought new in 2003. I also have a set I have just taken off a 31k mile engine. The coating on the 31k ones are perfect, hard, and green. I will have to figure out what to do with the "newly" purchased ones- they do not look as though they will last.

I just bead blasted and wire polished a used gear. I also brush polished some other aluminium parts like water bridge. Without a doubt, the original gear is the softest aluminium part I have seen. That coating is no more than good powder coat, but once worn off, it almost appears to be designed to destroy the belt.

I'm pretty sure the original gears that are no longer available were made from some sort of Magnesium alloy. Probably why they are so soft.

The new gears however could be Aluminum, since they weight more.

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Everything I've ever ordered from Carl has had some sort of issue. I would never trust him to design a critical engine part for me. If I have the choice of ordering a part from Carl or a part from Porsche for close to the same price, there is no question. I would order the part from Porsche.

It's hard to tell from the pic's, but this might help. I took one of the pic's (as indicated) and did some simple cropping and rotating, to get the two tooth profiles aligned so that they can be compared easier.

For sure the new sprocket is not the same profile as the Porsche sprocket shown in the lower pic-- more "V" shaped vs "U". I do not know if it is significant or not, but it would be a source of discomfort to me.

Attachment 588280

Attachment 588281

Doing further photo editing, it appears as though the valley has the same curvature from stock to new.
However the walls are much more inclined, this would mean that they would be more prone to the belt teeth slipping out. Meaning that a loosely tensioned belt would be more prone to skipping a tooth or more.

The other thing that was almost impossible to tell and especially from a photo is the depth from the peak to valley. It looks close, but appears to be ever so shallower, which would mean more stress on the teeth of the belt.

Isn't there an alternative belt tooth profile that has a shallow V at the top of the tooth?

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.