928Myles

I wonder how many 928's Porsche tested the new updated pullies on before they started selling them? My guess would be none.

Maybe we should all wait until those that have installed them have 10,000+km's on them before we use them as well?

As said above, there is a differrence between a design in theory and in application. It would seem to me that even Porsche didn't get everything right with these cars first time - why should we trust them this time?

I think that Carl should take the opportunity (if possible) to get these gears out on some non-interferance engines for real world testing. In addition, when he can get the 04 gear back he would be wise to compare the tooth profile with his new gear just to make sure nothing went wrong at some stage of the entire design/manufacturing process.

Just my 2 cents.

Myles

heinrich

Terrible guess there are many records and Porsche tested the engines for literally millions of hours before asking a customer to pay for them

Giovanni

I have not frequent this site in a long time but reading this thread with all the illustration reminds me of South Park. Not sure why...

Carl Fausett

Thanks for your support, Myles. Unfortunately, the 32v motors are 10:1; 10.1:1, and 10.4:1 compression ratio. Hence they are all interference.

I will be installing a pair on my own race motor, and on 3 engines that are in here for rebuilding currently. No problems.

Carl Fausett

From Post 92: From Post 91: If thats what you mean, then sure, I can do that easily. I will wrap a belt round my new pulley and photo it no problem tomorrow.

But I doubt it to end the questions. It is still the wrong price, I am told. And i have learned from experience that photos rarely end debate - they usually inspire more.

Because I do not have my Porsche 04 sprocket in my hands - can someone who has one to look at (and knows what to look for) tell me if it is a machined product or made from a casting?

GlenL

Ridiculous. That's over 100 engines running constantly for a year.

There are some critical parts that are aftermarket alternatives and listers promote them incessantly that had very little testing. After 5,000,000,000 miles (a reasonable estimate) there will be identified weak points in the cars. Innovative alternatives aren't a panacea.

A sprocket may have complex forms to design but if it fits it'll work fine. Carl's design roughly copies the existing design. Choose the right material and it won't fatigue. This has a high likelihood of being successful.

928Myles

"Terrible guess there are many records and Porsche tested the engines for literally millions of hours before asking a customer to pay for them"

Heinrich,
thank you - I was not aware that Porsche still had enough 928 engines around to TEST THESE NEW PARTS ON to this extent ! I guess this inspires confidence in their long term total support of the 928.

Education is a wonderful thing.

Myles

ROG100

As there are only 9 of the 04 gears here in the USA and I have 4 of them that could be difficult.
As I have been in the Aerospace machining industry for the last 10 years of my Corporate life and ran one of the largest machining houses in the USA would you take my word for the fact that they are machined. Frankly I don’t care if you do or you don’t.
I also know that no pulley stock exists that matches the tooth form on the 01 and 04 pulley. As I tried every avenue to find it in my quest to come up with an economically priced alternative gear.
Machined from solid with the exact same tooth form as Porsche brought the costs into the same realm as the Porsche gear.
Using pulley stock (close but no cigar) with a close resemblance to the 01 & 04 tooth form I could sell the gear for less than $200 without trying.
I talked with all the major cam gear manufactures and also many specialist gear shops to achieve this conclusion.
I may not be a member of the SAE but I am a hell of a buyer of product.

M. Requin

Carl, if it is 7075, as has been averred here, I think it cannot be a casting. It almost has to be machined from billet or finish machined from a forging. Engineers in residence, feel free to correct me!

SeanR

Where is Greg Brown on this, I'm slightly disappointed he's not put his expertise in here. I know he was working on getting these made and did have some good points in the deleted thread.

heinrich

but it isn't a new part to Porsche is it THey've been having these same gears manufactured to the same specifications since 1976.
Not ridiculous. The original design of which the new gears are the exact same, from a new manufacturer was tested for many many hours by Porsche. Did they test these new gears? The answer is: "Did Porsche ever sell any part that was not tested? If not, why would we assume that they would do so today? And does that mean Carl is a-OK in not testing a COMPLETELY DIFFERENT aftermarket part?"

GlenL

What?

You are conjecturing and making things up out of thin air. If you want to think they did a long-term test on a new part for a car that last was made in 1995, go ahead. They will have checked it against the print. They likely put it on a cam and fitted a belt to the teeth. I doubt they put it on an engine and fired it up. Why would they? It's a freaking sprocket!

Here's a clue: No company, anywhere, tests things for literally millions of hours. Whatever you want to think should be done, it isn't done. Period.

jeff spahn

Hell we didn't test our Tomahawk missile parts for anywhere near this long. Then again, they were a one use part. Only had to get the thing there.

yardpro

ok children... there is room in the sandbox for everyone, so play nice....

i don't see why there is the uproar...
here is a guy that is making a part that we all will need at some point, at a decent price point for the work and cost involved in making it... WHY would all you guys be busting his chopps.... must be something personal.....
did the release of the sharktuner have this much friction? heck.. it could melt out motors with super lean mixes, etc....
did the porken chips get this much friction? they could also toast a motor in a very quick time...

what about the MANY other enthusiast created mods/parts for our cars.... come on guys..
WE are a very small group, and there are some very creative talented individuals in this group.. WHY do we beat those up that come up with products that will help up keep our beloved rides going for longer...

i think that sometimes we can be like a shark thank here... waiting to pounce on those that are not in our click.....pitiful

heinrich

I may have exaggerated a tiny bit on millions. Point is the complete engines were heavily stress tested.