PorschePower

I'm developing a alternative cam drive system that will eliminate the timing chain and tensioner from 16V heads and replace it with an external belt drive. It would allow the use of heads that have the tensioner boss broken off, would be more reliable, and easier/less expensive to maintain. I'm expecting the it to cost about $700 to $900 and I a planning to have it ready around August or September. I just wanted to see if anyone else had any interest in it so I can decide if I want to put together more than just a few kits for myself.

944meister

these cars should have come from the factory with this setup. are you having special belts made?

john durdin

I would like to see what you end up developing. I have not had a problem yet , but it looks like weakness in the factory design , That could use a different approach. John

hacker-pschorr

Get your hands on some 928 heads - same overall design (different cam gears).

If your setup does work on the 944S, it could be adaptable to the 928 and you will have a huge market there.

fortysixandtwo

Will this be similar to the twin pulley setup that David Chen developed back in the late 90's? (two exhaust cams, with dual cam pulleys, that are smaller than stock [to clear the hood] and a matching crank pulley)

Jrboulder

This would be nice for a head that was wrecked, but there's nothing wrong with a well maintained cam drive setup on the 16v head. For $900 you could replace the chain tensioner twice...

Olli Snellman

Might be interested of this kind of setup

( Chris White built engine)

PorschePower

There are thousands of belts currently in production so the plan is to use a belt from another application to save the cost of having a custom belt made and ensure availability for future maintenance.

I am not familiar with that setup, but it is one of the design concepts being considered although I won't be using two exhaust cams.

My price target is actually lower than I stated. I am trying to be realistic, you can't design a quality system for pennies. It is easier to tell someone that it is going to cost less than they were initally told rather than come back with a higher price. I know people who race thier vehicles and replace their tensioner before every season. Even at $900 it would be more cost effective for them.

Thanks for posting this, I will need to research that setup. I am not interested in reinventing the wheel. If someone is already making a viable system, then I can just buy it from them.

Right now I am just focusing on 16V 944 heads. If it works out, I can always look at the 928 heads in the future if there is a need.

hacker-pschorr

Personally I don't see this as "fixing" the stock system, but giving us the ability to adjust the cams independently.

It's a bonus eliminating a system that is more prone to failure than a dual gear setup.

Not to mention when the stock system fails, it's a lot more than your head that's subject to destruction.
Less than 100,000 miles no my car when the chain snapped. This was less than 6 months after a dealership "inspected" the system and said all was good (this was 1998 or so).
My head wasn't damaged, my valves were not bent, both camshafts were destroyed - over $1,000 each from Porsche

pettybird

OK I'll take one of these.

gtroth

Not sure this system will be more reliable. Here's why-
Say we have 100 S's out there. 9 will grenade from broken timing belts and 1 from tensioner/chain failure in the next 10 years. Best you can do is go from 90% to 91% reliability if your your belt system is no less reliable than what the engineers at Porsche designed.
These numbers are made up to make the point, but you'll need to know them before you will know what you have done to the reliability.

944meister

the way i see it is, with this kit you are eliminating one of the two potential causes of failure: 1. timing belt failure 2. tensioner failure (caused by loss of oil pressure by a leak/crack in feedline, or failure of the tensioner itself). now if an existing timing belt application for this kit had a gates kevlar timing belt available, then we could address both issues.

dykaar

The sad reality is that the timing chains on my old Mercedes diesel and both the e28 535 and e39 540 will last forever, and the timing belts fail alla time, and you have to replace everything at half the recommended interval. Feh.

Regards,

doug

86 951 (http://www.pcaucr.org/visuals/photos...egory&catid=61)
01 E320 (W210) 4matic Wagon (http://www.benzworld.org/forums/w210...body-do-2.html)
00 540i-6 (http://forums.bimmerforums.com/forum...hp?albumid=976)
94 855 turbo Wagon (sold in 09)
85 535i-5 (sold in 07)
76 300D (sold in 92)
83 944 (sold in 86)
I apparently only buy cars designated by numbers

gtroth

Yes, we see it the same. Like most things in Engineering, until you hang numbers on it, you really don't know what you are talking about (to crudely paraphrase a quote by Lord Kelvin).
Might be irrelevant, but I always remember that chains are much more deeply embedded in the Porsche Engineering culture than belts, no doubt about that: