heinrich

I want a chain. How to convince Porken to develop one ... hmmm ..... bribery? Flattery? threats? Swampland with development rights? Some of the crew at Specialists? .....

Jim_H

How much chain noise would there be?

You still need to drive the other pulleys.

goliver

On the BMWs you can't hear a thing until the chain gets stretched way out (read, the end of its service life) and the tensioner can't compensate or the rails are too worn. On my F250 you can't hear the chain althogh it is relatively short. I have a friend that switched to gear drive on his vette and that baby whines like crazy but sounds kinda cool at the same time. I couldn't live with it for a daily driver.

mpesik

ATTENTION!!!-ATTENTION!!!!................ HEINRICH WANTS A CHAIN!-----me too please.

goliver

Jim is right. It should read chains plural. How indeed do you drive the rest of the stuff. Multiple chains for the w/p, oil pump? Gets pretty complicated.

heinrich

belts a la 924 for the water pump and such are fine

goliver

Be fun to have a spare engine laying around that I could play with and see what I could come up with.

sweanders

Wouldn't the biggest problem with chain drive be the oiling of the chain and the extra ponies robbed by the chain?

heinrich

I've got spare ponies.

Jim bailey - 928 International

Anders makes an excellent point about a chain and the requisite OILING . Chains must be housed in a sealed housing 911 or inside the head block BMW , Mercedes as I recall or you will have oil everywhere . I think it might be easier to swap in a Cayenne engine than built a reliable chain drive. Not that that would be easy either.

PorKen

heinrich,

Gear conversion:
*Housing - fab
*Oil spray, return - fab
*Gears - source from industrial provider
*Tensioner - source from industrial provider
*Development time - unfortunately, this would never get past management (ie. honey bunny)

What I'd be satified with is a Kevlar (or similar new material) HTD belt, sourced from an industrial provider, along with a proper tensioner/damper assembly.

Normy

-What might be an interesting idea is some sort of chain that actually fits in front of the belt and drives only the cams. This chain wouldn't be primary- it would only serve as a backup, to prevent belt slippage. Belts very rarely break- what happens is that the pulleys jump a tooth or two, resulting in disaster. It would probably only take a very small chain to prevent such an occurance.

N!

FlyingDog

Normy, belt don't like oil and chains need oil. That's a problem if they are running right next to each other.

SAABs run two chains in the 2.3L I4s. One drives the cams. The other drives balance shafts on either side of the block. The biggest problem is the sprockets wearing. Once one starts to wear, the rest of the system wears with it. You end up with clicking and rattling, and a lot to replace. Of course this usually only happens at 150,000+ miles.

I think a chain is a good idea, but it will take a lot of development work to get the tension and materials correct for long life and low maintenance.

Voytek

Does anyone know what is approximate life on low millage TB (after correct tenssion was set on a new belt)? Apparently TB teeth begin to crack with time and they brake off. However, I have not found what is that time to tooth failure. As I recall, 4 years and 7 years hard life intervals are recommended by different sources. Best times without a failure I have heard of are 10 yrears (MikeN herein) and 9 yeas (32K miles) on mine. I know - it will be replaced next week (and I do hope I can get to the shop safely).

FlyingDog

I think Porsche recommends 60,000 miles or 60 months. Most people around here seem to recommend 40-48,000 miles and 48 months.