cam chain tensioner shoe - can it be improved?

[Goran]

Hello,

I know they rarely go wrong, and can last over 300k miles, but I cant help wondering if they could be made from better material?
It would be nice to replace them with better ones when doing the cam cover gaskets at some point in the future.

Would aluminium be a bad choice because it would cause wear on the cam chain? (aluminium being tougher than the nylon plastic used on oem shoe).
Also I guess the chain running over an aluminium shoe would generate a lot of aluminium dust which would end up in the oil.

Is there a better plastic that bends rather than breaks, and that would not become brittle from heat inside the engine? I read about glass reinforced nylon would that be good?

Just out of curiosity I bought one of these from ebay, I'm going to do some destructive testing on it to see if its any good.

http://www.ebay.co.uk/itm/Vw-Audi-ec...37252755803325

[Goran]

I have been searching around and a picture from this website gave me an idea. If someone could make us a aluminium or steel casting with the plastic wear surface locked in like in this picture, it would be unable to brake off at the edge.

http://www.murtfeldt.com/products/ch...el-c-profiles/


some more info (I'm bored )

http://www.eng-tips.com/viewthread.c...=292501&page=1

so from the above it appears the Audi geniune ones that are creamy in colour are probably made of Nylon 4.6 (the better stuff) and the darker colour aftermarket ones are probaby the older type of Nylon 6.6 with added graphite as per above forum. However those assumptions are just based on the colour of the different pads.

[Goran]

Another find. Porsche pads appear to be almost the same as our pads. Except ring on bottom one and no holes. I'm hoipng to get a couple to see if they are are the same dimension wise, a hole is easy to drill if needed.

Porsche pads are different, they dont fit Audi variator!
//Maybe another option for replacement with a genuie OEM part since Audi wont sell us their pads individually.
//UK:http://type911shop.co.uk/shop/articl...6aid%3D2887%26
//States:http://www.koperformance.com/part-nu...ENUINE-PORSCHE
//Porsche part no. is 99610525300
Porsche pads are different, they dont fit Audi variator!

Does anyone know what the hole is for on our pads? is there a oil squirter or someting in the variator body that squirts oil through that hole or something?



Message for Nollywood: please ask your engineering friend who may make pads for us to look into Stanyl Diablo (recently selected by Fiat) and Duratron CU60 (apparently one of the toughest high-temperature plastics).

http://www.quadrantplastics.com/eu-e...ron-R-pbi.html

http://www.dsm.com/en_US/html/dep/ne...nyl_diablo.htm

[Goran]

more info. Stanyl are still pushing PA46 as the way to go for chain tensioners. Looks like they are the suppliers to the factory that casts the chain tensioner pads (still havent found out who that is, could it be Borg-Warner?). Although I could be worng, other factories make a material called PA46 too but with different properties, for example:

http://www.piedmontplastics.com/prod...n-46-pa46.aspx
300F is only 148C, not much above engine operating temperature.


http://www.dsm.com/en_US/automotive/...ng_systems.jsp
"The material gives you solid performance across the engine’s lifetime when dealing with high chain tension"

I have to disagree with them, the pad failures that have been posted so far is proof to me that PA46 starts losing its structural properties after approx 100,000miles in a engine oil environment, which is hardly the lifetime of the engine. Unless our pads are made of some other weaker PA46?

[Goran]

I posted on the Porsche forum, they say that Porsche updated the material for their pads.

http://986forum.com/forums/performan...-cleaning.html

*edit* - I received the Porsche pads, they look very nice but shape is different they wont fit Audi variator

[Nollywood]

The best way to improve would be if the tensioners have three rollers (sprockets) for the chains to ride on. Less friction, though would be quite expensive to engineer as aftermarket items.