Worn shims - - Why?

[ventura ace]

Thanks Bernie. I don't think the cams are messed up. I'll take a closer look at them when I pull things apart, and if they need replacement, I'll cross that bridge when I get there.

Do you have some for sale? Mine are the PBS regrinds. The exhaust side is S2 (70-30), and the intake side is B3 (40-80). I would have to stay with regrinds, since the valve stems have been modified to fit the reground cam base circles (I could change the valves also, I reckon, or modify them back to match a full base circle).

A

[baltobernie]

No, I don't want to part with my new 40/80 IAP set without first giving them a try. It'll be another month before I'm up and running.

[kilrwail]

Thanks Bernie. I don't think the cams are messed up. I'll take a closer look at them when I pull things apart, and if they need replacement, I'll cross that bridge when I get there.

Do you have some for sale? Mine are the PBS regrinds. The exhaust side is S2 (70-30), and the intake side is B3 (40-80). I would have to stay with regrinds, since the valve stems have been modified to fit the reground cam base circles (I could change the valves also, I reckon, or modify them back to match a full base circle).

A

Alvon - Have you looked at Webcam? They will take your old cam, build it up and regrind to a new profile - about $200 per cam.

Peter

[So Cal Mark]

I offer that service at $100 per cam

[kilrwail]

That's a great price! My experience was with a pair of Porsche cams, shipped here in Ottawa.

[ventura ace]

Thanks for the inputs guys. I haven't determined that there are any problems with the camshafts yet. The pitting that I have found has been on the valve adjustment shims. I'll take a very close look at the camshafts when I remove them. Thanks for the resources, in case they need attention.

A

[Tappy]

Ace, i had exacly the same pitting on the 4th cylinder shim , mine was caused because the bucket didn't slide all the time causing a anoying noise(it got stuck and slammed back all the time) a little bit of sand that flew in when assembling might have been the cause , cleaning cambox and bucket solved the problem for me

[mdrburchette]

Love your cartoon Phillip!

[Tappy]

thx, i couldn't resist to grab that one

[pope]

Alvon, I think your shims just need a little Proactiv acne medication. Are they in their teen years?

[ventura ace]

Alvon, I think your shims just need a little Proactiv acne medication. Are they in their teen years?

Teen years! Multiply that by 2 or 3 to be closer to the age. I guess the acne turns to scars by then!

A

[So Cal Mark]

Since I constantly research engine issues, here is an update about zinc-phosphorous additives and cam wear from the latest edition of Engine Builder magazine.
"Proper zddp level in break-in oil is critical for controlling the break-in wear. Zinc concentration of 2500ppm will provide proper protection for the cam, lifters and valve train during break-in. Following break-in, flat tappet cams must use oils that contain the proper level of zddp anti wear protection or cam/lifter/valve train damage may result. The zddp concentration needed is determined by the valve spring pressure and engine rpm levels. For normal operation in a street driven flat tappet cam engine, 1600ppm of zinc will provide the proper level of protection. For high perf and racing engines, 2000ppm of zinc is preferred.
Racing oils should only be used for the racing applications they were intended. Race oils lack the necessary additives for longer drain intervals and detergents to keep street performance engines clean"

[Tappy]

well i've been following this oil discussions for some time now , even went on a search for those high zddp level oils , so far with little luck. Because shipping polecies restrain shipping the additive from the states i'm currently driving without . I believe there's one oil available for me (castrol i believe ) but it costs over 15$/liter , seems very pricey to me. So i did some extra research on additives and came up with some Teflon bases additives , amongst those there's one that has very good reponses. Its Fin 25 from a firm called Interflon.

Anyone has experiences with this kind of additive ?

http://www.interflon.net/en/AdditievenN ... htxt=fin25

[pope]

Tappy,
I am not sure its the same. You should some more research on teflon. I would think it makes it more slippery. Slippery is not what you want. Zinc is a metal that takes the pounding of your cams on the tappets.
I think teflon is more like a Moly additive.

What kind of oil do the diesel trucks in you country use? I would start there.

[Kevin1]

An interesting approach to getting the proper ratio of ZDDP and detergent additives, take from this discussion of proper oils from a Porsche forum. The full article is here: http://www.lnengineering.com/oil.html

"If adding oil additives isn't for you, alternatively you can use Mobil 1 MX4T or V-Twin, as these oils have significantly more additives. If you were to blend 50/50 regular Mobil 1 and the Mobil 1 V-Twin, you will end up with Zn and P in the 1400-1500ppm range, which is basically like a SJ or CI-4. Similarly, you can blend 50/50 Mobil 1 0w40 and Mobil 1 10w40 MX4T (4T Racing) giving you a good level of Zn and P, balanced detergency, and the proper viscosity for required by your 986 or 996 (and later) water-cooled Porsche. This way you are mixing two similarly formulated oils made by the same manufacturer and you are most likely to have predictable results, like we have seen previously when we tested 50/50 blends of Brad Penn 0w30 and 20w50 and then compared back to back with test results of running the 20w50 Brad Penn oils."