Crankshaft pulley and oil leaking

[CG901]

I have searched the workshop manual but don't see an illustration of how the crankshaft pulley impacts the oil seal. I had a new aluminum crankshaft pulley made but not anodized. I am being told the anodizing is absolutely necessary to eliminate the wear on the pulley v-surface which can wear quickly and cause undue noise from the belt, also lack of anodizing will cause problems with the oil seal.
Anybody have experience with this? Thanks - Scott

[45bvtc]

Cast iron Scott, cast iron: NO Cheshunt and/or Wymondam factory twin-cam engine left the factory with an aluminium crankshaft pulley and I do wonder why that was?

[RichardHawkins]

Scott,

I have no experience of aluminium crankshaft pulleys. However, as a student I think I remember my metallurgy lecturer telling us that anodising had three purposes.

To enhance corrosion resistance.

To create an attractive finish (usually coloured anodising)

To produce a hard wear resisting surface.

Like most things it will be more complicated than my what I can remember. There are many different grades of aluminium all of them designed for a particular purpose.

In short I expect the advice about having it anodised is correct, but you probably need to research the grade of aluminium you need.

Richard Hawkins

[CG901]

Thanks to Richard, et al. Anybody see why the type of metal on the pulley may negatively affect the oil seal?

[Chancer]

2 possibilitys.

The surface finish of the turned aluminium pulley is unlikely to be as fine as specified by the seal manufacturers and will probably wear the seal, the standard pulleys are surface ground in this area which unless things have changed cannot be done to aluminium, in any case it will just go into a CNC machine as a block of alu and come out a turned pulley.

The hardness of the material may not be sufficient without anodising to resist being worn down by the seal, even hardened steel shafts have worn ridges from seals in use.

[robertverhey]

Third possibility....a speedi-sleeve where the seal runs

http://www.skf.com/au/products/seals/in ... index.html

[alan]

with the pulley hard anodized, i think the seal dia can be polished