Wrong part fitted - does it matter?

[belfry]

1978 911sc
Further to my post last week asking to borrow a fan pulley spanner, I ordered a new pulley and six pulley shims. Unfortunately I ordered the wrong part. I think I've ordered a pulley for a car with aircon. My car does have air con. It is about 2cm deeper. The section that holds the fan belt is identical to the old (worn) part. Can anyone tell me if there's a problem using the new pulley. It's on the car now and everything's working fine.

[Orangecurry]

What do you mean by '2cm deeper'?

The bit that's sticking out? Like an extra rim?

Put the old one next to the new one and take another photo.

My memory is telling me that Porsche changed the shape of something on this during 993 production, and so maybe all replacement parts (even for older cars) are changed as a result of lessons learned?

[belfry]

Yes, it sticks out further. I don't think it'll matter.
There was a choice of a pulley without "air injection" and a pulley with "air injection". I guess that means air conditioning.

The original part stuck out 2cm less.

[belfry]

Correct part (without groove for aircon belt)

[010101]

Air injection is probably about the emissions air pump. Not all sale regions would have needed it fitted.

[BrewsterBear]

The second groove is for the drive belt for the air injection pump which pumped fresh air into the exhaust ports to make emissions appear better. Most cars have since had this removed, especially in the UK. It is not needed to pass the MoT, sapped a couple of bhp, and was ballast to carry around. My car had the double pulley for many years without driving anything from the second groove. You'll be fine. It just looks a bit unsightly is all.

[johnmaddox]

I know they changed the pulley profile on the 993 as the original was wearing the belts prematurely. Had mine changed and new belts fitted many years ago.