Which serpentine belt to buy? 7PK 1470?

[carabuser]

I'm looking at changing the serpentine belt, idler and tensioner on my 35i for preventative maintenance.

The belt on the Z4 is listed as "7PK 1470" but I can't find a 1470 Contitech belt, only Meyle or Bando.

Is it just the case that the 1470 part is only available as a BMW branded Contitech part? The closest Contitech part i can find is the 1473 which is 3mm longer, this doesn't sound like much but I'd rather not have a shredded belt due to slipping.

 

[fmorelli]

Has anyone installed the Vargas shotgun yet?

After getting the pump mounted and the fuel and coolant lines done so basically the "last" step was getting the belt on. I was under the impression that the kit would come would a slightly longer belt to accommodate for the extra pulley... I saw its noted that the stock belt included will work...

www.spoolstreet.com

that should help. I'd run the 1473 probably.

 

[fmorelli]

Also note ... part no crossovers here: https://www.ebay.com.au/itm/163826366219

 

[carabuser]

I saw that thread and noted that a larger belt was needed for the additional hardware being added. Is the 3mm length increase inconsequential on a stock setup?

I found the idler part from INA which saves £30 but the tensioner looks to be BMW only too. The change on my 335i was much cheaper as everything is available OEM.

 

[fmorelli]

I think I read it was like a 0.21" difference

 

[carabuser]

I think I read it was like a 0.21" difference

I'll buy the BMW part for peace of mind.

Just while I've got your attention. Do you remember what seals your cam shafts had? Were they the steel ones or the new teflon parts?

I'm reading up about the cam ledge issues that some N54 suffered with and according to BMW they swapped to teflon seals some time in 2008 so all Z4s should have teflon but the only other Z4 owner that I know who has taken his head apart, Asbjoern, had the steel ones. I'm trying to work out if that's region related or if all Z4s have the old style.

 

[fmorelli]

My head has not come apart yet, so don't know. Good question, though!

 

[carabuser]

@fmorelli

My parts arrived from BMW. I have concerns about the tensioner though. Before I go to the hassle of pulling the old tensioner off and checking, do you think my tensioner looks OK?

Notice the lop-sided angle at which the pulley sits, is this a manufacture defect? I don't remember the 335i one sitting like that, i always thought both pulleys on the tensioner should be lined up.

 

[fmorelli]

Looks wrong to me.

 

[carabuser]

Looks wrong to me.

Think i figured it out. The pulley sits on top of a aluminium spacer which sits between the tensioner. It comes loose and can be re seated and it gets held flush when the tensioner is bolted to the block.

I took the pulley off and pried it apart and reseated it and it looks fine. I'll compare it to the one that comes off the car to make sure they are the same.

 

[carabuser]

Got it all sorted. The old tensioner had the same spacer but it was much easier to get seated so i reused that. I don't know how it got through quality control like that.

Belt has a slight wobble across the two pulleys on the tensioner but i'll put that down to fresh belt still having kinks from where it was folded. I did check all mating sufaces and even reseated it completely to make sure it was flush.

Procedure is almost exactly the same as the 335i just with 1 less idler and no steering pulley. Was a little easier as there's much more space up front once the fan is out.