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All these size without air conditioning must have the replacement idler pulley.

I don't run this and go from the alternator across the standard idler to the crank.

With a 15% Pulley and I think a +2% Crank Pulley I am running a 850 mm belt.

Changing to standard diameter crank pulley and wondering how much this would change the required belt size??

Thanks
 

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Here's something else to bear in mind that I just noticed whilst stripping my engine oil pump plate off.
The lower idler pulley is screwed into the oil pump plate at the lower right hand side, however just next to this fixing hole there is another hole the same size but it has a counter bored face and should have a flat head torx bolt in it to hold the plate on. However in my car the pulley had been fitted to this hole and the bolt put in the one that should be the pulley hole, getting these two round the wrong way will shift the idler pulley slightly horizontally from where it should be and will alter the running position of the belt
Anyone else noticed the same? I didn't take note which way these were installed on mine when the oil pump plate was taken off, but fitted them the correct (bentley manual) way when putting things back together, and now the 1368mm belt which should fit won't go on...

I had a Gates 1368 belt with -17% s/c, +2% crank, +5% alt, worked perfectly with about half a hole showing on the tensioner. I've now changed the s/c to -15% and I was told by Kavs (bought all pulleys from him) that the same belt should fit, but it's not even close to going on. Putting a tape measure on the pulleys shows about 1380mm, and thats with the tensioner locked. Makes me think that the idler pulley may have been in the incorrect location... or can the s/c pulley change (-17 -> -15) make such a huge difference?
 

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Update on my belt demystifying project... I tried 1380mm on my car (-15, +2, +5), and even that didn't fit! Then I remembered taking pics of the belt and pulleys when I installed the +2 and +5, and looking at those it was clear that the idler pulley had originally been at the upper location. According to the bentley service manual it should be in the lower... the upper hole is even countersunk for the bolt that is used to attach the timing chain cover to the block. But switching the idler to the upper location (and the bolt to the lower) resulted in the 1368mm fitting like a glove! Just like it should according to Kavs.

I wonder if the bentley service manual is wrong, or if the design was changed at some point...


 

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Reviving an old thread here as I'm getting myself confused over what belt to order with my aircon delete pulley (makes sense to renew the belt whilst it's being taken off).

My car has (should have) a 17% pulley and a 22% Franck according to the receipts. What belt do I need to order?

6PK1368 or 6PK1360?
 

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Hi all sorry to revive an old thread. I was about to replace the pulley and belt so measured across the diameter and it's 56mm. As I'm also getting 13.8psi of boost at 5800rpm does that mean this is a reduced size pulley already? Thanks in advance for three reply
 

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Possibly, but.....don't think of boost pressure as a good thing as such. It's a measure of inefficiency when you boil it all down. Think of it this way. If you take off a stock head and replace it with ported the engine will make more power but you'll see less boost pressure as its more efficient. What I'm basically saying is dont assume, take measurements and have a good rake about before changing anything :)


Hi all sorry to revive an old thread. I was about to replace the pulley and belt so measured across the diameter and it's 56mm. As I'm also getting 13.8psi of boost at 5800rpm does that mean this is a reduced size pulley already? Thanks in advance for three reply
 

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I'm going to be swapping some pulleys in the near future... current configuration is -15% SC / +2% CP / +5% alternator and I've been using the Gates 1368. It leaves half a hole visible and does not slip

I'm replacing the Kavs solid +2% CP with PRW fluid damper (for less NVH) and putting a -17% on the SC. So it will be -17% SC / stock CP / +5% alternator. Would 1360mm belt be a good guesstimate?
 
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