zd30 crd drive belt noise

hi all,
so some time ago i heard a chirping noise turned out to be the alternator pulley so i replaced it and while had it off i thought why not put a new drive belt on it.
tensioner assembly is new and genuine also.
i used a new dayco 7pk1640
previously had a genuine nissan one on there still great but thought ill rotate it to a spare.
after some time im getting belt noise sound like a slip or squeak
so i pulled the belt off and went back to the old genuine on and all good now.

the genuine is a 7pk1646, i see all after market belts listed for zd30 crds are either 7pk1640 or shorter like 1637 or 1635

why does the longer genuine belt go fine but the shorter aftermarket belts sound to be making a slipping squeak?
doesn't make sense.. i was close to removing the dayco 7pk1640 to fit a 1635. but the longer genuine belt is noise free.

ive read everywhere that these engine love genuine belts and i will keep using genuine now, and keep the dayco as a spare cause it will work in a pinch.

Attachment 81528

I was told by an "expert" that the Patrol pulleys have a unique pitch and that the only belt that lines up properly is the original belt. Don't know if this is true but I have tried a number of belts over the years and the only one that works without squealing is the original. Go figure!?

Quote:

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Originally Posted by Fireblade

hi all,
so some time ago i heard a chirping noise turned out to be the alternator pulley so i replaced it and while had it off i thought why not put a new drive belt on it.
tensioner assembly is new and genuine also.
i used a new dayco 7pk1640
previously had a genuine nissan one on there still great but thought ill rotate it to a spare.
after some time im getting belt noise sound like a slip or squeak
so i pulled the belt off and went back to the old genuine on and all good now.

the genuine is a 7pk1646, i see all after market belts listed for zd30 crds are either 7pk1640 or shorter like 1637 or 1635

why does the longer genuine belt go fine but the shorter aftermarket belts sound to be making a slipping squeak?
doesn't make sense.. i was close to removing the dayco 7pk1640 to fit a 1635. but the longer genuine belt is noise free.

ive read everywhere that these engine love genuine belts and i will keep using genuine now, and keep the dayco as a spare cause it will work in a pinch.

Attachment 81528

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They certainly do love genuine belts. I believe this isn't related to the length but rather the smoothness of the ridges on an aftermarket belt. The tensioner will take care of a little extra length

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Quote:

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Originally Posted by Mcflurry

They certainly do love genuine belts. I believe this isn't related to the length but rather the smoothness of the ridges on an aftermarket belt. The tensioner will take care of a little extra length

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7PK tells you its 7 rib and the the 1646 part is the metric outside length. As to why the shorter belt squeaks? Probably due to the belt material. Rubber ain't rubber. Belt groove pitch is identical. I've sold hundreds of 7PK1640's, in Gates brand however without one issue. Gates do make a 1645 aswell but for some reason list the 1640 for the Patrols.

Also the PK part tells you the pitch of the belt. Distance from groove to groove. All automotive belts are PK, its a world wide standard. Industrial can be PJ, PL or PM.

interesting, i might give a gates belt a shot in the future.
thanks