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  #21  
Old 16th August 2021, 04:31 AM
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27litres 27litres is offline
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If I remember correctly from my casual reading of cam chains on 40V engines, there's a different link count between the left and right bank cam timing marks?

Perhaps when replacing the tensioners the first time the same link count was used on both banks?
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  #22  
Old 16th August 2021, 10:27 AM
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Quote:
Originally Posted by 27litres View Post
If I remember correctly from my casual reading of cam chains on 40V engines, there's a different link count between the left and right bank cam timing marks?

Perhaps when replacing the tensioners the first time the same link count was used on both banks?
That is indeed the case. 15 for the left side and 16 for the right side, as documented by MJ in post #3 in this very thread.

It does seem strange from a non-mechanic that there should be any difference between sides, so an understandable mistake to make.
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  #23  
Old 16th August 2021, 10:51 AM
MikkiJayne MikkiJayne is offline
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Cams timed incorrectly is not something you'd find in a working engine though. It'll run lumpier than school cafeteria custard if one of the cams is out by a tooth and the ECU will be very cross indeed.
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  #24  
Old 19th August 2021, 09:58 AM
ThisWayUp ThisWayUp is offline
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All good information thanks.

I've gone a bit wild and bought two new tensioners. Slight glitch being I forgot to get the gasket to go beneath each. All is not lost, as I've got those on order now, and in the meantime I've increased my available car tinkering time by painting the hall and the kitchen.

I was quite intrigued by the difference in chain link counts. It's one of those operations where the instructions are indeed mission critical.

In other news I now have the link bar for locking the cams (thanks MJ for the recommendation on source) and I'll be interested to double check how well it's aligned up in it's 'as-found' state.
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  #25  
Old 19th August 2021, 10:17 AM
MikkiJayne MikkiJayne is offline
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Quote:
Originally Posted by steamship View Post
It does seem strange from a non-mechanic that there should be any difference between sides, so an understandable mistake to make.
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Originally Posted by ThisWayUp View Post

I was quite intrigued by the difference in chain link counts. It's one of those operations where the instructions are indeed mission critical.
Its because one tensioner is upside down compared to the other, so on one side the adjuster foot moves on the top and on the other side it moves on the bottom. 15 links on the tensioning foot, 16 links on the adjusting foot. The head that has 15 links between marks has 16 teeth underneath, and vice versa.

Its all done like that so they can have one casting for both heads with machining differences determining which is which. Thats why one tensioner is on the front and one is on the back - the heads are basically the same part flipped 180 degrees, rather than mirror images of each other.
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  #26  
Old 19th August 2021, 10:34 AM
ThisWayUp ThisWayUp is offline
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Quote:
Originally Posted by MikkiJayne View Post
Its all done like that so they can have one casting for both heads with machining differences determining which is which. Thats why one tensioner is on the front and one is on the back - the heads are basically the same part flipped 180 degrees, rather than mirror images of each other.
Thanks MJ - Certainly a nice approach from manufacturing & engineering design perspectives. A reduction of 'simillar to' components is always good.
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