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Chain Slop

Posted by vbares 
vbares
Vittorio Bares
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Location: Londonderry, NH
Join Date: 04/10/2007
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Audi 4k (3b conversion)


Chain Slop
September 21, 2014 09:22PM
Thought perhaps someone here knows; I'm indexing cams on a 20vt setup, I've got 7a ex cam, w/adjustable gear and 3b in cam w/adjustable gear. Adjustable cam gear on the intake does not have timing marks for TDC (which should open at 3deg BTDC). So I'm indexing with a degree wheel, got the dial indicator extension such that it is accurate - however, what I'm running into is chain slop - do I set timing based on no slop, a taught chain? or ignore and set based on whatever sag is in the chain as I manually turn the motor?
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wildert
Brian Klausen
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VW Golf GTi 16V


Re: Chain Slop
September 22, 2014 01:51PM
Neither - you take out the cams, measure the run out of the gears, throw away the bad one and get a replacement, then get a new timing chain, and mount it all up nice and proper.

Why do I know? 'Cause my 16V had the same problem with two adjustable gears, and I had valves (french) kissing the pistons due to lack of precision in the timing.

Do it right, do it light - do it wrong, do it long...



Brgrds
Brian

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vbares
Vittorio Bares
Ultra Moderator
Location: Londonderry, NH
Join Date: 04/10/2007
Age: Possibly Wise
Posts: 413

Rally Car:
Audi 4k (3b conversion)


Re: Chain Slop
September 22, 2014 09:41PM
Holy Cow!!

I had a new chain on the shelf - you could see the stretch in a side-by-side comparison - then installed a whole new scenario - nice an tight.

Have not started indexing again, but wow - I'll never build a head without checking that part again - let alone the whole motor.

I could literally measure 9degrees of slop on the timing wheel before the new chain...first time doing this cam indexing thing - so pardon the educational euphoria winking smiley
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aj_johnson
A.J. Johnson
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88 Audi 80


Re: Chain Slop
September 24, 2014 12:12PM
Mine was really tough... what with one camshaft and all.
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john vanlandingham
John Vanlandingham
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Re: Chain Slop
September 24, 2014 07:46PM
Quote
aj_johnson
Mine was really tough... what with one camshaft and all.

Didya finally get it ibn the end?



John Vanlandingham
Sleezattle, WA, USA

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aj_johnson
A.J. Johnson
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88 Audi 80


Re: Chain Slop
September 25, 2014 01:31AM
Just started it an hour or two ago. Feels snappier- loads too much fuel as I reverted back to initial mapping.
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