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(Yet another!) valve clearance question.

Posted: Fri Aug 18, 2017 12:43 pm
Author: Grog
Folks;

As it's the height of August and therefore raining I thought I'd sort out the annoying tappety noise from the top end - a couple of the shims are slightly undersized (now there's a novelty!) so time for a swap. Having measured them up and checked the adjustment matrix, if I'm reading it right the recommended replacements will leave me with 0.05 gap, e.g. current gap 0.2 with a 250 shim, recommended replacement 265 shim, new gap 0.05 if my GCSE maths is correct. So here's the question - given that gaps will only ever close, is it worth putting a slightly thinner shim (a 260) in to give a 0.1 gap instead of a min 0.05? I know it's Friday, so sorry for all the numbers...

Re: (Yet another!) valve clearance question.

Posted: Fri Aug 18, 2017 12:56 pm
Author: Julian_Boolean
In my opinion you should get them as close as you can to the max recomended clearance (I can't remember what this is) if you want to leave them as long as possible between changing them.
If they are on the minimum clearance you will get slightly more lift and maybe a slight increase in performance.

But wide clearance = noisy top end

Re: (Yet another!) valve clearance question.

Posted: Fri Aug 18, 2017 1:01 pm
Author: warren3200gt
Wasn't the recommended clearance increased from .05 to .08 < .18 because .05 was considered too tight? I always aim for the mid point but others have advised to aim for the larger gap, don't recall the reasoning though.

But Julian obviously does! :D

viewtopic.php?f=4&t=40901 this may help you especially the second post.

Re: (Yet another!) valve clearance question.

Posted: Fri Aug 18, 2017 4:22 pm
Author: kev edwards
I always aim between 0.10 and 0.15, never any less.

Re: (Yet another!) valve clearance question.

Posted: Fri Aug 18, 2017 8:10 pm
Author: chrisu
0.1

Re: (Yet another!) valve clearance question.

Posted: Fri Aug 18, 2017 8:15 pm
Author: ADRIAN H
0.1

Re: (Yet another!) valve clearance question.

Posted: Fri Aug 18, 2017 8:56 pm
Author: zed1015
0.10mm minimum.
Ideally aim for 0.15mm.
For high lift cams you can go to 0.20mm.

Re: (Yet another!) valve clearance question.

Posted: Sat Aug 19, 2017 8:54 am
Author: Grog
Thanks chaps - thinner shims it is then!

TTFN Grog