Valve Shim Query

[eddohawk]

Hi there

Well I've just spent today measuring my clearances (3 times) and have filled in the very useful spec sheet I found in these forums.  I was surprised to find most of the clearances were to tight. In some instances the shim sizes needs to drop from .280mm down to .230mm! This seemed a big change to me and was wondering if anyone else has ever had such a big change in shim sizes.

Regards and happy new year

Mark

[mz_rider]

Hi there

Well I've just spent today measuring my clearances (3 times) and have filled in the very useful spec sheet I found in these forums.  I was surprised to find most of the clearances were to tight. In some instances the shim sizes needs to drop from .280mm down to .230mm! This seemed a big change to me and was wondering if anyone else has ever had such a big change in shim sizes.

Regards and happy new year

Mark

Mark,

Valve clearances tend to close up rather than widen. This is because the wear in the cam is less than the amount the valve pushes it way into the cylinder head.

I've checked an adjusted the valves on the older of my two FJs for 100,000 miles and over that period most valves have had a one shim change and a few two - always a single size smaller (0.05mm). The shim number is in hundredths of a mm eg 250 = 2.50mm. Do you need a change from 2.80 to 2.30mm? this is 10 sizes!

Stuart

[racerman_27410]

Hi there

Well I've just spent today measuring my clearances (3 times) and have filled in the very useful spec sheet I found in these forums.  I was surprised to find most of the clearances were to tight. In some instances the shim sizes needs to drop from .280mm down to .230mm! This seemed a big change to me and was wondering if anyone else has ever had such a big change in shim sizes.

Regards and happy new year

Mark

when was your last valve check /adjustment ? 

the more history one has with an engine the more one can either be worried or relieved 

KOokaloo!

[eddohawk]

Hi again

Thanks for your replies.....I've rechecked my calcs and I need to go back to school and relearn decimal places!

Regards and thanks

Mark