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Piston to Cylinder Clearance.

Next in line in the "Low Budget" cylinder repair articles, is measuring the piston to cylinder bore clearance. There are few tools out there but keeping the budget in mind, not all of them will suit our purposes. Hence, a quick and easy way is to use piston fit fillers, something everyone should have in his toolbox. Piston fit fillers are cheap and very useful. You will need 0.002, 0.0025 & 0.003 inch fillers as these will cover most of your needs. 

You will have to measure the clearance on a 90 degree position in relation to the piston pin. Along the "boost" port is what I usually prefer. A 0.002 inch clearance is suggested for most engines (0.05mm) but consider going up to 0.003 inch (almost 0.08mm) as this will most probably save the race! 

Also check : 
a) Muriatic acid for removing piston deposits from nikasil cylinder. 
b) Cylinder honing

and a few more notes on piston fit fillers in the link below
Piston fit fillers.

Bye bye till the next time. :)


  1. When converting the suggested clearances from inch to mm I think a factor of 10 got lost.
    0.002" is approx. 0.05 mm, not 0.005 mm.
    I love your blog!

  2. Many thanks for noticing this issue! I've just edited the message with the correct tolerances. Cheers.


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