HPI F4.6 piston ring shims

[craig911]

ok i just took my engine to bits for cleaning and i noticed there were 4 shims totaling just under 1 millimeter in thickness what are they for and what would happen if i dont put them back in,

 

[ckeast420]

that engine has no piston rings,that is the shim for your cooling head,it shims your cooling head away from the combustion chamber,more shims=less compression less shims=more compression,you have to have atleast one shim to get a good seal but depending on your glow plug and your % nitro in your fuel you may need them all

 

[craig911]

that engine has no piston rings,that is the shim for your cooling head,it shims your cooling head away from the combustion chamber,more shims=less compression less shims=more compression,you have to have atleast one shim to get a good seal but depending on your glow plug and your % nitro in your fuel you may need them all

ok well i use a cool & medium glow plugs mccoy MC8 and MC9 and 20-25& nitro