Hey guys, at the moment my Nova Keep Off 7 has 2 silver ( I think each is .2mm) head shims, so a total of .4mm head shim thickness. Can I remove one to test for power and performance changes? - Thank you!

Not sure bout d keep off but depends on the % of nitro u using, if nova c6 shouldn't be a problem.

Some taiwanese motor love higher compression ratio, not sure bout nova

I dont know about the Keep off engines, but Nova's typically come with .8mm shimming and after a few gallons you can remove a .2mm and add a .1mm to get to .7mm. Chances are you are missing something, or the brass shim is stuck to the head button.

My understanding was the .8 shimming is good for 30%, and .7 is just right for 25%.

Hence why I thought they came shimmed for 30. IF they now come shimmed for 25 (.7) then that would be different.

I have a brand new keep off 4 crank shaft that I sent to Lance at RcRenew to be silicone filled. Never used, never installed. Pm me if interested

Thats the thing, there is no brass shim. ONLY 2 silvers. I would like to remove one. Wats the worst that could happen? pre detonation? It actually sounds like then Im already running a high compression ratio with .4mm which is what I was thinking, but Id like to raise it more....

Actually to be honest Im just assuming they are .2 because I thought all silvers were .2 but maybe they are thicker like .3 or .4mm shims each making a total of .6 or .8mm.... I cant measure them at the moment

the silver shims are .3

The copper shim may be sandwiched between the 2 .30 shims.

The stock setup is 2 .30 silver shims and one .20 copper or brass shim for a total of .80.

Thanks so much guys! Cool, so now I know I'm running a .6mm stack. Have any of you run .3mm?

i have a plus 4 that has just about had it. i love the engine, but its time to move on. whats the closest engine to it currently? i love the fact of how smooth it is in my buggy and would like to get the same from my next mill.

plus 21-4btts?

lmk if you are looking for one

new engines are drnt bore x stroke , the mito4

piston will hit the squish band on head button , engine will be toast

Thanks Monty! looks like ill be leaving it alone lol

I saw a Mito 4 run a few weeks ago. It was so linear and smooth all the way from bottom to top. Im sure you wouldn't be disappointed at all. The guy running it claimed he was getting over 11 and 1/2 mins run time too :0 Could have been a crazy small venturi he was running.... idk