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crankcase volume
Posted: Sat Sep 14, 2013 1:27 pm
by mickdale
is it better to have more crankcase volume or does this not matter?
if using a 7mm packer and 115/116 rod i believe the crankcase volume is larger than std
if taking the packer away and using a piston with smaller crown height reduces effective volume - is this wise or to be avoided....
any thoughts greatly apprciated
regards
mick
Re: crankcase volume
Posted: Sat Sep 14, 2013 3:23 pm
by rosscla
On a 70mm bore you'll add approximately 26cc to the total volume of barrel and crankcase simply by adding the packer.
Dependant on the stroke the volume will be larger by more or less than that at BDC.
Other variables such as the shape and size of the crank webs need to be taken into consideration when looking at primary compression.
I'm sure there was a fairly long thread on here somewhere discussing the pros and cons of high versus low primary compression set ups.
Re: crankcase volume
Posted: Sat Sep 14, 2013 5:03 pm
by mickdale
thanks rosscla
60mm crank
will try and find the thread
Re: crankcase volume
Posted: Sat Sep 14, 2013 6:29 pm
by wack 63
It will definatly use more petrol

Re: crankcase volume
Posted: Sat Sep 14, 2013 6:43 pm
by Darrell Taylor
what exhaust you planning to use
Re: crankcase volume
Posted: Sat Sep 14, 2013 7:06 pm
by mickdale
wow - i didnt think there would be a difference in fuel consumtion (thank god for diablo tanks)
darrell - pm sent