PermaBanshee Posted February 10, 2017 Report Share Posted February 10, 2017 Sorry for this noob post, but i can not understand what a ''4mill'' is, specially stroker build...and whats the difference between 421 cylinders and a 4mill setup. hope you guys can help me, thanks. (i understand that is more CC like 392, 421...but how you get more CC with a longer rod and same bore?) sorry for my english and nice forum Quote Link to comment Share on other sites More sharing options...
SlowMoe Posted February 10, 2017 Report Share Posted February 10, 2017 4 mill means the stroke has been increased by 4 millimeters, from 54 to 58 Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
hoppedupandcutdown Posted February 10, 2017 Report Share Posted February 10, 2017 Study this, should help http://www.bansheehq.com/forums/uploads/1337137915/gallery_8710_195_48423.png 1 Quote Link to comment Share on other sites More sharing options...
PermaBanshee Posted February 10, 2017 Author Report Share Posted February 10, 2017 4 mill means the stroke has been increased by 4 millimeters, from 54 to 58 Sent from my iPhone using Tapatalk Yes, I understand that, but how do you get this extra stroke with a longer rod and stock cylinder? by a more diameter crank? thanks for the reply Quote Link to comment Share on other sites More sharing options...
ban565 Posted February 10, 2017 Report Share Posted February 10, 2017 Sorry for this noob post, but i can not understand what a ''4mill'' is, specially stroker build...and whats the difference between 421 cylinders and a 4mill setup. hope you guys can help me, thanks. (i understand that is more CC like 392, 421...but how you get more CC with a longer rod and same bore?) sorry for my english and nice forum A longer rod does not increase the cc. Only bore and stroker crank will increase cc. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted February 10, 2017 Report Share Posted February 10, 2017 When someone says any "X" mil, they are referring to the additional stroke. If it's a 4 mil that means 4 mm more stroke over stock. And so on for 5, 7, 10, etc. Stock Rod length is 110mm. Typically when you hear long rod thrown out as a term, they will mean 115mm rod. The theory is the longer rod puts less stress on the piston and have a longer dwell time. There will be different pistons to run a longer rod. 421 will typically be 4mil crank, 68mm bore. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted February 10, 2017 Report Share Posted February 10, 2017 Thank you Quote Link to comment Share on other sites More sharing options...
Keno Posted February 10, 2017 Report Share Posted February 10, 2017 Yes, I understand that, but how do you get this extra stroke with a longer rod and stock cylinder? by a more diameter crank? thanks for the reply The pin for the connecting rod is moved 2mm out on the crankshaft web. This gives an additional 2mm up travel and an additional 2mm down travel of the piston. So 2mm+2mm=4mm Sent from my XT1585 using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
PermaBanshee Posted February 11, 2017 Author Report Share Posted February 11, 2017 The pin for the connecting rod is moved 2mm out on the crankshaft web. This gives an additional 2mm up travel and an additional 2mm down travel of the piston. So 2mm+2mm=4mm Sent from my XT1585 using Tapatalk thaaaats it, that's the answer i was looking for...thx for all the replys guys. i already understand that +4 mean extra stroke but my question was about the point on putting a longer rod, I could not understand how they got that extra stroke with a longer rod, now i understand with a ''bigger'' crank... sorry for my english again xD Quote Link to comment Share on other sites More sharing options...
PermaBanshee Posted February 11, 2017 Author Report Share Posted February 11, 2017 When someone says any "X" mil, they are referring to the additional stroke. If it's a 4 mil that means 4 mm more stroke over stock. And so on for 5, 7, 10, etc. Stock Rod length is 110mm. Typically when you hear long rod thrown out as a term, they will mean 115mm rod. The theory is the longer rod puts less stress on the piston and have a longer dwell time. There will be different pistons to run a longer rod. 421 will typically be 4mil crank, 68mm bore. ye, now i already understand what a 4mill is...the second question was about how people get that +4 setup with a longer rod (''4mill longrod setup'')...i got my answer by @keno , with a bigger crank Quote Link to comment Share on other sites More sharing options...
ClaudeMachining Posted February 11, 2017 Report Share Posted February 11, 2017 ye, now i already understand what a 4mill is...the second question was about how people get that +4 setup with a longer rod (''4mill longrod setup'')...i got my answer by @keno , with a bigger crank Where are you from? Quote Link to comment Share on other sites More sharing options...
bigweav81 Posted February 11, 2017 Report Share Posted February 11, 2017 You can put long rods on a stock stroke crank. Doesn't mean you need a bigger stroke crank. Sent from my SM-S820L using Tapatalk Quote Link to comment Share on other sites More sharing options...
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