cylinder head reprofiling

[holty]

Hi folks,
im just building up a budget 200cc lammy engine, its a smallblock conversion, it came without a head so ive got a 150 head which is the correct stud pattern, but the wrong diameter combustion chamber, anyway ive had it in my lathe and opened it out to 66mm, my question is, should the machining of the head be exactly the same curviture as the piston crown, or should i leave a larger gap as i move away from the gasket, hope ive not confused everyone there.
holty

[eden]

Depends what squish velocity your aiming for.

[holty]

was aiming for a squish between 1 and 1.5 mm roughly.

[eden]

I wasn't referring to the size of the squish.

[holty]

did you mean that the angle/ profile determines the squish velocity, does that mean theres angle best suited to a lambretta? or more to do with the piston crown shape ?
its not a subject a know a lot about, other than it can make a big diffrent to how an engine runs.
holty

[fairspares]

without getting technical basically you have the squish band and combustion chamber , have a read at mbs info it may help
https://www.lambrettaspares.com/info/ty ... -x+54.html

[eden]

without getting technical basically you have the squish band and combustion chamber , have a read at mbs info it may help
https://www.lambrettaspares.com/info/ty ... -x+54.html

predictably no mention of squish velocity there


this guy touches on it though
http://www.macdizzy.com/update39.html


this is very good for head design it wont tell you what to aim for but it makes it much easier to get what ever you do decide on
http://bimotion.se/Head/BimotionAdvancedHead_Manual.pdf

[Muppet]

without getting technical basically you have the squish band and combustion chamber , have a read at mbs info it may help
https://www.lambrettaspares.com/info/ty ... -x+54.html

predictably no mention of squish velocity there


this guy touches on it though
http://www.macdizzy.com/update39.html


this is very good for head design it wont tell you what to aim for but it makes it much easier to get what ever you do decide on
http://bimotion.se/Head/BimotionAdvancedHead_Manual.pdf

have you downloaded the software?

[eden]

its one of the ones I have ye

[Muppet]

msv meters per second formula?