pining,twin plugging,, bigger bores etc...

[Mike Dillon]

  I don't remember the referance but there was a artical in one of the 
airplane mag's on the big piston engines used in transports and bombers 
in the late 40's. They metioned that the max bore they could use for 
gas engines was in the 4-5 inch range, I think they said it was due to 
flame propogation rate. If you want to see some cool hardware look up
some referances to the piston aircraft engines just after WWII.

Mike D.
 

> From diy_efi-owner at esl.eng.ohio-state.edu Wed Mar 11 08:39 CST 1998
> From: "Matthew B. Watts" <mwatts at facility.cs.utah.edu>
> 
> 
> -----Original Message-----
> From: Shannen Durphey <shannen at mcn.net>
> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
> 
> ---------------SNIP------------------
> 
> > Certain Chrysler engineers believe that pistons over 4" dia. waste fuel.
> > Too much ends up collecting around the sides of the piston.  They were more
> > interested in complete burn for emissions, hence the V10.  Ford has tagged
> > along and released a V10 of their own, around 420 ci, I think.  Have you ever
> > noticed anything like this?  Maybe as more power for a given fuel consumption?
> 
> 
> What's the story on this one--I've heard that a bigger bore is more
> efficient and the opposite side that more, smaller cylinders is better?
> I got into a discussion about "thumpers" in a motorcycle mail list one
> time and nothing was every really resolved.
> 
> My gut instinct is that there is some practical limit of size due to
> simple mass of the piston trying to change directions all the time,
> plus burn rate of the fuel mixture.  A rule of thumb that I heard was
> around 600cc per cylinder; anything more and your outside of the
> "workable" range.
> 
> I'm still amazed after building Ford FE big block motors for a couple
> of years that a little 125cc dirt bike engine can produce so much
> power for its size and weight.  Someone needs to nail this matter
> down for future reference...
> 
> Matt
> 
> 
> 
> 
> 
> 
>