Porting an engine

mbartell /
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Damn I feel old and crusty, porting is when you take a little material out of the ports on the engine. Ports are the passage ways that the fuel/air and exhaust go thru. The idea is to increase the size of the passage to let everything flow better. In some engines it helps to have the ports smooth, to eliminate turbulance, in others you want it rough to increase the turbulance. This depends on the engine, and how good your carb. is at mixing the fuel and air.

Porting if done wrong can REALLY mess up an engine, especially a 2-cycle, because the timing of the intake and exhaust relies completly on the size and location of your ports in the piston wall. Also, it's really bad to get aluminum shavings and dust in an engine, so you have to really clean it up when you'r done.

Most of the time when you port an engine you clean up the casting flash and the rough texture left by the sand-casting process. This is relativly easy if you take it really slow and carefull.

The other "trick" is to gasket-match your head and engine. You take a gasket and trace the inside profile on each peice that mates together. You then remove material untill you reach the line that you traced and blend in the area untill it is smooth, with no abrupt changes. This creates a smooth transition for the gasses as they go from one part to annother.

Some advice- don't do this unless you have at least one spare engine that you are willing to turn into a PERMANENT door stop. It's really easy to get carried away, and before you know it, you have gone thru the side of the engine, or messed up a bearing-surface. You may even acidentially take out a strengthening rib, wich will cause a crack, or open up a bolt-hole from the back side. The piont is, before you start dremeling away, make sure that you know where everything is supposed to be, and don't screw up what already works.

Actually from the mopeds that I've dealt with, most of them can't really be improved from the original. (it's an almost perfect machine to begin with) That's why most of you havn't heard of porting, in relation to mopeds, anyway.

This single post is part of a larger thread. Start from the top or view this post in context.
Subject Written By Posted
  PORTED MY CYLINDERTopic by: chuck russo va chuck russo va 12/26/01 08:41PM
  Re: PORTED MY CYLINDERRe: Wayne Wayne 12/26/01 08:54PM
  Re: PORTED MY CYLINDERRe: RogNC RogNC 12/27/01 12:20AM
  Re: PORTED MY CYLINDERRe: casey casey 12/27/01 12:21AM
  Re: PORTED MY CYLINDERRe: XBrandon EdgeX XBrandon EdgeX 12/27/01 01:52AM
  Re: PORTED MY CYLINDERRe: Crisis--Cincinnati Crisis--Cincinnati 12/27/01 10:09AM
  Re: PORTED MY CYLINDERRe: chuck russo (VA) chuck russo (VA) 12/27/01 10:13AM
  Re: PORTED MY CYLINDERRe: Jeff Jeff 12/27/01 10:23AM
  Re: PORTED MY CYLINDERRe: Crisis Crisis 12/27/01 10:25AM
  Re: PORTED MY CYLINDERRe: Wayne Wayne 12/27/01 10:51AM
  Porting an engineRe: mbartell mbartell 12/27/01 11:18AM
  Re: Porting an engineRe: Don Don 12/27/01 06:54PM
  Re: Porting an engineRe: Crisis Crisis 12/27/01 08:14PM
  Re: Porting an engineRe: DaveI DaveI 12/28/01 01:22AM
  Re: Porting an engineRe: chuck russo (VA) chuck russo (VA) 12/28/01 02:41AM

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