[wvmudder]

I can't be the only person wondering. What is the purpose of the gas ported pistons and what applications are they beneficial to?

Thanks,
Dave S.

 

[Mark O'Neal]

The gas ports use combustion chamber pressure to push the ring into the cylinder wall, giving a more effective seal.

In the past they been use mostly to compensate for incorrect ring gap.

They are useful in applications wherein you are trying to minimize parasitic loss; in that they allow you to reduce ring tension when the ring is not loaded.

 

[Lem Evans]

Most used when the top ring is .043" or .043" with a back cut .

 

[wvmudder]

Thank you Mark. Direct answer from a piston manufacturer, this board is great.

I noticed them lately because people mentioned them in build specs and a couple in the auction block sections.

Sounds like a nice feature to to have. Low tension when its not needed and max pressure when you do. Is this an option for any of the pistons Probe offers Mark?

Thanks, Dave S.

 

[johndickjr]

but how long till the tiny hole are full of carbon

 

[03HD05ZX6R]

I always wondered that.

 

[2slow]

use lateral ports not top holes for less or no carbon pluging

 

[Lem Evans]

use lateral ports not top holes for less or no carbon pluging

Correct....the side ports eliminate that issue. The top ports should not be much of an issue with a dragrace only engine.

 

[Mark O'Neal]

use lateral ports not top holes for less or no carbon pluging

Moe tested those when I worked at ROSS...I can't quote that far back, but I can paraphrase: "Lateral Gas Ports have the additional advantage of not changing anything".

 

[Mark O'Neal]

Thank you Mark. Direct answer from a piston manufacturer, this board is great.

I noticed them lately because people mentioned them in build specs and a couple in the auction block sections.

Sounds like a nice feature to to have. Low tension when its not needed and max pressure when you do. Is this an option for any of the pistons Probe offers Mark?

Thanks, Dave S.

We will do it......but the circumstance where they actually help is on the extreme end of the Land of Diminishing Returns.

 

[J. Shelfo]

I am trying lateral gas ports on my new engine, I have used top gas ports in the past with good success. My new pistons have very close tolerance on the ring lands, which I believe will need the entry of cylinder/combustion pressure through the lateral ports. In addition I run nitrous which may reduce the expansion of the piston in all areas. I also run the engine on the cold side (130*).

 

[CutawayAl]

Gas porting is a technique that has largely come and gone. People that at one time recommended it aren't doing it anymore.

Current practice is is better and narrower rings, higher ring placement that traditional SAE standard. And in some cases, more clearance between the piston and cylinder above the ring.