Vertical o side piston gas porting

[Irelac]

From the two ways that I know of milling gas ports for rings in a piston, vertical or sideways; Which will work better? I'm thinking on using one of this methods in a 383 project.

 

[enginebob]

It is generally done drilling down through the top.

 

[ivymike]

Either should work fine from the standpoint of gas flow. Sideways (removing semi-circles of material from the top flank of the top groove) seems less likely to result in structural problems.

 

[Tmoose]

I think Gas porting is pretty much only necessary (or desireable) if the ring side clearance is real tight.
Adding them to typical pistons which are already fitted with rings loose enough to pressurize via groove clearance might be wasted effort. What are your rings' back clearance? Tightening that up (via Speed Pro's groove shims used to be considered a good idea for high speed work.

 

[MaxRaceSoftware]

Either should work fine from the standpoint of gas flow. Sideways (removing semi-circles of material from the top flank of the top groove) seems less likely to result in structural problems.- InHiding
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i agree with InHiding

i've used pisons with gasports either way successfully

the only 2 things about the vertical gasports are

1-easier to do

2-makes piston more prone to possible ring land failure if into localized detonation in some engines depending on
how far top ring is down and ring land thickness

usually, the intake notch pad closest to piston deck, is where detonation will 1st likely to occur. Too many top gasport holes in this location, along with thin ring land due to high ring placement ..and cracks or failure occurs in this area (intake-notch -to- deck pad)

the horizontal or side gas ports help keep ring land stronger/intact than vertical gasports

also gasports are hidden from view <Rules cheating >

but i still drill my pistons with vertical gasports
in my fixture, i normally just use (8) .050" holes , instead of drilling 12 or so smaller holes like i've seen others do




Larry Meaux (maxracesoftware@yahoo.com)
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