New School Custom Pistons

[Five Reviver]

I now have the answer from RaceTec: the deck is .210 inches and milling off .114 inches would lead to a deck of .096 inches, and failure.
This doesn't concern me; I bought the pistons with a view to building standard stroke and I'm still happy with that.
Dan, when I said the pistons are the same spec as yours, I guess I was just saying that I gave RaceTec the same dimensions and the part number which they pulled from their records.

 

[spmdr]

I was contemplating having the pistons made with an additional 1/8" of CH to be able to use them with a 1600.

and mill them down for a 1725. But decided to have them usable as made.

When I first looked the piston over, I was surprised how heavy/thick it is for it's size.

If you look at the under side of the crown, you can see the forging is for a Pent roof type use.

And the piston crown is thinnest around the center and thicker as you go to the skirt.

CW has minimum piston crown thickness of around .150, depending on the piston forging and use .

One way to mod the piston CH would be to turn it into a pop-up type with the thin part of the piston in the dome.

DW

 

[spmdr]

Was out yard saleing and found a set of new pistons for supper cheap.

Turns out they are GM corporate 2.4L I4 88MM bore, a bit BIG.

They use the same Pin size 20mm (.788) as the "New School piston,

L O N G Rod" combo.

But, check out that compression height.

DW

 

[Mike O'D]

Read an article recently - may have been Hot Rod magazine - about lower operating temperatures and significant power gains from thin, low tension piston rings. Anyone doing custom pistons, it would be worth looking into.

 

[spmdr]

I just read the Hot Rod article.

My $.02

Clearly, New school is Thin rings.

But my VERY limited history tells me this:

Vintage Race Ford 289s Use up thin rings faster

than thicker rings.

Of course I/we are talking WAY fewer hours of use

than a street car.

AND way more harsh conditions.

The biggest challenge in the Vintage world,

compared to current, is Fuel control.

Vintage Racers LOVE to DUMP Gas into an engine

at every exit of a turn.

Not a good life for piston rings.


However, in my limited circle of auto engines,

Stock Sunbeam Alpine engines are the absolute Worst,

when it come to pistons and rings!

I can't recall ANY Stock Alpine engines, I disassembled,

that have pistons and rings working as they should!!

That is to say, pistons that DON'T have Black Carbon

below the top ring.


If there is black carbon below the top ring,

the top ring/piston has FAILED to do it's job!


Are the pistons and rings to blame on the Alpine?

Maybe..?

But my guess is mostly issues with carburation

and fuel control.


But the bottom line here is, thin rings are here to stay.

And thin rings are a whole new ballgame starting with MUCH

smoother bore surfaces.

NO more "Cross hatch" in your block prep.


Also, thin rings NEED better Fuel control!

..I step down from the soapbox....

DW