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Fingerported V6 Loopers 1996

D

daselbee

Advanced Contributor
"This an off-the-wall question

"This an off-the-wall question, but what is meant by "fingerported" when referring to the late 90's V6 models?
I have been researching pistons, and I see two variations from Wiseco, specifically separate part numbers for "fingerported" vs non.
I also looked at the Evinrude piston part numbers and can find NO difference in the V6's in that year range. 1995 thru 1999 200, 225 hp is what I checked."
 
"FP pistons,have holes in them

"FP pistons,have holes in them for fuel and exhaust,for loopers.
crossflow pistons,do not have this"
 
"Doug,
The link you posted se

"Doug,
The link you posted seems to refer to a cross flow engine.

A looper has several large holes on each side of the cylinder to scavenge the cylinder with the fresh charge from the crankcase. The loop charged theory being that the charge came in from opposite sides of the cylinder, meets in the middle, and forms a stream up the center of the cylinder. Once the stream hit the head, it would mushroom out and flood the cylinder from top to bottom pushing the exhaust out in the process.

In time, the engineers found that adding two or more smaller "finger ports" near the main ports allowed them to fine tune the above process for different RPM ranges. The result is better low end torque and better midrange performance. The top end power sees little change, as that's where the main ports do their best work.

Most if not all the "Eagle V6" models had finger porting from the factory. Some years of the 90 deg V6 had them, some didn't. I've read it is possible to add them to engines not originally equipped as a performance mod."
 
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