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220 GPU

Osceola Stumpy

Well-known member
how much is the gain in HP by changing the pistons to dome top from stock dish top pistons?
Is the gain worth the cost of the pistons?
 
Ya will run better,but you have to run avgas!If you need pistons Chuck letme know and I will get you a deal.
 
Ya will run better,but you have to run avgas!If you need pistons Chuck letme know and I will get you a deal.
 
crabby said:
Need Speed Willie to chime in here he could tell ya[/quote
That's wheelie , Speed wheelie...Man I'm white like the rest of ya'll LOL!!!
If he puts in 0470 R pistons there the best..And yes you will feel the difference :D
 
speed wheelie":11x7eka6 said:
crabby":11x7eka6 said:
Need Speed Willie to chime in here he could tell ya[/quote
That's wheelie , Speed wheelie...Man I'm white like the rest of ya'll LOL!!!
If he puts in 0470 R pistons there the best..And yes you will feel the difference :D
Your the man Crabby!!
 
put domed pistons in my 220 a couple years back...
but had part of dome cut..made a good bit of difference .
had to put more pitch in prop..oh yea,with the pistons cut
i do run 93 . have not ran av gas just oct booster. been running good and hard
3 years now no problems just watch temp
 
Another thing to watch out for is the load on the crank shaft. I had a couple of Friends
that hopped up their 0470 and the crank snapped. :shock:
 
those 220 cranks are pretty darn hard to hurt unless you grind them down for oversize bearings

one of my 4 bangers has 470 cyl with dome 7.5 positions and I run 93 with out anything can run 87 octane if i get in a bind on fuel but I spits and sputters when i shut her off then
( I know Av gas is better I just like the easy of reg gas)
 
I run a dual-mag GPU with the domed pistons. It definitely has more power than my stock GPU. Also runs warmer. All I use is av-gas. Oh yeah, I have broken a crank. Funniest thing, sounded like a tree in the prop. Crank broke between last cylinder and prop flange, engine still running, prop not moving. Broke as soon as I brought it up off idle.
 
watched a guy come thru the pig trail and into the back side of the bus alittle while back with a pe90 he was easing along like he had 200hp power , it got the best of me so i walked over an took a look at his boat, pretty heavy hull and huntin metel works built for strength, turns out speedwheelie put the little motor togeather, seems it had a speacial cam grind, 470 pistons dual mag , drilled gpu jugs for the bottom plugs, now what really blew my mind was this little motor was turning a 68x 36 paddle wood prop by seninch 3150 he needed more prop, not much empresses me but that little boat was the bad to the bone :shock: does my heart good to know you can still get bad boat for less than 30,000.00much less
 
rjonesboy":18xofyqx said:
I run a dual-mag GPU with the domed pistons. It definitely has more power than my stock GPU. Also runs warmer. All I use is av-gas. Oh yeah, I have broken a crank. Funniest thing, sounded like a tree in the prop. Crank broke between last cylinder and prop flange, engine still running, prop not moving. Broke as soon as I brought it up off idle.

Larry's crank popped in that same are also.
It was not being run hard when it let go either.
 
i guess if your gonna pump em up ya better split the case and make sure you got a good crank std maybe 10 under, also timing with high compression is critical
 
I got one cylinder assembly(.015 over 470R domed piston, rings, dual plug cylinder, and all gaskets) from Daves Air Parts and I bought another assembly from Glenn(Hairdo) at Southern Enterprises.
 
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