f2t pistons in fe3

[mazda-head]

Originally Posted by bakmans

no were talking about a f2t crank in a fe3 block with fe3 rods and shaved f2t pistons

yes, youre also talking about a combustion chamber size increase of at least 16cc... that is too much to make use of F2T pistons in a FE/F2 dohc. if you shave the quench you'll get too close, way too close to the top ring land and will probably end up cracking it. F2 pistons, now that is more realistic, however they may not have the silicon content that F2T pistons have making them less tolerant to detonation, also combined with shaving = even less suitability for FE/F2 dohc turbo use

[chief tool]

I believe that the SR20 piston on an FE3 rod with an F2 crank in the FE3 is the way to achieve a stroked combo...I wouldnt bother trying to use F2 or F2t's
The SR20's have a 32mm c/h...if you dont want to stroke it but just drop the c/r then "apparently" the 3SGTE ones fit.....

I've not tried either (yet) but there are some posts about it elswhere on the site...

[fredio54]

back on topic, if the f2 pistons are the same as fe3 ones in most respects, then for a stock 2.0 unstroked motor, they might be an excellent choice. the f2t ones as stated would yield a far too low comp ratio.

point taken about the hg+shave+big dish. though other dude has a point about ringland thickness. i'm thinking i was silly for not pinching the pistons that were hanging off the end of the f2 crank i scored ages ago. could have had a low comp fe3 for cheap. ultra low comp = ultra high boost = big power on pump gas.

fred.

[chief tool]

Originally Posted by bakmans

another thought:

the fe3 crank is 86mm and the f2t crank is 94.

what if i put the fe3 rods whith f2t pistons on the f2t crank. acording to my calculations the pistons would rise 4mm above deck.
is it posible to shave about 3,7 mm of the f2t pistons?

I do take Fredio54's point that I might have been a bit off topic suggesting the SR20 pistons...but 3.7mm is far too much to shave off a piston..it'd probably develop a nice hole. using SR20's would be safer.

[NSXR]

The question was raised before:

F2T pistons in FE-DOHC = Too low of comp ratio
F2 pistons in FE-DOHC = Using NA pistons that are not made for turbocharging.

I would stick with the 3S-GTE option Youask used in his setup once.

Peace
NSXR

[fredio54]

tool, i didnt mean your post. nsxr, prove that the material is any different. very few manufacturers use forged pistons. i'd bet only the comp ratio differs between the two.

my fe3 pistons seem to take turbocharging quite nicely ;-)

its just an octane and comp thing at the end of the day.

honda dudes are making 400hp from 1.6l on suzuki low comp vitara pistons.

they werent made for boost, they just happened to be good for their low comp ratio.

if the 3sgte pistons sit below deck, then that solution is no better than a thicker head gasket. proper quench should be considered very important.

fred.

[bakmans]

if yu use the cupper gasket youd only have to shave 1,7mm of to get a 0,8.. quench ( thanks for the word fredio, overhere we call it squish)
shaving 1,7mm and the 94mm stroke would compenate for the extreem low compresion?

[fredio54]

the figures for dish of the f2 and f2t pistons are sitting around on this site somewhere, sick will know where they are... do the calculations, then you will know for sure.

fred.

[proberider]

the f2t pistons are hypereutectic.

[fredio54]

does anyone with some credibility and something to back up their statement say that the f2 pistons are not hyper?

hyper pistons seems to me to be like forged rods. ie, not a big deal. fe3,f2,kl,<any jap engine you can name> has forged rods and decent pistons. it seems to me that it was portrayed in the fe3 faqs as something special because yank tank donks dont or at least didnt have them.

ie, i bet the f2 pistons are just hyper too. would anyone care to prove otherwise?

fred.

[shwine617]

if your looking for a cheap way to lower the compression ratio, then you shouldn't be getting any machine work done to the pistons, because it will probably cost a lot and not be nearly reliable as forged ones. What about the stock kia sportage pistons? i think they bring the c/r down a bit and require no modification. I actually threw a set out to put my forged ones in. F2t's have been known to crack ring lands under high boost, so if you plan on making a lot of power, then don't even bother. and in my opinion if your not going to be making a lot of power with your fe3, then don't bother building it and stick with the f2t. Also you better know how to tune, or know someone that does because f2/f2t won't take much abuse from a mistune.
now I know direct replacement forged fe3 pistons aren't cheap, but there are other options out there, besides machining stock pistons. I don't know for sure on how close a fit but like someone mentioned you can use
3S-GTE pistons and i think 4g63 pistons fit to and they are cheap to come by,even forged ones.

[chief tool]

I saw a post of someone who had melted the top ring land out of a kia sportage piston...admittedly it was a turbo engine.
But the Kia pistons could well just be the same as the mazda ones out of the 9.2:1 non alloy sump engine.

I havent had much luck with the quality of metallurgy in Kia products over the years.

[proberider]

Originally Posted by fredio54

does anyone with some credibility and something to back up their statement say that the f2 pistons are not hyper?

Does mopping floors for Ford count? Look up new f2 and f2t piston. The f2s are cast. I suppose you're going to make me dig out the books.

Anyway, my point was that the f2t pistons are not forged, so don't be a dick.

[fredio54]

i know they arent forged, but a chunk of metal is a chunk of metal to some extent. ring lands DO NOT CRACK OR MELT without mistune. no engine will take much mistune at high power levels. the tune needs to be right.

i wont make you get out the books, but i will continue to doubt that they are of any different construction to the f2t pistons.

i've been on here for a long time now, and all the engines that have died with the few exceptions of non piston/ring/headgasket failures have died because of non ideal tune. the vast majority have been stockers modded for higher boost on oem ecus with stock maps or maps chucked in by someone in a different city that they just cross their fingers is correct.

you arent going to melt a piston or crack it without detonation. it just wont happen. if the f2 pistons fit and have the right deck, and pin, and valve reliefs and a good ~= 7:1 - 8:1 comp ratio, i bet big power could be made on them with pump gas. for pump gas, low comp + high boost = big power.

what schwine said is also right,

and in my opinion if your not going to be making a lot of power with your fe3, then don't bother building it and stick with the f2t.

i disagree about the piston comment though. ya kinda contradicted yourself there...

what forged pistons provide is a resistance to poor tune and detonation that the stockers dont have. you headgasket will eat dust if your pistons are strong. neither will die if you are just making good safe power.

will try to find a pic of another member which i saved a long time ago of a hg.

end rant.

[fredio54]

here it is :



if this is your pic, and you have a problem with me having it in my account, and you have the original link, i will take it down at your request. (cant see why anyone would care, but you never know...)

fred.