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Discussion Starter · #1 ·
i had some forged pistons made up to suit my SOHC FE turbo motor but now that i have an FE3 i want to use them in that motor istead of paying out more money. if i use my SOHC rods which are 2mm longer and a lot more beffier than the FE3 rods will that help with my compression. i realise that i am going to have to machine the pistons for valve and head clearence but will the extra traveling distance give a better squish. SOHC pistons are very dished and this is why i will have a very low C/R if i dont sort something out.
 
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dmonicTX5 said:
i had some forged pistons made up to suit my SOHC FE turbo motor but now that i have an FE3 i want to use them in that motor istead of paying out more money. if i use my SOHC rods which are 2mm longer and a lot more beffier than the FE3 rods will that help with my compression. i realise that i am going to have to machine the pistons for valve and head clearence but will the extra traveling distance give a better squish. SOHC pistons are very dished and this is why i will have a very low C/R if i dont sort something out.
Your 8-Valve FE motor has a close chambered head, the FE-DOHC has an open chambered head. Your pistons are probably too dished for your needs.

The extra stroke from the rods would increase your compression, but at the cost of your R/S ratio.
 

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Discussion Starter · #3 ·
RE: Flyswat

Cheers for the info, but how much do you think it might increase my c/r and also what is r/s and how will this be affected by an extra 2mm of travel by the rods. if i have to get new pistons can i by thm off the shelf or will i have to get them made also i will be looking at getting them in Australia. my block has already been bored out 20 thou to suit the pistons i already have. i was looking at running really high boost cause being a FWD i wanted to bog the motor down a little at take off to reduce wheel spin maybe a low c/r isnt that bad. 6.1:1 is way to low though.
 

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My suggestion are too put those pistons up for sale and try too get atleast the half of the cost too make set of pistons for the FE DOCH.

I know money are an issue but your plans seems too me like a far from optimum solution.

1: taking 2mm of these pistons would probably make them as weak as the stock FE DOCH units.

2: machining new valve pockets migth be difficult or even expensive.

Ps i do remember that a guy in Denmark was searching for pistons for a FE-T a while back. if you end up selling them i can trow up some lines at their board with your contact info. selling trougth eBay could also be an option.

Ps2
Longer rods do NOT make a longer stroke (it will just move both TDC and BDC further up in the cyl
and the r/s ratio will NOT get worse
stock FE DOCH: 150 mm rod/86 mm stroke=1,74:1
stock FE SOCH: 152 mm rod/86 mm stroke=1,77:1
 

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Discussion Starter · #5 ·
well it looks like i might have to sell them then. if you could let anybody know about them that would be great. they r made by special piston services in Dandenong Australia. they r 20 thou oversize and have been made to give an 8.5:1 c/r. also another question when i got my motor the inlet manifold says that it is a 1.8 injected motor. could someone just have put the wrong inlet manifold on it. the head has FE3N stamped on it and the crank is the same as my 2lt sohc crank. the turbo SOHC crank and rods are so much chunkier than the dohc ones. when i have the pistons made up to suit the FE3 will i have to advise them of the extra 2mm of travel or will they still clear the head.
 
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Sounds like you have a F8.

The only difference between the F8 and the FE-DOHC is the stroke. Its just a destroked version.

Though, I think I remember VeltPak telling me that the F8 has a different intake cam though.
 

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Discussion Starter · #7 ·
ok then say i do have an F8 how can i tell and am i going to have any trouble putting my 2lt SOHC internals into that block. also when i get the pistons made up i have to send an original piston for them to copy. what sort of info am i going to have to give them to make sure i get the piston to head and valve clearences correct and a low enough C/R for a big turbo.
i think this will be a build up and messure, pull down and create and rebuild again.:mad: :confused:
the only differences i have seen in my two motors besides the obviuos number of cams and oil drains is the twin cam has the oil squirters and the size of the counterweights on the crank being bigger on the turbo SOHC one that i want to use anyway. i thought this might have been because of one engine is turbo (SOHC) and one being NA (FE3 or F8) or whatever it is
 
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The FE-DOHC/F8 Block also has different oil returns in the block.

However, putting your FE engine crank into the F8 will stroke it back to 2.0, making it identicle to the FE-DOHC.

Don't quote me on this, but I believe your supposed to use the FE crank with the F8 rods and pistons to bring it back to 2.0.
 

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FlySwat said:
The FE-DOHC/F8 Block also has different oil returns in the block.

However, putting your FE engine crank into the F8 will stroke it back to 2.0, making it identicle to the FE-DOHC.

Don't quote me on this, but I believe your supposed to use the FE crank with the F8 rods and pistons to bring it back to 2.0.
yup the 2.0 crank will go into the F8 perfectly. (if it says FE50) But you'll need the FE rods, the F8 rods at ~160mm is way to high for the deck, and they are light forged rods so theyre really only good for high rpm/na. if you turbo your F8 converted to FE3 engine, you'll benefit from cleaning up that single plane manifold and using the F8 intake cam. That combo is great for spooling quickly! (longer duration, almost no overlap, high intake charge inertia).

Did anyone know the diff F-block pistons all have different compression heights? This might come in handy

compression heights

FE3 1.417" - 35.99 (36)mm
FE 35.48 mm
F2 36.83 mm
 

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Discussion Starter · #10 ·
ok so this is how i will be doing it.
FE 2lt SOHC Crank and rods.
Lower comp forged FE3/F8 pistons, about 8:1 i'd say. Can i buy these off the shelf from somewhere or do i have to get them made?
Leave the head as is other than a clean up, valve stems, reseat, polish etc.
My haltech E6S that i already have.
4X550cc 13bTT injectors. Already have. should i go bigger?
The F8 inlet manifold.
Fuel pump, any ideas. Bosch 019 maybe.
Garret T28 BB turbo. Already have.
some decent sized front mount intercooler.
and then in my dreams maybe some NOS. why not i say.

Will this be succesfull for atleast 300 or so H/P? i hope so. could never achieve that with 8 valves. the TX5 owners in SA will have to look out soon. cheers fellas you've been a great help.
 
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Block deck ht difference F8 to FE

My sources suggest that the F8 has a deck height of 269mm vs 289 mm of the FE/FE3 2000. This represents a height difference of 20mm from crank centreline to top of block face. F8 with 77mm stroke uses same 152mm rods as FE SOHC. FE DOHC uses 150mm rods with 86mm stroke. Thus, it seems to me if you use 152mm FET 2.0 rods and pistons in an F8 block, with FE crank (as you are proposing), the pistons will poke proud of the deck by about 11mm (9mm if you use FE DOHC 150mm rods).

Just get a FE 2.0 block! (or use pistons with 9mm lower comp ht...almost impossible, very hard to find pistons with CH less than 30mm, with a 21 or 22mm pin!!!!!!!)

Hope this helps!
 
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Re: Block deck ht difference F8 to FE

FE3-4ME said:
My sources suggest that the F8 has a deck height of 269mm vs 289 mm of the FE/FE3 2000. This represents a height difference of 20mm from crank centreline to top of block face. F8 with 77mm stroke uses same 152mm rods as FE SOHC. FE DOHC uses 150mm rods with 86mm stroke. Thus, it seems to me if you use 152mm FET 2.0 rods and pistons in an F8 block, with FE crank (as you are proposing), the pistons will poke proud of the deck by about 11mm (9mm if you use FE DOHC 150mm rods).

Just get a FE 2.0 block! (or use pistons with 9mm lower comp ht...almost impossible, very hard to find pistons with CH less than 30mm, with a 21 or 22mm pin!!!!!!!)

Hope this helps!
Veltpak has dissasembled both motors, the blocks are identicle.

Your source could be mistaking the F8 measurements for the F series Diesel (Can't remember engine code), or the F2t, as both are taller blocks.
 
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