Pistons Flat Top Or Dome

[mocky]

Hi

I am hoping someone can answer this question for me. I have a 1974 FJ40 with what i think is the 1.5 F Transitional engine. Engine No F543191. The engine uses the same oil system as the 2F ie no oil feed line up to the rocker shaft and the oil filter on the same side as the fuel pump. At the moment i have the head off the engine and the pistons are flat top, is this correct or should the pistons be the higher compression domed type.
Any help appreciated.

Mocky

[dow50r]

The question is...how good is your fuel??? If you can get premium fuel, domes will work.....sorry, i dont know which it should have, but im guessing your fuel is the reason you have flat tops...the old 2f ran 7 and 8 to one comp, here in 0z we tried to get 9-9,5 by shaving heads because out unleaded likes that comp ratio....i believe they are flat top for high comp and dished for low. Never seen domed f pistons
Andrew

[Hamo]

I stand to be corrected here
But i think you will find flat top piston's are for a closed chamber head
and dome'd piston's are for a open chamber head

[matt.mcinnes]

I stand to be corrected here
But i think you will find flat top piston's are for a closed chamber head
and dome'd piston's are for a open chamber head

You are correct, so I would take a guess the head is either a later 2F to suit flat top pistons or the original head has been skimmed to suit.

All you need to know here

http://forum.ih8mud.com/40-55-series-te ... st-2f.html

[bj on roids]

i've never seen domed F or 2F pistons, did they exist?

[matt.mcinnes]

i've never seen domed F or 2F pistons, did they exist?

I have a set here from my original rebuild in 04.





Now running flat tops.

Soon to be rebuilt again but this time with these in 08

[RAY185]

My 1975 2F had flat tops.

[bj on roids]

awesome, its like a hemi