Flat top pistons

Does anyone know if the flat top pistons for an FE3 engine will fit without mods into an FE SOHC 8V 2.0L engine without any or much modifications? The research I've done so far seems to indicate they would fit. The unknown I have yet to determine is with the closed chamber of the 8V SOHC head will there be valve clearance issues and will the static compression be to high for the FE engine to withstand and remain durable for daily use.

I'd like to increase the static compression in order to gain a few extra hp. I'm not expecting a drastic increase but if I could get a 50% gain from increasing compression ratio and other simple little mods then it would be worth it. I think these engines NA and carb'd should be able to get in the 120hp range and still be usable as a daily driver.

I'd like to know what you guys think.

The stock FE pistons are already flat top so I don't think you are going to get any gains from swapping in F3 pistons. The stock HP for the FE motor is 86 HP so maybe your best bet is putting in an entire FE motor which puts out 140 hp with fuel injection.

mazdatweaker_2- Where did you get the information the stock pistons were flat top cause all the information I've seen about the SOHC 8V motors have stated they were dished with valve reliefs?

That would make sense since the stock comp ratio is stated to be around 8.6:1. My personal opinion is I know some of the older muscle cars and such have comp ratios closer to 10:1 or greater. I think a NA motor with Al heads running 10:1 ratio is streetable and would expect with OEM cam specs to be able to gain an extra 20hp with this single modification alone. You add in a Weber carb, Pacesetter headers, and a port/polish job maybe get it to 120hp.

Just my thoughts.

I read on a site for miata's where the guy was modding an FE3 motor about the differences in pistons. He had posted this photo as example. He was saying the piston on the left is an OEM SOHC 8V piston, the middle is a SOHC 12V piston, and the one on the right is the FE3 flat top.

I have the information from personal experience. When / if you pull the head off your 2.0 motor you will see the evidence for yourself. You could rent a bore scope and look at them through a spark plug hole and see that way too. The 2.2 pistons are concave to keep the compression ratio at 8.6. You could go to an auto parts store and they could probably pull up a diagram of the pistons that come stock in a FE motor. You just aren't going to get anything worthwhile in the way of horsepower from the 2.0 motor. That is why Mazda dumped them in favor of the 2.2, which is also a dog.

You mentioned that "older muscle cars and such have comp ratios closer to 10:1 or greater." What you overlook is that at that time, lead was an additive in the fuel that was utilized to combat pre-ignition and detonation which occurred with low octane fuels. When the EPA took lead out of gasoline the engine manufacturers started retarding ignition timing and utilizing things like EGR valves to dilute the intake charge so that the engines wouldn't destroy themselves Name one vehicle that came stock after 1976 with a high compression engine. That is when lead was outlawed.

I understand the whole situation with regular gas and unleaded. You are correct with the retarded ignition and such also. The modern LS1 engines are high compression ie 10:1 but not as high as race motors with +13:1 ratios.
I own a 1.8L yota car that is 12yrs newer than my 86 b2k that is factory rated at 120hp. Granted it is fuel infected but it is still NA. It has way more seat of the pants power than my truck. I know it has to be possible to get another 40hp or close to it from the 2L FE without fuel injection and off the wall crazy modifications. I know forced induction would do as would NOS but I'm not talking about those options.

I appreciate your thoughts mazdatweaker. I have a street bike with a 600cc motor that is rated over 110hp. I know that's comparing apples to tangerines, but I mentioned it to prove displacement is not necessarily what determines the power output of a given engine.