Piston Choice Question

[jmh61]

I am in the process of rebuilding my '86 3.2 motor. The pistons need to be replaced. Eventually I would like to go with PMO carburetors but budget constraints don't allow for them now. I would like to put in JE pistons now, so I can run higher overlap cams when I get the carbs. My question is what downsides are there, if any, to running JE pistons with the stock Motronic induction system. Exhaust emmissions are not an issue for me. Thanks,

[Steve]

Hi,

You may use the standard double valve relief JE's in your engine provided your CR remains compatible with pump gas. If you elect to bump that up, you'll need a chip re-tune and that person should be informed of the changes.

The only thing that may suffer is fuel consumption since the Motronic pistons are designed for improved swirl. I'd be using the best fuel you can find since these are more detonation resistant than the JE's.

You might also think about having your head machined for twin-ignition as that's really nice to have on a carbureted motor as well as permitting more CR on pump gasolines.

[jmh61]

Thanks Steve,

I am having the heads machined for twin plugs, but am planning on sticking with 9.5 CR and single plugging for now. I live in Georgia and we are fortunate to have 93 octane gas readily available here. I have a chip setup for 91 octane but run the 93. Hopefully that will be enough margin to prevent detonation with the JE pistons.

[Steve]