WHAT PLUGS SHOULD I BE RUNNING ?

[alloydave]

Hi ,

Ive finally pulled finger after 2 years and decided to get the old girl going . The head is a XE alloy EFI unit and im running the XE distributor .

Im not 100 % sure what plug i should be running . The late efi engine with TFI ignition used the long reach NGK BRE 527-11 plug and the early carb engine used NGK BP5ES .

My old plugs book has differnt plugs for different models of falcon , but i dont know what model the engine was out of.

I have the long reach in at the moment and all seems ok although they seem a bit dark after running in the cam. I havent set the idle mix on the edelbrock 500 4 barrel yet so that may have some effect on the plugs.

On the plus side, the engine sounds strong ( open headers allways sound good). neighbours gotta love that for 15 mins .

Cheers Dave

 

[xctasy]

I used to swap the plugs from my Cortina V6 and my Falcon. The Falcon was Lpg, and I could clean a set of petrol Cortina plugs up in a weekends driving.

Long reach plugs are only better if they go with a better ignition system.


Match like with like. Basically, the XE needs XE short reach plugs. With moonshoot 2.77 gears, the XF was always an engine on the cusp of detonation, and unless you have everything the way Ford intended, you can mess up. You can upgrade the XE ignition with later stuff and get a great performance boost, but never put earlier ignition on a later XF.



Like you say, the XF were a lean burn head, and TFI ignition. The XF marked a heck of a lot of little changes that gave about between 0% to 8% more power, and at least 8% better fuel economy. Most of it was by greatly increased mixture motion, achieved by having a much bigger, better flowing intake valve which then is totally counteracted by a deap flow ramp which hurts incomming airflow. The fuel economy gain was in having very expensive, higher engergy ignition to spark the engine with the new kideny shaped combustion chamber.

 

[wagon]

I tried XF type 'long-reach' plugs in my XE once (XF efi system, XE motor, at the time) - they fouled up quickly and hurt power too. The short XE ones worked best (a couple of points colder didn't hurt, either ie ngk bp6es (for around town) and bp7es for highway (carbon up around town).

Kendall.

 

[Anonymous]

What kind of gap can you get away with?

 

[addo]

On the stock Bosch electronic dizzy and coil - 50 thou seems fine to me.

 

[wagon]

Hello all!

What is the current theory on plug gaps and power / economy? Is a smaller gap better or is bigger better? Or is it different for every motor? (in this case I am talking x-flow)

Kendall.

 

[addo]

My theory for a DD is: the bigger, the better. Check it every year or so and close the gap up again (Bosch ignition eats the metal at 50 thou gapping)...

If it's a performance motor, there might be other considerations. You would probably favour some more consistency under increased turbulence of cylinder filling/compression (piston speed)...