Help with plug gap
 

For various reasons I want to try a set of NGK plugs, I am also unsure of the plug gap that the original builder settled on when he used Bosch coppers.

Please help me get a good starting point or at least point me in the direction that will help me learn a good starting point.

Through search of this sight a have a new set of NGK BP8ES plugs.


The engine:

2.7 with RS P&Cs, matched and ported heads
S cams
40 webers
Permatune

The engine is very well sorted - with the only real change of late being new plugs (Bosche platinum) - engine isn't running bad....but it does not seem as "crisp"

Autox and track day car

Thanks in advance guys!


Don

I run my NGK BP7ES at .036 and they run great.

Thanks! - it's at least one data point


Don

I use BP7ES at about 1.3mm and they work great.

Thanks John

Thats quite a bit larger than the .036 quoted above.

I installed the BP8ES at .036 last night - all I was able to do was start up and idle last night (being kind to my neighbors). I have an autocross this weekend - we'll see how they work.

Anyone have a good source to read up on how to evaluate gap in order to determine if a change +/- should be tested? just curiosity


Don

Your coil type will dictate the gap. I assume that you run a stock coil so you should keep gap at stock specs. If you were running coil packs then you can run .05 gap. Over-gapping a plug usually results in over heating the coil.

At the end of my journey thru the tuning of my 2.7, I found an MSD 6AL, MSD Hi-vibration coil, 8.5 mm Magnacore wires, & NGK BP7ES plugs gapped at .05....humpf, where did that stuff come from?
I have 9.7:1 compression, Solex cams ( great AX cams, I've found), & the infamous Webers. It's been trouble free for 5-6 years...he said while knocking wood.:D

2.2E stroked to 2.4E
Webers
BP6ES @.045
Crane XR3000 Ignition
PS-91 coil
Clewett Wires
9.6:1 Compression
E cams
Over 165 HP at the wheels