TheSamba.com :: View topic - Projected tip or non projected tip spark plug for NA

Wed Apr 29, 2020 12:02 pm

There has been lots of good discussions here recently on ignitions, CDI, resistor vs non-resistor, so what about projected plug tips on spark plugs.

Do you prefer projected tip or non projected tip plugs on a NA dual carb engine and why?

Wed Apr 29, 2020 1:07 pm

I like non projected. Because projected plugs made my engine run on after it was switched off
Same heat range plug too

Wed Apr 29, 2020 3:15 pm

I use projected for everything now. It could allow you to pull some timing.

Wed Apr 29, 2020 4:07 pm

GARRICK.CLARK wrote: I like non projected. Because projected plugs made my engine run on after it was switched off
Same heat range plug too
Interesting. you must be right on the border to need a colder plug then. The general consensus is that non projected is what these engines came with stock, - 40 years ago. OK. Now normally the projected plugs allow for a little colder plug due to the plug electrodes being exposed more into the chamber. This makes the plugh just a little bit hotter, which again allows the plug to "clean itself" better after say a long idle.
In general I use projected tip plugs whenever I can. But in say some higher compression 356 engines there is no room for extended plugs, so regular is in order there.