Wrong plug or not?

screw it in an then turn the engine over very slowly to see if the piston hits the spark plug.
 
the "p" isnt great, projected tip, but otherwise its fine... they work.

its always a good idea to research things first...like checking out things like this...

ngk.gif



and then you can see that all that matters is;

the first letter, which is the thread diameter. B in our case....
the number, which is the heat range. stick with 5-7 with ngk plugs.
the letter after the number...anything with an E (or Z on closer inspection?) is bad news for these engines.

and other than that, everything is pretty well much interchangeable... the P i mentioned, projected tips...can hit pistons. why its a good idea to check for clearance when installing odd ball plugs. i see that K can mean the same thing too... always learning!

taper seats work but are not ideal, either...

what is funny is that NGK will not supply a list of all possible plugs they manufacture unless you are a manufacturer! i have asked... i dont see why they cant?


what they sent you is the stock standard lawnmower/brushcutter plug. perfectly fine.
 
I know this is a bit old but I have a question regarding the popular Iridium NGK plugs and determining if it's too long, and may hit the piston. I've already done what Jaguar has recommended and I rode down the street and back, and check the plug after that. It looked fine.

Could the plug be very very close to hitting the piston and with more heat and expansion could it hit later on? That's my only real concern. Thanks!

The engine is an "Arrow 7hp Big Block". My bike is listed as KC Kruiser's White Racer. A Trek 930 mountain bike frame.
 
I know this is a bit old but I have a question regarding the popular Iridium NGK plugs and determining if it's too long, and may hit the piston. I've already done what Jaguar has recommended and I rode down the street and back, and check the plug after that. It looked fine.

Could the plug be very very close to hitting the piston and with more heat and expansion could it hit later on? That's my only real concern. Thanks!

The engine is an "Arrow 7hp Big Block". My bike is listed as KC Kruiser's White Racer. A Trek 930 mountain bike frame.
Presumably that's a question for @KCvale ?

Or I would try some Blu Tack, Play Doh, chewing gum lol, and just turn the engine over slowly to squash it between the piston and plug, then take the head off and see what the clearance really is.

I love my NGK BPR6HIX but it's on a completely different engine, and anyway it's the thread length (H) combined with the projected tip (P) that makes the difference to piston clearance, not the iridium anti-corrosion plating (IX) on the ground strap.
 
Thanks Furry, I'm in Phoenix, and KC just moved up north to a small town. He finished my build about 6 months ago.

I'm just curious, as an amateur, if I will cause any damage by running the NGK Iridium BPR6HIX in my engine for a longer period of time? Considering that I already did a tiny test run without a spark plug wire first, and then ran it for a lap down the street, with no sign of damage on the plug.
 
Thanks Furry, I'm in Phoenix, and KC just moved up north to a small town. He finished my build about 6 months ago.

I'm just curious, as an amateur, if I will cause any damage by running the NGK Iridium BPR6HIX in my engine for a longer period of time? Considering that I already did a tiny test run without a spark plug wire first, and then ran it for a lap down the street, with no sign of damage on the plug.
If it did cause any damage, the damage would be that the gap in the plug was closed.
As long as your engine is able to turn over now without squashing the plug gap, it'll not damage any other components. It's always good to have a spare plug around just in case but I think you're safe. :)
 
Back
Top