who can teach a short spark plug class?

bob johnson

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Feb 25, 2009
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my manual list 4 different spark plugs from champion for my motor. two for regular use and two for extended idleing.

I have looked up some nomencalture and have found that the "Q" in front means 'resistor".
now my book lists QL16V, L16V,QL77J4, and L77J4

is one hotter? how can you tell by the codes?

then just two years later on the same style motor, with almost all completely identical parts that model motor lists ONLY QL78YC

I have to believe that the QL78YC and the QL77J4 are doing the same thing...whats different about each plug( i only have one in front of me now).... I think...THINK, i remember one with a much longer thread!!!

what is considered extended idleing...20 minutes at a time?

i often set and pick up my decoys while idleing around slowly and it can take 30 minutes at times ....where the motor never gets over 1500 rpms....is this extended idling?


bob
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: who can teach a short spark plug class?

Here is a link to a page that then links to the plug manufacturers part number break down

Spark Plug Manufacturers Code & Reference Guides

specifically, here is the champion break down

http://www.gsparkplug.com/shop/media/images/extras/code_champion.pdf

The Q is resistor for CDI ignition
the L is your 14mm thread and 1/2" reach
the 8 or 7 is the heat range (the higher the #, the hotter)
the Y is standard projected core nose
the C is copper
the J is cut-back gap, modified tip
the 4 is wide gaps required.

so the difference about the plugs are the electrode tip and heat range.

your reach is the same between the two

yes, that is extended idling.
 

bob johnson

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Re: who can teach a short spark plug class?

2vx58o6.jpg


a QL78YC on the left and a L77J4 on the right.....thats what i am talking about, when i said i thought they extended deeper into the head!! its not the length of the thread, is the protrusion of the end of the plug ..

i wonder if they found out, they got better combustion with the spark igniting the gas out in the center more


bob
 

boobie

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Re: who can teach a short spark plug class?

That's why the QL78YC is recomended.
 

bob johnson

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Re: who can teach a short spark plug class?

That's why the QL78YC is recomended.

soooooo it is a a wise idea to use the QL78YC in the 1995 motor as well???

( actually what i have been doing for the last 3 years)

sort of like a retro up grade?

bob
 

boobie

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Re: who can teach a short spark plug class?

Yes.................
 
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