14mm H/C head spark plugs

[Hedd_Jones]

The engine in the RP has a H/C head on it. Champion L86c plugs. 

I have narrowed down its poor cold starting to fouled plugs. Dry & sooty. Not wet and oily as I have experienced with this head before.

Once the b@stard has fired once in the morning it behaves very well. Other than I had a single fluffed fire the other week, pulling very hard in 1st gear. 

The engine has a checkered past, Ive changed heads recently. There was not an excessive amount of deposits in the combustion chamber. And it doesnt use a terrific amount of oil. Less than one of my other cars, perhaps a bit more than the third.

I dont doubt it may be running a little rich.  

I'm hoping some hotter plugs may improve things. 

The current champion system makes my head hurt. Whats hotter than a L86c?

I have some J8's, though at 3/8 reach they 'should' be too short. I've a feeling from the charts that these are cooler in anycase. Unfortunatley I only have two L10's which should be 'hottish'. And three Lodge HS14's which I believe are pretty 'hot' plugs. 

In the past ive used some NGK B5HS on an oily engine. 

Any comments gents please?

[Reckless Rat]

B5HS seem the best choice for me. The BP5HS tend to soot/oil/clog up more due to the extended nose.

[Alan]

I use B5HS too.

[Charles P]

The engine in the RP has a H/C head on it. Champion L86c plugs. 

I have narrowed down its poor cold starting to fouled plugs. Dry & sooty. Not wet and oily as I have experienced with this head before.

Once the b@stard has fired once in the morning it behaves very well. Other than I had a single fluffed fire the other week, pulling very hard in 1st gear. 

The engine has a checkered past, Ive changed heads recently. There was not an excessive amount of deposits in the combustion chamber. And it doesnt use a terrific amount of oil. Less than one of my other cars, perhaps a bit more than the third.

I dont doubt it may be running a little rich.  

I'm hoping some hotter plugs may improve things. 

The current champion system makes my head hurt. Whats hotter than a L86c?

I have some J8's, though at 3/8 reach they 'should' be too short. I've a feeling from the charts that these are cooler in anycase. Unfortunatley I only have two L10's which should be 'hottish'. And three Lodge HS14's which I believe are pretty 'hot' plugs. 

In the past ive used some NGK B5HS on an oily engine. 

Any comments gents please?

With Champion traditionally a lower number is harder/colder (the opposite of NGK) . However most Champion automotive plugs run in a 1-20 sequence (I run D14's which are 18mm). Technically the L86C is a small engine/industrial plug so in a different number sequence but the higher/lower principle remains the same. You could go L90.  The NGK B5HS looks a decent option to be fair. However I've found Champion more reliable lately.


Charles

[Ian McGowan]

With a similar set-up I have happily run L86C plugs for over 10K miles (same set of plugs) My understanding is that these replace the old L10 and L7 plugs that my Tiger Cub used nearly 60 years ago!!