Replacement Z8C Spark Plug

[Seth Kunz]

I have a Z8C spark plug that is done. I am sick of cleaning it for a half hour ride. Where do I get a new plug. What would replace what I have.

 

[crassius]

a lot of folks use NGK b6hs - bp6hs is same with slightly longer tip if your head has room for it

 

[Seth66]

I posted this when I wasn't logged in. I just went to O Reilly's and they gave me a NGK b7hs. the porcelain is a bit longer but other than that it seems to be the same. It works great so I'm happy.

 

[smordarski]

The NGK B6HS is a replacement for the engine under normal use.
The NGK B7HS is for an engine that has been upgraded for higher performance or if you are going to run it hard, since the B7HS is a cooler running plug.
I'm about to try out NGK's iridium version of the B7HS, which is the NGK BR7HIX.
I'm curious how it will run. I'm also upgrading it to a "racing" carburetor and a reed valve intake.

 

[Chainlube]

Iridium plugs take more energy to fire than can be constantly supplied by a M/B mag. But for me it's the $4 plug compared to a $20 plug to do the same job. My little pick up uses those plugs and it's an $80 service, good thing I only have 4.

 

[Frogslayer]

The NGK B6HS is a replacement for the engine under normal use.
The NGK B7HS is for an engine that has been upgraded for higher performance or if you are going to run it hard, since the B7HS is a cooler running plug.
I'm about to try out NGK's iridium version of the B7HS, which is the NGK BR7HIX.
I'm curious how it will run. I'm also upgrading it to a "racing" carburetor and a reed valve intake.

I bet you won't be able to tell the difference.

 

[Frogslayer]

Iridium plugs take more energy to fire than can be constantly supplied by a M/B mag. But for me it's the $4 plug compared to a $20 plug to do the same job. My little pick up uses those plugs and it's an $80 service, good thing I only have 4.

How can this be? Shouldn't they have the same resistance?

 

[HumanPerson]

NGK B7HS, cool weather.
NGK B8HS, warm weather works for me so far.

 

[Wrench]

Iridium plugs take more energy to fire than can be constantly supplied by a M/B mag. But for me it's the $4 plug compared to a $20 plug to do the same job. My little pick up uses those plugs and it's an $80 service, good thing I only have 4.

Iridium S/P require less voltage to fire because the electrode is thinner and harder. Requires less voltage to cross the S/P gap.
Iridium metal is not as good a conductor as copper. Iridium spark plugs are used on cars so they don't have to change their plugs as often. But a Iridium plug should be taken out and cleaned every 20,000 miles or ya run a chance of it seizing in the S/P hole.
It's a waste of money to use a Iridium S/P on a M/B. A reg copper S/P has better conductivity for a M/B. I'm sure no one is gonna leave the S/P in their M/B for over 20,000 miles. Besides one can buy 5 reg plugs instead of 1 Iridium plug for a M/B and your M/B will run better.

Regardless of what Iridium S/P manufactures claim

 

[DrSubs]

The NGK B6HS is a replacement for the engine under normal use.
The NGK B7HS is for an engine that has been upgraded for higher performance or if you are going to run it hard, since the B7HS is a cooler running plug.
I'm about to try out NGK's iridium version of the B7HS, which is the NGK BR7HIX.
I'm curious how it will run. I'm also upgrading it to a "racing" carburetor and a reed valve intake.

I just got the bp6hs we’ll see how it runs