Spark plug help

[Mel Ruffner]

Hi everyone. Was wondering what spark plug I should use for a early Mac motor .

[Romero Llamas]

Autolite 353 for the short reach round head.

Autolite 411 for the later Mc91 square heads.

[Mel Ruffner]

Romero is that for gas or alky?

[steve miller]

im pretty sure be safe with NGK plug B8S short
B8ES ..like 91,s etc..
work good for either gas or Alky ..

[ted johnson]

The letter before the "S" is the reach. "H" means a 1/2" reach, no letter means a 3/8" reach. The "E" means 19.0 mm, and those are TOO LONG for any Mac kart engine. The "S" means copper core center electrode. For an early Mac with 3/8" reach, the B7S for gas, and the B8S or B9S for alcohol. On a newer 1/2" reach head like the later 91's or 101's, and for West Bend 610 or 820, B7HS for gas, B8HS or B9HS for alky. I've been running B9HS on modified alky engines for ten years. They are very long lasting and perform great. I don't know how Chuck Giacobbe's stocks are holding out, but I buy NGK's from him. He has good prices. Ted

[steve miller]

thanks ted... I never can remember exactly ..

but I do know a 7 pretty hot ..Id run 9s for gas 8,s for alky ..ngk lower number hotter plug ..I think 9 to cold for alky
I run champions ..Lol..

[Romero Llamas]

Those are the plugs I use on alky Mel. I have also used the NGK plugs mentioned.

Romero

[Mel Ruffner]

So what champion plug for Mc 5 running gas. Thanks everyone

[David Luciani]

So what champion plug for Mc 5 running gas. Thanks everyone

i'd just use the ngk's but heres a cross reference link mel.
that link lists the most common plugs in usa available


njk bs8 cross reference chart


if you want to change the search use this line in search window but change which plug.
ngk b8s to champion
so you'd switch ngk b8s to ngk b9s or ngk b7s
hope this helps

[Terry Sullivan]

I run Champions, like they did back in the day.
J6c
J8c