Page 1 of 1

0-320 spark plug

Posted: Thu May 09, 2019 8:39 am
by DWATTS72
i bought a Lycoming 0-320 and it had multiple spark plugs in it what is the best plug to run in this motor? :dontknow:

Re: 0-320 spark plug

Posted: Thu May 09, 2019 9:21 am
by GMAC 76
imo…..the new autolite #386 nickel plated....gapped at .022-.024

Re: 0-320 spark plug

Posted: Thu May 09, 2019 11:47 am
by diamondback0320
X2

Re: 0-320 spark plug

Posted: Fri May 10, 2019 9:55 pm
by DWATTS72
thanks for the info guys gonna try them.

Re: 0-320 spark plug

Posted: Sat May 11, 2019 12:45 am
by Slidin Gator
DWATTS72 wrote:i bought a Lycoming 0-320 and it had multiple spark plugs in it what is the best plug to run in this motor? :dontknow:
This question is about like asking how long is a piece of rope, it depends on what you need. Decoding spark plug part numbers is a lifelong process, each manufacturer has a different system.

GMAC's recommendation of 386's will certainly work.

But... The best plug for mags is non-resistor since mags run at lower voltage vs. newer electronic systems (that's why mags run on solid copper wires) The best heat range for an air cooled motor is the lowest that does not not foul in your motor.

With Autolite, second to the last number = even = resistor, odd is non-resistor. The lower the last number, the cooler the plug. The 386 is a resistor plug and a medium heat range. A 383 would be lower heat range, but still resistor. The 373 is non-resistor and a lower heat range.

The 386 is easy to find at the autoparts store, the 373 is usually a day out. Others may take a while. I suggest trying the 373's to keep cylinder temps down but still get maximum spark from mags. If the motor is an oil burner, run the 386's.

https://www.sparkplugs.com/Data/uploads ... System.jpg

If you have a real problem with fouling, particularly if you spend a lot of time at lower RPM (like frogging), try an auxiliary gap plug like the Champion UD16. This link explains the auxiliary gap well.

https://www.yesterdaystractors.com/cgi- ... &th=345062

Re: 0-320 spark plug

Posted: Sat May 11, 2019 4:18 pm
by DWATTS72
thanks for the info!