Surface gap plugs?

[tater76]

Just another quick question, my 1973 55hp Chrysler that now has ignition from an 1985 50hp Force will not run with surface gap plugs. I have tried several different brands and numbers, but it gives me grief. When I install a new set, it will start up and idle fine for about a minute or so, then it will act like it loses spark in one cylinder. I can then install a new set of NGK BR6HS or L82C Champions and it starts with barely a tap on the key, idles smooth, and runs out great. Frank A told me to be cautious about possibly melting a piston with the non surface gap, so I am a little worried. I have had it out on 5 trips this year with approx 20hrs of solid run time. I have not seen any damage from the electrode style plugs? Will timing effect the ability to fire a surface gap plug? and am I reducing my power output from running the non suface gap plug? Any insight is much appreciated

 

[huskerdaninva]

Re: Surface gap plugs?

Frank is right about the potential for piston damage from the electrode type plugs. I believe he (Frank) has stated previously to run the coldest plugs possible when using the electrode type plugs in place of the surface gap plugs. The surface gap plugs take a higher voltage to fire since there is no electrode, so possibly your "new" set up isn't designed to generate enough spark to properly fire the surface gap plugs? Just a thought...

 

[tater76]

Re: Surface gap plugs?

According to the manual I should be using the surface gap plugs with my 1985 Force ignition. However, I am (as Frank A stated) "in uncharted waters" with my new setup. So I may be ok with the electrode plugs, I just don't want to rebuild this dang thing again ya know

 

[fucawi]

Re: Surface gap plugs?

new suface discharge plugs have a surface coating that gets them started until there is a build up of carbon.....timing is critical as what you yanks call pinging ( pinking in europe) can lead to pre ignition...if you have 20 hrs on and the plugs dont show any sign of over heating it all sounds good .....retarded would be better than over advanced..colder plugs with standard nose ..not extended would be good

 

[tater76]

Re: Surface gap plugs?

fucawi, that is what I was leaning toward. I think I will be ok unless I mess with the timing again. If anyone has done an ignition swap like mine feel free to chime in I would love to pick your brain!

 

[fucawi]

Re: Surface gap plugs?

if its running good why not measure the timing idle and wot if you can so you have a reference for the future if you have to work on it ...