Autolite 3116 Spark plug questions

bcraig2N

Member
Seems as though most say to use the Autolight 3116 spark plug in Z134 engine.

I put 3116 plugs in my 1964 MF 35 Z134 Engine and after running them
found the terminal ends keep unscrewing I suppose from vibration.
How do all the users of this plug keep them tight?

I am also going to buy some copper washers to use with the plugs instead of the regular washers to get a better seal against the engine.
outside diameter is 18mm right?
What is the thickness of the factory washer?

Thanks
 
With the washer I'd keep it under .0625" (1/16"), something like .035" at the thinnest. The id of the washer should fit the threads just enough that you have to screw them on (if you remove the washer that came with the plug by unscrewing it). On the terminal end of the plug I just tighten them some with pliers. You can also ever so slightly"smash" the end of the plug wire that pops on over the plug terminal so that the plug wire can't swivel on the plug terminal, that will help keep the plug terminal from loosing up.
 
As ptfarmer said, the first thing I do when I pull out a new plug is to use pliers to tighten the top, next is to check the gap.
 
Question for ya ....... why do you think copper washers will give a better seal? Do you suspect the factory washers are not
working properly? I've never heard of anyone having issues with the ones that come with the plugs from the manufacturer.
 
(quoted from post at 07:32:44 09/29/17) Question for ya ....... why do you think copper washers will give a better seal? Do you suspect the factory washers are not
working properly? I've never heard of anyone having issues with the ones that come with the plugs from the manufacturer.

I have removed the plugs several times and they are crush washers so I think I probably need some new washers anyway
I know there was a little bit of oil seeping around the plug on one cylinder and soapy water was bubbling a little when sprayed around the plug and where the plugs seat against the engine
I was thinking that i either needed to replace the washers of lap the plug seat slightly as they are Pitted ever so slightly.
 
(quoted from post at 23:38:54 09/29/17) Autolite has a 388 resistor plug that is a little hotter than the 386.

Thanks
I wonder if gapping the plug tighter or more open would have any effect on the plug getting a better spark with the excess oil in the chamber,and or filing the plug back some like some of the race car drivers do?
 
(quoted from post at 23:51:45 09/29/17)
(quoted from post at 23:38:54 09/29/17) Autolite has a 388 resistor plug that is a little hotter than the 386.

Thanks
I wonder if gapping the plug tighter or more open would have any effect on the plug getting a better spark with the excess oil in the chamber,and or filing the plug back some like some of the race car drivers do?



Probably not, the only way to get a better spark is to go to a electronic ignition. As long as the plug has the sharp edges on the electrode its as good as it gets. If the edges are rounded the spark won't be as good.
 

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