Indexing washers for 200 18mm plugs

[indyman13]

Anyone know who sells an 18mm indexing washer kit? Or am I looking at using an insert and converting to 14mm?

If I convert, how will that affect the position of the electrode in the cylinder?

 

[CoupeBoy]

I thought the low buck way of performing the indexing was to use a black marker on the spark plug porcelin where the ground strap opens. Then buy 8 or 10 spark plugs and thread them into the holes, if a plug ends up with the pen mark in an acceptable position then you leave it in the hole, if not you move on to the next hole and try the same plug again, due to manufacturing differences and the location of where the threads start on either the plug or head you can eventually get plugs indexed into an acceptable location.

The thing that concerns me about indexing washers is that it is one more thing to cause the plug to be not tight or one more thing to lose plus the thicker the washer the farther from the combustion chamber center the electrode and ground strap get.

-ron

 

[indyman13]

Yep, I got lucky on 3 of the 6 and they lined up OK. I'm going to pay attention to where the thread starts on the plug in relation to the open gap and ask my parts guy to let me sort through them.

I totally agree on the effect it'll have on depth. Those 18mm plugs are short anyway and 1/2 to 3/4 of a turn could cause some problems.