[HeadDoctor]

Hot - Cold Issue

Here's a tip look up the MFG on the web get a catalog coming from each plug company, turn to the "Technical Info" page in each catalog and study what they say.

Plug color 1) The housing & ground electrode should show some heat after you make a run and turn the engine off, coast to a stop and check the plugs. To look at the porcline you need a doctors light with the ear attachment. look deep into the core of the plug where the porcline meets the housing and read the color there - should be light to medium gray if you run leaded gas. Look for a ring on the porcline & remember where that is (make a drawing for your records).

2) Look at the ground electrode - What you're looking for is a shiny blue ring at some point along the length of the ground wire - that ring tells you where the timeing is as a relationship to the lean-rich mixture.

3) Look at the face of the plug where the ground wire is attached - When the plug is new and you just made a run - there should be traces of heat - This looks like the cad plating is being worn off - the more heat the farther it runs down the plug into the threds.

You're running a naturally aspirated gasoline motor - You're probably not going to see more than 1` thread of heat. White on the porcline is A-OK must have a very good ignition or tht won't happen. Be sure your running cad plated plugs and not the black ones, otherwise change to Denzo, NGK or Champion. Use the cross-over chart in your cataloges. Always find the Batch Number (MFG Part Code #) not the actual plug number.

Denny@JDS Induction Products - HeadDoctor out