I don't know if anyone else has had this problem with the older heads,but there are a limited number of plug ( heat ranges ) available for the 18mm spark plugs.I ordered a set of these adapters and they solved the problem.Now I can use the newer 14mm spark plugs and adjust heat range accordingly.Contact this guy if you are interested (great guy to talk to) www.garrettmachine.com
How do you get those out if you want to go back to the big plugs? It seems like the first time you install those, the plugs will come out but not the adapter. It is hard enough gettting the plugs out of a Mav, with shock towers and headers in the way, getting something that small out of that space seems almost impossible. How is the clearance between the spacer and the electrode, is there a gap or space that would collect carbon etc?
I think if you put these in,you would have made the decision not to remove them.As far as the clearance,these are machined with very tight tolerances.When you insert a plug and look at the end,it looks like one piece. Again,these are an alternative to using and installing the older style plugs.The newer 14mm have a bigger variety of manufacturers. i.e. Denso/Iridium-Platinum etc. If you are looking for some hidden horsepower,this is another way to find it.IMO even a daily driver can benefit from the newer style plugs.
