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Discussion Starter #1
Most of us run into a bad plug or two. I ran into 3 bad plugs with my new raise port heads. Previously I had 2 problem plugs and went with Jacob ceramic boots. While they solved the problem of burn boots I still had a problem with the wires running under the headers right next to the block and still had to tie them back to keep them off the headers.
‘While the Jacob boots worked it wasn’t the perfect solution.
The local speed shop called me and aske me to look into Spark plug extenders as a possible solution for both their and my problems.
http://www.wrenchrat.com/index.php?r=5
I contacted Steve the owner and inventer and he sent me 3 of the extenders.
They arrive last night and I really like the looks and quality of the units but HOW do they fit.
This is a picture of one of my problems. You can see the boot laying against the header tube. Yes I ran a sock over it for a 20 mile test drive and it did survive but the sock was discoloured , the boot is a little white and I really don’t trust it over extended high speed runs.

These are the 3 units I received. They come in a lot of colors but I chose silver.

This is the unit snapped onto the plug and ready for a plug wire

This is a the plug wire reinstalled. Notice how the connection is taken away from the heat Also look at the boot and notice the white starting? Even wearing a heat protection boot it is starting to discolour
To me dropping a cylinder while on a long cruise can spell disaster for that cylinder

This is another angle of the same boot showing how the delicate boot has been removed from the source of heat.

These extenders can be run right against the tube without a problem. They are complete ceramic so unaffected by direct contact. The silver is only a coloring over the ceramic.

This is another problem plug. This one is using a Jacob ceramic boot but the wire needs to run under the header causing another problem with a loose wire touching a hot tube.

This is the extender snapped onto this plug again taking the boot away from the heat source


I did 3 cylinders with the extenders and only time will tell if they are a good solution.

Did I run into problems ?? Yes.
The extenders are made for up to .445 diameter porcelain. My one set of Accel plugs were .410, perfect but the set in the motor also accel were .450 Too big for the extenders. I took one of the oversize plugs and using a normal bench grinder spend a few minutes rotating it in my hands while grinding down the porcelin. I ground it down to .435 so it easily fit the extender.
The other problem is the snapping on of the little brass/steel end cap. I found the fit too tight. With the plug in the engine it was difficult to snap the extender on with that nice comfortable snap. To solve this I just put the plug in the lathe and with a file lightly filed the brass/steel cap until the extender snapped on with a secure feeling but not too much effort.
I like how they fit, plug porcelain can be iffy but I would test fit the plug on the bench first and then install in the motor.
Time will tell how they work but my intial impression is a very nice unit, fits well after checking on the bench and hopefully ends all future problems with tight fitting headers.
If I find after a few hundred miles of testing any problems with the units I will repost on this but as of this post I really like the extenders.
They are $30 each but for a problem cylinder well worth the expense.
Thank you Steve for a great product.
http://www.wrenchrat.com/index.php?r=5
 

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Discussion Starter #2
Guys here is my recommendations for fitting a plug.

First I found my 5/8th plugs are .410 diameter and my 13/16 plugs are .450 Since the extenders are .445 maximum it would not fit my larger 13/16 plugs.
If I was getting the extenders for the first time I would pull the plug that it is going on. Remove the little brass end and then try sliding the extender over the end of the plug. The depth of the extender is .900 so it should easily slide over most of the insulator. If it just starts way 1/4 inch the insulator is too big.
Using a normal bench grinder just hold it too the plug while rotating the plug by both threaded ends. This takes about 2 minutes maximum.
This is one of them that I had to do. It was all yellow before. The white is the reduced diameter.
Honestly 2 minutes maximum on the bench grinder

This reduced it to .435 well within the range of the extender.
Don't bother measuring just slide the extender over the end, If it slides over most of the way it is right.
This fits the spark plug. NOW fitting the little brass end.
Put it on the plug and then retire the extender. If it doesn't snap on nicely I just reduce the brass a little with a file so that it is a nice snap fit but not too tight.
This plug also has a slightly filed brass/something not brass end.
The extender now goes nicely over the plug, snaps on with only minor effort and I know I am good to go.
I custom fit the first 2, installed them and stopped to do this post and then I will install the 3rd one.
They really seem to take the boot away from the heat and are easy to snap on and off the plug.
I am very optomisitc they will solve any burning boot problem
 

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Discussion Starter #5
69 DIRTY RAT said:
I have that same problem! although I only have 2 burning plugs, 1 very bad the other not so bad! Great Thread, helps me significantly! I think I will have to get some.
They are sold individually so only get 2. They will fit anything since they are completely swivel headed. Find what angle you want and then lock it with the supplied allen screw.
 

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Just ordered mine. $10.00 for ups ground, that seems high. You could send it US priority mail for a quarter of that. Anyway thanks for the info I will let you know what I think.
 

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i keep getting a burnt boot on the same plug. ive used different plugs, and two different wires. ive just come to the conclusion that its too close to the manifold. is there some wort of wrap or guard you can put around the plug wire boot? it looks like you have it there, that silver mesh stuff. can that be purchased at any parts store?
 

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Discussion Starter #9
Emeryz28 said:
i keep getting a burnt boot on the same plug. ive used different plugs, and two different wires. ive just come to the conclusion that its too close to the manifold. is there some wort of wrap or guard you can put around the plug wire boot? it looks like you have it there, that silver mesh stuff. can that be purchased at any parts store?
That is a heat resistant sock that goes around the plug boot. It still shouldn't lay against the header. In time it will transfer enough heat through to the plug boot to cause it to melt.
Why not just break down, spend $30 and get a permanent fix with the plug extender.
I paid $12 each for the socks.
 
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