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

 

can water get in the joint ???

 

They are NOT NOT water proof. While water must run uphill to get inside the extender they are again NOT water proof.
Hopefully I never drive in rain that soaks the complete motor like that. I would hope the heat from running and the fact the hood is closed would keep the water from totally flooding the plug

 

thanks,,so if you did hit a big puddle and steamed onder the hood you probably get a miss then it would clear out ??

 

I just knew there'd have to be some modification/fabrication somehwere in this post. Otherwise it wouldn't be a Norval thread.

Thanks for posting the info.

 

Jughead I am a fanatic that everything must fit properly. I won't do micky mouse installations. I have got to feel it is a good job or I won't run it. Porceline diameter changed from one set of plugs to another. I would test fit any plug on the bench before installing and in my case I had to drop about .015 on one plug.
I feel it is a very good solution to burnt boots.

 

Being a basic sheeney cheap bastard, I just crafted some galvenized sheet metal squares and modded them with hose clamps to the headers, they seem to be working fine so far....

GENE

 

i know you just have the new combo. out but about what is your plug life ???

 

good to hear the news... i was waiting to hear how these worked out.

as for the water... I dont drive the vette in the rain anyway (unless i get stuck), so it shouldnt be a problem.

I may have to get a few of these!

Thanks

 

I really like them. Two are on my car right now and the 3rd is waiting for me to finish this post.
RAIN? Why should it hurt. The hood is down, the motor is warm and the water would need to go uphill to get between the plug and extender. I wouldn't worry about it but again they are advertised as NOT waterproof.

 

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

 

Gene if you have a boot touching a header how is adding a piece of sheet metal going to help?? My boots would fry and to drop a cylinder at high speed on a long cruise would destroy a cylinder with gas wash and I wouldn't notice it.
I also go to cruise nights and take too much pride in my work to stick some sheet metal with gear clamps on it.

 

Plug life. I have run this blower motor since 1999 and I was still on the same plugs. These are new heads, expensive new heads that required different plugs but I expect another 5 to 10 years before I consider replacing the plugs.
I do hope to jack the heads and intake up next winter and drop a new mega block under there.

 

Jughead if I find a new product that I feel can help us with a problem I am more then willing to test it and if it works for me recommend it.
That's how you guys got the hydroboost, the hydraulic clutch and the cheap T5 swaps.

 

HA!

your too much.... i want a ride in that bad boy!!!

 

As always Norval, great information and suggestions.

 

After I ditched the block hugger headers I got for $50 for the $86 summit long tube headers I noticed I didn't have any more plug clearance issues. Honestly I think better designed headers results in better plug/boot life.

 

When you are dealing with specialty heads , large 2 or 2 1/8th inch tubes , a steering box, you are very limited to space.
Raising exhuast ports is a good thing but it plays hell on spark plug angles. While normal exhaust ports clear the plugs raising them puts them right in the path of the plugs.
I built most of the tubes and just ran out of space to put them. I would gladly reroute them if there was a spot for them to go.
While my headers drop in really easily and bolt up without a problem every available space is occupied.
No header design wouldn't be very simple

 

Although I don't have a wire burning problem this is great information for the future if it ever starts happening. Thanks