Does anyone bother using copaslip or something else (little grease or oil) on spark plug in an alloy head to stop them seizing in ??

thanks

You should not use anything on spark plug threads, especially grease products which will insulate the plug and weaken the spark.

yours, Pete.

Sorry to disagree, Pete, but I have used copper based grease on plugs for the last 25 years with no ill effects, especially on tapered types - it makes them much easier to get out again, and being conductive, it increases the surface area thus improving the spark (maybe!?)

I know some people will dissagree, but i'd have to go with Peteff, you dont want anything in there that may act as an insulator, its one of those places where its gotta be metal to metal....

is coppaslip just a grease with copper in it?

It would seem that copaslip is suitable for sparkplug threads. It says so in the blurb.

I'd rather run the risk of having a slightly weaker spark (which is doubtful), to stripping the threads out of an alloy head......
FWIW use the copaslip.

I believe you will find that the contact will be improved by use of a conductive grease. It would be very easy to measure th resistance with the use of a multimeter.

Er..... Coperslip is NOT conductive! I've tested it.

My mistake - just assumed it would be - thought it was a version of a conductive copper grease we used on aircraft...

opps... another can of worms opened. My thoughts were that I did not want to risk damaging the head hence the copasip idea, However the insulation argument makes sense. So the solution would be to find a grease that is conductive and everyone's happy.......

Anyone know of such a product and where to get it ?

Plan B:

Lightly rub locksmith's graphite into the plug threads before inserting the plug. Run the plug in most of the way using only your fingers, using the plug spanner for the last tightening. If you can't run the plug in most of the way by hand, stop and find out why.

Just my 2 pee (or not 2 pee)

David

I found this out years ago when a friend of mine insulated his battery terminals with a generous coating of it.. He cured the sulphating though.

yours, Pete.

you can not get a good reading with a multimeter because of the low voltage try it with a mega and i think you will find that it dose conduct.

I'v Just thort of a good test to do get a good size bolt and test the resitance niped up with no copper and then lag it up with copper slip and test it and see the difference ? (which will be non)

allso i think the more you coppress it the smaller the gaps between the copper (less resitance)

I would use the copper slip it has been used in garages since time began with no complants.

but thay complane when you stip the thread.

just checked my Carlube Copper Grease tube it specifically states not to use on electrical parts of the braking system, this suggests it may be conductive ?

TBH, it doesnt matter whether it is conductive or not.
Think about it logically. The spark has to jump a gap from the rotor arm to the dizzy cap. It then has to jump at least a 25 thou gap at the end of the spark plug in a highly pressurized atmosphere. The slight insulation that *may* occur between spark plug and head aint gonna bother it one iota....

For the record, try coating a spark plug with copaslip, tighten it in the head, and measure the resistance Between plug and head. Try it again with the next plug along, but this time install it dry. You wont notice any measurable difference. Dont forget the sealing washer is also conductive-if you are really worried make sure you dont put any lube on that!

Time to let it lie, I'm going to use the stuff. As others have said better to have a slightly weaker spark (which is unlikely) than strip the threads in the alloy head.
Each to their own.

thanks for the advice