Quote:
|
Originally Posted by nhdoc
Since the threads conduct the ground side of the electrical circuit you are supposed to use an anti-seize formula which will is specified to conduct electricity, those are the copper based formulae and they are the most costly types available...make sure you don't use an electrically insulating anti-seize compound.
|
Hogwash!
The threads in mating metals contact each other and make good electrical connection regardless of whether one uses an insulating grease or not!!
One Glow plug manufacturer recommends not using antisieze (without defining whish type of antisieze). I assumed it to mean the grey silvery anti sieze which is made from Molybdenum disulphide. I have used that stuff for glow plugs for years and never had a problem. So last time I had a job on my present 603 engine I used the copper-based antisieze. Now I am not so certain that was the right decision but I won;t know for a few (hopefully many) years.
Actually there is antisieze material made for aluminum called NO-OX-ID. It is employed in the electrical field to prevent the oxidation that occurs in aluminum wire. Aluminum wire was banned in the US for use inside houses but it is still used for high current leads such as drops from a power source to the point where it is metered and in big industrial applications where weight and cost can be reduced by using aluminum.
I suspect No-Ox-Id is available in Scotland from a good electrical supply house (presuming aluminum wire is used there also - I just don't know for sure!)
see:
http://www.chem.hawaii.edu/uham/conduct.html
I have a tube of Sanchem material I bought off eBay. I believe that it will prevent possible GP oxidation in the aluminum OM602 and 603 heads used in later diesels. In the iron head (617) engines it probably doesn't matter much what is used, if anything!
BTW, stuck glow pugs seem to be more common in the aluminum head engines and use of a anti-sieze is probably much more important with that type of engine, but in any case if there is a bunch of carbon that has coked onto the GP it will prevent the plug from coming out and can result in having to remove the head if a GP breaks off. I think this is a more nefarious problem than you think, because if you can't see it and just because the threads come loose on a plug don't wrench it out if it hangs up on carbon inside on the shaft of the plugs.
A local mechine shop had a recent MB diesel (2003?) that a mechanic at the Mercedes dealership broke a plug off in, it was a real long thin GP unlike the ones in the 602/603. Maybe that makes them more prone to breaking off? Whatever, it cost somebody big time to get that one out!