Hi Guys, I am going to change the plugs on my GD 1.4 does any one the torque setting for the new plugs and does any one use copper slip grease on the plug threads just asking
There are instructions on the plug packet of hand tight and then 1/2 turn extra for a new plug, this will squash the sealing gasket the correct amount, For a used plug it is hand tight and then 1/12 turn as the gasket already squashed. Using copper grease will lower the friction of thread and you should reduce torque by 20% - I always use hand tight + 1/2 turn method as then it does not matter if copper grease used or not.
I used to use a thin smear of copper grease on non-iridium plugs because the thread coating was passivated zinc and if left in too long or overheated the zinc could bond to aluminium of cylinder thread. With Iridium and other long life plugs designed to be left in for 70,000 miles they now have a tri-valent nickel coating which is designed not to stick to cylinder thread, so no copper grease required. If you are going to look after plugs and change them on time maybe copper grease not needed, but only use a smear in any case. Dry Graphite or molybdenum disulphide grease better than copper grease, but copper grease much cheaper and easier to get.
In any case warm up the engine before taking out plugs, the aluminium of the cylinder head expands more than the steel of the plug and will relieve the pressure on the plug thread a bit, making it easier to remove the plug.
If the plug thread is a bit tight coming out after you have initially slackened it off use plus gas or similar to try to lubricate the thread and try to turn it a full turn out and then half a turn back till it gets looser, trying to force it out by just constantly unscrewing against a tight thread can snap the plug (the actual steel wall of plug body where hexagon meets the thread is not very thick).
Good luck..