glow plugs


hi all

i currently fit new glow plugs in my 1986 daihatsu rocky 2.8 diesel non turbo thinking thats why it was so hard to cold start but i am having a few problems that i need help with. when i bolt the new ones they dont go all the way down instead they just bolt to about a little more than half way and wont screw no more so my question is:

-is this normal
-do they need to go all the way down in order for it to heat up correctly
-or as long as they remain tight and secure it will do the job correctly

i put the metal bar and connection correctly over the plugs but unfortunately still wont cold start quickly and when it does a cloud of smoke comes out.

i am thinking is the glow plugs relay thats not sending electricity to the plugs in order to heat up correctly but the strange thing is that whenever i turn the key it clicks but its not heating up the plugs ( at least thats what i am thinking) or maybe is that the plugs need to go all the way down.

i bough the correct ones with the correct volts and tested them and it all works fine.