hi guys! new to this place but a long time holden owner and first time commodore owner. lol I've replaced the sparks in my vn s twice now and i only replace them with the recomended one i use the NGK BPR5EFS-13 (that was the first time) and then the NGK iridium. now both times over about 3 weeks they have loosened themselves and gives the car a rough idle. Can anyone tell why this is happening? I ended up gettig the iridiums cos autobarn had no stock left of the standard and i couldn't be stuffed to go anywhere else with a screaming bub in the car! thanx guys
Only thing I can think is that you need to tighten them a bit better mate. Never had any of mine come loose any any car.
thnx mack....i just sent hubby out to tighten them..i'm just scared too do em so tight that they crack or whatever and crap goes into the engine. hubby did this to his VR i think and ruined 2 pistons? or so he says. hubby has about knowledge as me! but i'll let u guys know how it is in about 2-3 weeks time when i check the sparks again.
The threads in the head are possibly loose. You can tighten them fairly hard and it won't crack at all. After all, the heads do put up with alot of pressure
I have cracked a spark plug once, this was because the angle I had the socket over the plug was wrong. If you have it lined up nice and straight, screw them in by hand untill you cant anymore, then get the socket out and get it over the spark plug nicely then give them a tighten, I have the tenancy to over tighten my plugs and they become a bitch to replace lol.
The general rule for tapered seat spark plugs, as VN are, is as tight as you can go using just your hand to turn the 'plug socket (tool) then add an extra 1/16 of a turn using the ratchet. The engine should be cold. If they are tightened like this there is no reason why they should come loose, unless the seat is damaged. Yes, it is very easy to crack the 'plug insulation . Here you go, from the horse's mouth: DENSO SPARK PLUGS
thanks guys...u all been real helpful...and iv'e taken all ur advice on board..i never thought about the fact of the engine having to be cold..cos usually i take the car around in the back lane to work on it as the area i live in is real snobby and they look at ya funny like ur trying to steal the car if u work on it out in the street! So bad sum 1 called the cops on me while i was working on the car!!!!!! i told the cops where to stick it...easy being a chick! anyways thanx again guys!
