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  #11  
Old 22-05-2010, 14:25
londonsilvia londonsilvia is offline
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i got the plugs out today...

no.4 is slightly rusty on the top and blackened at the spark end
no.3 was wet from oil, blackened and not so tight as the others
no.2 was blackened
no.1 was blackened and was impossible to get off as it was on so tight


http://img269.imageshack.us/i/22052010392.jpg/

http://img525.imageshack.us/i/22052010391.jpg/


but this is probably due to sustained missing from trying to fix it? its no.3 i am concerned about. i split a load of oil on the rocker cover through filling up with oil the week before, then after that run it sat for a week which is when it buggered up after 3-5 mins of warming up... maybe the oil heated up and got in there?

also the spark plugs are set to .70mm. in this post alundra shows a picture of the 'stock' plugs gap to be 1mm: http://www.nissansilvia.co.uk/vbb/showthread.php?t=5027

Last edited by londonsilvia; 22-05-2010 at 14:35.
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  #12  
Old 22-05-2010, 23:17
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Dr Silvia Dr Silvia is offline
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was number three finger tight or thereabouts? if it was loose it could cause low compression and a miss that improves with rpm...

Oil on one plug is a little concerning, so would be worth a compression test if tightening the plugs properly doesnt yield results.
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  #13  
Old 23-05-2010, 00:37
londonsilvia londonsilvia is offline
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no.3 was medium to take off with a tool, so pretty easy.

what do my plugs look like? ive been reading when they look like that along with the white tops its a problem with the fuel mixture i.e. too rich.

what are the spark gaps for NGK Rs? they are .70mm.

cheers
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  #14  
Old 23-05-2010, 08:03
umpkin umpkin is offline
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how old are the plugs?? i think for piece of mind i would change them anyway, ive had similar trouble before with a dodgy spark plug, also was the problem there brfore you changes the plug leads, as our forklift at work used to run on 2 cylinders, untill you revved it, and that was leads.
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  #15  
Old 23-05-2010, 10:48
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just quickly about the plugs.

being an NGK r really doesnt say much about the plug. Its detailed specifications are buried, encoded in the part number, for example bcr6es and bcr7es. the numbers relate to the heat range of the plug

a 0.7mm gap shouldnt cause any problems although for mild tuning is a bit narrow. From memory until you're running aproximately a bar then a 0.8/9 mm gap did people fine with the heat range 7 plugs.
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  #16  
Old 23-05-2010, 12:42
londonsilvia londonsilvia is offline
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they are bcr8es plugs. ive set them to .9mm...

the car is running 1 bar of boost.

i will put them in today and fingers-crossed it will work.
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  #17  
Old 23-05-2010, 13:52
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I'd put them back to .7 tbh otherwise you might get the spark blown out at that boost.
A compression test is what I'd be doing first on this car.
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  #18  
Old 23-05-2010, 15:30
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ye, 0.7 on 8s is right for that boost
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  #19  
Old 23-05-2010, 17:37
londonsilvia londonsilvia is offline
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well just put it back together...

started it after 20 seconds of cranking...

it began missing, but then kicked into life with all four going... after about 20 seconds of being on all four, it started to resist and drop onto three, then it wasnt long before it stalled.

whenever i put my foot on the accelerator it began to die.

why would it be so hard for it to kick into life and then die after 20 odd seconds of being fine?
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  #20  
Old 24-05-2010, 11:17
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Do a compression test and post the results.
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