Damaged spark plugs

[dpellizzaro]

Hi guys,

 

I have been slowly getting things back together on my 260z with L28 and swapped a set of flat tops for some round tops and after it was very roughly running(back firing and coughing a lot) for a few minutes i decided to look at the spark plugs and check if they were in good condition. i started checking from the back and when i removed the 3rd plug i noticed the firing end had been bent pretty badly and when found this to be the same on cyl 1 as well. Is there any thing i should be looking for other than some debris in a cylinder? i have a little inspection camera and i am going to look more into it, but i dont know what else would be doing it.

 

Also is it possible if it is an item that has found its way into a cylinder, is that item able to move to another cylinder or would it most likely be trapped?

 

thanks

David

[Linton]

highly unlikely for anything to go from one cyl to the next as it must pass through the carby to get into the cyl, it was was in the pot before the plug was installed or the plugs have been dropped prior to fitting, the firing end that you describe as bent is actually the earth. did you fit the plugs originally?? or did someone else. if someone else you will never know ,crank the motor over without the plugs to blow out any debris check with your camera if ok put it back together

Linton

[Scoota G]

What sort of plugs did you fit? I would remove the head.

[dpellizzaro]

Thanks for the replies. I have removed the plugs a few times and altho i haven't throughly inspected them, i hadn't notice the damage before. There were NGK plugs i cannot recall the product number but i purchased a full set of 6 just to replace them all and see what happens.

 

I was thinking if i missed the damage and have swapped the plugs around then i might only need to look for 1 problem cylinder... How big would the debris need to be to cause the damage? are we talking a 8mm nut?

 

How hard is it to remove the head?

 

Thanks again

[Scoota G]

Takes about three hours. Saves destroying your engine. I had a piece of piston ring do similar.