Can the piston hit my spark plug???

GTStang31 · 07-21-2006

Okay so a few months back I posted threads about my number 3 spark plug being bend inwards and causing all kinds of hell. We'll today whil driving home my car started reving really bad and just felt like it was missing bad. I turned the corner into my driveway and rev the engine up a bit. Then it happened again the bang followed by a really rough inconsistent idle. So I decided to tear out my spark plugs and guess what I find. The number 3 spark plug is bent again. I got a flash light and looked in through the number 3 spark plug hole and I think its the top of my piston (they aren't flat tops right?) and you can see a small gash where the spark plug hit the piston. I have a feeling that its been tapping away at it slowly because I could swear I heard a tapping sound, but the dyno made everything seem okay. For now I replaced all the plugs with iridium plugs and hope the piston stops hitting the spark plug if thats whats actually happening. One of my injectors are cracked in the spray side so I need to a new one tomorrow.

markwondi · 07-21-2006

yes, it can hit the piston. What plugs were you running? Autolite and NGK copper plugs, and Motorcraft plats are what you call "extended reach" plugs. Meaning they are 3mm longer than standard plugs and are made that way to help wi th a better combustion. The downsize to this is the lack of margin of error for hitting them.

It's all to common on these cars. I'm suprised you didn't actually blow the plug straight out of the head, that's what happens most of the time.

GTStang31 · 07-21-2006

Well I know that there is a small gash in the piston is that going to be a problem? or will it be okay?

markwondi · 07-21-2006

It's fine, so long as you don't have a cracked piston. The piston hitting the plug has also put extended stress/wear on the rod bearing for that cylinder. If it's been a prolonged thing, it could have weakened it severely.

GTStang31 · 07-21-2006

Well I put back Denso Iridium plugs are those any good?

markwondi · 07-21-2006

Quote:

Originally Posted by GTStang31

Well I put back Denso Iridium plugs are those any good?

yea, they're just fine

GTStang31 · 07-21-2006

Well i got her running again but i didnt know how to bleed the air out of the fuel rails and when i started it up it stummbled like !@!@ tthen after a minute it returned to a normal idle. When i give it a little gas it revs up then stumbles a little comming back down. Did I mess it up?

baravelli · 07-22-2006

Drivers side fuel rail fuel pressure sensor has a three pin connector on top and a vacuum line on the side. Check the vacuum line. It may have pulled when the plug wires were moved. To mechanically check the FPS, sniff for fuel. O-ring on the bottom may have failed resulting in loss of pressure when fuel pump is off.

GTStang31 · 07-22-2006

Well now the motor is just screamin for an overhaul. it will idle fine and smooth after start up. It revs fine till 4000rpm, any past that and all hell starts breaking loose. It backfires and clanks and sputters on its way down from the rev. I dont know whats wrong. It will drive fine in the city where the revs never go paast 3500 rpm but if I have it in park and rev it up it sound terrible. I dont know what to try next. I changed all the spark plugs to denso iridiums and gapped them all to .54 but its still acting up any ideas??? Thanks for all the replys.