4.3 what size spark plug wrench

acke61

Seaman Apprentice
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Aug 11, 2007
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i tried using a 5/8 spark plug socket and it doesn't seem to be working, i broke one plug off in the ceramic, its dark out and i can barely get my head in there to see the plugs under the manifolds...


4.3 mercruiser carb engine
 

Bt Doctur

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Aug 29, 2004
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Re: 4.3 what size spark plug wrench

Only if your working on mercs or Volvo`s. You need to grind off/ machine off the hex portion of the socket for clearance. A taper .
 

Bt Doctur

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Re: 4.3 what size spark plug wrench

Thanks to Don s that we have this pic.
 

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Don S

Honorary Moderator Emeritus
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Re: 4.3 what size spark plug wrench

Another problem is the length of the spark plugs. Champions are longer than NGK or AC. Which will cause breakage no matter what type socket you use.
Merc and Volvo both had clearance problems on earlier manifolds.
 

liquidlew

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Feb 14, 2008
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Re: 4.3 what size spark plug wrench

Hmmm... I just happened to put on new plug wires yesterday and found a couple of loose spark plugs so I was thinking I was in for a rough time. Well, last year I put on new GLM manifolds and risers. I found, much to my suprise, my unaltered 5/8 socket fit up in there on all the plugs! Lucky me I guess. I couldn't get to them before with the old manifolds. I threw them out so I don't remember what brand they were!
 

acke61

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Re: 4.3 what size spark plug wrench

thank you guys....i figured this out....turns out i have water in 3 cylinders on left side...should i start a new thread for this?
 

liquidlew

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Re: 4.3 what size spark plug wrench

Yeah start a new thread. You can start by looking at your exhuast manifolds and risers, hopefully the problem is there and not a head gasket or a cracked intake manifold or head or ?
 

Gary H NC

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Re: 4.3 what size spark plug wrench

Just an FYI for others in the same situation: I was working on OMC Cobra with a 351 Ford Windsor engine and to say the clearance was tight is an understatement! None of the sockets I tried could get in there, even a tapered one. I finally broke them off to remove them. (It was that or remove the exhuast manifolds.) My local auto parts store had what is called "header plugs" made specifically for tight fits like this. They run the same heat range and the only real differnce is they are MUCH shorter and went right in with zero hassle.

Did the same job on the same motor a couple weeks ago..
Hardest spark plugs i have ever done.
Next time Bubba get a T handle plug wrench with a spring loaded swivel.
It was about 10 bucks at Auto Zone.....Well worth it.
 
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