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View Full Version : Broken Spark Plug Need Help!



donzi182003
07-24-2008, 09:08 PM
Guys,
I just bought my old 2003 18' 350 mag mpiback and I have discovered something quite ugly when removing the port rear spark plug.When unscrewing it the threads and pin stayed in the block. The plug wasnt melted just heavily corroded. What can I expect? How do I remove the thread out of the block? Look at the photo.

http://i20.photobucket.com/albums/b213/FastEddie1211/PIC-0118.jpg

MOP
07-24-2008, 09:14 PM
Man you have your hands full, IMO to make sure it comes out right I would remove the head. Even then it will be a job for a competent person or shop, I have done this stuff for well over 40 years that is a first.

Phil

EDIT: I have broken them off and gotten them out, but due to the rot I feel you will ruin the threads or worse trying to do it in place.

onesubdrvr
07-24-2008, 09:16 PM
I would definitely remove the head,.....

As rusted as that is, one has to ask why? Water in the combustion area / head? That much? How did the other plugs look?

Something aint right there

Wayne

MOP
07-24-2008, 09:24 PM
When you get eh head off send a PM I may be able get you through this "IF YOU HAVE GOOD HANDS" and listen.

Phil

MOP
07-24-2008, 09:30 PM
I would suspect a leaky exhaust hose on the Y blowing water up, that will rust the krap out of the back of a block.

Phil

donzi182003
07-24-2008, 09:35 PM
Guys. The rot came from poor rinsing on the prev owners part. All the plugs looked this corroded. Look at these photos showing the left over thread. It still has the firing point on the end of the plug. Do you guys think an ez out will work? In the last pic you can see that it didnt break off anything into the cylinder.

http://i20.photobucket.com/albums/b213/FastEddie1211/donzi001.jpg

http://i20.photobucket.com/albums/b213/FastEddie1211/donzi002.jpg


http://i20.photobucket.com/albums/b213/FastEddie1211/donzi006.jpg

ZekesterbluH3
07-24-2008, 09:47 PM
You don't have enough meat there for an EZ out, chances are you will chew thru the sparkplug left overs, and get into the head's threads...and you'll probably drop debris down into the cylinder...and who knows if that will come back to haunt you later...

Time for a conservative decision, pull the head, and you can work at delicately cleaning the threads with a dental pick, followed by a tap if you can get in nice and gentle like....

MOP
07-24-2008, 09:53 PM
You can try it, do not use a wrench on it as it will tip the easy out and can break it then you will be pulling the head for sure, instead use a four point socket on a fairly long extension with a ratchet that will keep the force torsional and will not break the easy out.

MOP
07-24-2008, 09:54 PM
You don't have enough meat there for an EZ out, chances are you will chew thru the sparkplug left overs, and get into the head's threads...and you'll probably drop debris down into the cylinder...and who knows if that will come back to haunt you later...

Time for a conservative decision, pull the head, and you can work at delicately cleaning the threads with a dental pick, followed by a tap if you can get in nice and gentle like....

BETTER ADVICE!!!!!!!!!!!!!!!!

DonziFreak
07-24-2008, 09:54 PM
That sucks....

I would definatly pull the head since thats a high-risk area your working with....drop something into that cylinder and your winter is gonna suck....

Is the thread completly intact or is it so rotted that with will just simply fall apart upon contact?

MOP
07-24-2008, 09:57 PM
Look get the head off, once off you will need a heavy drift punch the same size as the plug tip. A couple of whacks with a hammer will break the thread stiction, then you can use the easy out from the inside out. I know that works been there done that!

ZekesterbluH3
07-24-2008, 09:58 PM
A flute style stud extractor might work better, as it spreads the load through the stuck fastener, an ez out just loads on the edge you are gripping it at...but it still doesn't look like enough meat is there. With both extractors you are meant to drill a pilot hole in the snapped off stud...then insert the extractor with no worry of contacting the outer material...

In your case...I think you'll end up catching it...then it will be helicoil etc...

not worth the risk, sorry not what you want to hear, but at least with the head off, you can clean up all the damaged threads, and not worry again...

DonziFreak
07-24-2008, 09:59 PM
A couple of whacks with a hammer will break the thread stiction, then you can use the easy out from the inside out.


Thats exactly what I was thinking.

MOP
07-24-2008, 10:02 PM
Looking over the pictures again & again I see an added problem, some of the tapered seats are shot. That means you will have a bioch of a time getting some of the plugs to seat, depending just how bad will determine whether or not you will need a real machine shop. Put your camera on MACRO setting and shot the plug holes, I would like to see clear shots!

mrfixxall
07-24-2008, 10:07 PM
Get yourself a can of pb blaster and hose them all down..do this several times a day and do it for several days with out touching the broke off one..

if you tap whats left of the broken off piece eith a brass drift pin and a hammer it may brake loose. at this point what do you have to loose if it dont come out..ive got them out this way,bp blaster you can get at autozone and the stuff works wonders on rusry part..

good luck!

MOP
07-24-2008, 10:13 PM
Problem is -0- meat outside it must be hit from the inside to do little or no damage to the threads. I have a hunch there is more then meets the eye, more pictures please.

Phil

mrfixxall
07-24-2008, 10:17 PM
back in the day we use to take a map torch and warm it up around the rusted bolt and rub the area wit hcandle wax,it would seep in and around the ruster bolt and then they would come out effortlessly.

MOP
07-24-2008, 10:21 PM
What many do not realize is with any threaded item when it is tightened the inserted item pulls upward against the bottom of the threads in the fixed part, this leaves a finite/minuscule gap if the gasket or in this case the taper does not fully seal over time any moisture will work down the threads ruining them. You may get things looking pretty good only to find yourself stripping out the plugs as you go to tighten them, I have seen this far to many times being a salt rat.

gold-n-rod
07-24-2008, 10:27 PM
Wow, that is some serious corrosion for an '03. IIRC, you started with a boat with only a couple of hours. I know you cared for the boat. Too bad the following owner didn't. You have some work ahead of you.

donzi182003
07-24-2008, 11:04 PM
I cant thank you guys enough for all of the advice. Phil I will take the advice and have my mech pull the head. The boat ran like a scalded dog on Sunday so this was an unexpected and unfortunate blow, but it happens. To add to this I just ordered Stainless Marine manifolds from Madpoodle in an effort to ward away any corrosion issues. Needless to say my initial ownership cost is going to be pretty high. I discovered this issue while removing the OEM manifolds.The boat has 149 hours. The guy who bought it from me got it with 108. The rest of the boat is immaculate and looks great, and the engine still runs great. It wasnt poorly cared for, just slightly abandoned 40 hours in almost 3 years is not good for anything. What kind of cost am I looking at to get this done? I wish I had the time and the tools to self perform the work.:(

ZekesterbluH3
07-24-2008, 11:09 PM
The H III that fell into my lap has had 0 hours......in 9 years...

Tidbart
07-25-2008, 09:20 AM
I had this exact problem a few months back.

First, I chipped out the rust from around the area as best I could.

Second, shot it with AeroKroil for several days.

Third, heated the area of the head around the plug with a map torch

4th, tapped in a fluted extractor. More Kroil, more heat....

5th, Broke it loose with 1/2" breaker bar. Felt like I snapped the extactor in two when it finally let go.

This with the head still on. Luckily the node on the end of the plug stayed together and nothing got into the cylinder.

So, it can be done without removing the head, just a lot of time, effort and care.

A couple of months later, I ended up rebuilding the motor anyways, as some of you know.:doh:


Bob

DonziFreak
07-25-2008, 10:06 AM
This with the head still on. Luckily the node on the end of the plug stayed together and nothing got into the cylinder.

So, it can be done without removing the head, just a lot of time, effort and care.


Bob


Theres no doubt in my mind it can be done with the head on, the problem is just that theres not a lot of room for error in that area.....

DONZI
07-25-2008, 10:13 AM
Me, I'd try the extractor method 1st. Thats probably whats going to happen on the work bench anyways.
If that didn't work i cut a slot skillfully/slowly 1/2 thru the depth of the inside with a modified hacksaw blade. Trying to avoid the threads. It doesn't have to be that deep of a cut.Even 2 slots cut can weaken it enough.Then bring the cyl. to T.D.C.. Insert some rope into the cyl. and filling it.Tap a small angled wedge chisel between the material and cyl..Sometimes the piece will actually fall off because you've created space for it to seperate. If it begins to peel you can grab it with needle nose vise grips and remove it. Remove the rope and shop vac the cyl..
Just another thought.:smash:

MOP
07-25-2008, 10:27 AM
If you attempt doing it on the engine, turn the engine slowly with a stiff wire about 2" in the cylinder. You need to be sure the valves are not fully closed so when the piston hits the wire stop. Use a grease gun and pump a full cartridge, again turn the engine slowly forcing a little of the grease out. Then go about your try at getting the threaded piece out, once it is out turn the engine slowly until the grease comes out. Next get a big wad of rags held by the spark plug hole and spin the engine over with the starter that will get most of the rest of the grease out! No other way will keep the junk out of the cylinder!

I still do not agree with not pulling it apart as I feel the threads will show damage and not hold a plug, yes you can rig it but Heli Coils and inserts just are not trust worthy. I have see several blow out plug and all then you are back to square one doing all this krap over again!

Barry Eller
07-25-2008, 10:39 AM
The plug does not look like a marine sparkplug. I use Delco MR43T, they won't rust like that.

Tidbart
07-25-2008, 11:11 AM
Theres no doubt in my mind it can be done with the head on, the problem is just that theres not a lot of room for error in that area.....

You got that right. Actually, no room for error. At that time, I didn't want to remove the heads and got lucky.

Looking at the photos, the exhaust is off already. If I was at this point, the heads would come off. It is so much easier to do this kind of thing out of the boat. My guess is that it is not an MPI, so yank the intake and the heads (MPI being a little more of a job).

B

donzi182003
07-25-2008, 11:16 AM
The corrosion in the photos looks scary but 99% are the remnants of the corroded spark plugs around the holes. The rest of the engine is spotless and it is a 2003 at the end of the day. I observed that the other plug holes did not have any corrosion and the threads were intact. This issue happened due to a rusty plug. The rest of them came out only due to myself exercising precision turns in order not to strip them also. My mech told me that he has had this happen before and 70% of the time he can extract them no problem. I am reaaaaly keeping my fingers crossed. He made a good point. If we try to extract and it works we come out ahead. If it doesn't work, we gotta pull the head regardless. So it cant hurt to try.