First engine maintenance! Disaster?

[VONCE]

Last night I decided to tackle the seasonal engine maintenance - oil change and plugs. The oil change went fairly smoothly. Replacing the filters got a little messy but that's what rags are for. Only (less than) 2 quarts of oil came out of each engine. After reading through posts, this can be normal, try parking on an incline, etc. Oh well - I am not too worried about it. I'll probably just change the oil twice a year anyway to compensate for the oil leftover in the engines.

On to the spark plugs! Oh man, these are easy to get to! This is easy! Well, the second plug from the back on the starboard engine had some better plans for me. I gapped it, smeared some anti seize on it, threaded it in by hand. Put the ratchet on the extension and snugged it up. I always hold the ratchet with one hand up pretty close to the head of the ratchet so I don't have a lot of leverage to overtighten things. This has been my tried-and-true method for 10+ years and I don't plan on changing any time soon! Well, things started getting snug, I kept going a bit because I hadn't felt the washer crush, and then everything was loose again. The ratchet spun pretty freely. Uh oh, I think I stripped it. I grumbled a bit, pulled out the plug and found this:



So I was expecting the worst. I called my mechanic friend over. He hopped up in the boat and took a look. Pulled his flashlight out and looked down in there. Asked me to hand him a magnet. He uses the magnet and pulls out the threads (that I thought and assumed were stuck in the head). I handed him a new plug and it went in and tightened down with no problem.

Still don't really understand what happened. I don't understand how those threads just hopped out of the head. I know I tightened that spark plug down. And as I was tightening is when I felt the break. So those threads should have been stuck in there. But no, they were just sitting there. Oh well! Things are well, now! And I got some more time to catch up with my friend since he didn't have as much work to do!

 

[bronze_10]

Uh.... weird!

 

[PEARCE]

Been there done that! I had to back the threaded part out though. No big deal once I realized what happened and I had gotten lucky that the rest of the plug didn't break off with it. It doesn't take much torque to snap these little plugs. Just make them snug and call it good.

 

[Noko]

[QUOTE="VONCE, Were the threads inside the cylinder? If they were, I'd really make sure there aren't any pieces of that plug left sitting on top of the piston.

 

[ripler]

@VONCE A quick tip about keeping the oil change, I use a paint roller pan liner under the engines when I change the oil, this catches the oil when you remove the filter and I use my extractor to suck the oil from the liner. I also line the area under the engine with puppy training pads just in case.

 

[itsdgm]

Wow. Usually the threaded end of the plug is stuck in the head when that happens and requires an extractor to get it out. You dodged a bullet there for sure.

 

[Bruce]

The biggest danger is that part of the spark plug could remain inside the cylinder.

 

[merlinjet]

Been there done that! I had to back the threaded part out though. No big deal once I realized what happened and I had gotten lucky that the rest of the plug didn't break off with it. It doesn't take much torque to snap these little plugs. Just make them snug and call it good.

x 2...snug is good. Another tip for a clean oil filter change is to wrap a resealable baggie around the filter before you spin it off. Remove, seal it up...no muss, no fuss.

 

[Matt Phillips]

Wow...sounds lucky. Here's a couple of tips I've learned over the years:

On oil: Get yourself some puppy piddle pads and place them below the engines. They are cheap and help lots at catching errant filter spills that will happen.

On changing the plugs: Get yourself a magnetic spark plug socket if you don't have one already as this will hold it onto the socket better. I then use a 6" extender and tighten down the plug by hand, then it ONLY GETS 1/4 turn once there's resistance. They don't need to be any tighter. And ALWAYS use anti-seize on the threads as the #3 cylinder on those MR1s has been known to seize.

 

[Bennie]

I second @Matt Phillips - Hand tight then quarter turn. That is plenty enough to crush the washer. Remember that this is not a bolt.

Also warm up those engines for 10-2o minutes each before changing the oil, that will assist in extracting the oil in a less viscous form. Otherwise you might as well as be trying to pull up concrete... not fun. Then pre-lube the your oil filter and the seal on it.
(just little tips/tricks) Sounds like you did a great job!! Especially at dodging that bullet

 

[veedubtek]

What makes anything tight is resistance. Pulling an object (the spark plug) against the cylinder head is what causes the resistance and causes it to get tight (and slowly crush the washer). Once it snaps off, the resistance is gone. The threads and object threading should never be tight itself, else you have other issues. Perfectly normal scenario.

Could be a faulty plug. Could be the result of the never seize acting as a lubricant on the threads, but I won't get into my rant on that.