Author Topic: Spark Plug (Read 3055 times)

Nick1911 · « **on:** November 27, 2006, 03:21:22 AM »

I pulled the plugs out of my (non-running) engine yesterday. This is what #2 looked like:

Comments?

280plus · « **Reply #1 on:** November 27, 2006, 03:24:44 AM »

Yowch!

Is it burnt or was it smashed by the piston? What do the others look like?

Nick1911 · « **Reply #2 on:** November 27, 2006, 03:42:54 AM »

The others are fine. This one was damaged by *something* although I'm not sure what. Unless the connecting rod gave way (AFAIK it didn't), the piston can not hit the plug. However, the engine may have bent valves, which the piston did hit. I've pretty much written the head off as a total loss, however I'm hoping the cylinder doesn't look like the spark plug!

This engine does not have sleeves. If the cylinder is badly damaged, it will need a new block.

280plus · « **Reply #3 on:** November 27, 2006, 03:48:41 AM »

Yup, some kind of debris must have been beating around in there. I'll keep my fingers crossed for you on the cylinder wall. I'm sure you know that if you can hook a fingernail in any scratches it's junk. Couldn't you bore it? It's not unusual to bore one cylinder and replace that piston only. I wouldn't do it to the race motor but it shouldn't hurt the every day drive around one. Good luck.

Nick1911 · « **Reply #4 on:** November 27, 2006, 03:50:58 AM »

I may be able to bore it out. The only issue there is, I know it's going to cost quite a bit of $ to have it done, and the block is a bit too big to fit in my mill if I wanted to try to do it myself somehow or another.

280plus · « **Reply #5 on:** November 27, 2006, 04:12:22 AM »

Well, see what you got first then worry about it if you have to. If you can do the dismantle and rebuild yourself and take a stripped block to a local shop I can't see it costing too much to bore one cylinder. You'll have t buy a new piston and rings I'd say, and probably a new plug, that one looks done. grin

Nick1911 · « **Reply #6 on:** November 27, 2006, 04:17:09 AM »

Bah, that plug is good for another 50,000 miles

"Tis only a flesh wound!"

grin

280plus · « **Reply #7 on:** November 27, 2006, 04:23:56 AM »

LOL...

Sylvilagus Aquaticus · « **Reply #8 on:** November 27, 2006, 06:39:06 AM »

Does it turn over under the starter enough to get a compression test?

Regards,
Rabbit.

Nick1911 · « **Reply #9 on:** November 27, 2006, 06:40:35 AM »

Yes, it does. However - two of the rocker arms for cylinder 2 do not exist any more, so it wouldn't really tell me much for that cylinder.

K Frame · « **Reply #10 on:** November 27, 2006, 07:30:45 AM »

The only thing I've ever seen similar to that was an engine that had ferocious pre detonation problems.

280plus · « **Reply #11 on:** November 27, 2006, 08:03:00 AM »

Quote

two of the rocker arms for cylinder 2 do not exist any more

Yea, I think you need those.

Ezekiel · « **Reply #12 on:** November 27, 2006, 08:42:45 AM »

I had a high-revving 225hp turbo four that was filled with 87 when I'd been using 93. Massive detonation destroyed a plug: but I had a variety of gauges that told me something was wrong before it got TRULY ugly.

Man, I don't think mere detonation can do that.

Yuck! Sad

lupinus · « **Reply #13 on:** November 27, 2006, 08:46:28 AM »

I believe you need a new spark plug

El Tejon · « **Reply #14 on:** November 27, 2006, 09:05:30 AM »

Just what exactly are you building over there across the river that would do that to a spark plug? rolleyes

Should I just look out my office window and look for the column of smoke? grin

Nick1911 · « **Reply #15 on:** November 27, 2006, 11:13:00 AM »

El T -

Probably.

I'm working on this car at Williamsburg on the Walbash. Better be on the look out for flying debris.

grin

French G. · « **Reply #16 on:** November 27, 2006, 07:13:17 PM »

So when do you pull the head? My guess is the valve broke and the loose pieces mated with the piston and then proceeded to mate with the head/spark plug. I say piston trashed, valve already trashed as if you couldn't guess, combustion chamber not happy. Who knows, you may get lucky and the block is okay. I feel like you are coming to own this fine piece after the damage was done, mainly because the whereabouts of the rockers is a mystery. Tells me the previous owner knew they did a bad thing, just not how bad. What type of motor?

Matthew Carberry · « **Reply #17 on:** November 27, 2006, 08:15:55 PM »

Quote from: French G. on November 27, 2006, 06:13:17 PM

So when do you pull the head? My guess is the valve broke and the loose pieces mated with the piston and then proceeded to mate with the head/spark plug. I say piston trashed, valve already trashed as if you couldn't guess, combustion chamber not happy. Who knows, you may get lucky and the block is okay. I feel like you are coming to own this fine piece after the damage was done, mainly because the whereabouts of the rockers is a mystery. Tells me the previous owner knew they did a bad thing, just not how bad. What type of motor?

I guess that's what they call "angry love". grin

AmbulanceDriver · « **Reply #18 on:** November 28, 2006, 04:43:11 AM »

E-mailed this picture to my dad (he's a mechanical engineer, built and broke in race engines when he was young).

His reply was one word:

OUCH!

Nick1911 · « **Reply #19 on:** November 28, 2006, 05:32:26 AM »

Actually the rocker arms were in little bits under the valve cover - I removed them earlier.

I have no idea when I will have time to pull the head. Probably around Christmas time.

drewtam · « **Reply #20 on:** November 28, 2006, 02:16:25 PM »

I still think that the tip was broken off when the plug was removed. Even though I know that the valve train failed and has contacted the piston.

The fracture surface indicates a ductile failure.
There is not much material protruding into the combustion chamber for even a valve head to smack against it hard enough to snap it off.
If it failed ductily, then it wouln't snap, it would bend.

So my guess is that the tip was bent or warped into the head/combustion surface so that it was mechanically locked with significant residual stress. And that when the plug was pulled, the tuning of the ratchet snapped the tip off and the rest unscrewed.

Let me know how far off I am when you pull the head.

Drew

Brad Johnson · « **Reply #21 on:** November 28, 2006, 02:20:56 PM »

Quote

ductile failure

Does that mean there is also such a thing as a goostile failure?

laugh

Brad

drewtam · « **Reply #22 on:** November 29, 2006, 03:30:53 AM »

Quote from: Brad Johnson on November 28, 2006, 01:20:56 PM

Quote

ductile failure

Does that mean there is also such a thing as a goostile failure?

laugh

Brad

So many people to ignore. So little time.

Brad Johnson · « **Reply #23 on:** November 29, 2006, 08:37:41 AM »

You couldn't ignore me if you tried. My brother ignored me once. Once!

grin

Brad

p.s. - "It's an .88 Magnum. It shoots through schools!" -D. Vermin

drewtam · « **Reply #24 on:** November 29, 2006, 04:58:55 PM »

I just thought it would be rich to pull your signature to the side on you.

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Author Topic: Spark Plug (Read 3055 times)