Metal shavings inside engine

[Fourthbean]

You guys managed to help me get my sts 30 d30m started in a previous thread, we have been running the truck the past few days and although it was hard to start it had plenty of power and we always made sure there was blue smoke coming out (I hadn't gotten around to tuning the LSN yet).

Today it was being especially hard to start, I had taken out a shim from the head thinking it was only supposed to have one silver one in there (I pulled out one copper shim). (in afterthought I am not sure if this was correct or not).

I managed to get it started and was messing with the tune as I had goofed with the HSN getting it to start. There was almost always blue smoke coming out, however it seemed as the engine warmed up there was less of it (and I was richening it along the way). The power just wasn't there, I ran it down the field, braked, and then gunned it and the engine died. I brought it home to put the shim back in and see if that was the problem. After getting the head off I see that the glow plug is completely gone (no coil) and there are silver metal shavings about 1mm square in the combustion chamber. I continued to disassemble the engine and found more in the crankcase. I attempted to take some pictures but they are all blury.

There is a groove where the connecting rod moves around the crankcase and I can see where the rod has scraped on the side next to the bushing. I sprayed the engine out with carb cleaner and got the engine to rotate however somewhat clunky. When slowly turning it the correct way it will sometimes get caught where the connecting rod comes close to the crankcase on the downward stroke.

After explaining all of this it really seems stupid to ask if the engine is dead, as that does seem quite obvious.

Though I am curious what I did wrong! Will an air leak cause this? How many seconds of lean running does it take to destroy an engine?

Thanks for any help on avoiding this the next time I run an engine.

Hmm, it seems to be turning smoother now. Maybe there was still a piece of metal blocking something. It still has friction at TDC as if it still has pinch, however there are some nicks on the edge of the piston.

 

[jetmechG550]

If the sleeve is scored, chances are it's toast, since as an engine heats up it expands and the scoring in the sleeve will only be a greater problem. A couple things could have happened, when and engine runs lean the coil on the plug tends to turn white, and become distorted from the extreme heat. It's possible as it become distorted and brittle, it broke and was sucked out on the downstroke and that was what got beat around inside.

 

[olds97_lss]

Well... I've been running an OS21RG that I dinged up about 5 gallons ago. If you got all the metal shavings out, cleaned it up, lube it up, it should run. You might want to check and make sure your wrist pin clip is still holding the wrist pin in.

It's not uncommon for a new engine to have metal shavings in it either... I've laxed in my typical new engine process of tearing it down, cleaning it out with DA and lubing heavily with ARO before the first time I start them... got too excited when I got my LRP to do that. But, even my OS engine had aluminum dust/shavings in it when I cracked it open the first time before ever starting it. Out of the box brand new and there was a film of aluminum shavings in the crank case. Must be from the milling process.

Anyway, I dinged my piston because I stuck a plastic coated handle of a steel plier in the exhaust port to hold the piston and keep the crank from turning when I installed the flywheel nut... hind sight, bad idea. It put a nasty dent in the edge of the piston that made it "catch". It did that for about a gallon... doesn't do it anymore (5 gallons later). I'm sure I lost some compression by damaging it, but it still runs. It's my winter engine now in my aftershock.

 

[Rolex]

It sounds like the whole problem was due to running too lean. If the LSN is too lean, you'll get great punch off the line, but the engine temp will get very high, no matter how much you richen the HSn.
If it will still start and run, consider yourself lucky.

 

[Fourthbean]

It must've been my LSN then. Thanks for the tips, I am going to try and start it today as I cleaned it up nicely and put the backplate back on with some silicone yesterday.