Impeller touched slightly, possible cause cylinder damage?
 

When my supercharger ran dry and seized, the impeller touched and sheared off a small amount of metal. The particles probably would have been very fine. I am wondering if they could have etched the cylinder walls when going thru the intake tract. Or would they have settled in the huge HKS S type intercooler I am running?
I ran the engine probably 2.5 hours NA while waiting for a replacement HKS blower and it seems OK though not optimally tuned. Startup isn't as smooth and sounds like knock at initial crank but I'm not sure. Would the heavier 40 weight oil I am running have better suspended any trapped particles? I am not so worried that I'd have the pistons removed at this point and will pay attention to any suspect compression loss when I get a new blower in place. Should I maybe change the oil just to be safe?
Since a centrifugal blower runs like a turbocharger compressor, surely people have had turbo impeller touch in the past.
Anybody here with experience in this type of scenario?
Incidentally, if I remember correctly one of the features of the FAr0 engine is that the pistons can be removed just by opening the bottom of the engine (not sure how crankshaft is removed). I am hoping there is no functional damage.

Normally I'd say scope the cylinder but that's a bit difficult with the FA20...

Totalled

Change the oil, like you said. If you find the need to, maybe drop the oil pan and take a peek up in there and see if you can see anything. You might need to remove the oil pickup and some baffling to get a clear view.

How big was the chunk of metal?

Yes, I've had an engine ingest turbo impeller fragments. Engine required a rebuild.

Sorry man!

Well, back in the day, we would have run a compression check ....... that would have told us whether or not any piston compression rings were damaged or any valves were not closing all the way.

Of course it was easy then, just pop out the spark plugs, insert compresssion gauge in the spark plug holes and crank the engine over.......:popcorn:


humfrz

It's not quite THAT easy with a Boxer.... but doable.

Yep, kind of looks difficult ..... :bonk:

I reckon when my FR-S needs new plugs ...... I'll just trade it in for a new one ..... :D


humfrz

I've had engines swallow entire plug tips and survive with merely superficial markings on the pistons. I wouldn't say the engine is a total loss, by any means, but I would still inspect what I could just to verify.

More likely to be stuck in the intercooler, so I think you're fine. But by all means, compression check would be the easy way to verify.

Beat me to it, sir. Just look for any "significant" difference between the cylinders.

Seems like the pieces could be shaken out, no? Shop vac with a little shaky shaky tap tap?

I'm going to bet that the massive intercooler I am using (HKS S Type, popular for Surpras) has some oil in the bottom from the original owner, in which case the metal particles will be trapped there forever.I am planning to install my replacement supercharger and keep my ears and butt focussed initially if I sense anything is off. I am concerned, but not enough to have the sparks removed to scope the cylinders unless something seems off. I wanted to see if someone would say thats a definite danger, I must have the engine opened up or else. Hopefully the fine particulate is in the intercooler or was fine enough that 40 weight oil trapped it and it eventually burnt up or passed below the piston rings to eventually get caught in the oil filter. Just hope it didn't badly score the rings/cylinder walls.

bore scope or compression test first. if you have to lower the subframe and motor