2005 Thunderbird with a Chewed up Piston... you're not gonna belive this!

[anupmathur]

Oh, maybe it's the terminology we are using!
Seized is used when an engine has totally jammed and refuses to move/turn.

The pics of the piston of your bike show severe scuffing but I would not term it as a seized engine if it could be cranked or started.
Such scuffing marks are not visible on the RE piston photos. The liner walls have what seems to be a glazed portion or it could be deep scratches, but that does not look like scuffing to me.

[Yogesh Sarkar]

Sir doesn’t engine seizure = Piston expanding due to heat and coming in contact with the cylinder side wall?

As far as I have heard, engine seizure in modern four stroke motorcycles doesn’t normally leads to permanently jammed up engine and as the piston starts to cool down slightly and contracts somewhat, engine can be switched back on. Of course a lot of this actually depends on the materials used to build the piston and oil flow design.

[anupmathur]

YS, I'd call it scouring or scuffing if the engine is not jammed up.
Piston seizure is when the piston has locked up solid and nothing can be moved.

[Yogesh Sarkar]

Hmm... could be, though mechanics call it seizing. In any case, as long as the machine is running and performing upto a certain level, it really does not matters.

Mohsin you might want to check whether or not the oil strainer/filter in your bike's engine was clogged and were you using the recommended spec engine oil?

[KurtRules]

RE's!! One incident that happened to me day before yesterday .. Took puneet's RE to delhi ... was steadily cruising at 90+ ... Near Ambala, the gasket tore! The engine lost pressure, resulting in oil leakage and the engine throwing oil back to the filter ... Had to take it back to chd at a speed of 20-30, more than which wud have surely resulted in a seizure, at the rate the machine was losing oil ...

[mohsinp]

Thanks all for the awesome responses. Well, to begin with, I agree with Anup's assessment. The piston is scuffed and broken in my bike. The engine however, did not seize. An engine seizing to me is a total failure of the piston to move causing the entire engine to freeze during operation. It is totally conceivable that an engine allowed to cool down sufficiently can 'un-seize', however, the damage has already been done.

In my case, I think that the piston lubrication hole near the gudgeon pin may infact have been blocked. The piston is lubricated by a thin film of oil that is pumped up into the cylinder walls with each stroke. The piston rings prevent the oil from reaching the top of the combustion chamber. The scuffing may have happened when the piston crown fractured causing oil to enter the combustion chamber preventing lubrication of the cylinder and piston walls. The primary event in any case seems to have been the disintegration of the piston itself.

I'm going to have to take a close look at the oil strainer. If there are metal shavings there, then that would indicate that the crown broke apart first, then the scuffing. I've talked this over with my mechanic and he claims that the metal shavings will not pose a problem in the future, but I know otherwise. I'm going to insist that he split the engine and clean out the oil channels. He claims that the RE Thunderbird '05 model's engine is very difficult to get running smoothly one the engine has been split. Any comments on this? And yes, the oil was of the recommended spec. I got a new piston yesterday, that cost me about 944 bucks. And I've have the cylinder re-sleeved. The valve and valve heads have been refined and smoothened out to get a better seal. The only thing that happened was that a I lost power while riding and there was a definite loss of compression while engaging the kick.

Kurt, good think you saw the oil leak. I hope that you get the engine checked out. If the pistion has been scuffed, you can probably fix it now and save yourself the kind of crap that I've been through.

And yes, this is a part of bonding with the machine. I love that beast even more now. Any pointers on running this thing in properly will be very helpful to me. One day, I'm sure I'm gonna meet up with you guys at Leh!

Anything else that I should look at before I fire this thing up on Tuesday?

Originally Posted by anupmathur

YS, his RE engine did NOT seize! That's a bit perplexing.

And how could you have gone on to make two two trips to Ladakh on a seized engine?

Yogesh,did you ever see white smoke coming out the exhaust? If you did, then the piston was scuffed and the rings were not dong their job in maintaining compression pressure inside the cylinder. You would have noticed a drop in power. If you didn't then the scuffing happened after Ladakh. A seized engine is one that refuses to move (crank, turn over) after reaching operating temperature. An engine can possibly seize then cool down and restart provided that the primary incident did not damage major components beyond hope. In my case, I never seized. I gradually and steadily lost power until the engine died and never started again. The kick was free. TOO free. I know the reason now, NO compression!

[anupmathur]

Originally Posted by mohsinp

He claims that the RE Thunderbird '05 model's engine is very difficult to get running smoothly one the engine has been split. Any comments on this?

Yes, two thoughts:

1) The mechanic has not done the job before and/or did not get it right the last time he did it! Hence the advice not to fully dismantle. Please confirm.

2) There is a possibility that there is no locating pin or dowel to seat the cylinder EXACTLY on the correct axis with respect to the crank. If the piston is not in exactly the correct position, there will be rapid wear of the liner, resulting in another big failure!
Some engines call for the assembly to be done with the piston slightly displaced from the centre axis. Correct posture is acquired after reaching operating temperature!
These are details that ONLY the RE office can provide.

I am not familiar with any motorbike engines. My advice is based purely on my understanding of engines in general.

[Yogesh Sarkar]

Just a thought, wouldn’t cleaning the engine with diesel i.e. pouring it inside and then using the kick starter to let it flow to various sections, clear out most of metal scuffing?

Originally Posted by mohsinp

Yogesh,did you ever see white smoke coming out the exhaust? If you did, then the piston was scuffed and the rings were not dong their job in maintaining compression pressure inside the cylinder. You would have noticed a drop in power. If you didn't then the scuffing happened after Ladakh. A seized engine is one that refuses to move (crank, turn over) after reaching operating temperature. An engine can possibly seize then cool down and restart provided that the primary incident did not damage major components beyond hope. In my case, I never seized. I gradually and steadily lost power until the engine died and never started again. The kick was free. TOO free. I know the reason now, NO compression!

I know scuffing happened before my trips to Ladakh, because I know when it happened. It happened when I was trying out Mobil 1 5w50 engine oil and was returning from Rohru in June and the valves had developed some problem. We were riding fast and hard in June heat and the engine died twice, just like it had last time it “seized” and service center guys had replaced the piston and cylinder kit for free, even though the bike was out of warranty!

After reaching Delhi, I got valves changed, but didn’t get the engine opened to get it checked and it continued to perform nicely till my second trip to Ladakh, where it took a severe beating and had to be changed afterwards.

[anupmathur]

Originally Posted by Yogesh Sarkar

After reaching Delhi, I got valves changed, but didn’t get the engine opened to get it checked

YS, you can do a fairly reliable check even with the cylinder head removed for valves renewal. With the piston at BDC, take a good look at the bore/liner. If there has been any scoring/scuffing issue, it will be painfully obvious on the walls of the liner.

[mohsinp]

[QUOTE=Yogesh Sarkar;65510]Just a thought, wouldn’t cleaning the engine with diesel i.e. pouring it inside and then using the kick starter to let it flow to various sections, clear out most of metal scuffing?

You mean, clean out the metal shavings from the oil channels right?