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Discussion Starter #1
First let me say I got this entire 1995 T-Bird (well, 80% of it, anyway) for under $300, and I knew it was a basket case.
Now the question: what would you do with thsi motor?
As you can see, somehow this engine sucked in a nasty and it got by the valve. "Pinging" the previous owner heard was the piston masticating this bit. I got it with the top end already apart.
I'm thinking if I replace just that piston, and all rings, and have the jugs honed, that I might be okay...? Perhaps try to smooth the pock marks out of the head, but maybe just leave them?
All else on this engine seems to be hunky dory, and the valves or seats are not damaged for this cylinder (which is either #1 or #3 - not sure which end Triumph counts from). If the odo is to be believed, this engine has only 6,100 miles, so it seems like it's worth a try to save it.
 

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It will be interesting to see what the people with the knowledge & experience say on this. I think piston/hone & ride it as long as the valves are good. I'm not an expert, just what I would prob do based on a quick look at your pictures.
 

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If I were doing it, I'd replace that cylinder liner and find a different head. If you want to do it on the cheap, you can try honing the bore, but it looks like it's got some pretty deep scratches. The head must be smoothed off. All the high spots will become hot spots and cause preignition, which will destroy the engine.

Did you find the bit that caused it all?
 

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Might can smooth out most of the dings in the head with a stiff, straight wire brush in a high-speed electric drill. Try not to remove any more material than absolutely necessary to avoid altering the head ccs/compression in that cylinder.

Try honing the liner to see if that removes scratching. If not, one new liner.

Same wirebrushing on piston top (or glass beading). Maybe even a tiny bit of flat plate/sandpaper milling to smooth out. If it looks ok after that, use it; if not, one new piston, but match weights to the other two. New rings, of course. And might as well hone and re-ring the other two, just to even things up.

JMHO.
 

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Same wirebrushing on piston top (or glass beading). Maybe even a tiny bit of flat plate/sandpaper milling to smooth out. If it looks ok after that, use it;
If you do this (I wouldn't bother) pay close attention to the top ring clearance in the groove. Most likely the groove has been mashed shut somewhere. Also, check the piston skirt for out of round. If the piston gets whacked too hard it will distort the skirt. Sometimes you can see evidence of the piston skirt scuffing on the cylinder wall.
 

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I'd part out everything else and find a running bike. I'd rather be riding than wrenching.
If you're only in $300, listen to Ssevy.
 

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Sevvy is right on this one. Look at all the spare parts you have for $300!
Aside from a new bike, used pistons and cylinders can be bought for reasonable prices (cheap).
 

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Discussion Starter #10
Thanks for the replies. Interesting that they seem about 50/50 for and against.
with all due respect to the "dump it and ride" precincts, I love wrenching, especially when i have a fair chance of putting a neglected or forgotten machine back on the road.
am still weighing my options on this one, and not liking finding out that apparently just the gasket set for this engine is around $180! Can that b right? Other than that, a decent used piston is no big deal, and if i have to replace the sleeve, i can live with that. I would definitely try to re-use the head before ponying up the $$ for another.
now back to hemming and hawing
 

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I picked up a set used daytona liners with the pistons, rings, rods and bearings for less than the price of that head gasket. The head gasket is just the price of doing business, I guess.
 

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Discussion Starter #13
In the photo of the piston, it sure does look like a crack. But I checked and there's no crack. It must have been a hair or something on it when I took the pic.

Thanks again for all the replies.
 

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"I picked up a set used daytona liners with the pistons, rings, rods and bearings for less than the price of that head gasket. The head gasket is just the price of doing business, I guess."


Ditto. Waiting on this winter to get the block milled out to fit the larger liners and bump up to 955 CC's. Purchased liners, pistons, connecting rods and bearings out of a bike with 7K miles on it. Also thinking of going up to the FCR flat slide carbs as well. Will require new rings, honing the liners I got with the pistons and a new head gasket. Seems an awful lot of work for 70 cc's though? I think it's more about bragging rights at this point. lol
 

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Mine aren't from a 955, just plain old 900 Daytona parts. I was wanting more compression, but these pistons don't appear to be domed, so I have a set of parts if I need them.
 

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Domed would be the rare higher 12:1 compression ones? Using those would be the better route, as you stand to gain more then HP with less effort. I bought these as an insurance policy in case the motor didn't turn over and the pistons/liners were scored/seized. A salvage yard I get parts from had them, and offered me the whole block for next to nothing. Got the red cams as well, but didn't use them. Went with the green instead.
 
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