Piston rings

**Tue Sep 06, 2005 9:32 am » Post: #1 » Download Post**

Bit of a bugger trying to decide which is the top ring. Finally sorted it by putting them in a vernier caliper, but there's not much in it is there?

You'd think they could stamp t and b on there wouldn't you?
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**Tue Sep 06, 2005 9:46 am » Post: #2 » Download Post**

Oh, Mr. Ett... and you work on aircraft! Shocked

You can SEE the difference in the rings! Confused

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**Tue Sep 06, 2005 9:55 am » Post: #3 » Download Post**

Hmm. Snot easy though is it? I even read the workshop section to check, and I'm not sure I understand what you're getting at with the 'keystone' bit.

Maybe it's just the bad light in the workshop, cuz my eyes are perfect.

Or more likely the skinfull I had last night has blurred my brain! Confused

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**Tue Sep 06, 2005 10:40 am » Post: #4 » Download Post**

Here you go.

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**Tue Sep 06, 2005 11:56 am » Post: #5 » Download Post**

Cheers bud. I assume 'keystone' is a Honda description, but I'm not sure why they arrived at it.

I'd call it a chamfer...
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**Tue Sep 06, 2005 11:59 am » Post: #6 » Download Post**

Always been a keystone as long as I can remember.

Referred to as a keystone ring by Haynes right back in the old MBX125 days, and that was a long time ago! Shocked

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**Tue Sep 06, 2005 12:31 pm » Post: #7 » Download Post**

Having pondered this since the last post... it may be because when building a stone arch bridge, there was a 'key' stone at the centre, shaped as the ring is, which held the whole bridge together.
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**Tue Sep 06, 2005 12:41 pm » Post: #8 » Download Post**

Dave Ett wrote:
Having pondered this since the last post...

Don't you have anything better to do?! Laughing

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**Tue Sep 06, 2005 12:56 pm » Post: #9 » Download Post**

Yeah, I'm rebuilding my engine, but I can do that, reply to forums and think at the same time! Wink

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**Tue Sep 06, 2005 1:58 pm » Post: #10 » Download Post**

What did you do about that cyclinder I lent you? Just gonna slap it all on or what? I dont want you killing it or anything you hear, ive got about 6 dead ones at home now anyway... and i dont need any help. Wink

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**Tue Sep 06, 2005 2:15 pm » Post: #11 » Download Post**

I've cleaned all the gasket crap off, and the corrosion as best I could, and it's now torqued down. i don't want it killing my piston either!

Once we've decided where I should send my barrel to, and I've had it replated, I'll swap them over and send yours back. Unless I sieze it first, in which case I'll fix it then send it back!

Incidentally, What do the L2, L3 and H3 marks on the side of them signify?
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**Tue Sep 06, 2005 11:19 pm » Post: #12 » Download Post**

If you put the top ring in the bottom groove it won't move freely in the groove or at all. Then you know it's wrong. I'v done it !
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**Wed Sep 07, 2005 6:47 am » Post: #13 » Download Post**

So I shouldn't have tapped it home with a mallet then? Shocked

Only joking. It wouldn't fit so I left it off... Laughing

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**Wed Sep 07, 2005 7:18 am » Post: #14 » Download Post**

The idea of the keystone top ring is for it to expand against the bore to giving better sealing. It's also helps against the ring sticking inthe groove.

It will only fit comfortably in the top groove the correct way up.