Author Topic: Engine blown - Cylinder spigot fractured  (Read 9978 times)

Online RichardL

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Re: Engine blown - Cylinder spigot fractured
« Reply #15 on: 28.11. 2011 21:19 »
I'm anxious for Australia to wake up and chime in.

How about this theory: Around the base of the good skirt, and where the broken skirt should have been, are apparent machined landings not present on the eBay barrels or, to my recollection, on my own. What if, some years ago, an ingenious Indian machinest decided that the best way to sleeve the bores was to remove the cast skirt and create a combination skirt and sleeve that installs from the bottom and is shouldered to stop at the machined landing?

Any takers?

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline Duncan R

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Re: Engine blown - Cylinder spigot fractured
« Reply #16 on: 28.11. 2011 21:47 »
Could someone tell me the mesurements of the flanges ie. thin vs thick. It would be useful to know in case I come across some

Thanks

Duncan
Anglo - Indian A7SS (Actually is a 650)
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Offline chaterlea25

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Re: Engine blown - Cylinder spigot fractured
« Reply #17 on: 28.11. 2011 21:52 »
Hi Bill, Richard, Duncan
Bill,
Yes, you are probably correct , when I opened the pic in photo editor and magnified it, the intact side looks
1 piece, in A cylinders I have seen relined the liner fits inside the original cast piece (spigot??) below the base line
and does not replace the original, as in Duncans,
They are just a push fit at the bottom so as not to burst apart the thin piece of the original barrel
(I hope I'm explaining this ok???)

Richard,
yes, I can see a machining mark on the liner, this is common enough when fitting liners from the top
it gives a lead in and in some cases its also a stop to prevent the liner dropping down, jacket will have a corrisponding step machined

Duncan, 
Thick flange is near enough 1/2 inch,

Regards
John O R
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1963 RGS (ongoing)

Offline Duncan R

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Re: Engine blown - Cylinder spigot fractured
« Reply #18 on: 28.11. 2011 22:07 »
Thanks John
Anglo - Indian A7SS (Actually is a 650)
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Offline MG

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Re: Engine blown - Cylinder spigot fractured
« Reply #19 on: 28.11. 2011 22:40 »
Wow, what a dreadful thread to find!!! Sorry to see that sort of damage, Duncan.

I think Richard hit it on the head, the (probably damaged) rhs spigot was machined off and a liner pressed into the barrels. The liners are usually low-grade nodular or vermicular cast iron, with little tensile strength and low braking elongation, i.e. not very strong and more or less brittle material (but with good running and lubrication properties due to the carbon content and surface structure). The thin liner is exposed to a bending load by the piston changing its lay-on side at BDC, and without the support from the original cast-on spigot it did break caused by fatigue, right where you would expect it to.
I bet the liner wasn't even stepped, although that wouldn't have helped a bit anyway! It would break right where the change in diameter is (stress concentration in the notch), and not prevent the liner to move downwards with the pistons. The only thing that makes sense is a flange on top of the liner, with a matching recess in the barrel's mating surface, so that the liner is fixed in both directions as the flange is clamped by the head (mating surface has to be skimmed of course). This and a good press fit in the barrels make sure the liner won't move, another method is to braze the liner to the barrel top and bottom, this also reduces the load on the now thinner/weaker barrel to crankcases mounting flange.

Anyway, hope you'll find a good set of barrels, Duncan. Good luck!
What about the SRM barrels? Still no go? They should give us the dies, and we'll organize a decent quality production run  ;) *contract*

Cheers, Markus

1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

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Online RichardL

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Re: Engine blown - Cylinder spigot fractured
« Reply #20 on: 28.11. 2011 22:59 »
Markus,

As you know as well (better, really) than I, there is so much more to it than just sand casting the iron.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline MG

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Re: Engine blown - Cylinder spigot fractured
« Reply #21 on: 28.11. 2011 23:05 »
yes, but nothing that couldn't be solved, as always it's a question of demand (and money).
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

www.histo-tech.at - Restoration, Repairs, Racing

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Online Brian

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Re: Engine blown - Cylinder spigot fractured
« Reply #22 on: 28.11. 2011 23:30 »
Did SRM actually have some made or did they only think about it ?

With modern metals and CNC machining it should be possible to make better than original ones.

The usual problem though, its costs a lot to get a batch cast taking into account pattern costs. There has to be a reasonable demand to make it worthwhile. Plus you have to have people that will actually part with the money, usually plenty say they will buy a set but when it comes to actually parting with the money its a different story.

Nasty thing to have happen Duncan but it could have been a lot worse. A set of barrels and pistons is all you will need hopefully. Once you get the motor apart and have a good look you will know for sure.

Offline MG

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Re: Engine blown - Cylinder spigot fractured
« Reply #23 on: 28.11. 2011 23:38 »
Afaik SRM had a batch made in the 80s and anounced production of a new batch 3 or 4 years ago, so they should have some sort of patterns or dies, whatever technology they are cast with.
The greatest problem definitely is financing the thing as you say, and how to gauge interest? For sure it's nothing you can sell hundreds of in short order, rather a constant trickle I'd suppose.
Prices are rising however, just last night a thick flange set went on ebay US for more than 500 USD, in good condition (no broken fins, but followers seized/rusted in place) and on a well worn STD bore though.

edit: 566 bucks!!!
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

www.histo-tech.at - Restoration, Repairs, Racing

Austria

Offline Duncan R

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Re: Engine blown - Cylinder spigot fractured
« Reply #24 on: 29.11. 2011 00:21 »
Thanks to all for showing so much interest, it has been good to have some info as to why this has happened. My thoughts yesterday turned to selling the bike, A lot of money was spent last year sorting all the bodges to the bottom end and I was happy that the bike was running well. I had just finished fitting a new wiring loom and was hoping to finally getting the charging system working with a new DVR2 having sourced a decent dynamo from Bob, the final projects of overhauling the gearbox and getting the speedo reconditioned were planned for the winter then this happens. I am going to stick with it as I now know this disaster is a result of another bodge and is not a common problem. I think selling it would be a decision I would later regret
Anglo - Indian A7SS (Actually is a 650)
Kawasaki ZZR 1100
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Online Brian

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Re: Engine blown - Cylinder spigot fractured
« Reply #25 on: 29.11. 2011 02:15 »
Stick with it Duncan, believe it or not it will be worth it in the long run.

I can assure you we have all felt like giving up at some time or another, there is nothing like a old British bike to drive you to the point of despair.

I've been working on A10's for 40 years now and there are still times I feel like pushing them off a cliff.

But, when its a nice day and the bike is running well and you are cruising along there's nothing better.

Hang in there.

Offline trevinoz

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Re: Engine blown - Cylinder spigot fractured
« Reply #26 on: 29.11. 2011 04:20 »
Duncan,
                 The barrel which I used on my '55 Flash is a thin flange type which had been machined flush below the base, for some unknown reason.
The fix was as seems to have been done to your barrel, stepped liners machined from cast iron hollow stock.
They were pressed in and brazed to the base then bored to size.
I am running 7.25:1 pistons and so far no issues.
I have seen barrels as bad as yours repaired and put back into service but if you don't have the means and skills to do it yourself the cost would be prohibitive.
You will have to completely strip your engine to get all of the stray bits of piston out and check your rods for straightness..

  Trev.

Offline cus

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Re: Engine blown - Cylinder spigot fractured
« Reply #27 on: 29.11. 2011 04:44 »
Hey Brian,
If ever you are feeling like that again..."just send me a quick PM & let me know what cliff!"

Cus
56 G/Flash project

Online Brian

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Re: Engine blown - Cylinder spigot fractured
« Reply #28 on: 29.11. 2011 05:32 »
I had one of those moments recently Cus. I assembled the complete primary drive on a B31, including the front tin piece of the chain guard. Put oil in the case and then went to put the footrest on and realised I had forgotten to put the splined tube the footrest mounts on in. Without the front tin section of the chainguard you can put the footrest tube in afterwards but not with the tin section in place.

I put my tools away and went and had a few beers  *doh*

Offline cus

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Re: Engine blown - Cylinder spigot fractured
« Reply #29 on: 29.11. 2011 05:43 »
I think we all know were your coming from there,

Cus
56 G/Flash project