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Atlas Barrel - rebore to +0.060, hone or ditch?

Norton Models (not Commando or P11)

Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby bill » Sat Apr 08, 2017 6:01 pm

dave it is not just the lower spigot that is prone to breaking off. the 750 cylinder is also week above the base flange with some worse than others.


dave M wrote:I understand that boring out the existing barrels with something like +80 weakens the existing lower cylinder not the cylinder casting as such, this can lead to a higher risk of the bottom part of the cylinder that protrudes into the crank case cracking off.
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby bill » Sat Apr 08, 2017 6:18 pm

when you look at this pic you can see the core shift by the amount of material left at the inside edges. like i stated the cylinder is weak ABOVE the base flange and are known to break there also with a large over bore. you keep going back to a 16H with a sleeve and again it is chalk and cheese. yes you could use a thick wall sleeve with an OD of .060 from std than bore to std but it will be only a .030 wall of the sleeve left. that is NOT a chance i would like to take. if some one wants to risk a lot of expensive engine parts on a sleeve job than go ahead BUT i sure would do it or recommend it. i have sean what happens when a cylinder breaks at the base and you better dig DEEP to fix it.

Rohan wrote:And a couple of pics on this very forum, for an Atlas that has been sleeved back to std

Image


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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Rohan » Sat Apr 08, 2017 7:10 pm

bill wrote:yes you could use a thick wall sleeve with an OD of .060 from std than bore to std but it will be only a .030 wall of the sleeve left. that is NOT a chance i would like to take.


Thin walled sleeves are very common in the automotive world - well proven technology.
Yes, even in 16H Nortons and myriads of dommies !!

So why then are Anthony Curzon and Peter White of the NOC mentioning they have had more than a few engines (750 Norton engines) done with this ? And even recommending folks to do it.

Just because you have doubts doesn't mean it can't be done, successfully, by skilled operators.
LA Sleeve have sold gazillions of sleeves for all types of engines.
Search here and see how many folks mention them...

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby wakeup » Sat Apr 08, 2017 8:36 pm

I agree with Rohan, I've had a few cylinders sleeved with great success, and the sleeves don't have to be of huge wall thickness.
However back to the OP. That set of barrels looks pretty much like scrap to me as they are, because of the one rusty bore. So why not sleeve them, before the bores get too big to be sleeved, rather than trying to overbore and see if they clean up. If they don't clean up the bores are likely to be oversize for sleeving, then the barrels really are junk.
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Fast Eddie » Sun Apr 09, 2017 12:39 am

I cannot believe a 0.030" thick liner would work in this application, especially with the con rod cut outs already creating an 'area of concern'.
But I've never tried it, has anyone else?
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby bill » Sun Apr 09, 2017 5:28 am

as i stated the thinnest wall that LA sleeve lists is .0625 THAT IS considered a thin wall sleeve. as to curzon and white doing it that is there choice and NOT one i would do nor comnoz anymore from our chats as he has seen the same thing, it has worked on SOME but it is to risky. you KEEP going back to OTHER cylinders with no trouble and i agree it can and has been done on a lot of stuff BUT a norton 750 cylinder IMHO is NOT the prime candidate.

Rohan wrote:[.
Thin walled sleeves are very common in the automotive world - well proven technology.

So why then are Anthony Curzon and Peter White of the NOC mentioning they have had more than a few engines (750 Norton engines) done with this ? And even recommending folks to do it.

Just because you have doubts doesn't mean it can't be done, successfully, by skilled operators.
LA Sleeve have sold gazillions of sleeves for all types of engines.
Search here and see how many folks mention them...
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Hortons Norton » Sun Apr 09, 2017 6:23 pm

Hello Mike, If it were me I would see if there is someone close by that could take a close look at it. To me it looks like a cut down to the next size or two might do it. Some can tell just by looking at it, if they say no well then....... I'm not sure what the safest size to go down to is, I'm sure that also will bring out some more discussion. I can't tell by the photos just how bad it is. Chuck.
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby swooshdave » Mon Apr 10, 2017 10:05 am

Are the original barrels of for the Nortons sleeved or was it cast all as one piece?
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby bill » Mon Apr 10, 2017 5:05 pm

it was a one piece casting than machined.

swooshdave wrote:Are the original barrels of for the Nortons sleeved or was it cast all as one piece?
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Mike T » Mon Apr 10, 2017 8:51 pm

Thank you all very much for your great feedback. I really appreciate it and it's given me a lot to think about. I'll let you know how I get on in the next couple of weeks.
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Bernhard » Tue Apr 11, 2017 6:24 am

by swooshdave » Mon Apr 10, 2017 7:05 pm
Are the original barrels of for the Nortons sleeved or was it cast all as one piece?

postby bill » Tue Apr 11, 2017 2:05 am
it was a one piece casting than machined.

No, no ,no :!:
The barrel quite clearly was cast iron, with a spun cast liner pressed into it- it is NOT one piece, the twin cylinder came as 3 yes THREE pieces :!:

The liner was bored out on a lathe, then pressed into the barrel the boredout to size then honed- anyone who disputes this is talking out of his/her socks :!: :shock:

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby swooshdave » Tue Apr 11, 2017 1:01 pm

Bernhard wrote:by swooshdave » Mon Apr 10, 2017 7:05 pm
Are the original barrels of for the Nortons sleeved or was it cast all as one piece?

postby bill » Tue Apr 11, 2017 2:05 am
it was a one piece casting than machined.

No, no ,no :!:
The barrel quite clearly was cast iron, with a spun cast liner pressed into it- it is NOT one piece, the twin cylinder came as 3 yes THREE pieces :!:

The liner was bored out on a lathe, then pressed into the barrel the boredout to size then honed- anyone who disputes this is talking out of his/her socks :!: :shock:


I didn't know windy wore socks! :mrgreen:
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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby lcrken » Tue Apr 11, 2017 3:36 pm

The Norton twin cylinder blocks have been a one-piece iron casting since the original design of the 500 cc Model 7 Dominator introduced in 1948. That has been the design for all the descendents of that engine, including 600 cc, 650 cc, 750 cc, and 850 cc variants. I don't know where you got the idea that they had liners, Bernhard, bit it's completely wrong. I have cut a number of them apart, as well as boring the 850s out for 920 kit sleeves, and they are definitely all one piece. You can find the same info in the Norton history books, like Roy Bacon et. al., but I'm basing my statements on personal examination.

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Rohan » Tue Apr 11, 2017 5:31 pm

Yes, if the iron cylinders had been sleeved from new, we wouldn't need to be having this discussion.
Just press out the old sleeve, and in with the new.

Nortons did fit sleeves, into alloy cylinders (inter and manx - and 500T ?).
As did Wellworthy, who provided some cylinder (and heads) for some models.
But they were cast in, so getting them out isn't simple at all.

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Re: Atlas Barrel - rebore to +0.060, hone or ditch?

Postby Bernhard » Thu Apr 13, 2017 6:30 am

lcrken wrote:The Norton twin cylinder blocks have been a one-piece iron casting since the original design of the 500 cc Model 7 Dominator introduced in 1948. That has been the design for all the descendents of that engine, including 600 cc, 650 cc, 750 cc, and 850 cc variants. I don't know where you got the idea that they had liners, Bernhard, bit it's completely wrong. I have cut a number of them apart, as well as boring the 850s out for 920 kit sleeves, and they are definitely all one piece. You can find the same info in the Norton history books, like Roy Bacon et. al., but I'm basing my statements on personal examination. Ken


Original question refers to ATLAS :!: :shock:
Atlas Barrel - rebore to +0.060, hone or ditch?

by Bernhard » Fri Apr 07, 2017 6:03 am
Bore looks too far gone with all that rust, the normal method would be to have the rusted sleeve pressed out and another pressed into the barrel –I have had this done in the past HTH

Since I have had this done in the past, when the liner broke at the top and dropped down in the barrel locking up the crankshaft, you are 100% wrong, as I was referring to the Atlas 750.
There are spun cast iron liners available for the 650, 750 (Both spigoted and non spigot)
You are not paying attention there :!: :(

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