Author Topic: Getting barrels over piston rings.  (Read 2087 times)

Offline alanp

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Getting barrels over piston rings.
« on: 31.07. 2010 17:24 »
After the 6th failed attempt to lower my barrel over my 'super duper' Wiseco pistons/rings I began to think that I was losing it! How many times had I lowered barrels over pistons over the years so I hoped there was a good reason apart from age related incompetance. I was using ring clamps but I couldn't get the transition over the very thin rails on the 3 piece oil control ring, so had a look for a reason. I found that the barrel bores bottom edges were sharp so, I Dremeled a small 1/32" 'ish rounded chamfer on the bottom edge. The barrel then slipped over the pistons/rings before I could even say a short prayer to the God of home mechanics.
Hope this helps someone.
Alan.
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Offline MG

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Re: Getting barrels over piston rings.
« Reply #1 on: 31.07. 2010 17:41 »
Quote
Hope this helps someone.

Too late.  *lol*
The 3-piece oil control ring of the Wisecos is a real p.i.t.a., isn't it?

But I'm sure you will be very pleased with the pistons, I am by all means.
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Re: Getting barrels over piston rings.
« Reply #2 on: 31.07. 2010 22:18 »
G'day Alan,
                   they are a pain but I believe they work better than the solid type. Over the years I have had two rails that bent over the edge of the groove un-noticed. Destroyed the bore in minutes.
I have double trouble with the cafe. The new sleeves finish 3/32" above the bottom of the barrel skirt, giving me two steps to get the rings over.
Cheers
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Offline BSA_54A10

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Re: Getting barrels over piston rings.
« Reply #3 on: 01.08. 2010 13:05 »
A little trick that a now deceased racer showed me.
Now he use to play with Manxs & Goldies so the method needs a bit of tinkering with to use on twins but it dose work.
He used to cut some lengths of old hose to space the barrels just high enough to have the spiggot clear of the case mouth.
These were all split so that they could be removed latter on.
So the pistons were wound to BDC, hose slipped over the barrel studs , barrels dropped over the studs & sitting on the hose.
Really big Stilsons ( pipe wrench to some ) attatched to crank in about 2 'O clock position.
The weight of the Stilsons rotates the crank, gently pushing up the pistons while you have two hands to compress the rings and guide the pistons up the bores.
When in, rotate the engine to TDC, move the Stilsons to 6' O clock position, remove the hose and gently lower the barrels onto the crankcase.
It is really, really, really easy.
For A10s I used some lengths of old wooden broom handle.
Drill a hole in both ends, slip a dowel in the top and leave the bottom open so you can drop it onto the studs in the cases.
Same drill, pistons @ BDC, spacers on studs, Barrels on spacers, spanner on the crank, two free hands to play with the rings.
Turns an all day battle of witts to a ten minute doddle.
My biggest Stilsons is only 12" so I hang a 2kg diving weight off the end of it.
Done it this way with real ring compressors, Coke cans & cable ties , beer cans & hose clips and just my little pinkies.
Every time I vow to buy some proper Terrys ring clamps and make up some proper spacers from hex bar with threads & studs to hold the barrels firm but some how I always seem to end up with another shortened broom.
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Offline iansoady

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Re: Getting barrels over piston rings.
« Reply #4 on: 01.08. 2010 16:19 »
That sounds like a really good trick, although I've never had problems with ring compressors (the Terry type).

But I didn't quite understand:
When in, rotate the engine to TDC, move the Stilsons to 6' O clock position, remove the hose and gently lower the barrels onto the crankcase.

Why not just take the Stillsons off altogether?
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Offline BSA_54A10

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Re: Getting barrels over piston rings.
« Reply #5 on: 02.08. 2010 03:36 »
Because you want the barrels to slide down over the pistons and not the crank to rotate as there is a chance of hitting the rods with the barrel spiggots.
If the crank is held in place you can just about drop the barrels onto the cases.
I leave one spacer in place while I coat the cylinder base gasket with Hylomar then hold the Stilsons between my legs while I slip the barrels down. I can not stress just how easy this method is and I have not damaged a piston or ring since I was shown it.
Also this way you don't end up damaging the piston skirts as you would using the "manual" method.
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Offline wilko

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Re: Getting barrels over piston rings.
« Reply #6 on: 02.08. 2010 09:01 »
Or fit the pistons and rings first into the barrells with only the inner circlips and then slide the gudgeons in last! A heat gun helps on the pistons for fitting the gudgeons!
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Offline t20racerman

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Re: Getting barrels over piston rings.
« Reply #7 on: 07.06. 2011 23:08 »
A little trick that a now deceased racer showed me.
Now he use to play with Manxs & Goldies so the method needs a bit of tinkering with to use on twins but it dose work.
He used to cut some lengths of old hose to space the barrels just high enough to have the spiggot clear of the case mouth.
These were all split so that they could be removed latter on.
So the pistons were wound to BDC, hose slipped over the barrel studs , barrels dropped over the studs & sitting on the hose.
Really big Stilsons ( pipe wrench to some ) attatched to crank in about 2 'O clock position.
The weight of the Stilsons rotates the crank, gently pushing up the pistons while you have two hands to compress the rings and guide the pistons up the bores.
When in, rotate the engine to TDC, move the Stilsons to 6' O clock position, remove the hose and gently lower the barrels onto the crankcase.
It is really, really, really easy.
For A10s I used some lengths of old wooden broom handle.
Drill a hole in both ends, slip a dowel in the top and leave the bottom open so you can drop it onto the studs in the cases.
Same drill, pistons @ BDC, spacers on studs, Barrels on spacers, spanner on the crank, two free hands to play with the rings.
Turns an all day battle of witts to a ten minute doddle.
My biggest Stilsons is only 12" so I hang a 2kg diving weight off the end of it.
Done it this way with real ring compressors, Coke cans & cable ties , beer cans & hose clips and just my little pinkies.
Every time I vow to buy some proper Terrys ring clamps and make up some proper spacers from hex bar with threads & studs to hold the barrels firm but some how I always seem to end up with another shortened broom.

I read this post carefully a few days ago before fitting my A10 barrels - a job that I really find hard to do as - a) I haven't bothered to buy any ring clamps, b) I'm too weedy to hold the barrels up for ages, c ) I have arthritis in my hands, which doesn't help...

Anyway, I modified this method a bit and tried it tonight - works a treat. Thought I'd add a photo to make it easier to explain - hopefully I've attached it correctly.

I cut up four short lengths of wood each about 4 inches long. I drilled a hole in the end of each just larger in diameter than the stud diameter and not quite as deep as the stud is long. This meant that the wooden pieces would slide onto the stud nicely but would NOT rest on the gasket. This took a bit of fine tuning and I had to trim one piece a bit shorter to stop it touching the gasket. Once this was done I ensured that all were the same overall length.

I then fitted the gasket, greased up the bottom of the barrel mating surface and rested the barrel on the wooden blocks as shown in the photo. Then with mole grips on the crank, suitably tensioned with a bungee strap I fitted the rings quite easily. Still a fiddly job, but with no barrel weight forcing downwards, the chances of breaking a ring were minimal, and the stress of holding the heavy barrels was zero!

Having done the job now I'd strongly recommend fitting the pistons to the barrels first, as wilko suggested, as that would have made the job an absolute doddle. I would have done this, but I wanted to see how the method worked with the tension on the mole grips pushing the pistons lightly upwards.

Thanks so much BSA_54A10 for writing this piece as it inspired me to try something new that worked brilliantly.  *smile* *smile*

PS If you are wondering why I used the wood shapes I did, it was because I had a 2 foot long strip of it lying next to my bench when I looked around for a suitable material!





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Offline BSA_54A10

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Re: Getting barrels over piston rings.
« Reply #8 on: 08.06. 2011 02:14 »
Quote
I cut up four short lengths of wood each about 4 inches long. I drilled a hole in the end of each just larger in diameter than the stud diameter and not quite as deep as the stud is long. This meant that the wooden pieces would slide onto the stud nicely but would NOT rest on the gasket. This took a bit of fine tuning and I had to trim one piece a bit shorter to stop it touching the gasket. Once this was done I ensured that all were the same overall length.
Glad that it worked for you.
I never thought of sitting the props on the studs just proud of the base gasket but it is a good idea that I will include in future.
A lot harder to describe than to do.

The same props would be needed to use the fit the pistons first method.

The method described in the manuals is basically the same as used in the factory. There was a video around a while back that showed a worked shoving barrels on at a lightning pace but for those of us who do it once every 30,000 miles the skills never seem to be gained.
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Offline Goldy

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Re: Getting barrels over piston rings.
« Reply #9 on: 11.06. 2011 17:55 »
You are spot on wilko I have never done it any other way.
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