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#131503 - 12/30/07 5:28 pm Re: breaking in rings  
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HawaiianTiger Online content
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Maui Hawaii
Quote:
Originally posted by Nick:
I DON'T HAVE TO TAKE THE THING APART AGAIN FOR A LONG, LONG TIME!
This is the kind of stuff I'd like to see more of. Nick, if you ever have the opportunity to disassemble one of your engines, I'd love to see pics of it to see how good this works. Also, with all this talk about ring seating, no one has ever bothered to describe manual ring seating for those who are interested. This makes discussions about ring seating academic only. Also, I would like to hear more about "planar honing"
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
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#131504 - 12/30/07 5:53 pm Re: breaking in rings  
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John Healy Online content
John Healy  Online Content



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Problems, as a percentage of sales, with products we have distributed to dealers over the past 15 odd years, problems with high oil consumption and initial heat related pistons seizures are right up there.

There was a period in the late 80’s where we were receiving a couple of sets of pistons back a week that had suffered heat related pistons seizures. It didn't matter which brand, all seemed to be involved. Plus as many calls from dealers complaining about rings not breaking in and high oil consumption.

Today we rarely get these calls from dealers because all this was discussed and dealers came to grips with it quite a few years ago. No all understood, but devised of ways to deal with the seizures they were experiencing.

But he world has changed and as the Internet allows people to buy pistons and take them to their local automotive machine shop, we have started to hear about this again. Also a lot of people who have an interest in these bikes have taken his up as a retirement business or a career change.

Some thought the cause was old time Triumph dealers using piston clearances specified for pistons made by Triumph for their "lo-ex" (low expansion) aluminum alloy pistons that were given a thousandths or so smaller than the Hepolite used from 1966-67 on.

They would bore the cylinder to .003 to .0035" rather than AE/Hepolite recommended .0042 to .0072" (if you are interested, most dealers have settled on .005" for both Hepolite and JCC which are made from similar alloys). But this in itself would not cause as many problems as we were experiencing.

For long time oil was considered to be the problem and we would recommend using non-detergent SB or equivalent oils, this certainly helped, but I don't think we were addressing the cause. But I think it was giving the dealers clues. When I first experienced this it was 1978 and our shop was doing several 836cc cylinders for Honda 750 fours a week. This is where, I was told by Ken Tippton of MTC Engineering who made the kits, to use a “drier” assembly technique I am sure you have read about. This worked for me for many years, until I began to understand the problem better.

1978 was when what I call modern oil was beginning to be introduced into the US. The problem: put one of these 836 kits together with modern oil and it would smoke badly. If you ever worked on one of these Honda 750 you realize to do a top-end required removing the motor from the frame. AS you might imagine doing the job over and over until you found out why it smoked was more than a bit of bother. In the same period Triumph T140s we sold often would smoke right out of the box and would require re-ringing before they were given to the customer.

Spring ahead ten years and there were a lot of theories: Oil, rings, gasoline, break-in procedures, etc. were blamed... the one similarity seemed to be the age of the rider: over 50; the mileage: 50 to 100 miles; and the conditions: pulling up a grade in high gear (which required moderate to mid throttle openings). It got to a point where I would respond to a dealer’s phone call with, “Over 50 years old, 50 miles on motor and he was pulling up a grade in high gear,” and he would say how did you know.

Because we couldn't always see the cylinders we had no idea that a lot of these bores had been prepared with 280 plus cylinder finish. But a clue came in the fact that the rings on the undamaged piston showed that the rings were not seating. Except for a couple of places where the ring was seated, it looked like it just came out of the box.

We sent AE/Hepolite in Bradford, many sets of their rings and pistons and their conclusion was the owners were distorting or bending the rings when they removed them to check the ring gap. They even got one of their retired engineers to come in a look at the rings and pistons as the younger ones were not familiar with the engineering. All this was passed on to dealers, but we continued to have the problem.

One of my better dealers located in Arizona, was sure that it was piston design was causing the problem. The way AE machined the taper on the thrust faces of the piston had changed. Gone was the long, straight approx. .007” taper. The thrust face of the piston was nearly parallel ending with the .007” change in diameter just under the oil ring. Because of how narrow it is it could not be measured with a micrometer, but was easily measured with a shadow-graph.

His theory was there was not enough taper on the skirt of the piston and Hepolite performed tests and confirmed that the dimension just under the oil ring, where a lot of heat related piston seizures start, was correct and not causing the problem. Modern computer controlled machinery made it possible to reduce the overall taper and increase it only under the oil ring rather than the typical straight line where the taper starts at the bottom of the skirt.

Somewhere along came the idea that we need to know what we are working with.

So the next time you buy a set of cast iron rings, have the cylinder honed to a 280 plus grit, install SM rated oil in the tank, put a low motor octane gasoline in your bike, lug the motor (high load using wide throttle openings) don’t be surprised that you experience a heat related seizure. How you avoid this is your choice. Some dealers want to put several hundred miles on a rebuilt motor before giving it to the customer. There is no single answer.

If you reel from what I am trying to say above... read it again.

Learning o trying to understand is not doom and gloom.

Your “expert” would no sooner put a set of chrome plated steel rings in a bore prepared with 150 grit. Neither should you put a set of grey cast iron rings in a bore prepared with s 280 plus grit.

Most dealers have learned this lesson and come up with their own way of dealing with this. Whether it be using racing gas for break-in to toughen the motor against detonation thus allowing the rings to break-in with less chance detonation and resultant seizure. Using SB rated oil or break-in oil (which is available over the counter in the UK). Using “drier” assembly techniques, or what have you.


#131505 - 12/30/07 8:19 pm Re: breaking in rings  
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HawaiianTiger Online content
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I have to say that I am surprised at how much effort has gone into such a simple thing as ring seating on old and obsolete motorcycles. Somehow I have avoided these pitfalls over the last 20 years or so perhaps due to the effort put forth by you Mr. Healy and others. I have never experienced a ring or piston failure in any of my Triumphs that I have built myself, although I have had to put right several that others have done incorrectly. I did mistakenly run one engine on synthetic oil from new which you know what the outcome of that experiment was. The rings seated themselves in about 1k miles after I switched to mineral oil.

Many of the engines I have built have been returned to standard bore by purchasing new cylinders and pistons through JRC. I ran them as recieved but set ring gaps prior to assembly. I ran them on Castrol 20w50 exclusively and assembled them wet. Bill Getty advised dry assembly and running very thin running in oil but I never got around to trying his suggestions. I check compression repeatedly during break-in to see how things are going. My engines have fully seated rings by 150 miles or so according to these checks. I never start an engine until the bike is fully ready to ride. I start the bike, check for oil pressure, put it in gear and go for a ride. I do not abuse my engines but I ride them in normal traffic conditions like anyone else.

I am running Harris pistons now and set them at .0035 for my bikes, .0045 for others who might not treat their motors as kindly as I do. I haven't heard any feedback on Harris pistons on this forum but would like to. I found them to be beautifully machined, of identical weight and dimensions. The same cannot be said of Hepolites. But the proof is in the running isn't it?

Also, I have experienced tapered bore jobs by machine shops who are inexperienced with motorcycle cylinders. I think it is inexcusable not to run a bore gauge the full lenght of the bore after the job is done but this does happen occasionally. The seizure will occur at the bottom of the piston skirt, not where you would normally expect it.

If I begin to experience failure to seat with my rings, I am inclined to seat the rings myself using the old race method of manually dressing the rings before assembly. This could help to avoid the nastiness of which you describe. I do understand however that as a hobbyist, time is not a concern and for other it is critical.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
#131506 - 12/30/07 9:16 pm Re: breaking in rings  
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John Healy Online content
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Boston, Massachusetts
Harris pistons are made by JCC. If you examine the castings you can see they are the same and you can see where the JCC logo has been ground off.

Seizure at the bottom of the skirt is typically a lubrication failure - oil pump, rod bearing shell failure blocking oil flow. Not a heat related or clearance seizure.

I cannot remember the last time I saw a oil related - bottom of skirt seizure. This must not be confused with a heat seizure where the alloy melts under oil ring and is dragged down the face of the piston.


Because of the way pistons are design they control the flow of heat, and thus piston expansion, very little, and some times no clearance is needed at the bottom of the skirt. The bottom of the skirt does not expand very much, if at all.

As an aside our machine shop used to bore refirgeration compressor motors used on trucks and when finished properly the pistons were a slight intereference fit. - no clearance at the bottom of the skirt at all.

JCC pistons are no-less or no-more to these sorts of problems. We have had as many complaints with them as AE/Hepolite. The problem doesn't lay with the piston.

While agree that Bill suggests "drier" assembly, he has been supplying Aerco break-in oil which is not "very thin oil." It is a 40 weight oil, rmulated for break-in which in includes very little in the way of additives, except ones that help prevent rusting if the bike is not put into service immediately, but let sit around. Oil needs anti-oxidant package and the trouble with most break-in oil is it doesn't contain any. The theory is the motor is going to be put into service upon assembly so it is not needed. While break-in oil is common on the dealer's shelves in the UK, you cannot find it on our shelves.

All this could go on forever.

Your experience can vary.....


#131507 - 12/30/07 9:51 pm Re: breaking in rings  
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Blapper Offline
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There is no doubt in my mind that there is now a lot of doubt in my mind eek John's argument is logical and well reasoned, Bills lack of problems is comforting.

Now... eeny-meeny-miney-mo.....

In my case, I had no smoking (after wet sumping cured) but the honing marks are nearly gone so do you recommend I put it back togther as is, or do some hand honing to re-seat the rings?

Blapper redwine

#131508 - 12/31/07 12:32 pm Re: breaking in rings  
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I was out on the Triumph yesterday and at the bike stop was a restored 65 Thruxton Bonneville which is a real rarity and it didn't make any smoke! There were several other old bikes, some obviously restored and none smoked so that was a 100% success rate. I also noted of three 650 Triumphs, the Thruxton was the least rattly and must have been carefully put together.

I think that a 650 Triumph must have terrible problems to smoke because mine is not exactly first class. The bores are like quite shiny and the valves are wobbly but it is fine. The may go down slightly but not anything to even warrant a top up between oil changes.

Please stop worrying. Get a reputable shop to match the rings to the grit, or whatever.
Dave

Dave

#131509 - 12/31/07 2:49 pm Re: breaking in rings  
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John Healy Online content
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Blapper:
The cylinders purchased by Bill from JRC were made by Aerco in the UK (aka Velocette Motorcycles). These cylinders are manufactured and supplied with a 150 grit.

Blap, in a different way Bill, Dave and I are saying the same thing! If its done right, or some accomodation is made, drier assembly, break-in oil, or other things dealers have done to work their way through this, you will be ok.

Some people are curious about what can and will go wrong and try to undertsand what happened and how it can be avoided in the future. While the science of what caused the problem never changes, it is human nature for people to search for different ways to deal with it. Others don't want to here about it and just want an answer, and often any answer will do. Whether it is right or justifying a shop owner's boat payment.

Some people look at a piston and see a lump of aluminum, steel and iron. I like to look a piston and let it tell me a story... If you see a different story, tell me about it, I like to learn as much as the next guy.

If all this works out for you I am happy for you. But tell us more of why it worked. Ring type, cylinder finish, beak-in rpm, dynamic cylinder pressure (avoiding lugging motor), other modifications that you utilized to toughen the motor to detonation (as this is what causes the probelms in the end), fuel used (especially the motor octane number - and no, our pump 92 is not the same as the UK motor 92 - think about that for a bit Dave), etc, etc

john


#131510 - 12/31/07 3:34 pm Re: breaking in rings  
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co.down n.ireland
'deves' four piece oil control ring, have just received replacement rings for the racer and was supplied deves brand rings two cast iron compression and scraper with four piece control ring, these are not common in the uk anyone got any experience????pls thanks


rickman trident racer
dresda t140 racer
1956 matchless g80cs
1960 matchless g2csr (wifies)
#131511 - 12/31/07 4:25 pm Re: breaking in rings  
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btour Online content
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btour  Online Content
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Hi Blapper,

I notice that no one has answered your question:

"In my case, I had no smoking (after wet sumping cured) but the honing marks are nearly gone so do you recommend I put it back togther as is, or do some hand honing to re-seat the rings?"

It is easy for people to miss something said.

I do not have the answer to your question, that I myself am certain of, but I was told by a person of huge experience, in answer to the same question, that if you take a part an engine, that had its rings seated correctly, you can just put it back together, without re-honing and new rings.

I am not sure why this would work. I wonder if you would have to careful to make sure the rings did not rotate, or if they will just rotate back to the original position. One could see how this would be most important with "traditional" cylinder preparation, with its "out of round" out of square, relationships. So I do not know if his comment applied only to more modern careful preparation.

BTW, what was yours? Do you have grey rings, or ductile rings?

Let us know, and then why don't you just try it, and let us know what happens. What is the worse that can happen? If you use race gas, to protect from detonation (with some oil, from negative results), it will just smoke, and you will see lack of seating from compression test, and then can take it apart and try re-honing and new rings.

I would guess that if you decide to re-hone in advance you should get new rings, too.

Or maybe someone with experience, unlike me, will answer your question:

"In my case, I had no smoking (after wet sumping cured) but the honing marks are nearly gone so do you recommend I put it back togther as is, or do some hand honing to re-seat the rings?"

BTW, what the heck is hand honing? Just scuff it up with emery paper? Why bother? I would think, either new rings, and proper hone with correct cross hatch, or just reassemble, and nothing.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#131512 - 12/31/07 5:13 pm Re: breaking in rings  
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Emsworth, sunny south of Engla...
btour- That's exactly what I have done several times- put the engine back together with the old rings and no hone and it was fine (as I said earlier I didn't put the rings back with the gaps in the same position). I had no idea that you couldn't do this smile

You don't need to change the rings if they are shiny all the way round on their working surfaces, and if there is no significant browning below them on the pistons. Why bother?

Dave

#131513 - 12/31/07 5:37 pm Re: breaking in rings  
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John Healy Online content
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Bob:
rings rotate in cylinder as a matter of course. The position you put them in is irrevilent. In several revolutions of the motor they won't be there anyway.

Hand honing refers to the use of a hone mounted in a hand held drill. It uses the same type of stones and holder as a machine hone.

There are two basic machine hones: horizonatal and verticle. Horizontal are often used a a multi function machine while the vertical is typically dedicated to cylinder honing. Both can create the proper finish and cross hatch. The modern verticles are computer controlled and by monitoring the current being drawn by the motor can sense where more material needs to be removed and "dwell in that area increasing the metal removed at that point.

Of course this is also done with an older horizontal, but it is the operator that senses the load through his hands holding the cylinder. Experience is what is at work with the older horizontal or hand hones.

Yes, you can certainly reinstall rings that are broken-in where neither the cylinder or rings have been damaged. It is done as an emergency procedure by racers all the time. Though it does not work every time. You will often see a bit of oil on the rings until the rings seat again. This can make reading the spark plug impossible until things settle in.

I will say that I see a fork here: If I am doing this with grey cast iron rings that have not seated and still show the original machine marks on the faces, and the cylinder shows signs of being glazed, I would run a 150 grit (or your choosing) thru the barrell. It only takes a couple of turns to re-establish the cross hatch on the bore. The other fork is: If the face of the rings indicate that they have been "honed" round by the original surface finish I would install them with the bore just as it is. There are distinct choices here - not a one fits all answer!

We stock and use Deves rings. Their 4 piece oil ring will not fit in late Triump 650 Hepolite oil ring grooves. They are not deep enough as Deves oil rings need .110" depth and the Hepolite 650 pistons are .090" deep.

Oil control with Deves rings comes at the expense of ring tension. On motors that experience oil control problems they work very well, but one has to think that if one could maintain oil control (and we are not tlaking smoking, but oil on the spark plug) with an oil ring with less tension, that it would be a better choice.

On T140, where oil control can be a bit of a bother using conventional single piece oil rings, the Deves work quite well. They are a good replacement where the original two piece Hepolites are not available.

For a period where we were having oil ring control problems with a 500 we were racing and we used Deves 4 piece oil rings. This is a motor that consistantly saw 9,000 plus. When we found a solution to the cause for the problem (we could not get the plug free enough of oil to read it - the motor DID NOT SMOKE even on decel) we went with a RK Japanese ring supplied by Aries pistons.
John


#131514 - 12/31/07 5:55 pm Re: breaking in rings  
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glastrywhippet Offline
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co.down n.ireland
f a o john healey, john i have a racer with puma alloy barrells 81mm ford liners and pistons the pistons are cut to suit big valve nre 8 valve head, as the replacement rings are deves four ring , i had some minor smoking due to a cracked liner thats now been replaced, i have the original rings but just wanted some feel good about the deves type?? any thoughts on deves as a brand we dont normally come across them here, ta


rickman trident racer
dresda t140 racer
1956 matchless g80cs
1960 matchless g2csr (wifies)
#131515 - 12/31/07 5:57 pm Re: breaking in rings  
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Hi John, Bob, Dave,
I am going to rebuild the engine with the same rings in the same positions on the same pistons, but not rotated to the same position because I don't know what it was. I am not going to worry about it as I have never had a problem before.
HOWEVER, I am certain that John is right because petrol has changed so much recently. So because I have concerns about the detonation due to oil contamination problem, so I am looking to upgrade the fuel during the break-in period.
Has anybody ever used 'power pills' or any fuel additive with good results? I don't have access to racing fuel.
If all else fails, I will get new barrels because mine are +0.040" now, get new pistons of the same type and get them weight matched with the existing to avoid another balance. I will then be asking very detailed questions of the suppliers regarding bore finish and ring type.
As to type of rings on my pistons now, I don't know. If you tell me what to look for, I'll be able to tell you.
Be assured too that I will feed back results of all aspects of this exersize to the collective.

Happy new year guys and thatks for your responses.

Blapper redwine

#131516 - 12/31/07 6:23 pm Re: breaking in rings  
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btour Online content
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btour  Online Content
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Hi John,

Thank you. Really good info as always.

There is just one thing, I cannot understand logically, as to its consequences, and that is this:

"rings rotate in cylinder as a matter of course. The position you put them in is irrelevant. In several revolutions of the motor they won't be there anyway."

There must be some intuitively, obvious bit of info. that I am missing.

If it is a given that traditional cylinder is egg shape, ie. not round., and that the grey rings wear in to fit that shape, then they either have to stay in position (which is seems to me they would tend to do, as an egg in an egg shape would be like a lock and key situation, not quite a square in a square, but not a round in a round either), or if, and I can see how they would as they float, they do rotate, then they, the rings would have to wear into their new position ( which the glaze would inhibit), or they would have to snap back to the their previous/old/orginal worn position of the egg to egg fit. Or if none of the above, then there would not be a fit or seating.

Now I can easily understand how with a modern cylinder, which is perfectly round and sufficiently cooled and round rings this is not an issue, and they can rotate to their hearts content, and only in those brief moments when the gaps align is there an issue.

But it is with the traditional egg I can not see it.

Unless all this is just semantics. So, my guess is, yes rings rotate, but they tend to seek home egg fit for most of the time (if they seated at some time). So, all is mostly well, but one can not say always well, or always perfectly seated or fit. Or it may be even more as I guess, and that during compression, when the rings are having that compression force them outwards, they would tend to snap back to the egg fit, (unless of course they were stuck).

Wouldn't it be great to actually see this process in action. I can imagine an experiment, where rings are marked by say radioactive marker, so that there position could be monitored.

I am glad you clarified the "hand honing", because I have heard some guys say just scuff it up with emery paper to break glaze and throw it back together. So that is tremendous stuff, about the resistance thing, either feeling it or having a machine that can, that I did not know.

Thank you, once again.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#131517 - 12/31/07 6:23 pm Re: breaking in rings  
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triton thrasher Online content
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scotland
Quote:
Originally posted by Blapper:

If all else fails, I will get new barrels because mine are +0.040" now,

Blapper redwine
I know I say this quite often, but +0.060 rebores seem to take any punishment I can hand out. And you know an old barrel is a ripe casting.


Amateur Loctite enthusiast.
#131518 - 12/31/07 6:28 pm Re: breaking in rings  
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Blapper Offline
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Hi TT,
That is a good point, I only said that because I have read so many times that the +0.060 bores are unstable?

Blapper redwine

#131519 - 12/31/07 6:37 pm Re: breaking in rings  
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btour Online content
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btour  Online Content
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To all on the forum:

I must say, that this visualizing of spacial relationships, where I must imagine it is my weakest area of intelligence, except of course for the ability to remember a series of numbers, or see a pattern in a seres and predict the next one.

But I was quite strong in plane geometry and doing proofs, but one can see that.

I remember as a child, an old British woman giving myself and my friend Russel, blocks to play with. He excelled at it and I did not. She predicted he would make a good builder and guess what that is what he is.

This is just an apology, an explanation, to those people I am sure I have irritated, by what must be to them tedious, and unnecessary questions.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#131520 - 12/31/07 6:44 pm Re: breaking in rings  
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triton thrasher Online content
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Quote:
Originally posted by Blapper:
Hi TT,
That is a good point, I only said that because I have read so many times that the +0.060 bores are unstable?

Blapper redwine
The fact that +80 thou is available is slightly reassuring about the +60 ones.


Amateur Loctite enthusiast.
#131521 - 12/31/07 7:03 pm Re: breaking in rings  
Joined: Mar 2005
Posts: 9,971
John Healy Online content
John Healy  Online Content



Joined: Mar 2005
Posts: 9,971
Boston, Massachusetts
Bob: They don't /can't seal perfectly all of the time in these old air cooled motors. They will typically burn a pint of oil in every 1,000 miles - some even more and be considered normal. This is oil getting past the rings.

Thus it is amost imposible to get oil consumption the same as an H2O cooled modern motors. There are momentary gaps when the ring is not against the cylinder. We do not get situations like modern vehicles where little if any oil is burnt in 3,000 plus miles.

Take a Triumph 500 that is run hard and consistantly up to 9,000 plus rpm. There isn't a gasket surface that isn't moving against the mating surface. The parting surface of the crankcases actually work so hard against each other to a point where an aluminum oil paste develops. It is the same for the cylinder base and it becomes impossible to use a base gasket as it pulverizes it. We started using copper base gaskets, crankcase dowels in these motors 20 years ago. It is so bad that most people do not use a base gasket when racing a 500... just seal it up with gasket sealant - though we believe the copper gasket is a better choice.

What do you think the bore of the cylinder looks like when the crankcase is twisting like a pretzel?

Blapper... please don't worry... i don't think your 750 will be used this hard.
Bob... this is not plane geometry... there isn't anything plane about it. An old air cooled motor is hot metal in motion with engineering adapted to make it all work.

And it works very well thank you... just don't think that you know more than the people who designed it with out going through a few failures of your own - just like the engineers of the past.


#131522 - 12/31/07 7:29 pm Re: breaking in rings  
Joined: Oct 2003
Posts: 3,524
dave jones Offline
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dave jones  Offline
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Joined: Oct 2003
Posts: 3,524
Emsworth, sunny south of Engla...
I was wondering about the +60 thing as my barrels are on +40 now. In the book it says no more than +40 but that is one place I wouldn't mind being able to save some money and not have to buy new barrels. I have just assumed, like Triton Thrasher, that because I can now buy +80 from a reputable dealer that it must be ok.

I don't know what the relationship is between the octane numbers used in the US compared with here in England but I normally use 98 although 95 doesn't seem to make any difference in my Triumph Trophy 650 1967. Also the petrol here is of consistent quality all over the country which doesn't seem to be the case anywhere else, according to this forum.
Dave

#131523 - 12/31/07 8:21 pm Re: breaking in rings  
Joined: Jun 2007
Posts: 5,467
HawaiianTiger Online content
BritBike Forum member
HawaiianTiger  Online Content

BritBike Forum member

Joined: Jun 2007
Posts: 5,467
Maui Hawaii
The .040 rec for overbore applies to the pre-unit cylinder barrel which as you know has the head bolt holes closer to the bore than the nine bolt barrels. From personal direct experience I know you can expect cylinder wall distortion from the head bolts when they are torqued down on the pre-unit cylinder barrel with overbores exceeding .040. You cannot see this once the motor is assembled. However, you will have one wimpy-assed running bike. Would you like to know how I know this? There is a bodge that will allow you to use .060, but it is afterall just a bodge.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
#131524 - 12/31/07 8:43 pm Re: breaking in rings  
Joined: Dec 2006
Posts: 3,771
btour Online content
BritBike Forum member
btour  Online Content
BritBike Forum member

Joined: Dec 2006
Posts: 3,771
Massachusetts, U.S.A.
Hi John,

Thanks for the reply.

"What do you think the bore of the cylinder looks like when the crankcase is twisting like a pretzel?"

smile Yikes no idea. Mindboggling. Talked to someone with tremendous experience, who had I think titanium rods made, and he explained the crankcases were limiting factor. They just can't take too much. I saw that there were plans for Triumph to use magnesium ? cases? wonder how far one can go? Not me thats for sure. I am no millionaires son.

I burn about a pint every 1000. Depends on the weather or something, or how hard I juice it. I add a touch every take off.

Think the darn thing is doing really well after 35K, and sitting for 20+ years, Thanks to you and others here. Still 150 compression in both sides now, and no plug fouling at all anymore. So I do not now when I well go for the re-build, especially with so much that go wrong.

But I have to plan for the future, and make a decision. So if you could just indulge me one more time, while we are on the subject of breaking in rings and such.

What advantage/disadvantage is there in nikosil treating the cast iron barrels? And the same about "gapless rings"?

John, do you have any input that you can add about those two?


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#131525 - 12/31/07 8:49 pm Re: breaking in rings  
Joined: Aug 2007
Posts: 4,542
Blapper Offline
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Blapper  Offline
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Joined: Aug 2007
Posts: 4,542
Kent UK
I remember seeing a tv program about Cosworths re-entry into F1 about twenty years ago. They had no trouble producing the new power levels, but couldn't understand why the engines were blowing up until - I think they used high speed photography - they found that the previously unbreakable V8 was flexing the crankcases so badly the engines exploded!

Blapper redwine

#131526 - 12/31/07 8:50 pm Re: breaking in rings  
Joined: Aug 2001
Posts: 3,913
Britbodger R.I.P. Offline
In Remembrance
Britbodger R.I.P.  Offline
In Remembrance

Joined: Aug 2001
Posts: 3,913
Houston Texas
Quote:
I don't know what the relationship is between the octane numbers used in the US compared with here in England
There are two main methods for determination of octane rating - RON and MON with the latter being more conservative.

In the US, octane rating stated on the pumps is the average obtained from the two methods (RON+MON)/2. In the UK I'm pretty certain that the less conservative RON method is used and that is the main reason that ratings in the UK seem to be higher than here in the US.

HTH sleep sleep sleep

#131527 - 12/31/07 8:58 pm Re: breaking in rings  
Joined: Sep 2006
Posts: 156
marinatlas Offline
BritBike Forum member
marinatlas  Offline
BritBike Forum member

Joined: Sep 2006
Posts: 156
FRANCE- DINARD -BRITTANY
Hi there everybody and HAPPY NEW YEAR.
I am more or less on the Norton side , but I red with lot of interest your topic , because I had got same problem , with Teikoku pistons in one of my Commando, I had put the say "common "
3.5/4 thou clearance, but smoking and oil spluterring through exhaust, just to notice the oil ring rinfg control was not the same elasticity (tension?) as the hepolite ones, so the rebore follow .........at that time I do not wash up till clean the jugs after rebore, wea re there to learn , and many thanks for all the lessons, cheers from the frog land Pierre

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