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Re: 1928 Ariel Model C [Re: Magnetoman] #721740
01/11/18 2:22 pm
01/11/18 2:22 pm
Joined: Nov 2012
Posts: 291
Isle of Wight, UK
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koan58 Offline
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I'm only throwing ideas out, with no experience of what you're trying to do.

If both keys are frozen in place, is it likely that both have been soldered in place? If so, I'd have thought that indicative of a radical crank failure, if the soldering is to fill damaged key slots. Are the flywheel slots showing any sign of damage?
If the crank had become sufficiently loose, wouldn't the tapers be wrecked?
With these old taper-fit cranks, wasn't it the idea to finally knock or press the components into "precise" alignment?
Whether the flywheel is orthogonal to the shaft to the Nth second of degree is surely unimportant?
Isn't the important thing that the 2 mainshafts and the crankpin are precisely parallel?

If the flywheels precess minutely, is that important? I'd suggest that if you think it is, then you should also individually balance the flywheels.

I think that you are making unnecessary work for yourself, by machining out the key slots. It sounds like they are very happy where they are, and if their external bits are sound, what improvement are you likely to achieve?

Your description of the oiling system is fascinating.

The offset circular cam - the Triumph pump is effectively the same.

The oiling priorities can be clearly seen (I assume you meant a slot in the mainshaft bush?) deals with that vulnerable area first. I think we'd usually expect a high pressure supply here nowadays, but I suppose things hadn't come that far from drip-feed, and the pump is probably more about flow than pressure? Anyway, this bush is the only bearing that needs continuous positive oilfeed.

Then the use of centripetal force (pretty small at the crank axis increasing greatly towards the crankpin, drawing the oil from the hollow in the flywheel.

I would then assume that the bigend bearing would be as full of oil as the pump supply would allow. Oil spraying from both sides of the rod supplying the piston/bore.

I'd see the only neglected bearing to be the driveside main, so my instinct would be to put the open end of the crankpin in that direction, as there will be some pumping effect from the bigend rollers through the drilling in the crankpin.

With regard to the issue of draining the sump every so often, I don't know what mods you're allowed, but if you could allow more oil throughput you may increase your chances of success.

Dave

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Re: 1928 Ariel Model C [Re: Magnetoman] #721758
01/11/18 4:57 pm
01/11/18 4:57 pm
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Magnetoman Online content OP

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Originally Posted by kommando
Better to make a fresh cut taking the current key out and leaving a proper cut key slot in its place which will be both structurally and dimensionally correct
+1. In addition, heat causes warping, which is a very good reason to avoid it if possible. The problem with the non-orthogonality of the shafts may well be due to the soldering. The taper is ~10o (~5o per side) so whether or not it can be fully corrected by lapping without the spindle moving too much into the flywheel remains to be seen. If it does move too much, hard chrome plating and grinding, or machining a new shaft, are possible solutions, although I hope it doesn't come to that.

Originally Posted by koan58
Whether the flywheel is orthogonal to the shaft to the Nth second of degree is surely unimportant?
Isn't the important thing that the 2 mainshafts and the crankpin are precisely parallel?
It sounds like they are very happy where they are, and if their external bits are sound, what improvement are you likely to achieve?
It's not the Nth I'm worried about, it's N-8. As I discussed in a previous post the TIR of the crankshaft was ~0.008" when I removed it from the engine, which is ~8x larger than permissible.

If you think about it, getting the two mainshaft spindles and the crankpin all to be precisely parallel (as well as the shafts coaxial) when neither shaft is perpendicular to its flywheel is a losing battle with geometry. Only by knocking each of the three shafts out of ideal alignment with the four tapers might it be possible to get somewhat close (say, within 0.008"). The reason I will be cutting the keys from the shafts isn't because I'm trying for perfection, it's because I need to achieve good enough.

Originally Posted by koan58
(I assume you meant a slot in the mainshaft bush?)
Actually, no, although there is a slot in the mainshaft bush that is currently in the bike. An oilway in the timing cover casting exits into the case and flywheel cavity at the OD of the mainshaft bush. The bush currently in the engine has a linear groove at the top that feeds from the always-full timing chest. Although there is a breather in the timing chest that exhausts to a tube that drips oil on the chain, apparently the two flapper valves on the crankcase that bring oil mist into the timing cover keep the pressure in the chest higher than in the crankcase so oil is pushed along that groove in the mainshaft bush from the chest into the crankcase.

Last edited by Magnetoman; 01/11/18 8:37 pm. Reason: added coaxial and reworded a sentence
Re: 1928 Ariel Model C [Re: Magnetoman] #721760
01/11/18 5:37 pm
01/11/18 5:37 pm
Joined: Oct 2017
Posts: 21
England
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George Kaplan Offline
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Originally Posted by koan58
Isn't the important thing that the 2 mainshafts and the crankpin are precisely parallel?
Dave



Yes but also both mainshafts have to be on the same axis, If you just go for parallel irrespective of how perpendicular the shafts are to the flywheels then you would lose the battle.


Originally Posted by Magnetoman
If you think about it, getting the two mainshafts and the crankpin all to be precisely parallel when neither crankpin is perpendicular to its flywheel is a losing battle with geometry.


Not that I have done this either but I am pretty good at basic geometry.

John

Re: 1928 Ariel Model C [Re: Magnetoman] #721769
01/11/18 8:36 pm
01/11/18 8:36 pm
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Posts: 382
Cork Ireland
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chaterlea25 Online content
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Hi MM and All,
Quote
from there out the end of the crankpin to the cylinder wall on that side of the piston. However, unlike the crankpin that came in my Ariel the Alpha crankpin (which was used in other Ariel engines as well as mine) has a hole completely through it that is plugged at both ends by small hex screws, so it's not clear if the second oil escape route is important for my engine. Or, toward which side of the engine it should point if it is important. For what it's worth, the previous rebuilder aimed the outlet hole of the crankpin toward the timing side.


???????
The crankpin rotates within the crankcase and does not go near the cylinder or piston (usually?)
If oil escapes from the crankpin end then in my opinion that oil has missed the most vital bearing in the engine !! The Big End
Oil escaping from the sides of the big end will be thrown towards the underside of the piston and small end during the period
before and after TDC
This will be enough to lube the small end and as the new piston has an oil ring and holes/grooves through the piston wall
oil will find its way to the upper bore
The flywheel rims also dip into the oil in the crankcase and distribute this radially around the case, reaching the bore as well.
Oil will drain down the crankcase wall and lube the main bearings, which in reality only need a mist

I would leave the crankpin ends plugged,
The Ariel lube system is similar to period J.A.P engines, some have solid pins where the oil is just fed into one end of the big end bearing,
via a hole in the flywheel adjacent to the crankpin
On hollow pin engines the oil is fed through the pin as in most later design engines

I have experience of several different make 20's engines where the total loss lube system just drips oil into the crankcase
and leaves the rest to the splash effect of the flywheels
The big end life on these engines does not seem much shorter than positively lubed big end bearings (to a degree depending on design and use)
The small number of large diamater rollers used in Blackburne engines is not one of the cleverest, especially if the engine is used hard
I have converted my Blackburne engine so the total loss oil is directly fed to the big end via drilled mainshaft flywheel and crankpin
20's Rudge engines use a wide big end of "small" diamater with small diamater long rollers, no method other than splash lube is employed
but the big end bearings are very reliable

Lapping the mainshafts into the flywheels needs ultra care ,
The sharp ends of the tapered shafts will leave a ridge in the tapered bore in the flywheels
In order to get the shafts to seat in the reground tapers the ridge must be removed or the ends of the shafts relieved to clear the ridge
Blueing and scraping the tapers is my preference

John

Re: 1928 Ariel Model C [Re: Magnetoman] #721774
01/11/18 9:16 pm
01/11/18 9:16 pm
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Magnetoman Online content OP

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Originally Posted by chaterlea25
The crankpin rotates within the crankcase and does not go near the cylinder or piston (usually?)
Er, um, blame this on a temporary mental swapping of big and small ends...

Thanks very much for your insights and inputs into this.
Originally Posted by chaterlea25
I would leave the crankpin ends plugged,
The crankpin I will be reusing has one end open with two small holes in the middle under the rollers. However, I doubt if much oil will leave via that route since the area of those holes is much less than the area bringing oil into the big end so most oil will flow on through to the other end of the crankpin.

Originally Posted by chaterlea25
Lapping the mainshafts into the flywheels needs ultra care , ... Blueing and scraping the tapers is my preference
Duly noted. My plan, subject to you pointing out fatal flaws in it, is to blue both the flywheel and spindle tapers, mount the spindle in a Z collet (7/8" or 1", as appropriate) on the mill, and with a dab of grinding paste lightly touch down in the flywheel taper to reveal the scope of the problem. Depending on what I find I'll either use a scraper to start working on the high areas, repeating as required with more bluing, or use the scraper to slit my wrists.



Re: 1928 Ariel Model C [Re: Magnetoman] #721778
01/11/18 9:27 pm
01/11/18 9:27 pm
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Posts: 382
Cork Ireland
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chaterlea25 Online content
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Hi MM
Quote
The crankpin I will be reusing has one end open with two small holes in the middle under the rollers. However, I doubt if much oil will leave via that route since the area of those holes is much less than the area bringing oil into the big end so most oil will flow on through to the other end of the crankpin.


Ok slight misreading on my part
In that case I would plug the open end of the crankpin that you are going to use, to "force" all the oil to the rollers

John

Last edited by chaterlea25; 01/11/18 9:28 pm.
Re: 1928 Ariel Model C [Re: chaterlea25] #721790
01/11/18 11:53 pm
01/11/18 11:53 pm
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Magnetoman Online content OP

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Originally Posted by chaterlea25
I would plug the open end of the crankpin that you are going to use, to "force" all the oil to the rollers
Will do. Upon close inspection when I got home this evening I found the open end is countersunk for a short distance but then tapped 1/4-26 for a distance before continuing on further into the crankpin. I'll make a custom fastener to fill as much of the volume as possible to minimize the number of mg of oil that can enter and totally disrupt the balance factor after it's set.

Re: 1928 Ariel Model C [Re: Magnetoman] #721800
01/12/18 3:00 am
01/12/18 3:00 am
Joined: Mar 2013
Posts: 298
Irene, South Africa
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robcurrie Offline
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Originally Posted by Magnetoman
Depending on what I find I'll either use a scraper to start working on the high areas, repeating as required with more bluing, or use the scraper to slit my wrists.

The profile of a scraper in not conducive to slitting wrists.

Rob C

Re: 1928 Ariel Model C [Re: Magnetoman] #721883
01/13/18 1:08 am
01/13/18 1:08 am
Joined: Feb 2008
Posts: 4,137
New Jersey USA
Tridentman Online content

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MMan--suicide is permissible during the Cannonball Run --but not during the preparations!

Re: 1928 Ariel Model C [Re: Magnetoman] #721893
01/13/18 4:36 am
01/13/18 4:36 am
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Magnetoman Online content OP

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I made good progress today so the scraper hasn't touched anything organic. But, there's still plenty of time...

Following chaterlea25's advice to plug the open end of the crankpin I machined a 2" 1/4-26 cap screw to do the job. The hole in the crankpin starts with a 60o taper, followed by ~3/4" of thread, followed by a 3/16" hole to a total depth of 2". So, I trimmed the head of the cap screw at 60o to fit the taper and reduced much of the length to 3/16" dia. to fill the hole. This left 3/4" of hollow which, when it fills with oil after I balance the engine, will upset things by approximately 0.4 grams. Oh well, I'll have to accept this error. I briefly considered machining an extension to solder on but decided to spend the time on something else instead. I cleaned the threads thoroughly and used red Loctite.

Next was to remove the Woodruff key from the drive-side spindle. Following the procedure I mentioned in a previous post I moved the cutter against the edge of the spindle to set the '0' of the DRO then used gauge blocks to make the old key parallel to the mill bed. I then lowered the cutter to the top of the same blocks, then dropped it another 0.008" to adjust for the difference in height of the worn key. A few minutes later I had milled the new 3/16"x3/4" keyseat. Without a DRO and calculator (to add/subtract the various gauge blocks and other dimensions) it would have taken a lot longer. When done I found a 0.005" strip of metal at the bottom so my keyseat was that much shallower than the one from the factory (I removed the strip so now it's the same).

I'll have to be even more careful on the timing side. A few thou. doesn't sound like much but if I'm off by 0.005" sideways (not in depth, which isn't that critical) that will change the valve timing by 1/2 x 0.005" x 360o/(3.14159 x 7/8") = 0.32o. While not huge, it isn't 0, either.

Tomorrow the bluing goes on to see how the tapers mate.


p.s. the Cannonball web site is finally working:

http://motorcyclecannonball.com/



Re: 1928 Ariel Model C [Re: Magnetoman] #721958
01/14/18 1:02 am
01/14/18 1:02 am
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Magnetoman Online content OP

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It turns out that the devil is in the..., well, Woodruff key. Which is, after all, a detail.

Today I mounted the now-keyless drive-side spindle in a 1" Z collet with the flywheel on the mill's table below it, brought the spindle down to center the flywheel and then clamped the flywheel in place. I then raised the spindle and coated the mating tapers with engineer's blue.

After it dried I inserted the spindle in the flywheel, removed it, and looked for high and low spots. However, as far as I could tell, there were no high and low spots. So, I removed both pieces from the mill and tapped the spindle into place, still without a key, and checked the runout of the rim of the flywheel between centers. Within the several thou. roughness of the flywheel the runout was no more than 0.002".

I then took used abrasive paper to remove ~0.001" from a new Woodruff key to make it a tight, but sliding fit in the slot in the flywheel, and then removed about twice that from the lower portion to make it a snug, but not too tight, fit in the spindle. The depth of the slot in the flywheel was 0.100" (specs. call for it to be 0.100"), but after pressing the key into the spindle it projected above the shaft by 0.110" even though I had cut the keyseat to the specified depth of 0.214". That clearly would be a problem even without looking at the spec, which calls for the key to project above the shaft by 0.094". So, I filed it down to the required dimension.

In light of the previous paragraph, plus the excessive runout when I first removed the crankshaft it from the engine, I speculate that the Woodruff key that was in the drive side projected by too much, forcing the shaft to be tilted. Unfortunately, I hadn't thought to measure the height of the cheap, disposable key before I cut it away so I can't know for sure. But, circumstantial evidence strongly suggests the Woodruff key was the cause of the problem on the drive side. The devil truly is in the details, and the fit of even something as insignificant as a Woodruff key can't be taken for granted.

The TIR of the timing side always was much better so instead of removing its spindle again I decided to press the crank together. Whether it was the assembly jig I had made, or beginner's luck, or both, straight from the press the TIR of the timing side was 0.003" and of the drive side was 0.004" when turned between centers and measured next to the respective flywheels. Although I pressed the crank together I didn't use full force, nor have I torqued the bolts yet. This is to allow some ability to tweak the alignment.

Both shafts have their high and low points in the same orientation indicating that one or both flywheels isn't perfectly straight on the crankpin. So, I used a C-clamp to squeeze the flywheel rims at the orientation where the shafts are at their highest excursion from straight. The TIR of both shafts measured next to the flywheels dropped to 0.002". I had to quit for the day at that point, but in light of these results I'm (over)confident that I can get the TIR to below 0.001" tomorrow. Of course, that may just be the margarita I had at dinner talking...

Re: 1928 Ariel Model C [Re: Magnetoman] #722076
01/15/18 12:57 am
01/15/18 12:57 am
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Magnetoman Online content OP

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I sneaked up on the max torque I could apply to the crankpin nuts with a 3/4" breaker bar and large ring spanner (more than 150 ft.lbs. but less than 200), checking the runout as I went. Between centers I ended up with just under 0.003" TIR next to the flywheel at the drive side and just under 0.0005" (a half.thou.) on the timing side). In a previous post I found the timing side center was accurately drilled but the drive side center was off by 0.001" so it would have a TIR of 0.002" even if both spindles of the crankshaft were perfectly coaxial. Correcting for this, the actual TIR of the drive side is 0.001" and the timing side is 0.0005".

This measurement pushes the limits I can trust for the locations of the centers so I then moved it to my rollers. Instead of holding the crankshaft at the ends of the shafts, rollers support it on the shafts themselves fairly close to the flywheels. Because of the way it is supported the runout near the flywheels is "forced" to be zero there so any deviations from being coaxial, or if the shafts are bent, will be in the form of TIR of the ends of the shafts. Unfortunately, the drive-side end consists of splines that have suffered from wear and rust so the TIR measured there isn't too meaningful. The timing end has a taper and the crankshaft "walks" sideways slowly as it is rotated on the rollers causing the indicator to slowly move up or down the taper. Because of this it isn't possible to get a precise measurement of the TIR. However, it is no more than ~0.001".

The above means I've reached my goal of truing the flywheel to within 0.001". This also means I can line bore the timing side bush with respect to the drive side bearing and the 0.002" clearance of the bush will be sufficient to keep that end of the crankshaft supported on a cushion of oil without the shaft wearing into the bush.

The minimum side clearance of the connecting rod should be 0.006"-0.012" so I had a moment of real disappointment when a 0.006" feeler gauge wouldn't fit, until I found it was stuck to the neighboring 0.007" leaf. The clearance turned out to be 0.008" (min. clearance on one side as well as side-to-side movement).

The time I spent making the crankshaft alignment jig probably wasn't break-even on the time it saved truing this one, although I now have it for any future crankshafts and it will more than pay for itself on the next one. But, even for this one, having done an initial test fitting and knowing the jig easily got the alignment to within a few thou. meant I had no hesitation assembling, testing, and disassembling several times as I felt my way through the process of accurately truing a crankshaft.

With the crankshaft done this young man's fancy now lightly turns to thoughts of electroplating. Once I get the drive-side bearing plated and installed in the case I can slowly start putting the engine back together again. Unless it's Humpty Ariel...


Re: 1928 Ariel Model C [Re: Magnetoman] #722160
01/15/18 8:22 pm
01/15/18 8:22 pm
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Cork Ireland
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chaterlea25 Online content
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Hi MM,
I'm glad to hear that the crank is back together !!!
"Tuning for Speed" suggests turning up a tight fitting collar to fit tightly on the splined shaft so that it can be indicated
I usually sit two ball bearings on the mainshafts and those in V blocks, adjusting the blocks so the shafts are level if there are different size main shafts and sit the lot on the mill table
Rotating the crank like this run out is easy to check and not dependant on centres
Place the bearings as near the flywheels as possible and check the outer ends
Then move the bearing out along the drive side shaft and check near the flywheel

I am not sure why you made a complicated plug for the big end pin?
The pin will never be filled with oil on a total loss engine, so the weight of the oil volume/ /balance issue does not matter
in my opinion

Keep up the good work
John

Re: 1928 Ariel Model C [Re: Magnetoman] #722180
01/15/18 11:42 pm
01/15/18 11:42 pm
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Magnetoman Online content OP

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Originally Posted by chaterlea25
"Tuning for Speed" suggests turning up a tight fitting collar to fit tightly on the splined shaft so that it can be indicated
I considered doing that, and still may since I'm not quite done with the crankshaft yet. I still have to balance it in its present form once I make my final decision on which piston to use, and also to eliminate the ~10 g imbalance I found at 90o when I checked it in its original form. However, the measurements I made convinced me that I have the crankshaft trued about as well as is going to be possible, and within the 0.001" TIR that was my goal.

I have no experience with truing old cranks (although I've interacted with a few on Britbike... but, I digress), but going by Radco's description, when held between centers a "True Assembly" has no more than +/-0.0015" runout at the drive end (i.e. 0.003" TIR) and +/-0.001" (0.002" TIR) at the timing end. My crank is now trued to ~3-4x better than this which is why I'm prepared to declare victory and move on.

Originally Posted by chaterlea25
I am not sure why you made a complicated plug for the big end pin?
The pin will never be filled with oil on a total loss engine, so the weight of the oil volume/ /balance issue does not matter
I plugged it because:
Originally Posted by chaterlea25
I would plug the open end of the crankpin that you are going to use, to "force" all the oil to the rollers
Actually, when plugged it will be filled with oil because there are two small holes in the middle of it that are there to force oil to the rollers when the same pin is used in later engines with pressurized lubrication systems. Alpha lists the same A5 crankpin that they supply for mine also for other Ariel engines through 1953).

If the end of the crankpin is plugged it allows for the possibility of it filling with oil through those holes. If it does fill, the extra weight of the oil will alter the balance factor, albeit by a very small amount. Since I was going to plug it anyway, as per your suggestion, I filled as much of the volume as possible with the plug I made for it. Now if the remaining volume fills with oil that will be just 0.4 grams to upset the balance.

Re: 1928 Ariel Model C [Re: Magnetoman] #722265
01/16/18 7:34 pm
01/16/18 7:34 pm
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Cork Ireland
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chaterlea25 Online content
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Hi MM,
I must have misread or not "taken in" the route the the oil takes from the flywheel groove to the big end
I thought that the oilway through the flywheel lined up with the oilway into the crankpin (mid taper) as on later Ariel's & BSA's
and from there to the two holes that feed the rollers (provided the crankpin end plugs are fitted)

John

Re: 1928 Ariel Model C [Re: Magnetoman] #722287
01/16/18 10:06 pm
01/16/18 10:06 pm
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Isle of Wight, UK
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koan58 Offline
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As MM described it a post or so ago, the lube system is "eccentric" almost literally, using centripetal chambers as stepping stones to the bigend bearings.
I'm not clear exactly how the timing side bush is lubed, is it just by immersion?
And the drive side bearing, is the little fling from the big end enough? That's why I thought maybe an open end to the crank pin may assist. The rollers would tend to pump oil into the pin, and hence to it's end? Only a thought.

Re: 1928 Ariel Model C [Re: Magnetoman] #722296
01/17/18 1:18 am
01/17/18 1:18 am
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Magnetoman Online content OP

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Magnetoman  Online Content OP

BritBike Forum member
Joined: Nov 2011
Posts: 4,072
U.S.
Originally Posted by chaterlea25
I thought that the oilway through the flywheel lined up...
I knew the total loss system didn't "need" the plug you asked for in a pin that had been made so it would cover a range of models, but mine was not to reason why, but to do and, well, make a plug and trust the Loctite to keep it in so the engine wouldn't die.

Originally Posted by koan58
I'm not clear exactly how the timing side bush is lubed, is it just by immersion?
And the drive side bearing, is the little fling from the big end enough.
Ariel's description is that after the oil makes it through the big end "it is thrown on to the piston and cylinder wall, from which it drains back to the bottom of the crankcase, where it is picked up by the flywheels and re-distributed by splash." That splashing is what lubricates the drive-side bearing.

The "oil-laden air" that is splashing around the crankcase gets driven into the timing case by two one-way valves. Once it fills the case to a predetermined level it drains through a small hole back into the crankcase to keep plenty there to splash around. The crankcase itself has a breather to the outside that is at the height of the bearing, but it's hard to believe oil gets that high because it would cause quite a drag on the flywheels if it did.

The level in the timing case is such that "the timing pinion is constantly running in oil." The timing pinion is above the crankshaft so the bush at the timing end of the crank is lubricated by immersion. The bush in it now has a long slot at the top (0.046"x0.046"x1.9"), which is 0.65" below the "official" drain hole of 0.086"-dia. Although the area of the slot is only 29% of that of the hole, and the slot is longer, which also would slow the flow, it still represents a drainage path into the crankcase so it could cause the level to be too low in the timing chest. Even if the flow into the timing chest is faster than that out through the slotted bush so it would fill to the proper level in steady state, it will drain down to that level when the engine is stopped overnight. I'll have to give some thought to this when I make a new bush.

The oil in the engine and timing case is supposed to be drained every 1000 miles and the timing case refilled with 1/4 pint. After doing this you turn the oil flow valve fully on, take several big puffs from your asthma inhaler, and run the engine gently until you no longer can see anyone standing next to you and all mosquitoes within 1000 ft. are dead. Then turn the oil valve back to its normal position and start off, knowing you have fresh oil and that the planet now will be 0.1 degree warmer than it was.

Re: 1928 Ariel Model C [Re: Magnetoman] #722562
2 hours ago
2 hours ago
Joined: Aug 2001
Posts: 3,511
argyll. scotland, uk
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
BritBike Forum member
Joined: Aug 2001
Posts: 3,511
argyll. scotland, uk
MM , luvvin it so far, the crank is 8 times better, great !, glad it was just the key. Fitting keys correctly is 2nd year apprentice stuff, you were very right to go through this motor, I reckon it will run like a sweetie, bad crank and twisted rod wouldnt have got too far.

,One thing that got a lot better after the 30s was exhaust valves, got any special plans there? Have you considered staged drops of castrol R , smell is a huge advantage.

Last edited by gavin eisler; 2 hours ago.

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