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Hello Peg,
I assume that's foxtrot alpha golf?
Haha, my fault for not previewing. Perhaps the idiot word police don’t like cigarettes😊
Yes F.A.G.
Fischer's Automatische Gussstahlkugelfabrik,
 

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Discussion Starter · #182 ·
Hi Peg & Mick, Thanks for clearing that up! I’m not that smart. I’ll see what I can find in that brand.
Don
 

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Hello Don,
Don't worry, you're smart enough, it's just that US English and UK (ok, English) English have some interesting differences,
Mick.
 

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Discussion Starter · #184 · (Edited)
Hi All, Thanks from your help & input! Been busy with family & home improvement. But today had some time to focus on main bearings.

I will speak my mind in a straightforward way on how I made my decision. Right or wrong, not beating around the bush. I don't want or intend to hurt anybody's feelings. My opinion. Take it for that.

John Healy got back to me on clearance for timing side roller. With roller use CN, with ball use C3. Roller CN gives similar clearance as ball C3 due to the way rollers are rated. They have sold many rollers with plastic cage, no problems with fitment or durability. 60-7362

Today, called Coventry Spares Brit bike parts importer/distributor to learn exactly what bearing they are currently selling. . This is John Healy's company. Very nice man on phone. Very knowledgeable. He filled in many blanks I had on bearing availability. He said the bearing world is in changing. Various manufactures are starting production in India, Brazil for various reasons, including duties charged by different countries as a way to reduce costs/price. So.... at this time Coventry Spares has been stocking NSK NUP306ET. CN clearance, made in Japan. I will purchase from a vendor supplied by Coventry spares.

Finally today had time to discuss bearing quality with my son & his experience from work. He graduated collage '94 Mechanical engineering degree. Went to work in engineering right away & has been working in field ever since. Last several years working in the field of designing robots for industry & manufacturing. The robots can often run 24hrs. a day. Use lots of ball & roller bearings. He is skilled machinist & welder as well. He can build what he designs. So.... He found SKF Japan was best in world, maybe still is. F.A.G. was outstanding until they moved to India. Others moved to China with similar results. Even though these were modern plants things changed & the bearings just didn't fit & work the same. Not so durable as before.

At the same time he feels the Triumph motor doesn't really put all that much strain on T.S. bearing so any of them would probably last ok. He feels currently the next best bearing after SKF Japan, is NSK Japan, buy a very close 2nd place.

Again his thoughts & opinion only. May be right or wrong.

I have decided to use the NSK NUP306ET made in Japan with plastic cage that Coventry Spares sells. I will order tomorrow from a Triumph parts vendor I like that got it from Coventry Spares. I'll report how it fits later.

Since John Healy states the plastic cage gives no problems in service I'll go with that. Others on this forum have had similar good experience.

The brass cage of the F.A.G. India I'd like better, but the reputation of made in India scares me more than the plastic. Time will tell. May take 40k miles. 6-8 years, or maybe a lot less to cover that.

So that is one more hurdle jumped. Now to fitting it.... If it's too tight for any reason I'll install C3 roller. Will know that in a few weeks of all goes to plan.
Don
 

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Discussion Starter · #185 ·
Hi All, Sorry for so many delays. Back on the motor intermittently now.
Here's some photos of the timing side ball roller. Most oddly only light growl on cold motor. Warm motor silent! I can't explain why.

I decided to change to 3 piece roller on timing side. Turned out to be a fight. I got NSK made in japan CN clearance roller plastic cage as was advised & sold at most parts sellers. Turned out to fit too tight. Crank was light press fit into rollers. It would go but had to be really pushed really, really hard with all my weight. Once in turned freely. Absolutely no play could be felt when moving crank sideways at the drive side end. Just felt tight. Then I couldn't pull it out no matter how hard it tired. Ended up driving it out.

Got NSK made in Japan C3 clearance from Quality Bearings Online. Leeds UK. $110US with shipping. Fair price.
Removed CN bearing & installed C3. Crank fits perfectly. Nice slip fit. A trace of wiggle at drive side end of crank if I wobble it. Stacking of production tolerances or something demanded a C3 in my case. Whatever, I'm very pleased to have it installed & crank spinning well. Now I can move forward with weight matching rods & final assembly.

I'll post some photos on what it takes to convert to drive side roller after it's assembled & I verify all is good.
Don
 

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Discussion Starter · #186 ·
Hi All, For now I'll just post a few photos of the 3 piece roller bearing. Basically the outer race contains the rollers. The race partially covers both end of rollers.

The inner race looks like flat race with a lip on back side that the end of rollers can ride against. The retainer ring looks like a ground large flat washer that actually fits over end of crank & presses against side of inner race. So the right end of rollers can press against it.

So there is a lip at each end of rollers so the inner/outer race cannot move sideways. It does have a tiny bit of end play of the rollers though. Maybe .001-.003". The ball supports the up/down loads as well as left right loads. The roller does the same. Possibly the ball can take more end thrust, but the roller is much stronger on the up/down forces. End force of crank is not very high so wear on tips of rollers doesn't seem to be an issue.

It is important to remember to install the retainer washer into case first before installing rollers as the washer OD is too large to pass through bore of case. I made a little holder to keep washer & rollers as one. Made installing a little easier as prior experience showed my case bore for roller is on the tight side.

The photos may show C3 steel cage or CN plastic cage. Only difference is C clearance & cage material. Dimensions are the same. I have videos of all the work. If someone is interested PM me your email & request.

Lots more info later.
Don
 

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That timing side bearing was certainly shot up. Back in 1978, i had one ball with a small chip of the ball chrome damaged and it was quite a loud noise. No damage to the track though. Last time i replaced the main bearings, it was the roller side on the primary side. The track looked like someone had run a grinder around it. During my broken crank fault, those replaced bearings were still OK so re-used them and been running quiet for about 9 years now.
 

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Removed CN bearing & installed C3. Crank fits perfectly. Nice slip fit. A trace of wiggle at drive side end of crank if I wobble it. Stacking of production tolerances or something demanded a C3 in my case. Whatever, I'm very pleased to have it installed & crank spinning well. Now I can move forward with weight matching rods & final assembly.
i have a billet crank in one machine that took some fussing to fit, as it started out as a T140 crank. the right side bearing is a no-wobble slip fit, which i didn't like. but its been good for very hard use at very high rpm, so i'm okay with it. no noise, no increased clearances.
 

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Are roller bearings only available for specific Triumph years/models and are they generally superior to the alternatives?
 

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My double engine racer has a no wiggle slip fit on all main bearings...JH said to use bearings with the tightest internal clearances and it should be ok for limited duration racing...Make sure the bearing securing nuts are tight...Ain't blowed up so far....
 

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Discussion Starter · #191 ·
Hi Jeff, The rollers depend on year. The balls depend on year. So each motor has to be looked at in it's own right.

Specifically for my case, on the timing side, the factory switched from inch sized bearings to metric sized bearings sometime in 1971. The bearing race is physically different size. Similar in look & construction, but due to size will not interchange. In the 80s (I'd have to look it up) Triumph introduced the 3 piece roller for the timing side. It's supposed to be more durable. Even though it's a roller, the outer, inner diameters & thickness matches the dimensions of the metric ball bearing.

That's all I know, which is not much. Where the "C" clearance comes into play is due to the diameter of inner races grows, when pressing onto crank. How much, depends on how tight the press fit is. The outer reduces inside diameter as it's fitting tightly in the case. So depending upon exactly how the factory machined the crank & case at hand the clearance can change enough to need a different clearance than what is most common & the Triumph part # would indicate.

So with inner race on crank, outer race in case, you get "fitted clearance". The real life clearance. Too tight it will damage bearing, too loose, it can knock & I expect shorten life as well.

NSK puts out a very nice bearing manual that allows you to calculate what the fitted clearance will be. Very accurate measuring tools are required. I can measure outside diameters accurately, but not bores. Close doesn't work! Has to accurate. So I defaulted to trial & error. It is very surprising how much the bearing changes in clearance after they are fitted. I was very surprised. Never had to deal with this at work. You went to parts, got bearing, put it in. All good. Germans tend to be pretty precise on production tolerances.

I ordered the bearing said to be most common & most often gives good fitted clearance. It turned out too tight. So I did some study & after a very steep learning curve I have a little bit of understanding. Hind sight is always 20/20. There is no substitute for real life experience. On my motor the inner race fit very tight on crank. Never seen one this tight. The outer race tended to be on tight side as well. I knew when I took crank out I was in trouble! It took 3 times the force to remove crank from right case/ball bearing. I was afraid of breaking case to tell the truth.

Not justifying anything, just giving insight to what real life is like, when you lack experience. This is my first time dealing with bearing conversion. I prior replace bearing with same clearance as I took out.

So what to do? Do you start too loose & chance a knock? Do you start with the most common clearance size? I asked known experience motor builders. All found the very tight fit on crank puzzling. Suggested CN normal clearance.

Of course I now did my homework on bearing study. My money, my decision. After mulling all over the safest bet was CN. If it worked I win. If too tight I know what to do. Get larger clearance. I will know I didn't hurt myself by guessing too loose.

From my past experiences & training I could tell by feel I had light press fit getting crank into rollers. Even though it rolled freely. I had to actually drive crank out of the rollers in case! Looking at NSK manual it specifically stated do not fit with press fit cold. Zero clearance is ok, but not interference fit. Again were talking about the rollers to race clearance. Making it harder, there is overlap of C clearances. Do you have a loose CN or snug CN, or middle CN?

Nominal clearance jump from CN (normal clearance) to C3 (looser than normal) is about .0004". So will C3 be good or still too tight? My experience with press fits & shaft clearance told me I should be good, depending on the tolerance of the new one I should be good. So I again had to do trial & error, but very educated trial & error.

Ordered C3. It arrived. On bench I could already tell it was much looser. Very easy for anyone to feel the difference of .0004". It's pretty obvious. I was quite hopeful. Fitting the inner race on crank, it was same very tight press fit. However I could measure the fitted diameter was .00045" less. Just for fun put crank into the CN rollers, still in right case. It felt really good. So I heated the case, removed CN & installed C3. After cooling fitting crank into the C3 rollers was same good fit. Possibly a trace snugger. Still went in freely & spins very freely. Needless to say I'm quite happy. Lesson cost me $100. That's real life. At least I can move forward.

So that's the saga of my 3 piece roller.

Online how can you describe a tight press fit? How can you describe light press fit. Having to drive it out is a problem & can be described. In an experienced work shop you are supposed to have master mechanics that come over to your bench & teach/mentor you. Makes it a lot easier. Speaking with some old time Triumph mechanics they'd make their best guess from experience. If it didn't feel right, they'd take that bearing out , return it to shelf & try another.
Don
 

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So that's the saga of my 3 piece roller.
Don
Very interesting reading and I like your analysis rather than just depending on what the 'experts' say you should fit.
I replaced my T140 timing side ball bearing with the later 3-piece roller in early 90s before the internet and fitted a C3 roller because the ball race was C3. It went together ok and 'felt' right so if the 'experts' say a C3 was 'wrong' it has done over 40k miles since and still all ok.
Anyone - nice read of your rebuild so thanks
 

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Very interesting reading and I like your analysis rather than just depending on what the 'experts' say you should fit.
I replaced my T140 timing side ball bearing with the later 3-piece roller in early 90s before the internet and fitted a C3 roller because the ball race was C3. It went together ok and 'felt' right so if the 'experts' say a C3 was 'wrong' it has done over 40k miles since and still all ok.
Anyone - nice read of your rebuild so thanks
The "experts" are correct. The reason Don has had to go to a C3 was because the timing side shaft is oversize, making the bearing inner far too tight on the shaft. Without having the facilities to get the shaft correct, C3 is the workaround. Yes, if you are in the same situation, that is the solution, but not in general. That said, as you have done 40K miles, maybe your particular engine was the same way as Don's - or maybe it is not that critical bar maybe a bit more vibration. What Don did do is find out why he had the problem and make a decision accordingly!
 

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Discussion Starter · #195 ·
Hi All, Trial fitted crank to cases today, bolted cases up tight.
End float of crank no pinion nut is .034",

End float nut tight is .010". Basically the lateral clearance in bearing.

I understand if drive side roller is shimmed it must exceed .010" to keep drive side bearing to keep it from taking crank thrust.

Rods not on crank. Comparing old ball to roller the the crank to left is same place it was before. It can move to right a little more. I don't know what lateral play of old ball was.

I've never tested crank end play before. Just put roller on left, ball & right. Motor worked fine.

Does the drive side race actually move to left in case while riding?
Don
 

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Hi Don,
It should appear to move to the right.
Or more precisely the rollers should run slightly to the right on the track of the outer race.
 

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Discussion Starter · #197 ·
Hi All, I played around with crank some more this evening. I did a work sheet.

I tested the end play of the first brg CN clearance. Inner race lateral (axial) play is also .010". This one has plastic cage.

With nut tight I moved crank to left. Zero'd indicator. Removed pinion nut. Moved crank until indicator on zero. Then pushed crank to left until it stopped. Moved .028".

Looking at old drive side roller I can see shinny area where rollers were running. Didn't look like they were contacting lip on outer race. Laying bearing flat on bench right side (inside) upwards. I could see rollers were low, meaning to the left when bearing is mounted. Just so happens Mercedes 722.3 transmission shims fit drive side of crank. I have a good selection. I stacked up .028" shims on bench. Placed brg over stack so the rollers were raised .028". Spot on where they were in while in motor. So the factory had more end play it looks like that .017". Hold that thought.

Measuring end play of old TIMING SIDE roller from John's '69 Bonnie I get .0025". Bearing still in good shape, just changed it to get fresh bearing during overhaul. One side .002", the other .0005" using straight edge & feeler blades. I have .0005" feeler blade. My bearing was too damaged to measure. I cut it in half anyway.

Looking like other than the extra .0075" bearing side clearance (axial end play). The crank & drive side rollers are in same position as prior.

Using Starrett combination square I reached down to flywheel bolt heads. The heads are end faced so I can see a slight pip in center. Lining blade of square up with case parting line the bolt heads are very close to perfectly centered. This is assuming parting line of case is in the center & the flywheel bolts are in center of crank.... I don't know that either is. Just seemed like they might be??

The math isn't perfect, but pretty close.
Don
 

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Hello Don,
Measuring end play of old TIMING SIDE roller from John's '69 Bonnie I get .0025". Doesn't the '69 have an imperial ball bearing?
Cheers,
Mick.
 

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Does the drive side race actually move to left in case while riding?
It should appear to move to the right.
Or more precisely the rollers should run slightly to the right on the track of the outer race.

Hi Don, this is the long version:
If we ignore the internal clearance and call the timing bearing fixed. When hot the crankshaft will expand, due to the fixed right bearing the crankshaft will appear to expand towards the drive bearing.
Steel coeficient of linear expansion is 12 x10 -6 per degree C /m/m (0.67x10 -6 DegF/"/")
We can calculate the expansion new length = original length , perhaps 12 inches x temperature difference x coefficient of expansion.
If we know the correct distance between the bearings and the difference between start temperature and final temperature-we cab calculate the expansion- a ‘ball park’ example is below.
for example nL= 12" x 90degsF x 0.000067 =0.0724"growth if you start at 86 degrees and run about 176 degrees F case temp
CRANKCASE;
The crankcases for convenience we can aproximate to a sphere, this will have a volumetric expansion, co-efficient of volumetric expansion is 3 x linear expansion, however we are not calculating volume, just the linear expansion within a spherical object, conveniently linear expansion parameters apply when calculating at two points diametrically opposite (think; spokes on a wheel). The co-efficient of linear expansion is not fixed, but differs at different temperature, for our small temperature range we can ignore this.

The co-efficient of /linear expansion of aluminium is app: twice that of steel
so the same example distances 12" x 90 degrees F x 0.000125 = 0.135"

This results in a crankshaft that effectively expands from the fixed timing bearing towards the drive bearing, but at the same time the crankcases expand the bearings apart at twice the rate at app: twice the rate.
Therefore the inference is that if there is clearance between the bearing races and crankshaft to start with, it will not be closed up by expansion, it should increase at running temperatures. The drive side rollers not being retained in their track just move over a little to accommodate the differences in expansion rates.

There are two implications to this:
centralising the con rods in the cases, (compound calculation)
setting the clutch/drive sprocket alignment for the primary chain.( Easy calculation )
To locate the crankshaft accurately within the crankcases I can see two paths.
Either both con rods and drive sprocket set at working temperature and measure before the cases/crankshaft cools.
or settings made at ambient temperature but calculated to compensate for expansion at working temperature.

regards
Peg
 
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"There are two implications to this:
centralising the con rods in the cases, (compound calculation)
setting the clutch/drive sprocket alignment for the primary chain.( Easy calculation )
To locate the crankshaft accurately within the crankcases I can see two paths.
Either both con rods and drive sprocket set at working temperature and measure before the cases/crankshaft cools.
or settings made at ambient temperature but calculated to compensate for expansion at working temperature".


I'd agree with your calcs, very interesting, one thing I can't see ( if it makes any difference) is the con rod centre, yes there's plenty of float on the rods, but working out the optimum is beyond me, perhaps someone can fill in the blanks?

Font Parallel Rectangle Schematic Diagram
Font Parallel Rectangle Schematic Diagram
 
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