Author Topic: Plain bearing vs roller conversion  (Read 4932 times)

Online Colsbeeza

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Re: Plain bearing vs roller conversion
« Reply #30 on: 26.11. 2017 23:21 »
Hi Dutch, Harvey,
I did also wonder whether Mr Eicher competed in the 1986 Paris-Dakar.
Clearly the article was written just as the 1986 Rally was commencing.
I have been unable to find any reference to whether he competed in 1986, and suspect he didn't.
It appears from the article that he was planning to do so right up to the start of the 1986 event.
So I have just emailed him to ask. His website is at http://www.eicher-classic.ch/.
Awaiting his reply and will advise.
Colin
1961 Golden Flash
Australia

Offline rocker21

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Re: Plain bearing vs roller conversion
« Reply #31 on: 29.11. 2017 10:22 »
many years ago back in the late 60's there was a firm that did a pure needle roller conversion that had a thrust washer made from phosphor bronze fitted to the timing side and all the bronze bushes were replaced by needle roller bearings, this was before devimead did it, i still have this engine in my loft, it was highly tuned with a polydine cam, 9:1 pistons, gardener carb and many other mods and it went like the clappers, no low down power and a very rough tick over, but it is still on that original needle roller timing side bearing, one major problem with fitting needle rollers to the idler shaft was oil getting in to the dynamo as there was no seal, nowdays you can get those bearings with a seal built in so that would cure the problem. building another engine on simalar lines but with a 357 cam instaed of the polydine as that would be dificult to ride in modern traffic.
1960 A7SS, 1954 Ariel fieldmaster 500 twin, motoguzzi Monza 500, motoguzzi V7III special, Yamaha sr400 (2014)

Offline Greybeard

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Re: Plain bearing vs roller conversion
« Reply #32 on: 29.11. 2017 14:17 »
many years ago back in the late 60's there was a firm that did a pure needle roller conversion that had a thrust washer made from phosphor bronze fitted to the timing side and all the bronze bushes were replaced by needle roller bearings, this was before devimead did it, i still have this engine in my loft
They last forever if you keep em in your loft!  *smile*
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Offline rocker21

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Re: Plain bearing vs roller conversion
« Reply #33 on: 29.11. 2017 16:01 »
did a lot of miles on it, as it was my only set of wheels at the time so it went every where including a trip to the italian lakes 2 up , proved very reliable although a bit intractable at slow speeds , i think the filtrate 20/50 plus oil helped a lot. pity it is no longer available, then i changed to a castrol strait oil with a graphite aditive and that seemed to work ok, going to rebuild it and put it into a light frame to have a go at hill climbing, seems like a bit of fun that. got a couple of other projects i need to finish first.
1960 A7SS, 1954 Ariel fieldmaster 500 twin, motoguzzi Monza 500, motoguzzi V7III special, Yamaha sr400 (2014)

Online Colsbeeza

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Re: Plain bearing vs roller conversion
« Reply #34 on: 05.03. 2023 07:37 »
I hate to stir up trouble again, but I do enjoy it!! *fight*
Recently I was in Bright Victoria, and found this article in a bike magazine at the accommodation I was haunting.
Interesting 1953 test by Enzo Ferrari. As some pointed out, a lot depends on the quality of the plain bearings.
Col
1961 Golden Flash
Australia

Offline BigJim

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Re: Plain bearing vs roller conversion
« Reply #35 on: 05.03. 2023 11:02 »
B....r, gonna have to get mine put back to bushes and worry about line reaming and end float again.  *help*
On a serious note, thanks col, interesting to think there are only plain shells in the van i drive.
 *computer* *beer* *bright idea* *beer*
Jamie,  Supporter of Distinguished Gentleman's Ride

Online JulianS

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Re: Plain bearing vs roller conversion
« Reply #36 on: 05.03. 2023 11:28 »
Attached January 1964 bulletin from BSA re the Vandervell bearings.

On a personal note my SRM end feed roller conversion has been working with no problems since 1985.

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Re: Plain bearing vs roller conversion
« Reply #37 on: 05.03. 2023 18:34 »
G'day Fellas.
Once again I have a foot in both camps. Plain bush in the plunger and bearing in the Cafe. The bush in the plunger has I think lasted 30+ years but was well due for replacement at the recent rebuild. The bearing in the cafe was done in the early 90's for the racer and only replaced after blow ups (barrels parting company from cases) a couple of times. Still delivering full oil pressure to the crank. I'm happy with both.
Cheers
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Offline Worty

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Re: Plain bearing vs roller conversion
« Reply #38 on: 09.03. 2023 17:34 »
Question:  Why did the plain bush last so well 60/70 years ago but does not fare well now?

One thing I didn't have a clue about when Bergs built my engine is the line boring, which I presume is how the bush is lined up with the crank????  Sorry if that's rubbish.  I think, when RM built my engine originally, he just shoved a new bush in and chucked the rest together (badly).  With Bergs and MWAS, the bush was engineered and line bored to the engine, and probably takes account of the amount of damage and wear to the other components.  When everything was brand new, this may have been unnecessary.  So, maybe the failure rate is down to the fact that bushes are put in without taking into account the tolerance variances of other components due to wear, etc??

I reckon the consensus is not a bad one, heavy, frequent and prolonged use may warrant a conversion.  For the rest of us with empty pockets, the bush may have to do.
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Offline RDfella

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Re: Plain bearing vs roller conversion
« Reply #39 on: 09.03. 2023 18:01 »
A plain bearing (bush) does not like contaminated oil, so the use of modern oils (without filtration) may well accelerate wear. Also, the original design was, I believe, while metal - which is more tolerant to impurities than the bronze usually fitted today. Type of bronze is important too, but don't ask me - there's a zillion different types - metallurgy is a subject all its own.
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Re: Plain bearing vs roller conversion
« Reply #40 on: 09.03. 2023 18:03 »
Question:  Why did the plain bush last so well 60/70 years ago but does not fare well now?

heavy, frequent and prolonged use may warrant a conversion.  For the rest of us with empty pockets, the bush may have to do.

Think the accent needs to be on the 'heavy' worty. On an initially unknown motor I got 50K miles out of mine before passing it on. At 30K-odd the bush was within the 1.5 thou tolerance and the ends and crank were unworn. A couple of years post-departure she's still running smoothly and well. That's without return line filters or anything except regular oil changes, bog standard 20/50 after cleaning the crank out, and moderate treatment. Which to me was 60-65mph cruising, and not going totally mad with the right wrist very often.
A nicely in-tune engine, upward gear changes when you know you'll be on the cam in the next gear (ie torque not revs) and I reckon these things can last and last as designed.
I don't think there's much point in flogging any of these things to death, because the difference between using full revs or 65-75% - in terms of time taken to get anywhere - isn't very obvious. And the olden day fun of blowing cars into the weeds has long gone - most moderns will see off most old Brit iron, and any 2 wheeler with an engine bigger than a mobile 'phone will too!
Bill

Offline Worty

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Re: Plain bearing vs roller conversion
« Reply #41 on: 09.03. 2023 18:14 »
Cheers Bill/RD.  I think that MWAS got a particular type of bush which Bergs rated, but you'd understand that better than me.  I had forgotten that I commented earlier in the thread about external oil filters, but that has changed after my experiences.  At the end of the day, I don't want bits in the oil being ground into the bush (after seeing the horror of my old one).  I'll continue with a mid-detergent mineral to get the debris through the filter, now that I know the sludge trap is clear.

With the regular oil and filter changes, I'm hoping that the motor will have a good life for some time.  Bergs said he'd put that motor in his bike, and that's good enough for me.
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Re: Plain bearing vs roller conversion
« Reply #42 on: 09.03. 2023 19:45 »
G'day Fellas.
The bush I put in (in the early 80's) lasted quite well considering the flogging it got. The plunger for quite a while was my daily and weekend tourer, had a spell on the race track and was my bush basher. So 40 years since I did it she was making a bit of racket. EIGHT thou up and down in the bush and 5 thou ed float but was still going, mind you I was using 70wt oil to help fill the gaps.
Cheers
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Offline berger

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Re: Plain bearing vs roller conversion
« Reply #43 on: 09.03. 2023 21:08 »
worty if it starts first kick again the engine is going in mine as mine won't throw over easily with the thick oil i tried it the other day, roll on summer.

Offline Worty

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Re: Plain bearing vs roller conversion
« Reply #44 on: 09.03. 2023 21:18 »
It does sound sweet.  Do I need to remove the PRV again to see if oil is still coming out?
Current Bikes😎
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