Author Topic: Pitting & Journals - Can I reuse this crankshaft?  (Read 1393 times)

Online muskrat

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #15 on: 26.02. 2019 19:54 »
G'day Simon.
Can you give us a close up picture of the t/s crank journal please. Is it machined all the way to the web or does it have a step about 1/8" from the web? You may be able to make your new bush with a thrust face the correct thickness to eliminate the need for shims under the d/s inner race.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Muskys Plunger A7

Offline SimonHolyfield

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #16 on: 26.02. 2019 23:22 »
It's machined all the way to the web. Notice how the oil holes only partially line up with the oil way in the journal! I'm going to turn a groove in the bush, connecting the bush oil holes with the oil ways in the journal.
cheers

Simes

'51 Square Four, '42 W/NG, '58 Huntmaster,  https://ariel-square-four.blogspot.com

Online ironhead

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #17 on: 27.02. 2019 10:50 »
G'day Simon,
Don't loose any sleep over the timing side journal size. Trihards use a near identical crank with 30mm ( 1.181")
timing side & 1 1/8" ( 1.125") drive side . The T140's put out a bit more poke than most A10's.
I've never heard of one braking in normal use.
As Musky suggested, you need to check the blending radius where the journal meets the cheek (a sharp corner here will almost certainly lead to a breakage.)
The crank pin radius mentioned in the service sheets  ( 0.090" ??) may be something to aim at.
If you were here in oz I'd offer a swap for a standard crank, it would save me some machining on a roller project in the pipeline. Postage is an absolute killer though.
SA

Online duTch

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #18 on: 27.02. 2019 13:06 »

 I'll suggest that at least one benefit of a larger diameter journal would be increased surface/ oil film area, the Triumphs have the ball race bearing to support theirs....
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline chaterlea25

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #19 on: 27.02. 2019 15:30 »
Hi All,
I don't like the look of the rust and crap on the outside of that bush housing *sad2*
If it's an original outer has the bush sleeve been pinned to it? It needs to be!
In an awful lot of cases the original bush has lost its proper interference fit

John
1961 Super Rocket
1963 RGS (ongoing)

Offline SimonHolyfield

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #20 on: 27.02. 2019 17:26 »
Good point, I have not had a look at that yet.

I'll be sure to clean and measure it before I go any further with that bush.
cheers

Simes

'51 Square Four, '42 W/NG, '58 Huntmaster,  https://ariel-square-four.blogspot.com

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #21 on: 27.02. 2019 19:16 »
G'day Simon.
There still looks to be a small ridge on the thrust face of the crank web. This will "eat" into the bush thrust face and give excessive end float after a while.
I don't trust those steel bodied bush's, and if the bore in the case isn't round and true to size a new bush will need to be made to suit.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline harvey mushman

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #22 on: 28.02. 2019 08:01 »
It looks like an A65 crank to me (top one)

Online ironhead

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #23 on: 28.02. 2019 09:17 »
A wider camera shot would be good. Can't see the alternator section.
SA

Offline SimonHolyfield

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cheers

Simes

'51 Square Four, '42 W/NG, '58 Huntmaster,  https://ariel-square-four.blogspot.com

Offline harvey mushman

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #25 on: 28.02. 2019 14:06 »
looks like a65 even more now, whats the stroke?

Offline SimonHolyfield

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #26 on: 28.02. 2019 15:49 »
I'll go and measure it. What are the features of A65? This was supposed to be a large journal A10...
cheers

Simes

'51 Square Four, '42 W/NG, '58 Huntmaster,  https://ariel-square-four.blogspot.com

Online JulianS

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #27 on: 28.02. 2019 15:56 »
Not A65, that would have a plain section and keyway on the primary side for the alternator rotor.

Offline harvey mushman

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #28 on: 28.02. 2019 16:14 »
apologies my mistake i had to go and check myself, julian is as usual correct.

pics show A10 and A65 cranks

 *smile*

Offline SimonHolyfield

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Re: Pitting & Journals - Can I reuse this crankshaft?
« Reply #29 on: 28.02. 2019 16:15 »
Excellent thanks Julian.

Next thing is, I found there's about 0.5 mm run out at the end of the thread. What's the best way to sort that out?
cheers

Simes

'51 Square Four, '42 W/NG, '58 Huntmaster,  https://ariel-square-four.blogspot.com