Author Topic: A10 crankcase indentification  (Read 877 times)

Online KeithA

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A10 crankcase indentification
« on: 27.08. 2017 18:57 »
Hello Members
Having a shed cleanup. I found this crankcase half. It is a bit oxidized, but otherwise OK condition.
I don't suppose the other half of it is lerking around out there somewhere, it would be good to make a matched pair again.
Any idea what the HHC letters refer to ?-High-Compression.

Offline muskrat

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Re: A10 crankcase indentification
« Reply #1 on: 27.08. 2017 20:44 »
G'day Keith.
High lift cam (357) and high compression.
Unless you have the other half hidden I recon there's three chances of repatriation. None, Buckley's and FA.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Online Greybeard

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Re: A10 crankcase indentification
« Reply #2 on: 27.08. 2017 22:28 »
Buckley's chance (uncountable)
 (Australia, idiomatic, informal) A very small chance; no chance at all.

Offline worntorn

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Re: A10 crankcase indentification
« Reply #3 on: 27.08. 2017 22:40 »
By the numbers that should be a 57 Road Rocket. I think the cam for that would be the 356, didn't the 357 show up in 61-63 Super Rockets ?

Glen

Offline coater87

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Re: A10 crankcase indentification
« Reply #4 on: 27.08. 2017 22:58 »
 The only numbers the other half is going to have is 552.

 That is not a unique to anything number. So you could probably find a 552 somewhere.

 Finding the actual 552 that came with that case?  *conf*

 Lee

Central Wisconsin in the U.S.

Offline coater87

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Re: A10 crankcase indentification
« Reply #5 on: 27.08. 2017 23:01 »
 Does anyone know how those numbers came to be?

 Was his case number 552 of the month of October?

 Was it the 52nd case made in the 5th month?

 Lee
Central Wisconsin in the U.S.

Online KeithA

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Re: A10 crankcase indentification
« Reply #6 on: 28.08. 2017 05:08 »
Yeh might be a long shot, but never know, I might end up with a matching pair, or else some else might. He's a picture of the casting number as well.
Thanks

Online BSA_54A10

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Re: A10 crankcase indentification
« Reply #7 on: 28.08. 2017 10:36 »
Does anyone know how those numbers came to be?

 Was his case number 552 of the month of October?

 Was it the 52nd case made in the 5th month?

 Lee

It was 451 from Aug 1st when the production run started.
And the 451 is the total number of A series twins so that would include any cooking version A 7 or A 10s
Each engine configuration ran in sequence regardless of weather is was a sports or Std , larger or smaller capacity.
BSA numbering system left a lot to be desired.
The A 7 - A 10- A10 R- A 7S etc got stamped in at the start so the assemblers put the correct bits in and as they came off the line the serial number is stamped in which is why the numbers a so higildy pigilty and why sometimes they are all in one line, some times the model type is first and sometimes the model type is last.
They were made in batches to order so if the first order was for 500 A10 RRs then they would all be in sequence
Bike Beesa
Trevor

Online JulianS

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Re: A10 crankcase indentification
« Reply #8 on: 28.08. 2017 11:26 »
552 is simply a matching  number for cases machined as a pair. If you found the other case you would find it also stamped 552 in a corresponding position. It is not a dating feature.

The 67 357 cam was used on the A10 Spitfire scrambler from its introduction - described in 1957 by Hap Alzina as being fitted with 67 357 special full race cam.

Offline worntorn

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Re: A10 crankcase indentification
« Reply #9 on: 28.08. 2017 13:18 »
Did not realize the 357 was around that early on.
This case is from a Road Rocket tho, and it's my understanding that the RR plus 58-60 SR came with the 356 cam?

Glen

Offline coater87

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Re: A10 crankcase indentification
« Reply #10 on: 28.08. 2017 13:27 »
552 is simply a matching  number for cases machined as a pair. If you found the other case you would find it also stamped 552 in a corresponding position. It is not a dating feature.

The 67 357 cam was used on the A10 Spitfire scrambler from its introduction - described in 1957 by Hap Alzina as being fitted with 67 357 special full race cam.

 I guess what I am getting at here is what was the significance of the 552 number, beyond that it matched the other half of the case?

 Its possible, but I would not think that number to be meaningless. You would not rely on he guy doing the stamping to just choose three random numbers willy-nilly.

 So did he start with 111 on monday morning? Or did he start on he first of the month with 111?

 Or is it as stated already it went by batch, and its possible you might see 5 bikes a week with 111 stamped on them?

Lee
Central Wisconsin in the U.S.

Online JulianS

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Re: A10 crankcase indentification
« Reply #11 on: 28.08. 2017 13:59 »
On cams - you will find a number of CA10R cases stamped HHC, both Road Rocket and Super Rocket. The 1957 US brochure describes the Road Rocket as having a "super sports" cam but the Shooting Star  described as having a "sports" cam

Offline worntorn

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Re: A10 crankcase indentification
« Reply #12 on: 28.08. 2017 18:51 »
This is the brochure I was thinking of.
http://bsa.hailwood.com/1961a10srbrochure.html
So HHC on a 57-60 Super Rocket or any Road Rocket would appear to reference some cam other than the 357? I guess the various parts book would also show the different cams used.

Online KiwiGF

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Re: A10 crankcase indentification
« Reply #13 on: 28.08. 2017 22:55 »
Hello Members
Having a shed cleanup. I found this crankcase half. It is a bit oxidized, but otherwise OK condition.
I don't suppose the other half of it is lerking around out there somewhere, it would be good to make a matched pair again.
Any idea what the HHC letters refer to ?-High-Compression.

Unfortunately it is often the case (groan) that only one case is left useable after a blow up. So the other case was probably junked  *sad2*

But it's not a huge job to match another case to it by a machinest who knows how to do it (I've had it done) and it would not cost much to buy just half a case! At least you've got the more valuable half  *yeah*

Mind you, Sod's law says if you keep it as a spare and have a blow up, it will the other side you need  *problem*

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Offline Sluggo

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Re: A10 crankcase indentification
« Reply #14 on: 12.09. 2017 00:10 »
have to agree with Kiwgf,
It is nice to have matching case halves, and you should check any machine for such, But not having both matching halves is not the end of the world.
Competent builders know how to align the critical surfaces.  To be fair, Most of these early British bikes were built to very loose tolerances and quality control was not great.
Any casting has certain points that need to be in alignment but a great deal of latitude can exist in other areas.
I know of several people making replacement case halves and in some situations only  1/2 is beefed up or replaced.  (IE: Steve Maney, Kenny Dreer).  Dreer eventually did make both halves as well as heads, cyls and timing covers for his VR880 Nortons but I have 2 sets of cases of his early production and only the drive side was new.
It has been my experience with BSA, that they tend to get core shift and distortion over time.
On one 650 twin the Crank bearing bores were off side to side by 20 thou in one direction the cam bushes were off by 40 thou in another direction.  When bolted up the cam and crank locked solid.  Only after careful machine work was tolerances restored. I have pictures of famed tuner and tool & die maker "Sir Edward" Bilton-Smith doing the work.
I have also seen Goldstar cases shift (Matched sets from the factory) and well off the mark. The symptoms were abnormal wear in the cyl bores.
Dialed in on measurement it showed significant alignment issues.  Ironically the owner of said machine in one case felt that the cost to correct it was excessive. He bolted it back up and Sir Eddy reported wistfully the fellow seized the motor on his next outing.
So, in my book, 50-60 year old alloy castings should be carefully blue printed whether they are matched case halves at the factory (With matching stampings) or mismatched halves pulled from parts bin shelves or swap meets/autojumbles.
The results of NOT doing so is predictable.
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