Crankcase repair

[Nourish]

How could this fracture be repaired?- These are Pre - XA7 600 cases. Also what are that little uniformed patch of of dots at the 10 0'clock position in the picture?

[berger]

well my opinion on those is maybe someone punched them for identification purposes in the event of theft or getting swapped at a bike shop before the fracture  as for that damage if i wanted to use them i would let my mate robin the specialist welder attack it and then give it to mwas  [ man with amazing skills ] to machine back to normal . but if you don't have a welder mate or a man with amazing skills i think you need to price the repair work .

[RichardL]

I want to be adopted by Berger so I, too, could have Robin and MWAS (Berg’s brother, I believe) to jump in when things are desperate.

Unless we can come up with a technical
meaning for 124 or EIH (Morse code), Berg’s may be right about the dots being a personal identifier for a former owner or, maybe, a line inspector.

[RichardL]

What does ChatGPT say? (Yes, I’ve weakened and realize there may be information in this world I don’t have in my head already. The trick is to weed through AI for what you are actully looking for.)

(The photo of the dots didn’t paste.)

You said:
Any idea what the set of dots at 10 o’clock (with respect to the bearing housing) represent on this BSA engine crankcase?

ChatGPT said:

Yeah — those little dots are almost certainly factory punch marks, not damage or later “code” added by an owner.
On BSA crankcases (and lots of British engines of that era), small prick-punch dots near the main bearing housing were commonly used for one of three related reasons:

Most likely explanations (ranked)
1. Factory inspection / quality control marks
This is the most common.
After machining the main bearing bore, an inspector would punch a small group of dots to show:
bore size checked and accepted
alignment OK
case half passed final inspection
The clustered, irregular spacing you see is very typical of this.
2. Bearing fit grading / selective assembly
Some manufacturers used punch marks to indicate a slightly oversized or undersized housing so the correct bearing (or case half pairing) could be chosen during assembly.
Not always well documented, but very common practice in British factories.

3. Stress-relief / stop-drill marking (less likely)
Occasionally a punch was used near a machining transition to discourage crack propagation, but the neat cluster and location say “inspection mark” rather than structural fix.

What it is not
❌ Not a crack repair
❌ Not balance marks
❌ Not a serial or date code
❌ Not damage from a slipped tool
Those cracks you see lower down are casting stress cracks / age-related fatigue — separate issue — but the dots themselves didn’t cause them.
Big picture
If this is a BSA unit or pre-unit single/twin crankcase, those punch dots are normal and nothing to worry about. Almost every untouched case has some variation of them once you know where to look.
If you want, tell me:

exact engine model (A10, B44, B25, etc.)
drive-side or timing-side case
…and I can be more specific about whether BSA documentation exists for that exact marking 👍

[Nourish]

Very good Richard! It's an A7 1946/7 long stroke twin early XA7 just below 600.

Regarding the repair I wonder if it would be a good idea to machine out that inner diameter to remove the damage and press in a ring to hold an oil seal?

[Swarfcut]

The case may have enough sound material to simply be machined out to use the standard oil seal, together with the later post '53 drive sleeve.... The splines on the crank are the same.
 However, the Long Stroke engine uses a deep groove ball race which is not the same OD as the later design roller bearing and care must be taken that the outer race will still be axially supported to the outside of the crankcase after material is removed. Time for a bit of precision measuring.....  The damage looks relatively minor and a weld repair may be sufficient to retain originally. No oil seal  is fitted on this early variant.

Swarfy.

[BagONails]

These marks are the previous owner recording the number of hammer blows it took to drift the bearing out of the casing.
Unfortunately he missed the target a few times!

I can only hope he smashed his fingers the silly bugger!

[chaterlea25]

Hi All,
My opinion for wha it's worth
Welding the cracked area could/ would  distort the main bearing housing
As mentioned if the bore can be opened  up to take a seal but leaving a shoulder to locate the bearing i would go that route.
Alternatively a plate with a raised boss to simulate the bearing retaining lip and accept a seal could be attached to the outer face with countersunk screws if there is enough space to clear the primary chain.

A " McGyver" repair would be to reinforce the cracked area with chemical metal and hope for the best

John

[Nourish]

I was left alone in the house so I put the crankcases in the dishwasher - and on cleaning them had a good look and I don't think I'll use them.
Beside the damage shown there are quite a few cracks and chunks taken out of them. These were registered with a '47 rigid frame I bought that must of been a 'Custom' bike as the all the joints around the frame had been blended with filler (bondo) and consequently the cases have been polished - yuk!
I have a set of '49 cases that also came with the sale that I don't think had been split before. The big ends on the crank need grinding but the rest is nice.