Barrel not fitting

[Nourish]

I've just received some thick flange barrels off e Bay but they won't sit in my BA7 crankcases - it looks like the spigot is fouling on the piece of crankcase between the mouth and the cam follower opening - is this usual - should I relieve the barrel spigot or the crankcase?

[RichardL]

A picture is worth a 1000 words, as they say.

[Briz]

Never had this problem putting thick-flange barrels on plunger cases, but If I did, I'd definitely be relieving the crankcase not the barrels.

[orabanda]

Not A65?

[Nourish]

A10 Barrels?

[Stephen Foster]

They look like  A10 barrels to Me ?
I have never seen A65 ones however so cannot comment with certainty .
Perhaps You could photograph the flange view for confirmation ?

Steve ...

[bsa-bill]

You could photograph the flange view for confirmation ?

and the op of the crankcase

I'd say A10 defo as well

[bikerbob]

I have an A65 and they are definately not A65.

[muskrat]

No two sets of cases are 100% the same. It's just the way castings were machined back in the day.
Adjust the cases not the barrels.
Cheers

[Nourish]

That's two of you who say to relieve the cases and not the barrel - as it's under the flange and not where they usually break - Why?
Hope you can see where I've marked where they are contacting
Cheers

[muskrat]

The skirts of the barrels are thin enough. I've seen them brake off without too much provocation.
The cases won't be weakened by a little grinding there. I had to do similar to a set of CA7 cases.
Cheers

[RichardL]

Well, I think this photo of my crankcase may answer the question. As you can see (and as I had never noticed before) the crossmember is relieved in the same place Nourish's/your's will be. It seems to me that the reason relieving the member ( ) was not previously necessary is that this is the first time the larger bore A10 barrels are being used on the A7 cases.

I have a frustrating, but now over, side note to this. In looking at crankcase diagrams, I noticed the alignment dowel in the crossmember. Before putting the cases together, I had forgotten to confirm the dowel in place. This meant disassembly, to be certain. Luckily, it had not been so long that the joint sealer had set, so the job was not horrible, but an hour of my life not coming back. The dowel was there.
'
Richard L.

[Briz]

You could probably do without that dowel. The cases align via the register around the circumference of the mating surfaces. This ensures the alignment of the main bearings.
As long as the barrel flange is then properly flat they would be OK.

[WozzA]

A little hard to see in this pic.... 
but my A10 cases have been releived of some metal at some stage like Richards,
I always wondered why.... now I know..   
 

[RichardL]

The look of the relief in Wozza's/your crankcase is very similar to the work in mine, which makes me think this was factory done.

Briz, I'm sure you're right about not needing the dowel for case alignment, but I was done by the time you wrote. Anyway, I was concerned that the dowel was also intended to provide an added element of stability for the slim crossmember. The fact that it's part of the breather path is probably not an issue.

Richard L.