BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: Jackson on 26 Oct, 2018, 11:09

Title: A10 Oil pressure relief valve size.
Post by: Jackson on 26 Oct, 2018, 11:09
Sorry to bother you all again.
I'm trying to remove my oil pressure relief valve and the flats are fairly mangled. I need to get the right size spanner/socket on it. Problem is I can't get an accurate measurement a/f.
1.1" is the best I've managed but I'm not convinced, it doesn't seem to correspond to any standard size. Does anyone know the actual measurement or even better the proper spanner size please?
Thanks in advance,
Adrian.
Title: Re: A10 Oil pressure relief valve size.
Post by: Bess on 26 Oct, 2018, 13:08
Hi,
    1.1" across flats is correct. 5/8 whit, 11/16 BSF or 28mm metric.

Best wishes...
Title: Re: A10 Oil pressure relief valve size.
Post by: Jackson on 26 Oct, 2018, 15:41
Thanks very much Bess.
Adrian.
Title: Re: A10 Oil pressure relief valve size.
Post by: Bess on 26 Oct, 2018, 20:03
You're welcome  :)
Title: Re: A10 Oil pressure relief valve size.
Post by: mashermick on 27 Oct, 2018, 16:50
you cant get a socket on because its to close to the crankcase,the flats get rounded with an open ender , I removed the outer part and tack welded on a bolt ,then removed it  with a socket  !
Title: Re: A10 Oil pressure relief valve size.
Post by: Jackson on 27 Oct, 2018, 18:09
Ta, I'm  going to try a box spanner and if that doesn't work machine a socket down to fit.
Title: Re: A10 Oil pressure relief valve size.
Post by: Bess on 27 Oct, 2018, 20:38
Hi,
    It's worth machining a socket, when fitting a new or refurbished PRV it's important to refit at the correct torque setting (unless you can use a box spanner with a torque wrench). The threads if distorted will exacerbate oil pressure loss between the threads.

Best wishes...
Title: Re: A10 Oil pressure relief valve size.
Post by: Jackson on 28 Oct, 2018, 18:39
Ta, it looks like I have one after all but it will need machining to fit.
I'll try after the box spanner arrives, but you're right I won't be able to get a torque wrench on the box spanner easily. I think the box spanner will be safer for getting the old one off, the hex is pretty mangled. SRM suggest tightening up to the fibre washer and then a sixth of a turn if a torque wrench isn't available.
Adrian