Crankcase oil sump plate holes - poor repair

[limeyrob]

You want it the way BSA did it on cases: Whitworth into the ally, and cycle on the nuts. Plain nuts with plain and lock washer and loctite the stud in.  I would not use nylocs, they have a habit of unwinding the studs so you end up with the nut staying on the stud and it just behaves like a bolt.

[Swarfcut]

 Studs into alloy are the way to go. Original thread size was 1/4" Whitworth into the crankcase. The conundrum here is to restore to original, which means a stud with Whit on one end, and BSCy "Cycle Thread" on the other, or to go metric for the odd stud.

 Aftermarket replacement studs are available, Whit/Cycle, but in many cases even the original BSA material sheared off more often than not, how many cases have we seen with the damage that started this thread...along with enlarged and mis drilled holes  and broken stud extractors.  I reckon the average Wassell part will be of the same fence post quality. I'd use a higher tensile material and make custom studs.

 Swarfy.

[Worty]

To avoid a major job when I had one of my studs strip out was to find a bolt slightly larger than the hole and *very, very* gently self tap it in.  I reasoned that a steel stud into softer ally would work, but was wary of creating a crack.  I had a metric bolt just about the right size, self tapped it in, removed it, cut off the head then double nutted it back in - worked perfectly so far.

Simlar issues arise with the fork slider bolts wearing the thread - many people, including me, have opted for studding instead.  There's also a Loctite option too if you want extra security.

[limeyrob]

Helicoils are a good fix, I have a pathological hatred of using metric threads on an old British bike or car.  3 spanners will strip 99% of any BSA until someone adds some UNF or metric, then its a faff.  These bikes are now giving good service at 70 years old because the BSA engineers knew that they were doing.  Whit thread form is smoother and stronger than metric and cycle is a wonderful thread, holds against vibration at a modest torque with no need for nylocs.  I keep a set of BSF and cycle taps and dies and most threads can be recovered by tapping slightly deeper and using a new slightly longer bolt.  Cycle threads do not need to be done up tight, period spanners (and BSA tool kit ones) are about half the length of a modern spanner for a reason.

[Worty]

Helicoils are a good fix, I have a pathological hatred of using metric threads on an old British bike or car.  3 spanners will strip 99% of any BSA until someone adds some UNF or metric, then its a faff.  These bikes are now giving good service at 70 years old because the BSA engineers knew that they were doing.  Whit thread form is smoother and stronger than metric and cycle is a wonderful thread, holds against vibration at a modest torque with no need for nylocs.  I keep a set of BSF and cycle taps and dies and most threads can be recovered by tapping slightly deeper and using a new slightly longer bolt.  Cycle threads do not need to be done up tight, period spanners (and BSA tool kit ones) are about half the length of a modern spanner for a reason.

I don't like using them either, but if it keeps me on the road, I'm not going to be too precious about it (not saying you are, by the way).  I've lost engine bolts and nuts, and mudguard fastenings, not to mention the sump hole stripping and the fork sliders.  My philosophy is that, one day, when it all comes apart again, I may fix it as original.  Problem is, a small fix like this can cost in terms of tools, labour, etc, etc.  I tend to find what I can in my garage and see if the issue can be fixed with the minimum of expense.

[limeyrob]

Guilty as charged: I am precious about threads, its a (slight) obsession.....

[berger]

worty i hate to say this but the next time yours comes apart it will have either blown apart or been taken apart and thrown in the scrap bin ... this will save on way too many beer vouchers and hours of work getting THOSE cases and the rest of it to work as a - sort of normal A10 engine . the engineering on mine that had no where near the problems yours had cost over a grand by the time i'd done with new parts.....now you can have a beer and relax , i am  . ps when you get the experts who know exactly what they have to do regarding getting things correct you need a money pit . remember the work they did on mine welding the spigot and machining it because when the cases were tightened they were pulling all over the place? remember the hassle i had with yours when that  one last nut in the crankcase mouth was nipped up a bit  and it locked the crank and i had to sort it with marking blue and a scraper, all because your cases had been welded up when it threw a rod years ago-- i sent you that video of me with spanner on the nut and crank turning and then locking up? anyway this is what they did with mine. thankyou for listening way off topic but there is also a photo of my sump plate that i think will get me back on topic?? i had to alter this and get rid of the ribs/ fins at the corners so studs and nuts could be used, the fins/ ribs got in the way of the corners on the nuts and stopped them turning . time for another black & tan the berger build has driven me mad today but that's another story

[muskrat]

G'day Angus.
I'm pretty sure (not 100%) the studs and nuts for the rockerbox covers will do the job. I use the extended nuts as well.
Cheers

[Worty]

Fear not Bergs, I know this is the last throw of the dice for this motor, and I remember all too well your updates as I sat crying into my beer   Thing is, rather than RM chucking it back together and charging me for it, why didn't he just say the motor's shot - at least I could have (maybe) sourced another motor and used/sold the good bits for spares

The only bright spot in my case was I payed next to nothing for the complete bike - at least that offset the extra cost of having to have it rebuilt again.

My plan is to ride the beastie without worrying too much.  I like givin' it a good 'andful (fnarr, fnarr), and if I bust it so be it.  Having said that, it rides lovely at the moment.

[berger]

musky if i had long sleeved nuts  [  i would be in films  ] i wouldn't have got rid of the ribs on the plate, but i have found lots of confusion about what is sold for rocker box studs and nuts and sump studs and nuts  BSF or CYCLE  i ordered long sleeved rocker inspection cap nuts and found out they didn't match the studs that were in so had to shove a tap down them, or maybe they have been changed over the years

[muskrat]

 

[berger]

been a long day boing time for bed sed zeberdi , . worty locks -----, misky i mean musky ok gone zzzzzzzzz

[Rex]

Guilty as charged: I am precious about threads, its a (slight) obsession.....

And why not? When I were t'lad there were Imperial, SAE and metric threads on various machines, and if someone was caught using the "wrong" fastener (or spanner) the p*ss-taking would be endless and unrelenting.
Rightly so. Nobody wants to be stuck on a breakdown at 03.30 b*ggered by some tw*t having lazily replaced a UNF setscrew with a close metric replacement just because they too lazy to do it properly the first time.

[Worty]

Don't worry Rex, my bodges are much better than that

[ADP91]

Well two steps forward and one small step backwards it seems...

I was cleaning up the recently welded area and a small pin hole developed near the bolt hole.

It being such a small hole I'm a bit torn about how to address it. My initial reaction was to put a very small amount of JB weld over it and call it a day. Thoughts? Another possibility is using aluminum brazing rod but I don't have much experience with it.

Last resort would be to re-weld it but I have some concerns about the amount of heat cycles I've put the crankcase half through already (cracks? distortion?).

As always appreciate any advice.

Cheers