The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: Peter in Aus on 10.03. 2016 07:54

Title: Magnetic gearbox drain plug
Post by: Peter in Aus on 10.03. 2016 07:54
Has anyone fitted a magnetic drain plug to the gearbox and are they available to fit the A10/7.
The drain hole could be made bigger if needed, I think, and what are the pros & cons?
Peter
Title: Re: Magnetic gearbox drain plug
Post by: beezermacc on 10.03. 2016 09:05
Sounds like a good idea. As the drain plug screws into aluminium and doesn't contact any steel within the gearbox there is no problem in just magnetising the plug itself. A neat job might be to drill the plug and fit one of these......
http://www.ebay.co.uk/itm/100pcs-Small-Neodymium-Disc-Magnets-N35-Grade-reborn-3mm-x-1mm-/191109150043?hash=item2c7efe355b:g:40IAAOxyhXRTLBPH
Make it a tight fit and peen the surround. It shouldn't want to come loose 'cos it's a magnet, but who knows?

Title: Re: Magnetic gearbox drain plug
Post by: bsa-bill on 10.03. 2016 11:19
two points I would want to consider

1. make absolutely 100% the magnet is secure (you don;t want anything roaming around free in there)
2. practically all the churning happens beyond the inner cover, the drain plug is not in that part, so probably to be effective that is whee your magnet wants to be.

Those points considered I'd be inclined to drill and tap a new drain plug hole in the larger compartment and use a magnetized stud rather than a magnet attached to a stud and some way to incorporate a tab washer
I like the idea, lot of work though but when has that ever stopped any of us
Title: Re: Magnetic gearbox drain plug
Post by: chaterlea25 on 10.03. 2016 20:17
Hi All,
Bill, the drainplug is in the main casing, level plug on the outer cover

Personally I would not fit a magnet to the inside of the plug, its fairly near the big first gear
What about adding the magnet to the bolt head?
One of my pet hates on the BSA gearboxes is the original shallow hexagon head on the drain and level plugs
quite often the head is half buried into a thick fibre washer  *problem*
making it a pain to undo  *work*

John
Title: Re: Magnetic gearbox drain plug
Post by: RichardL on 10.03. 2016 20:25
Is a little swarf in the gearbox any kind of big deal? It's much different than circulating in the engine. If a big piece of a gear breaks off and is going to cause any damage it will probably happen before the magnet catches it, if at all.

Richard L.
Title: Re: Magnetic gearbox drain plug
Post by: chaterlea25 on 10.03. 2016 21:22
Hi Richard and All,
Quote
Is a little swarf in the gearbox any kind of big deal?
that may be ok but if a tooth broke off I would rather it stuck to a magnet then getting stuck between rotating gears *warn*
When I got my SR project back in 1990 the boxes contained the remains of an RRT2 gearbox that had been
in the bike
I suspect a tooth had broken off first gear or a stray piece of metal had jammed between first and the drainplug, punching a hole in the gearbox case :o
it had been patched with fibregalss *pull hair out*

A while later a coincidental meeting at an autojumble led to a swop being arranged for a very nice tank for the bike *smile*
and I sourced a standard box for the bike

John
Title: Re: Magnetic gearbox drain plug
Post by: bsa-bill on 10.03. 2016 21:43
Quote
Bill, the drainplug is in the main casing, level plug on the outer cover

ah true, looks like I had a moment there
Title: Re: Magnetic gearbox drain plug
Post by: Peter in Aus on 11.03. 2016 00:40
Thanks all for your input, it is not the big bits that I was thinking about but the fine bits that are floating around in the oil that the magnet would catch.
It is these fine bits of metal that causes a lot of wear in the bushers, bearings and gears, I think!
I think what I will do is make the drain plug a bit bigger 3/8 and magnetise the plug, I know that the magnetism brakes down after a while but it should last long enough to do the job between oil changers and I will just re magnetise the plug again.
The other thing that could be done is glue a magnet to the head of the drain plug so as the magnet is on the out side and if it comes off, on big deal.
Peter
Title: Re: Magnetic gearbox drain plug
Post by: bsa-bill on 11.03. 2016 09:54
Quote
The other thing that could be done is glue a magnet to the head of the drain plug so as the magnet is on the out side

another thought on that (hopefully I'll get it right this time).
Is there room to drill the larger hole a little way off the existing hole which you could use for a stud for a tab washer or just use a magnetized washerplwnty of ideas here
http://www.ebay.co.uk/sch/ir3n3l33/m.html?item=191109150043&hash=item2c7efe355b%3Ag%3A40IAAOxyhXRTLBPH&rt=nc&_trksid=p2047675.l2562 (http://www.ebay.co.uk/sch/ir3n3l33/m.html?item=191109150043&hash=item2c7efe355b%3Ag%3A40IAAOxyhXRTLBPH&rt=nc&_trksid=p2047675.l2562)

same site as beezermaccs, fascinating page
Title: Re: Magnetic gearbox drain plug
Post by: Rocket Racer on 16.03. 2016 05:01
personally I wouldn't bother with modifying the gearbox drain plug, i would just change the oil as per the book after a run and check what state its in.

The gearboxes take a lot of abuse. if teeth start coming out in the oil change you've got problems  *eek*.
Title: Re: Magnetic gearbox drain plug
Post by: bsa-bill on 16.03. 2016 16:30
Quote
personally I wouldn't bother with modifying the gearbox drain plug

No me neither but sometimes there are things you just want to do for the hell of it, and I ain't about to believe you don't know that RR  *smile* *smile* *smile*
Title: Re: Magnetic gearbox drain plug
Post by: Rocket Racer on 16.03. 2016 19:39
Quote
personally I wouldn't bother with modifying the gearbox drain plug

No me neither but sometimes there are things you just want to do for the hell of it, and I ain't about to believe you don't know that RR  *smile* *smile* *smile*

I'm still trying to figure out how I can get a TT industries BSA gearbox past management  :-\

Both my A10's have been struggling to get my attention . The sidecar is getting a freshened up SC box as the old STD was starting to blow out of top after five years of abuse. But while regular oil changes figure, no magnetic drain plug will. My big problem with the rig is oil swill on anti clock wise circuits. The poor gear change needs further attention as is can't keep the oil in, once all the oils in the rh case, so an oil ring or seal is in the pipeline for the box.
Title: Re: Magnetic gearbox drain plug
Post by: shuswapkev on 09.04. 2016 12:48

  I just drilled into my drain plug and filler plug and inserted a rare earth magnet...well that's what it was sold to me as..?? if you drill 30-40 deeper than the magnet...you will never ever get it out
I get ,m from china ebay..real cheap...if you don't like drilling that deep...just make a longer plug...can see in the picture I made a brass bush for the longer oil plug which allows me a bigger magnet...that magnetic oil plug  will pick up an 8 inch king dick adjustable...that magnet is about 3/16 x 5/8 long

  gear box magnet...think it was about 1/8 x 3/16?? will hold a screwdriver pretty securely.....  also  made a new alloy block for the bottom of the motor...use a 1/2 inch plug there with a bigger magnet...collects a lot of black sludge at frst ... 1500 k,s later and now maybe a finger wipe...then the drain on my oil tank and another on the dipstick...on the return I have a spin on oil filter..
the filter fits 2015 Toyota diesel v8...and likely a hundred others..  the oil pump has no issues pumping back thru that...  my return line must be misaligned... as if I rev up a bit will fire oil out of the filler cap (well some flies out).....
the black sludge in my oil tank...wondered why how it was getting thru the filter...did some research....turns out the oil filter is only supposed to filter less than 20% of the oil that comes its way...  the rest goes thru the built in bypass in the filter!!
 well...not to worry Toyota......my magnets will pick up what your filter doesn't
the black sludge quantity dropped off quite a bit after about a thousand miles

if drilling and fitting magnets is not your cup of tea...can always stick a BIG magnet on the outside of the oil tank...maybe near the drain

the oil tank...I had to make  as I used a big fin head in a rigid frame..with the rigid the seat tube is about 7/8 inch from the carb mouth and the original side oil tank is so close the carb...no room to fit air filter... I have a 48 frame 51 motor with big fin top end..  for the cap..  I used and old fork bush and cut a few grooves to fit o rings...