The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: TimK on 13.06. 2016 07:02

Title: Sludge Trap?
Post by: TimK on 13.06. 2016 07:02
I finally got around to splitting the cases on my Gold Flash, and rather than the slotted plugs I was expecting to find sealing the sludge traps they're sealed by blank plugs. I've attached a picture of one of them below, but they're both similar. I'm thinking that a PO may have given up after failing to drill them out and has welded up *conf* the drill holes to re-seal them. Has anyone seen anything similar and are there any ideas to remove them bearing in mind that my shed isn't very well equipped.
Title: Re: Sludge Trap?
Post by: beezermacc on 13.06. 2016 07:41
I don't think the plugs have been welded in. Even with the slots they can often be difficult to remove. The plugs are only about 8 mm deep and are usually made of soft iron so they shouldn't be too difficult to drill out. I would recommend starting with a smallish drill, maybe 3 mm, in the centre, and gradually increasing drill size until you are almost touching the threads, then break the remaining ring of sludge trap with a sharp pointed punch. Obviously you don't want to damage the threads but, even if you do, you can use some threadlok on the new plugs when they are fitted. I've seen some really horrible sludge trap damage in my time and it can always be repaired with the correct tap and some threadlok. Have fun!
Title: Re: Sludge Trap?
Post by: muskrat on 13.06. 2016 09:22
 *work* *pull hair out* *bash* The things we find *ex*
I'd drill and try a large 3/8" easyout first. As beezermacc said the plugs are soft so if the easyout won't work proceed as he suggests. Just try to get your first hole as close to center as you can.
Cheers
Title: Re: Sludge Trap?
Post by: a10gf on 13.06. 2016 10:01
Quote
The things we find
Curses from previous owners :O)

If drilling out until threads is needed, I'd say get access to a bench drill, with the crank tightly secured (somehow) and everything finely adjusted before drilling.
(http://www.epple.co.uk/bmz_cache/6/6588479067232488df8c2555d86a012d.image.200x200.jpg)
Title: Re: Sludge Trap?
Post by: Greybeard on 13.06. 2016 10:03
I'd drill and try a large 3/8" easyout first.
If you do use an Easyout please use a good quality one. I've had cheapo's break in the hole and you don't want that!
Title: Re: Sludge Trap?
Post by: TimK on 13.06. 2016 10:49
Thanks for the collected wisdom gents, I do have a drill press, so I'll have a go at drilling it out. I'm thinking I should lightly drill the punch marks first - what do you think?
Title: Re: Sludge Trap?
Post by: a10gf on 13.06. 2016 12:22
Quote
the punch marks
If it looks like it may help, maybe a touch of cleaning up with a dremel for the inwards indentations ?

Doing this may allow for a better result if trying Easyout instead of drilling. Heat the crank and then cool down the plug with electronics freeze spray, then spray with lube, may help in breaking the old thread bond before applying force to the Easyout.

And patience is the best tool :O)
Title: Re: Sludge Trap?
Post by: groily on 13.06. 2016 13:22
I'd also invest a couple of beer vouchers in a suitable-size and easily available 'centre drill' to give you a better chance of a central hole. Being short fat and rigid in the shank department, they are much better at this sort of thing as they don't wander. They also have a tapered cutting edge beyond the short pointy bit that really helps with countersunk screws (if they are countersunk, can't remember but think they all are). I use them all the time to get messed-up dynamo pole shoe screws out without harming the female threads, which is a similar problem.
Title: Re: Sludge Trap?
Post by: a10gf on 13.06. 2016 13:49
^^^
Quote
easily available 'centre drill' to give you a better chance of a central hole. Being short fat and rigid in the shank department, they are much better at this sort of thing as they don't wander.
Good point. Regarding no-wander, take a look at this 'twin-tip' kind of drillbits > https://www.machinemart.co.uk/p/dt7926qz-29pce-extreme-2-drill-bit-set/

Have used those extensively at work here, excellent stuff for controlled & clean drilling.
Title: Re: Sludge Trap?
Post by: Billybream on 13.06. 2016 14:00
Yes most are battle to get out, but has to be done to reveal the cranks inner secret. On mine I ground a suitable Allen key, leaving the straight peice to drive into a appropriate sized drilled hole in the sludge trap plug, then with a wrench they unscrewed quite easily. When you order you replacements I would try and get the Allen Socket version.
Title: Re: Sludge Trap?
Post by: RichardL on 13.06. 2016 14:13
Following-up what Billybream has mentioned, here is a link to a more detailed description for using an allen key. Specifics are about 1/2-way down the page.

http://bsa.hailwood.com/endplug.html

Richard L.
Title: Re: Sludge Trap?
Post by: mugwump on 13.06. 2016 17:22
I always try the simplest of methods first, before you start drilling holes. Try and remove any punch marks and then heat up with a blow-lamp and try punching it round with a relatively broad punch, say approx 3/16" tip. If a thread lock/lock-tight goo has been used the heat can loosen some makes.
I have removed some in the past like this. Being a relatively wide dia bung you can exert fairly good torque on it this way.
Title: Re: Sludge Trap?
Post by: RichardL on 13.06. 2016 17:37
Maybe, but considering the recess of the plug, there is good chance of slipping off and putting a really good gouge in the threads. It's not like the plug is going to be preserved, so drilling won't be spoiling anything. So, just for fun, I have US$5.00 to wager with any one (and only one) taker that the punch-for-torque method doesn't work in this case. Anyone interested? Winner (I mean "I", that is) would be paid by PayPal. Of course, TimK would have to try it and report the results.

Richard L.
Title: Re: Sludge Trap?
Post by: groily on 13.06. 2016 21:20
Hadn't seen those 'extreme 2' bits before - look like a very handy addition to the weaponry. Best get some I think. Thanks to you A10GF.
Title: Re: Sludge Trap?
Post by: coater87 on 13.06. 2016 22:54
 I have given up completely on any easy outs. The only easy part is the "easy to break off in your hole" part.

 A buddy of mine put me onto left hand taps and bolts for larger stuff like this. Drill it, tap it, then you could even use an impact if you wanted. Worse that could happen is you strip the threads.

 Much better than trying to drill, punch, twist a broken easy out while you sweat, cuss, and bleed...
Title: Re: Sludge Trap?
Post by: BSA_54A10 on 14.06. 2016 09:30
Yep,
Really big fan of left hand drills.
Clean up the punch / drill area with a Dremmel on the plug only.
Do not touch the crank. it has been butchers enough already.

Got a pile of grade 8 left hand bolts and nuts.
Drill hole with a left hand drill. usually this spins out broken bolts all by itself.
Follow up with a left hand tap then a left hand bolt with a couple of nuts on it.
Snug in down tight then screw it out, never failed.
Don't use easy outs any more.
To get the drill press to turn left hand get a double A belt and fit it figure 8 on one of the pulleys.

Because the belt will be rubbing across itself you do not want to use it like that all the time but once in a while to drill out a broken bolt is a really worth while investment.
Running the drill press backwards menas you can put a good amount of down pressure on the drill making it bite hard
Two or three increasing sized drills works even better as the enlarging drill really puts a lot of rotational force on the bolt ( plug )
Title: Re: Sludge Trap?
Post by: mugwump on 14.06. 2016 11:03
I'm no engineer so go easy on me if this is a daft question, but why use a left hand drill. Won't a left hand tap still cut well enough into a r/h drilled bore? But using a l/h bolt is a great idea.
Title: Re: Sludge Trap?
Post by: muskrat on 14.06. 2016 11:53
Sometimes the drill it's self will be enough to unscrew the plug/snapped off bolt. Tapping the hole might do it or screwing in the bolt. If it still hasn't budged a lock nut on the bolt and heave ho.
Cheers
Title: Re: Sludge Trap?
Post by: bsa-bill on 14.06. 2016 12:24
bought a set of left hand drills about four months ago from one of those shopping channels (yeah I know but I took a chance)
Within  a week or so I used one to remove a stud, worked a treat, (remember to have the drill going the right way though)
Title: Re: Sludge Trap?
Post by: chaterlea25 on 14.06. 2016 14:45
Hi All,
I use the  LH drill mehod to remove broken studs quite a bit

Heres what SRM do with the the sludge trap plugs  *ex*
Drill a 3/8 hole in the plug and weld in a high tensile bolt (usually an old flywheel bolt)
The weld will expand the plug and when it cools it will unscrew easier

John
Title: Re: Sludge Trap?
Post by: a10gf on 14.06. 2016 14:49
Lots of nice tips, experience and suggestions here. Excellent.

Now looking forward to TimK's choice of process(es) and the (great) result :O) Pictures please !
Title: Re: Sludge Trap?
Post by: TimK on 14.06. 2016 23:35
Thanks for all the advice, I'll try an incremental approach - centre drill to get the hole in the right place, LH drill (if I can find one locally), LH tap (again if I can find one locally), hex key, drill out completely. I'll let you know how many increments it takes to shift it. ;)
Title: Re: Sludge Trap?
Post by: jjbsa on 15.06. 2016 11:02
I used to drill a line of 1/8" holes, close to each other, across the head of the plug, then Dremel them together into a slot, and use one of those 1/2" socket drive screwdriver bits (this came long ago from a jumble and has the MoD arrow to say it's a good'un) to fit the slot and undo the plug.  As several have said (the hailwood site mentioned has the most subtle description, I think) drilling out the centre punchings carefully makes things easier.

Nowadays I'm fortunate to have a Bridgeport mill, so with a bit of jiggery pokery I can get access to the plugs with a 1/8" end mill and make a slot for the screwdriver bit more easily.

Loctite do a viscous, treacly, thread sealant (number 577) which is gap-filling and is ace at locking replacement plugs in and preventing oil leaks down the threads (I've always found that when screwed in flush, the plugs still aren't that tight, so this sealant gives peace of mind).  HTH
Title: Re: Sludge Trap?
Post by: TimK on 16.06. 2016 06:07
Success! *smile* *smile*
After my good intentions for an incremental approach, my impatience and the lack of decent engineering suppliers in the local area forced me down a certain route. I couldn't get hold of a centre drill, LH drill or LH tap so I was stuck with what's already in my shed and the advice received in the replies to my original post. I lightly drilled out the centre punches on the plugs and drilled a pilot hole in the centre(ish) of the plug. This was expanded incrementally to 6.5mm which turned out to be a nice snug fit for a 6mm hex socket which was hammered in, a bit of effort on the socket handle and out they came. The plugs look as if they've been cut (by hand) from a bolt, they were so far in I suspect that the oil feed to the timing side main bush was partially blocked - which probably goes some way to explaining why the bush is knackered. Anyway, at least I can get on with the strip down and ordering the ever growing list of replacement parts. 
Title: Re: Sludge Trap?
Post by: muskrat on 16.06. 2016 10:45
Tim, anytime you need tools I'm just down the road (20 minutes). Only too happy to help.
Cheers
Title: Re: Sludge Trap?
Post by: mugwump on 16.06. 2016 11:40
Well done! and good luck.
Title: Re: Sludge Trap?
Post by: bsa-bill on 16.06. 2016 13:13
well done indeed, a certain satisfaction in such cases
Title: Re: Sludge Trap?
Post by: TimK on 17.06. 2016 00:39
Tim, anytime you need tools I'm just down the road (20 minutes). Only too happy to help.
Cheers
Thanks for the offer Muskrat, I'll give you a yell next time I'm stuck. Do you know of any local engineering suppliers which stock the slightly unusual stuff that we're likely to need? I know it's all available on the web, but it's often nice to see what you're buying before it arrives in the mail and isn't what you're expecting.
Title: Re: Sludge Trap?
Post by: RichardL on 17.06. 2016 01:14
I guess I'm not going to get my five bucks.

Richard L
Title: Re: Sludge Trap?
Post by: TimK on 17.06. 2016 02:58
I guess I'm not going to get my five bucks.

Richard L

Resorting to a punch was well down my list of options - the plugs were so deep that it would have been a real challenge to get any lateral force on to them with a punch. Maybe you should keep the bet open as "currently unproven" - I'm sure someone else will face a similar hurdle in the near future.
Title: Re: Sludge Trap?
Post by: Will on 18.06. 2016 23:01
Done mine today must have been lucky bit of heat and they came out one was bit butchered but impact driver got it out 👍
Title: Re: Sludge Trap?
Post by: Greybeard on 19.06. 2016 09:32
👍
Like your emoticon. Have you copied and pasted it from the PC Character Map tool?
Title: Re: Sludge Trap?
Post by: Will on 19.06. 2016 12:01
👍
Like your emoticon. Have you copied and pasted it from the PC Character Map tool?

No not that technical got it from I pad app 👍👍🏼👍🏼