The oil pressure relase valve, the most basic question !

[Nitti]

I hope to be excused for this basic question since I am a new kid on the block 

I want to check the function of the oil pressure release valve, but..., where do I find it?
Is it reachable through the sump-hole, or do I have to remove the timing-cover. Or...?

Regards
Nitti

[a10 gf]

Hi there, ask for anything, no new or old here, just a10-a7 owners.

Low front right on the crankcase. See parts 41 to 46 here:
http://www.a7a10.net/BSA/techpics/crankdrivescan.jpg
some comments: http://www.a7a10.net/BSA/oilrelief.htm

a10 site http://www.a7a10.net/BSA/BSAGoldenFlash.htm

e

[groily]

Hi Nitti, HAve a look just inboard and forward of the timing covers, on the front of the engine low down, on the right hand side there (if you're sitting on the seat), and you'll see the assembly that contains all this good stuff screwed into the front of the crankcase. . . . it comes to bits easily, there's a spring, and a ball or a plunger depending on  model. Nothing to dismantle to get at it, and absolutely nothing to be scared of - it won't all fly apart or otherwise self-destruct. A quick rinse in something like petrol and unless there's an obvious problem it should all be fine. Then shove it back together (minus the petrol!). There are sometimes oil leaks from round here - new fibre washers are a good idea if you've got some, otherwise, just do it up firmly without trying to prove you're the world's strongest man. Bit of gasket goo - sparingly applied to the washer - if you like. All it does is let off excess pressure (internally!) when the oil is cold. The 'all' is important, because if it sticks open it's bad news for the engine, which will lose most of its oil pressure - so a good clean is a good idea. As far as I know, this particular item rarely fails. Others here will know at what pressure the valve should open/close, should you want to try to measure it . . . afraid I don't. Groily.

[Nitti]

Thanks for all kind replies, i did find it in the place you suggested, quite visible   

Now, the next question !

It seems that the valve has not been removed before, or at least it must have been tens of years ago, since it is thoroughly corroded to the enngine case. With 5-56, heat and the "nut-machine" I managed to loosen the top bolt, but the other part is still stuck to the engine !

There are two solutions to this as I see it; 

either I let it remain wher it is until I undertake the major renovation opertaion ,which is planned for next winter. Will it be OK to just check and replace the spring and ball. If so, what is the trick to stick the ball to its seating when mounting the spring , a dab of grease ?

If the above is not to be prefered, what is the trick to remove the stuck part. The space between the flange of nut and the casing is restricting the use of a normal socket, or ring-wrench (?).

Regards
Nitti

[RichardL]

Nitti,

I don't know what you mean by "nut machine". Maybe you mean those roasters you find at carnivals for cooking and coating butter toffee nuts. I haven't used 5-56. Should I assume it is as good or better than "Liquid Wrench"? I don't know.

It seems to me that you should try to service the base fitting in conjuction with servicing the spring and ball. There is a filter screen in the base (in front of the ball) that needs to be clean for the valve to function. I am not sure things are going to get better with regard to removing the base once the engine is otherwise disassembled. In fact, holding the case-half in place while applying real force could be tricky.

I went out and checked my part and found that an SAE 1-1/8" socket fit over it, not perfect, but workable. The fit would be better if it were a 6-point instead of 12-point. Also, there may be a metric size that fits better, but mine don't go that big. I don't know what Whitworth size (if any) fits this part. I didn't try to acquire one for the purpose and I think it would be a lot of money for limited use. The point I am trying to get to is that the SAE or metric socket might be considered disposable or dedicated for this function only, justifying grinding it down to fit in the tight quarters. For my bike, I did not need to do this. I found that the adjustable open-end ("Crescent") wrench I bought for the fork top nuts and oil drain also worked on the pressure-relief base fitting. That wrench is a Stanley 12" model 87-794. Its jaws are nicely narrow and square and the fit stays pretty snug once tightened up. Even if the new wrench doesn't work for removing the base, it might be a nice addition to your tool collection.

I will be interested to hear if any of this helps.

Richard

[Nitti]

Hello again !

the "nut machine"  *smiley4*or more rightly, as I have learnt today, a "pneumatic impact wrench", is usually the best trick to convince stuck nuts and bolts,at least if they are of a decent size. But not this time.
I do not have exactly the right socket (SAE or Witworth), but a 28mm seemed to fit, I thought. So I grinded down the top of the socket, to get it to fit between the nut and the case,  but No. The nut must be something like 28,3 mm, whatever that is in inches.

Yes , I did try the adjustable spanner, of the type you mentioned, I have selection of these, but no, I can only get to two flanks of the nut, with any type of open spanner and now the nut stsrt to get rounded on the edges.

Now I tried tools, chemistry and heat, next step is probably explosives, or... ?

In all the misery there is positive thing, the nut being stuck this way proves that the engine has not been tinkered with too much, but on the other hand it would have been better if someone had checked the valve more regularly.........

Keep the good ideas coming please !

Nitti

[bsa-bill]

Yep - now you now why so many A10s sport a chisel mark on that nut.
I have an A65 pressure relief valve ( I think ) that has a plunger type valve instead of the ball and spring, this has a slightly smaller outer nut, as yet I have not tried it in position but I'm led to believe it fits and works better.
Thanks for shedding some light on the rockerbox part Nos

All the best - Bill

[G/F DAVE]

Hi, Bill I use a plunger type pressure relief valve on my A10, I think it is a triumph type, maybe same as A65 ?.Seems to work ok and is better engineered than the ball bearing type. Also you can use a socket to tighten it as plenty of clearance between case and valve body. Dave.........

[groily]

Inch and an eighth AF open ender goes on mine but wouldn't care to try to undo with it. Ain't enough room all round for my socket, which is 3/4 drive, but maybe a 1/2 drive would just go with minimal reduction in outer diameter? It's bigger than 28 as you say . . . . It's a little swine of a thing, and the nut's not really deep enough either is it? I'm surprised heat and an impact driver won't do it . . . can only suggest reasonable heat, a well-adapted spanner and a longer lever. The b**** ought to come in the end . . . Groily

[RichardL]

Nitti,

I suppose if you were committed to changing over to the plunger type (referring to valve stopper not the rear suspension) or some other type such as SRM, you could sacrifice the existing base piece. However, I am very hesitant to recommend this as it involves destroying an original part that someone else might want. But before going that route, I would exhaust the "well adapted spanner" (or ring, or socket) approach. I am going to throw a few ideas out here, but please consider them with respect to your own skills and needs. Each of these assume that the "well adapted..." did not work by itself. I think these are in order of desperation, least desperate first:

1.  Without the spring, ball and fiber washer, reintall the cap piece as tight as possible while holding the base with ring, spanner or adjustable spanner. Use blue (medium hold) Loctite. Do not let the base get tighter. Now, work the base wrench as hard as possible while adding to removal torque with the wrench or socket on the cap. This is the "double nutting" technique.

2. As above, but see if going a little tighter is possible, thereby breaking the bond between base and crankcase. This will have really tightend the cap so the double nut would be more effective during removal.

3. The previously mentioned chisel (chisel marks can be repaired with welding and/or filing if really necessary).

4. (This one is outside of my personal experience, so consider with caution.) As in #1, above, but with red (permanent) Loctite. If it works, and once out of the crankcase, torch the pair to char the Loctite, which should destroy its holding power. (My concern here is that the cap will round over before the base comes out, increasing your trouble.)

5. (Here's another one I haven't done.) Tack weld the cap to the base so you can still get wrenches on both.

6. As you mentioned, but with nuclear explosives.

As for sacrificing the base, that might involve much more agressive chiseling or using an "easy out" (left handed corkscrew thingie) of the correct size.

Richard

[RichardL]

HOLD ON!

I want to back off on the agressive chiseling idea, rather than being the cause of fracturing your crankcase.

Richard

[groily]

So glad you 'Held On' there Richard! Worst possible outcome is to have chiseled the thing to no avail and to the extent nothing will shift it bar taking the motor out and machining the remains off and out, which is a quite horrible thought in a not-too-easy place. In my very humble opinion, the best chance lies with a non-cranked ring spanner, with enough of its outer diameter ground down to allow it to go on the nut and move that crucial half a flat's worth of a turn. The closer to the plane of the nut's head that the power is applied, the less chance of rounding and wrecking it given how shallow the darn thing is. Ergo a socket is riskier unless a double-sized tool could be contrived which used the smaller  upper nut as a guide and support.
Suggest liberal dose of heat (but no oxy-acetylene lunacy) all around the site, a spray of some aerosol cooling agent (not sure what, but they exist) on the nut ONLY, when the alloy is heated, a wrench as described, the longer the better - and if necessary a sound blow with a heavy mallet to the end of said wrench. Light blows will be as useless as an air pistol against a charging rhino.
If that won't do it, then try Richard's point 5 above - but careful welding essential! Two ring-spanners might just do it.
If THAT won't do it, then frankly the choices are to leave the thing, with the attendant drawbacks mentioned, or to take the motor out, get an engineering firm to extract it by whatever means, and replace with one of the better options also mentioned.
Anything that puts the crankcase at risk has to be a major no-no-no. But it should come, it really should. I've got my fingers crossed and am touching wood. Groily

[Nitti]

HoHo,
Today it was x-mas again !
First of all we finally got some snow in the Stockholm area for the weekend, but more important the b.... thing is loose !

Today I bought a new socket, Inch and eighth as suggested, but it did not fit, despite quite thin walls !

The thing that did the trick, which I think could be useful on other nuts , where a socket does not fit, was to use a fairly long adjustable wrench, togheter with a "Bar-clamp" !!!!

I tightended up the wrench around the nut, thereafter I used the bar-clamp to press the wrench against the goods of the case. The bar clamp actually fitted neatly between the back of the timing case and the wrench. When everyhing was secured and tight, I gave the wrench a quick and firm blow with my copper hammer, and hey presto, it worked !

It was great to have the the little thing in my hand, especially since the filter needed some cleaning up.
Next time will the valve be screwed in with some copper-paste !

Tomorrow I will return the socket, if there is no other reason to keep it. It will not fit on my fork tube nuts, as some of you guys suggested. My fork nuts ar slightly larger.

Thanks for all the help and cheering !

Nitti

[groily]

And more cheering! Well done, however 'twas done. If it came off with an adjustable, it wasn't really all that tight - just nigh-on-impossible to get to - and needed the encouragement of Thor, the Hammer God. So it will be a case of 'all lived happily ever after' - until the next horrible thing reveals itself. Can't wait to hear what that will be!
Groily

[RichardL]

Ah! The old squeeze play. Well done. As for the 1-1/8" socket, you are correct, it would not fit the fork nuts, I was merely saying that the adjustable I bought would fit the fork nuts and also adjust for the pressure valve base which seemed to need the 1-1/8". Sorry for any confusion phrasing of mine caused may have maybe. It doesn't matter any more anyway.

Richard