How long is a dipstick?

[ian Howell]

I have always assumed that, as there was no sign of the oil level indicator on my Long Four, that it had gone missing - possibly damaged by someone removing the cap with the engine running - some many years ago.

But no -

With a very powerful lamp, I looked down the pipe where the wire indicator rises, and there was the 'stump' of the wire about 2" down the tube.

With a piece of thin plastic tube, I 'hooked' the remains and pulled it up. There was strong smell of rusty metal and the top end was very 'frayed' presumably corroded away with engine condensation.

I think I have devised a workable repair scheme that does not involve stripping the engine, but what SHOULD the indicator be like?

In various places I have read 'Minimum oil level indication 1/2" and 'if the oil pump fails, add oil until the indicator stops rising, and run carefully as a 'splash' lubrication system.

Questions: -

Where should the indicator 'sit' when the sump is empty? Level with the top of the tube? Well down the tube? Where?

How much indicator should be showing with the recommended amount of oil in the sump?

When the indicator stops rising, how much indicator is exposed?

Are there any 'Low', 'High' or other marks on the indicator wire?

As I may have remarked before, the devil is in the detail!

[AlanBartlett]

I too would like to know these answers , to try and make a modern type stick in and out dipstick, but would like to know what the markings are like.

[george garside]

no markings on float opperated wire. sump full is roughly abnout 2.5" of wire & as mentioned minimum saafe level is about half inch.

If using a mesuring rod, otherise known as a dipstick just mark in pints by putting them in one at a time & filing mark or notch on dipstick.

as far as running with failed oil pump my understanding is that it is fill to full as per indicator wire & then add another pint so that crankpins dip into oil

if remains of wire move up and down i.e push it furthur down & look down th'ole with said lamp to see if it bobs back up to at least where it was. no point in trying to restore wire to its former glory if the float is buggered. As far as I am aware the float cannot be replaced without taking the crankshaft out - unles somebody has come up with a cunning plan.
george

[Leo Bolter]

Hi Guys.

All the above knowledgeable discussion is right out of my league . . . I'm not at all familiar with those engines . . . . I'm dreadfully sorry, but I feel the overwhelming urge to put my pennyworth in!

If the wire that's prone to rotting away is to be replaced or if an engine is being overhauled my thoughts are that it might be a good idea to consider using stainless steel welding wire of appropriate diameter for a new one . . . . . . probably this is all very obvious and for that I apologise

Toodle looo, Leo

[Tony Fearn]

Hello Leo.

The wire needs to be springy like a piano wire (not the coil type).

This is because it's attached to a rectangular piece of cork that floats on top of the oil. The whole thing lies at the front of the engine casing, and as I've said somewhere before there's a bolt with a hole in its head that steadies the wire as it rises as well as keeping it in position.

The cork is of such a size that it misses the front of the crankshaft as the latter turns.

The oil level wire assembly has to be fixed in place whilst the engine is in bits and the crankshaft out, as your hand has to reach inside the casing to guide the wire up through the tube out of which it pops when you check the oil level. This in my experience is quite a difficult operation, and if non-springy wire is used, then when the wire is bent slightly to introduce it into the tube from inside the casing, the bend stays in the wire and touches the inner wall of the indicator tube. If this happens, then of course there is no free movement of the assembly and the cork stays submerged, so no oil level reading.

I would think it's very difficult to straighten a non springy wire once it's in situ.

After all that gumph, I realise that I don't know whether stainless steel welding wire is springy or not.

Regards,

Tony.

[george garside]

I'm in total greement with Tony - it should be piano wire, which is readily obtainable in 3ft (or more probably 3'4") lengths form model airoplane etc shops
george

[ian Howell]

Ah! Well now . . .

The wire in mine seems to be springy alright - but it also bent so it jams in the tube, although you can pull it up and push it down with a bit of hydraulic brake pipe (you know - the ones with oil in the rods!).

Having seen what you all have to say, it seems likely that either: -

The last engine builder (NOT Luther I am sure!) bent the wire as he was asembling it, or

The wire has got bent in use, possibly by the float getting caught on something. I seem to recall someone (George? Tony?) saying that you shouldn't take the cap off the level indicator with the engine running . . !

Either way, for now at least I am leaving it be! I don't want to strip the engine yet - there is plenty of other work to do - and the engine runs pretty well as it is. I will probably try the 'do-it-yourself' dipstick suggested by George.

[Tony Fearn]

Just a thought.

If you pull up the oil level indicator wire as far as you can, and introduce a wooden dowel rod of small enough diameter into the brass tube, you just might be able to "stroke" the wire against its bend within the brass tube thereby straightening it.

It's not an approved technique, and I've just visualised it, never used it, but make sure if you try it the whole dowel doesn't fall into the sump or bits break off.

Tony.

[george garside]

good idea, but perhaps safer with a metal rather than a wooden rod
george

[ian Howell]

Yes, I have tried this once using a bit of cunifer brake pipe.

It fits nicely over the rod, so I put a bit of a 'J' bend at the bottom and pushed it firmly but gently down and over the rod until it hit bottom.

The problem is that the rod then jams in the cunifer tube so when you draw it back the rod rises with it - could it come away from the float? Also you cannot grip the rod with the tube over it, but perhaps if I cut away the tube at the top so that the rod can be gripped and pulled up through it? Thanks for the idea!.

The oil level rod is clearly bent in one direction - it rests 'hard' against the nearside front of the tube, so with careful adjustment of the 'J' and equally careful orientation of the 'tool', I will have another go. Or two. Or three.

Watch this space. Better still, get on with some (Jowett related) work!

[Keith Andrews]

Re the stainless wire..springy
Ni chrome steel resistance wire sounds as if it would do the job.

[ian Howell]

Why not brass? Maybe a bit of brazing rod?

Of course, that would still mean stripping the engine, but if one got that far anyway, then . . .

I've just thought of something else: -

I will only be able to go down the rod as far as the guide bolt in the front cover. IF the rod is bent below that then all bets are off. Aren't they?

[Tony Fearn]

Hi Ian.

My thought was to put the dowel or metal rod (as George suggested) into the level tube alongside the wire and not a tube over it as you've already done. Perhaps "stroking" was the operative word.

I would expect that the bend is in the top half of the wire as when it's introduced into the tube from inside the engine casing, the steady bolt isn't located at that time and there's enough length below the tube bottom to keep the lower half of the wire straight.

If the cork float is original, then it will be quite fragile after all these years.
I don't have one to look at, but as far as I can remember, starting from the top of the wire, when it reaches the cork it turns at 90 degrees and goes through the cork about halfway along one of the longest sides halfway up the thickness, reaches the other side and turns 90 degrees horizontally about half an inch, and then horizontally at 90 degrees back into the cork to fix the position.



I would think that the fixing "U" bend is made first then the long wire pushed through the cork horizontally so the the "U" bend enters the cork to fix the wire and stop it turning when it's erect, and finally the long part of the wire is bent vertically so that it can be introduced into the bottom of the tube. Don't forget to locate the steady bolt on the wire before this.

Now this is a thought process and not documented fact:- If the long end protrudes out of the tube at the top, and there's no oil in the sump, then if the wire is cut off at the top of the tube, that shows 'empty'.

Springy piano wire does not take easily to bending, so someone else might tell us how to bend it. Perhaps the stainless wire Keith A. mentions might be more useful in this instance, and even the brass rod Ian's suggested would be an easier option, but it's all in the "springiness" as far as I can see.

P.S.
Alan:- Did you get an oil level tube cap. If not let me know, I've found one in the garage today.

[george garside]

I use piano wire regularly for the repair of accordions and find it bends quite easily even into complex shapes as in Tony's sketch of the oil wire. One end needs clamping in vice up to point of bending and bend needs to be slightly exagerated so that left to its own devices it springs back to where yu originaly intended it to be. Even 'hooks' or 'rings' can be bent using a round bar & the vice.

If wrongly bent, don't try to straighten it as itis very difficult, throw away & start again. Technique needs to be practices on spare length of piano wire.

If Jowetts used piano wire ( which I suspect they did) this accounts for the difficulty in straightening a bent oil wire.
george

[ian Howell]

Well that all makes sense. Now mine APPEARS to be complete but I did at first wonder if a bit had been lost off the top where it is rusty, hence my original enquiry about how much should be showing under various conditions.

At that time I anticipated that I might be able to straighten the wire enough to free the float, but that seems increasingly unlikely.

Still, I will give it another try with the 'stroking' idea - nothing much to lose - and then it's Plan 'B' and George's dipstick!

Just one thing: - How long should it be?

(There's a hole in my bucket, dear Liza . . . )!