Oil quantity and Distributor Points Gap

[AmilcarJohn]

I'm working on a vintage Jowett which is lacking the oil level indicator. Can anyone tell me how much oil I should fill it with as a guideline? Obviously I can guess from a (long) dipstick how much will be needed to cover the oil pump feed, but an idea of quantity would be helpful.

The same engine is fitted with a Lucas DJ2 distributor. I'd like to know what the points gap should be on this? I'm aware from working on other early distributor systems that the gap is sometimes much smaller than more modern experience would suggest.

Thanks in advance!

[Tony Fearn]

Hello John.
You don't say whether there is no brass tube which carries the oil level wire, or there is no wire in the tube.
Here are two photos. The front of a vintage engine, and a rough sketch of the early pre-war set-up I sent to another member. I don't know whether the vintage engine has the same system, but I expect it does.

IMG_0001.jpg

scan0006.jpg

1. The cork float lies on the bottom of an empty sump.
2.The piano-type spring wire is attached to the cork and comes just up to the top of the indicator tube when the sump is empty.
3. See photo of front of engine. The 1/4" nut holds the wire steady tube you see in the sketch.
4. Adding oil makes the cork float rise as it floats on the oil surface.
5. When the top surface of the cork hits the wire steady tube, it can't rise any further and the sump is full.
6. The wire then should protrude about 2" above the top of the indicator tube.
7. As an aside, if there is a problem with the big ends, fill the sump to the top of the wire, and then add another pint. This will allow the big-ends to dip into the extra oil in the sump, and may let you get home!!
8. The quantity should be stated in a relative instruction book which I don't have. Perhaps someone else could provide you with this information.
Hope this helps,
Tony.
P.S. Remember this set-up suggestion comes from my understanding of a pre-war engine and not a vintage engine.

[Keith Clements]

Have you looked at the manuals in the Pre-War section of the Technical library in the Gallery.

[AmilcarJohn]

Tony, many thanks for the comprehensive description. I don't seem to have any of this -there is just a plastic bung in the crankcase where the brass tube should be.

I found this picture on the web:

https://www.flickr.com/photos/imagetaker1/15113380797

I guess that is the brass tubs just visible behind the timing case?

I don't have a handbook, but as Keith points out there are some on-line. The earliest I can see there is 1931, which (hidden near the back) suggests 4.5 pints of oil in the sump. That sounds a good start!

John

[Tony Fearn]

Hello again John.
Here's a side view of the tube in position just in case you are going to replicate it.

Vintage engine for sale 011.jpg

The knurled brad cap is missing.
I think both ends of the tube are threaded, the lower one screwing into the aluminium engine casing.

3-8ths BSBrass thread.jpg

The tube threads on the original are 3/8ths BSBrass I've been told, but can't confirm.
A = a short length of the tubing.
B and C are differing patterns of brass cap.
Tony.

[AmilcarJohn]

Thanks -that's very helpful. It doesn't look difficult to replicate the tube -so I will do so if one doesn't turn up. In the meantime, I can use a long wire as a dip-stick and aim for 2 inches depth of oil in the sump.

Just so I understand properly -with the sump full and the wire protruding 2" from the tube, how does the cap fit on? Does it force the cork below the surface of the oil?

[ian Howell]

That's right, but my copy of the Jowett Instruction Manual says between 1/2" and 1 1/2" of wire showing.

Incidentally, the cap on my car's tube has a screw thread tapped into it and there was a screw in it when I got the car in 1966.

I have put a short piece of 'flat' link chain leading to a split ring, like keys are looped onto, and this hangs over the tube.

This means that even if I drop the cap - or it comes unscrewed - it will not get lost!

I believe Alan Bartlett lost a couple of caps this way at one stage but I don't know what he has done to prevent it.

Regarding the points gap - again my copy of the 15th (1930) Edition says 15 Thou. Have you located a source of spare points, or points that can be altered to suit?

[k. rogers]

As someone who has recently come into vintage Jowett ownership - a 1929 - I am a bit puzzled by the instruction book. I assume your engine is the true vintage variety, ie with the separate water pipes and inlet manifold? The sump capacity is stated as 3 pints, that's 1.5 pints less than that needed to fill the pre-war engine. So I filled mine with the 3 pints of new oil when I changed it. This resulted in about an inch of the indicator protruding from the tube. Fair enough, but as in the prewar manual, the book actually states that the sump is full when the oil indicator is at the highest point - that would probably require another couple of pints! Can anyone shed any light on this?
I can't help you with the points gap as mine is using a later distributor but you could try 15 thou which both my vintage and prewar are running at.

[Tony Fearn]

The wire then should protrude about 2" above the top of the indicator tube.

Hi Ian and Ken.
Glad you've added your thoughts.
I was in front of the computer when I guessed (from memory) the height of the wire at full sump, so thanks for that.
I never fill my engine to full sump and 1 and a half inches is about the most I see on the pre-war tell-tale wire.
This helps to keep the oil in the engine so that it doesn't spin out and contaminate the clutch plate.
Ian, did you like my attempt at sketching the chain to hold the cap in my drawing? Looking again, it looks like a string of pearls, especially as there's no reference to what it is!!
Tony.

[AmilcarJohn]

Thanks to all -I'll go with 3 pints and 15 thou as my respective starting points!

In the mean time I've taken the petrol tank off for a clean, so the engine will have to wait for that to be back in position before I try starting it. I'll report back when I do so.

John

[ian Howell]

Tony: -

As always, your drawings are artworks to be cherished!

I used the sort of chain that is made from pressed-out and folded brass sheet, so the links are flat.

This makes it easier to secure the end under the round-headed machine screw in the cap.

I couldn't see anywhere sensible to secure the other end and I didn't want a long chain hanging around, so the split ring on the other end means only about 4" of chain and it just slips over the indicator tube.

Of course it can be removed without leaving any trace - if necessary.

Regards, Ian H

[AmilcarJohn]

A quick update to say thank you for the advice.

For the record, I used 3 pints of oil and a 10-12 thou points gap, as advised in the Jowett Tech Notes. It runs very sweetly for around 10 minutes at a time until the (nearly dead) battery dies. A new one is on my shopping list.

The only trouble I had related to the oil pump and I notice that a previous post covered the same issue:

viewtopic.php?f=4&t=3519&p=19510&hilit= ... ump#p19510

I struggled initially to get any pressure, which I eventually put down to the thinness of the flushing oil I was hoping to run on. It seemed to me that this was just running back down the feed pipe before ever reaching the pump. With straight 30, a priming of the pump and a really good spin over on the handle with plugs removed, I managed to get a good throughput. On re-starting later, it again needed priming, however, after which it ticked over on 8-10 psi. Is priming always needed for these engines or is my pump especially feeble?

I think (but am not certain) that this is a 1924 engine in a 1928 chassis -engine number starts c4.....chassis number 8......