7Hp oil details

[ChrisE]

We have a 1928 (registered 1929) Full Four that was our families, my Dads, from mid 1970's to about 1995 (I think). We just got lucky and after years of watching managed t buy it back in August. Very excited.


Anyway, I think the oil grade is SAE 30. Is this correct, is it the same oil that goes everywhere (engine, gearbox and diff)? Where is the level indicator on the gearbox? Looks like we're loosing a lot through drips from the many fibre washers on every pipe union so I need to keep it topped up in the first instance


Thank you for the help

[Keith Clements]

Have you looked at the manuals in the technical library ?


You do need to be a club member to view these.
I think you will find it is Castrol XL for engine and Castrol D for gearbox and back axle.
Others can advise better on what the modern equivalent is but generally a hypoid oil is required in the back axle which is an EP80 or 90.
The gearbox usually needs a slightly thicker oil than the engine which is probably an SAE 30. The handbook suggests mixing the two, which I would not recommend these days.

[BarryCambs]

Hi Chris

That is an exciting find! Our own 1929 car has been in the family for decades. As Keith suggests, the technical manual will answer many of your immediate questions. Engine and gearbox are both SAE 30 and the back axle SAE 14OEP which is about as thick as it gets. I've used Morris Oils in everything for years and their SAE 30 Golden Film is well respected and slightly higher spec than the rest. If you are getting through a lot of oil, you might find you can get a 5 gallon drum from your local Agricultural Engineering company at a big discount rather than buying endless gallon cans! Don't be tempted to go to Halfords and buy Comma, as it is cheap, but very low spec.

The original owners manual for these cars recommends an oil change every 5000 miles, which I always thought was very strange given there's no oil filter and that 1929 oil was no where as good as modern. However, it also says consumption is 1000 miles to the gallon and after a while it struck me that over the course of 5000 miles, you'd have tipped in 5 gallons of nice clean oil, the equivalent of an oil change about every 500 miles! The oil change serving just to hopefully flush some of the sludge out of the bottom of the sump. That said, ours is treated to regular changes and the rebuilt engine using modern oil certainly doesn't use anything like that amount of oil.

You could try changing the fibre washers for copper too.

Barry

[AmilcarJohn]

Try Rye Oils for straight 30 engine/gearbox oil. £53 for 25 litres on eBay. I bought mine at Beaulieu Autojumble last year and it was even cheaper...As with any car without a filter, I’d change it very frequently, so cheap is good.

John

[Nick Webster]

Bit surprised to see SAE 140EP recommended for the back axle. EP stands for "extreme pressure" and the oil contains additives that are activated by the heat generated between hypoid helical cut gears. I am no vintage expert, but I sincerely doubt vintage Jowetts have pinion gears cut like this. Incidentally, it was the EP additives that were responsible for deterioration of bronze parts in older gearboxes and axles. I cannot say if this is still the case. Different additives may be in use and the use of non ferrous components has tended to decrease in modern vehicles on cost grounds. Personally I would avoid it and seek out an ordinary SAE 140 gear oil of which there are many. Plenty of choice on Ebay for example. In theory it should be cheaper too without additives.

Nick

[k. rogers]

I agree with Nick. I was warned about using HP oil in the diff or gearbox a long time ago because of the damage it can cause to the bronze parts. Also, on the subject of engine oil, I have always used 20/50 in both the Weasel and vintage and the best I can afford - I am sure that if it had been available in period it is what Jowett would have recommended. The only time I use straight 30 is in our VWs as it apparently helps to keep the engines cooler! I am fortunate in knowing one of the family owners of Opie oils based down here in Cornwall and he told me they carry out lab tests on all the oils they sell and only sell those which perform well. To quote him, all oils are fine when you first put them in your engine but their properties can degrade in a relatively short space of time with usage of the engine. He recommended Millers (still a family owned business in Yorkshire) but it became very expensive more recently with rebranding so I am currently using Silkolene and am very pleased with it.

[AmilcarJohn]

I agree about Millers -I use their 20/50 in the Jupiter. For a vintage engine (without filter) the main thing is that you don't chose an oil that has detergents in it, since this will pick up all sorts of gunk from inside the engine and (without a filter to clean it) will then continue to circulate the abrasive mixture evermore. So, either chose a cheap oil which doesn't have such sophistication, or a special 'classic ' one (at four times the price) which is 'designed' for old engines (but may well be the same stuff as the cheap one). I would also we wary of any oil which is too thin for the pump to move around the engine effectively (ie many of those designed for modern cars). All this said, when you consider the sort of rubbish these engines were designed to run on (in terms of fuel and oil) then I wouldn't worry too much. White metal bearings are much more forgiving of abuse than later high tech stuff.

[BarryCambs]

I put 140EP without thinking as that's what it says in the club technical spec, but you are right to say you need to be careful with the additives. I use Morris Golden Film AG140 Classic Gear Oil which is from their heritage range and is without the additives that can affect bronze.

I know a lot of people use 20/50 in these engines without issue, but as mentioned, I'd be a bit worried about using a detergent oil in an engine without paper filter. I know Penrite and possible others do low detergent multi grades specifically for vintage engines.

[AmilcarJohn]

PS My comments apply to engine oil. Regarding axle oil, I completely agree with the previous statements on HP oil -a 'straight' oil is much better for vintage cars