Engine oil

[Hedd_Jones]

Erich

for the back axle, use the same oil as the ford A guys use. 600W is the old spec. I'm told in the states they blend STP with ATF or something and it is very good.

With a spin on filter, why would you not use a detergent oil? isnt that the idea?, the detergent holds the sh1t in the oil after the wear has taken place, and before its sent around again the filter cleans it out. At least thats my simplistic understanding.

[Erich]

I think you are correct Hedd, about using detergent oil in the engine. It was built by Pigsty and with the filter it should be fine. I know that Ken Morton, who lives in Vancouver, uses Chevron Delo 400 30w which is a detergent oil meant for diesels, so it has more of the additives that have been taken out in recent years. Which leaves me with the gearbox oil question. The specs on the Delo say that although it has detergent in it, it also has anti foaming additives. I had always thought non detergent oil for gearboxes. I have a case of Castrol GP 40 left over from my Velocette days, so perhaps I could use that for the gearbox. On the Velos, we used it in the engine and the gearbox.

Erich

[Bob Culver]

For car synchro boxes all makes, generally engine oils were often recommended, commonly 30, and when stable multigrades superceeded, this typically became 20/50. Both have been detergent since the early 1950s.
But for more consistent synchro operation, since the 1980s the specialised manual gear box oils have become more normal recommendation for new vehicles.
 Abrasive (as distinct from fatigue related) wear in a Seven box is negligible on original pre war non additive oil, and all conventional oils now include anti wear additives.
For older cars consideration of noise and leaks were a major factor in oil choice.

[Erich]

It sounds, Bob, as if I would be OK with the Castrol GP 40 in the 3 speed crash box? But better to have a dedicated EP gear oil.

[Bob Culver]

From a lubrication point of view almost any oil is more than adequate for normal use. SAE40 would provide a generous protective film with or without anti wear or EP additives, but GP40  sure to contain some of anyway.  
Noise, leaks, and gear change characteristic more the factors determining choice. 
If intending to tow a trailer over the Alps Ruairidh will advise.

[Nick Turley]

Here are my thoughts to add to the discussion :

"Spit and hope" 2 bearing engines without external filters best on straight 30 SAE no detergents.
This however does require the sump to be removed and cleaned say every couple of years.
The sludge is the carbon dropped out of suspension and therefore not really doing too much damage.

"Spit and hope" 2 bearing engines with filter best on a good quality multigrade detergent oil.

Pressure fed - I always use an external filter with these.
Then run in on cheap multigrade mineral oil initially when the engine is newly built .
Change to the best quality silicone oil once the rings have "cracked" in.

As Ruairidh suggests the inside of an engine needs to be really clean to start with.
Not an easy thing do.

Back axles I always use EP140 on the advice of the chemists at Millers - they tell me that it does not affect bronze or brass when using modern formulations. I would be cautious about "old" oils in this regard.
They further told me that wear using EP140 is much reduced.
Following this advice I can report that the oil seems pretty clean after many miles.
Interestingly they still make non EP for those that do not choose to believe them !

[Bob Culver]

I am not sure there is a definition of a straight oil. Some take it to mean monograde. Some mean without any additive. The virtues of detergent are debatable although most oils have been since the 1950s and millions of cars without filters on the roads then and since, many with previously accumulated sludge, have used detergent oils often without even a clean of the sump.

Again I quote the later Beetle ; no filter, detergent oil, although did have a magnet.

The absence also of other modern additives; anti wear, anti acid, anti corrosive etc reduces oil to SAE SA or SB quality as typical to early 1950s, when wear was commonly several times today. I can recall the sump of our Seven around 1950 with an inch of grey sludge and main bearings rumbling at 10,000 miles. Doctors cars used for short runs were notorious for bore wear. Mere SE and later oils were a huge improvement. Oils can be too classic.

Modern medium and cheaper oils very superior to SE and wear very low. No Sevens will achieve 300,000 more miles, or will suffer mechanical failure before, so the nil wear of modern engines running top grade oils seems somewhat academic.

Most Sevens burn oil, do small mileage, have time based oil changes, so the expensive modern oils intended for very long service an extravagance.

Er, for SAE above read API

[Zetomagneto]

Look for oils with high ZDDP.Seven engines are not cheap to rebuild properly so use decent oil not based on brand or cost,but what it contains.

[Austin in the Shed]

Fit a magnet in the sump plug too.Surprising how much metal it picks up.

[Erich]

Thank you all for this discussion and advice. Dave, isn't there also a supplier who makes sump plugs with the magnet fitted?

What do all of you use in the gear box? A regular 30w EP gear oil?

Best,

Erich