What lubricant for this?

[Doug Hillary]

Hi,
this is a bit of the distant past revisited! What type of lubricant would you use in an inline 8 of 5.66 litres developing 646bhp at 5800rpm and 683ft/lb of torque at 3000rpm used in mid distance races and fuelled by:

86% methyl-alcohol
8.8% acetone
4.4% nitro-benzene
0.8% sulphoric ether

Interesting?

 

[toyota62]

I would use Mobil1 racing 0w-50.

 

[tommygunn]

Heh, probably something nearly a straight 50 weight to deal with the abuse and alcohol in that fuel.

 

[L_Sludger]

Something like Valvoline VR1 perhaps?

 

[Doug Hillary]

Hi,
thanks for the Posts so far - this engine's metallurgy is from the early 1930s

The engine also had a Roots supercharger!!

 

[mechanicx]

It makes sense that it has a Roots supercharger. I just noticed this engine makes tremendous torque for its size and a lot of horsepower at a relatively low rpm. How about 20W50?

 

[Stu_Rock]

Mercedes-Benz M125F engine?

Maybe an HDEO.

 

[Shannow]

Probably a 30 weight castor ?

Using 30s metallurgy, and bearing surface sizes, 30 weight lawnmower oil (e.g. Caltex 4 stroke/Delo straight 30) would probably be as good or better than what they used in the day.

 

[oliver88]

Sounds like an Audi Silver Arrow engine? Didn't they run Castroil R?

 

[edhackett]

The Alfa Romeo Tipo 159 was putting out nearly that hp out of 1.5L in 1951(420 bhp plus the 175 hp the superchargers consumed. The block was cast in 1938. They used castor oil, still do for track demonstrations. The fuel was methanol, with 1% castor oil and 0.5% water added.

Of course we all know what a pain it is to run pure castor oil. I'd be look for something made especially for nitro-methane in your case.

Ed

 

[Doug Hillary]

Hi,
Stu_Rock - Yes Is the M125 engine

It used various brews of lubricant I believe according to the fuel mix used. All were caster based and most likely the forerunner of Castrol R. I'll see what is being used in it today in the demo runs it wiil doing at Goodwood (england) in September

My first contact with these cars and their carers in Stuttgart was during the period when the old Museum was closed to the public because of the Bader-Meinhof terrorist activities

I spent many hours/days there then with their carers

 

[Silk]

I'd go for a modern castor oil - fuel ratio running alcohol is very rich and there will be fuel getting into the sump, that's when you need a vege based oil.

 

[morris]

where is the nitro?

 

[Shannow]

attached to the benzene ring.

 

[A_Harman]

Since castor oils are natural esters, perhaps something like Redline or Motul? Redline is supposed to be good at resisting the effects of fuel dilution.

Does this engine have conventional hydrodynamic bearings or roller bearings?

 

[Slick17601]

Pennzoil 25W-50 racing oil. Very popular with the Sprint Car guys as it handled methanol dilution very well.

 

[morris]

why do you ask about oil but you say nothing about the bearing clearance. the guy with the water should be kicked out.

 

[Shannow]

In all likelihood, bearing clearance was 0.001" per inch diameter.

Question has more to do with the fuel than the bearing clearance.

 

[Doug Hillary]

Hi,
Shannow - Yes, it will be interesting to see what they are using now. Typically in the past the Porsche and MB Museum Curators had freedom of choice and the carers were ex race Mechanics and Engineers that had a long history with the cars in all sorts of applications

With some good luck and a little bit of "licence" I should be able to see what the Auto-Unions are using too - in both fuel mix and lubricants

Thursday is a good day at Goodwood as with the right contacts and assistance most "doors" open quite freely. Once the crowds gather on Friday the door's remain a little more tightly "closed". I'll be there early on Thursday!!