Hmmmm, my mention of castor and lean runs sparked a bit of interest.

As far as I know, correct me if you know different..... all commercial model diesel fuel uses castor as the lubricant. Why should that be ? The manufacturers of our diesel fuel are hooked on the smell of castor ? Nooooooo, I don't think so.

The model diesel can place high loads on some parts of the engine, which are already operating at high temperature and with a somewhat hit and miss lubrication method.

To save typing I will use the following.....

QUOTE

Now for the castor oil question. NO model diesel engine maker recommends anything but castor oil for lubricant. I must have written this topic up more than a hundred times: in magazine articles, replies to readers, and in SMALLnet:

Castor oil is the ONLY -- UNIQUE -- commonly-available lubricant which becomes MORE viscous with heat. And the place that this extra viscosity ("film strength" is another way of expressing that) is vitally needed is NOT between the piston and sleeve, but at the wrist pin.

The wrist pin area is CRITICAL in all model engines, because every erg of mechanical energy that the burning fuel transmits to the piston has to be transferred via the wrist pin. It's the most heavily-loaded part of the engine -- and almost the hottest, because of its location so close under the piston crown.

Yet the lubrication the wrist pin receives is almost accidental. There's no "free flowing" fuel/air mixture within the piston's "underside cup". And an oscillating bearing is the hardest kind to keep lubricated. Unlike rotary bearings, where lubricating films tend to remain in place and renew themselves, oscillating bearings squeeze their lubricant out.

UNQUOTE

There is more but that should suffice. The other site that strongly advocates the correct amount of castor is the Diesel Combat site that has been quoted before, these guys know what they are doing and have a wealth of experience.

So..... castor is GOOD, castor will protect our engines, if we are looking for a substitute then it has also got to be good. Castor would be my first choice - we KNOW it works - but it won't mix well, or at all with paraffin without ether being present. The hunt is on for a substitute that we can PROVE works well, long term. If we run non-ether fuels then the penalty seems to be that we need increased compression - maybe not a lot - but still more than with an ether based fuel... thus the wrist pin ( gudgeon pin in the UK ) is under even higher stress.

Chevy is doing remarkably well with his used sump oil. I am glad he reported back again 'cos I have been wondering how his engine was "bearing" up (pun not intended). It's nice to see that he has got a mix that is working and has seen some hours use.

I can easily revert to used sump oil as I run a diesel car, however I would prefer something a bit cleaner ! I also want a fuel mix that doesn't need a propane torch to heat the engine first.

Olive oil may or may not do what I want, until I give it several hours running I don't know.
However, the guy who used non-ether mixes with modified veggie oil years ago cautioned me.
He seems to remember reading somewhere that olive oil as a lubricant created more carbon and lacquer deposits.

Whoooooaaaa, doesn't that sound like castor ??? More carbon deposits and lacquer sound very similsr to me !

Stewart.... you mention olive oil being used as a substitute for castor during WW1, have you any info or know of any sites online with more information. I have been trying to find information on using olive oil as a lubricant but without any success.

Reg