ORIGINAL: AndyW
Recycled Flyer,
Just read through the link you provided and found it most enlightening. Now I can put numbers to what I discovered experimentally. It's dated 1950 and 95% of the material is still relevant. Modern, castor formulations being the exception, of course, and no discussion is made about the qualities or grades of castor available at the time. Would that have been pharmaceutical castor?
What I find MOST interesting is that despite the advice, (given in 1950) that too much oil is detrimental and that 20% should be adequate, we STILL hear about the 1/3rd blend being a starting point. I made up a bored, MP Jets, ABC engine utilizing AP .09 parts.
http://www.youtube.com/user/hopeso#p/u/69/E8_aLl_eAzI This gave me about an .074 over the original .06. I used the 1/3rd mix and no amount of flipping would get that little b*gger started. This was in the fall and over the winter, on the Smallnet forum one fellow suggested that small diesels need more ether than larger. By the Spring I came upon information that kerosene had lubricating properties all on its own. So why so much castor?? So I made up a mix of 20% castor, 39% ether, 39% kerosene and 2% MEKP. First warm day in April, I took out that little beast, filled the tank, left the fuel line off and flipped while blocking the muffler. When the line showed fuel dripping out, I hooked it up and proceeded. I swear on any stack of holy books, I primed into the intake, gave ONE healthy flip and that impossible to start engine lit off and RAN. I didn't touch the compression OR the main needle from the previous attempts in the Fall. It just sat there, running as pretty as you please.
Wonder of wonders. From there, I never looked back.
Hi again Andy,
I am glad that you found that link good reading, some of those older authors seem to talk relaxed to you and I take in what they say much better than modern science talkers!
Pharmaceutical (medical) castor has a higher purity and I assume that it would be the prefered oil to use, and again that is the one specified on the PAWweb site -
<table cellpadding="2" border="1" bgcolor="#ffffff" width="60%"> <tbody> <tr> <td> <p align="center"></p> </td> <td> <p align="center">Med. Castor Oil</p> </td> <td> <p align="center">Paraffin</p> </td> <td> <p align="center">Ether</p> </td> <td> <p align="center">Iso Propyl Nitrate or
similar ignition improver</p> </td> </tr> <tr> <td> <p align="center">Running in</p> </td> <td> <p align="center">30%</p> </td> <td> <p align="center">35%</p> </td> <td> <p align="center">33%</p> </td> <td> <p align="center">2%</p> </td> </tr> <tr> <td> <p align="center">Fully run in</p> </td> <td> <p align="center">25%</p> </td> <td> <p align="center">40%</p> </td> <td> <p align="center">33%</p> </td> <td> <p align="center">2%</p> </td> </tr> <tr> <td> <p align="center">Fully run in
- BR Models</p> </td> <td> <p align="center">20%</p> </td> <td> <p align="center">48%</p> </td> <td> <p align="center">30%</p> </td> <td> <p align="center">2%</p> </td> </tr> <tr> <td> <p align="center">Fully run in
- TBR only
(Racing and Speed)</p> </td> <td> <p align="center">15%</p> </td> <td> <p align="center">50%</p> </td> <td> <p align="center">32-33%</p> </td> <td> <p align="center">2-3%</p> </td> </tr> </tbody></table>
The one third brew is very old fashioned and was designed to take up the manufacturing slack if poor tolerances were evident in an engine and it kept the power down to a very safe level in the public consumption arena. Basically if you ever ruined an engine using the old one third brew then you should look at an another hobby!
And I don't see that 20% castor is a problem in a fully run in engine as long as it has nice tight fits on its running parts.
Cheers.