Bull Plate?

[Springfield]

I have used a good deal of the Pennzoil 2-stroke oil for outboards and I can't tell it from the Bullplate I traded for years ago. Seems the same as the oil I get with my Mihec moulds. I have used the semi-synthetic also and it worked fine with my aluminum LEE moulds. May have to try the Stihl oil and see if I can tell the difference. Why would oil for air cooled be any different then oil for water cooled outboards? More heat resistance? Not sure it makes a difference with moulds, pretty sure the engines get a lot hotter than 700 deg.

[rbuck351]

Cyl head temps on aircooled engines normally run under 400 deg with 375 being about the usual upper limit wanted. Most oils start giving up at about that temp. Also head temps much higher than 375 will start to detonate the fuel mixture which will burn the top of the piston. Why synthetic 2 stroke oil works so well is beyond me. Probably the residue left after some parts of the oil vaporize. I haven't checked the temp of a mold that is at casting temp but I would think it would be around 400.

[Jniedbalski]

The two stroke oil works great. Also oil I got at autozone for car ac compressors also works just as good and it comes in a pint or ouart. I bought the pint and still have over 80% of it after 4 years of casting

[Jniedbalski]

The outboard engines are water cooled.so they run a lot cooler. The chain saw oil is differnt because it has to work at a lot higher temp. Racing brigs 5 horse motors in go carts often run head temps at 375 to 400 degrees. The ones running achool usally cover the air shroud to get the head temp up. Some say that the 400 degrees head temp run better and is at the ragged edge. If you have a head temp at 400 the exhaust temp is around 1100 to 1200 degrees. Aluminum melts at 1300 sompthing degrees. That’s why they change oil after one or two races