tashley

My Feedback: (9)

Does 50% with 18% oil 70% of the oil synthetic and the remainder castor sound about right for a K&B 3.5 OB? Experienced answers only please and thank you.

Dan S

you will be fine.

What brand of fuel is it?

I use Wildcat Promix - 35% Nitro and 18% oil, 95% is Synthetic and 5% Castor.
my Friend use the same but the Nitro is at 65%

Dan.

tashley

My Feedback: (9)

The fuel is Ritch's Brew, and thank you for your answer.

noisy

do you need to use castor now??????? i havn't used castor for years ..and i dont have engine problems....bob

tashley

My Feedback: (9)

Bob, castor offers superior film strength that synthetic does not possess and will save an engine on a lean run. It also helps to prevent oxidation caused by the hygroscopic effect of nitro and alcohol.


There are some engines out there that can be damaged, Cox for instance, if a little castor is not used. It's negative is that it's residue when left for a long time creates varnish, but then there are a lot of oils out there that will varnish as well.

Dan S

to carry on with the good explaination given by tash, in the end it pretty much comes down to personal preference.

Todays synthetic oil have improved quite a bit.
there are some fuel made with only Synthetic, some only Castor and some with both.

There are a lot of guy's that prefer to have some castor in their fuel.

I run Wildcat and Wildcat have different mix for each blend they make, for example.

The Promix Blend use an oil mixture of Synth and Racing Castor at 95%Synth and 5%Castor ratio.
the Elimix is 100% Synth,
the Premium is a mix of 80% Synth and 20% castor.

it all comes down to what do you like, if you do decide to add some castor to your mix make sure it is of top quality.

but the ANSWER to your question is "NO"

Dan.