Oil lines to cooler

I just made flex oil lines to cooler using 303 hose with 3/8" ID.
Is that the proper size for 0235? What size oil lines are most running
with 0320"s 1/2 or 3/8?

Thanks
Jim Miller

cooler

Factory Pitts uses 1/2" on 360 and 540. 3/8 is probably ok for 0 235 as many factory 0 235 do not use a cooler.

Number 8 size hose (1/2") is normally used on most four cylinder Lycomings (320/360). Using number 6 hose (3/8") will give you a pressure drop of about 26-27% compared to what #8 hose would give you for a typical 1-4 foot length of oil cooler hose. Using #6 hose might be OK for an O-235, I'm not really sure, but I'll bet I'm not the only one who'd recommend using #8 oil cooler hose instead.

Also I recommend using professionally-fabricated, stainless-braided and silicone-firesleeved teflon hoses with swaged fittings instead of legacy Stratoflex 111 / Aeroquip 303 rubber hoses for all aircraft oil cooler and fuel line plumbing under the cowl. The teflon handles heat much better, lasts practically forever, and the swaged fittings pretty much never spring a leak. The thought of an oil or fuel fire in-flight due to a hose leak is one of my worst nightmares.

We use -8 teflon, which is 13/32 (.406) ID.
Tom

In the plans, Vans says dash6 is okay for 320's and should use dash8 for 360's.

I ended up calling Lycoming and the rep said dash 6 has been used by
some airframe manufactures using 0235's but recommended dash 8 since
I am using a spring and plunger and not a vernitherm. This will make all
the oil go thru the cooler so I will just remake but as many said the dash 6
would most likely work fine.

Thanks
Jim Miller