#6 oil cooler lines instead of #8??

Hello all. I have an 0320 that came off a Cessna.
The fittings off the assesory case for the oil cooler are #6 and appear
to be in to stay. Concerned of breaking them trying to get
them out to replace with #8's.

Can I run #6 hoses to the cooler instead?
Vans specs 8's. My AP says the 6's worked on the
Cessna, should work on the Vans.

Any feedback from you engine gurus
would be much appreciated.

#6 oil cooler lines will probably work OK on an O-320 as long as they are short and have as few bends as possible, but #8 lines and fittings would certainly be much better, especially if you ever fly in a hot climate that would need maximum flow to the oil cooler. IMHO, #6 oil lines are OK for an O-235 but marginal for an O-320, especially in an RV where you're going to have much smaller cowl air inlets than those wide open barn doors on the front of a Cessna's cowl.

Have you tried heating up the old fittings with a hot air gun to see if that would loosen up any old thread sealant that might be gluing them into place?

Albit,

I am no guru buuuut... Pretty sure that the existing fittings aren't clocked properly.

Also, if you were to free them up, they might gall the threads.

Personally i wouldn't install a cooler on my new engine that wasn't at least yellow tagged.

With that being said, shoot an email to Pacific Oil Coolers and see what they say.

It could be worth your while.

CJ

Responses

Thanks for the input. I will try heating them up.
Also, Tom at TSflightlines who made the hoses has
suggested that he make up some adaptors. This may
be an option as well.

John. Good thought on the yellow tag.
By the way this cooler is relatively new but
surely wouldn't hurt.

Neal@F14 said:

... that would need maximum flow to the oil cooler...

Click to expand...

Just an educational note. The oil flow will be exactly the same with either size line because the flow rate is determined by RPM and the oil pump, which puts out a constant volume of oil for each revolution.

Smaller lines, tight bends, and long runs will heat up the oil more in transit to or from the oil cooler, but the volume flow rate will be the same.

Interestung

Same flow, obviously greater friction, higher velocity and
higher pressure caused by the same volume
traveling through a smaller hose. More efficient
with the larger hoses relative to cooling the oil.
Thank you for the input and knowledge.

I may have to leave the #6 fittings in as they
Almost seem to be welded in due to age. I am hesitant
as they may break trying to get them out. TSflightlines
Can put a #6 fitting on one end of a #8 hose. The flow
Will then be accelerated through that smaller fitting as discussed.
Not sure if this a problem? The oil will obviously not cool off as well as
If it was not restricted in its flow. Maybe then I will not have to
install an oil cooler door and on hot summer days will run
hotter.

agirard7a said:

Same flow, obviously greater friction, higher velocity and
higher pressure caused by the same volume
traveling through a smaller hose. More efficient
with the larger hoses relative to cooling the oil.
Thank you for the input and knowledge.

Click to expand...

Exactly. I would think that just having the two small restrictions with larger hose would mitigate most of the problem and avoid the risk of changing fittings.

I have #6 hoses on my O-360 RV-7. I also have the larger SW cooler. I live in Queensland Australia and daytime temps can get over 90 on many occasions. I have no cooling issues at all. Even on the hottest days, oil temps only get to 180 degrees max. So just give the #6 a go first and see how you go.