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Date: Sun, 07 Oct 2012 18:15:44 -0400
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Subject: Re: [LML] Piston oil cooling jets
From: Christian Meier <lancair@meier.cc>
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Tom,

I have a IO 390 installed which has the piston cooling jets installed. =
My cowl inlets a 4". Modifications on the cowl exit made little change =
in CHT but up to 10=B0F change in Oil temp.=20
My Oil cooler is installed in front of Cyl#2, its the biggest I could =
fit.
My oiltemps in 75% cruise are 195 to 205=B0 my CHTs are 375max in =
cruise. Never seen more than 390=B0 even on step climb in summer. Only =
the Oil gets hot up to 225=B0 but never the CHT's
I'm looking to lower my Oil temps now: little bigger inlets, tighter =
plenum, better inlet diffusors, ...
Check my Engine data: =
https://my.savvyanalysis.com/public/ca78361a-b091-4cd6-95f1-a3978b83679f

Hope this helps,
Christian


Am 07.10.2012 um 18:34 schrieb N20087 <n20087@yahoo.com>:

>> Folks
>=20
> This is addressed to the hard core engine experts on the forum.  I =
would love your feedback on this=20
>=20
> I am considering having my io360 crankcase modified so that I can =
install piston cooling jets which are standard in 200hp engines.  The =
reason being, I have had to take aircraft out of service twice, once at =
80 hrs and now at 160 due to lousy break-in and high CHTs. I have done =
all the obvious stuff such as plenum, timing, plugs, flowed the fuel =
servo to the rich side, baffles etc.. I am running 9:1 eci cerminil =
cylinders and they will hit 430 on climb out.  They went to 450 twice in =
the initial break-in. They will run 370 in 75% cruise and 340 lop
>=20
> All this aside, the pistons at 80 hrs (both times) were coated in dark =
varnish under the crown and the top of the crowns were heavily =
carbonized from oil blowback
>=20
> I am just getting tired of it and don't want to pul the engine apart =
again anytime soon after this downturn
>=20
> So,,,I am wondering if anybody has any experience or data concerning =
the cooling benefits of the piston oil nozzles.  Ie is it 5 degrees or =
20+
>=20
> Also, I am debating whether to split the crankcase myself or take the =
closed case (jugs and every accessory removed) with con rods still =
attached to the local shop and have them split the case, do the =
machining and reassemble.  The shop is very very reputable but of course =
the cost will be higher if I get them to do the breakdown and reassembly=20=

>=20
> As another cooling remediation measure I was thinking of opening up =
the cowl inlets to 4 inches but a little reluctant due to the increased =
drag and limited benefit.  I added an electric cowl flap by the way and =
achieved only a 2 degree CHT improvement in climb at 130 knots Go =
figure!
>=20
> Again, any feedback on my plan here would appreciated=20
>=20
> Thanks in advance=20
>=20
> Tom=20
>=20
>=20
>=20
> --
> For archives and unsub =
http://mail.lancaironline.net:81/lists/lml/List.html
>=20