REFLECTOR: Hot oil

[John Dibble]

I had a bad gound on my Rose EI and it caused the timing to be 20 degrees more advanced.

John

Doug Kanczuzewski wrote:

> My hottest cylinder is number 2, than 6,4,5,3,1 so the plenum seems to be working the best on the pilot side and the turbo is under the number 6 cylinder, which is the warmer side.
> Timing was my next consideration as I am running the dual Light Speed.
> Doug
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Bob Jackson (Jax Tech)
> Sent: Monday, July 04, 2011 8:59 PM
> To: 'Velocity Aircraft Owners and Builders list'
> Subject: Re: REFLECTOR: Hot oil
>
> Doug,
>
> To me, having your hottest CHT cylinder be one of your lowest EGT cylinders
> might mean that that cylinder is running more efficiently than the others,
> with a higher portion of the fuel/air charge burning inside the cylinder and
> doing work, rather than still burning on the exhaust stroke on the way out
> and in the exhaust stake (near the EGT sensor).  Maybe that cylinder has
> better rings with slightly higher compression (and valve sealing) than the
> others.
>
> In general, if your timing is a slightly advanced (but not too far advanced)
> the fuel/air charge has a little more time to burn completely (and more
> completely transfer power to the piston) so that less of the charge is still
> burning in the exhaust stack on the way out.  But if your timing is slightly
> retarded, the fuel/air charge doesn't burn as completely and can cause
> higher EGTs.  More power transferred and work produced results in higher
> CHTs (where the work is being done).
>
> Or if you're running ROP, that cylinder's injector may be providing
> relatively more fuel than the others, or if you're running LOP if may be
> providing relatively less fuel than the others to explain the relatively
> lower EGT.
>
> However, other factors, such as cylinder location (WRT to the best cooling
> inlet airflow, or proximity to a hot turbo, or a bad plenum seal) could be
> the more likely explanation for the higher CHT on that cylinder.  Which one
> is your hottest CHT cylinder?  Is it closer than the others to the turbo?
> Is it getting poorer cooling air flow?
>
> I would look for plenum and cooling air improvements first, then maybe
> consider changing your fuel injector sizing and balance.
>
> Bob Jackson
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Doug Kanczuzewski
> Sent: Monday, July 04, 2011 9:38 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Hot oil
>
> I just flew my plane today to try out the new pistons. Running an IO-540
> with turbo normalized and saw high CHT at 403 / EGT at 1319  with fuel flow
> at 22.3gph and oil temp stayed at 185 at 80 degrees out.
> When I circled the field at 6000 feet the CHT dropped to 389 and EGT to 1320
> with oil staying at 183. I kept the speed to 29" MP and 2400 rpm. Most times
> before the new cylinders I was showing 210-220 on oil temp
> but that was 40" MP and 2500rpm.
> Question for the group, my one hottest CHT at 403 was also my coolest EGT at
> 1219, why would that be?
>
> Doug K
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Bob Jackson (Jax Tech)
> Sent: Sunday, July 03, 2011 11:18 AM
> To: 'Velocity Aircraft Owners and Builders list'
> Subject: Re: REFLECTOR: Hot oil
>
> Scott,
>
> It sounds to me like your WOT fuel flow may be too low.  Ours (custom turbo
> IO-550N) is a different engine, I know but our EGTs range from 1375 to 1425
> at take-off power (31" MAP and 2700 RPM) with the fuel flow at the standard
> IO-550N 29 gph.
>
> Once we get to 1000 AGL and start our sustained climb to altitude (>10 Kft)
> we leave the power at WOT, but increase the fuel flow to 34 gph, as is
> standard to keep the temps as low as possible during the turbonormalized
> climb out, and the EGTs stabilize between a low of ~1150 and a high of ~1300
> all the way up.  It's often 95 OAT in Florida, too, and our oil temp's will
> reach 210 even 220 by the time we reach 10 Kft, and two of the CHTs will be
> around 400 degrees, though most are below 360 degrees -- we're still working
> on CHT cooling, especially at altitudes above 10 Kft.
>
> Bob Jackson
> Custom turbo IO-550N
> N2XF 'heavy'
>
> PS  I forgot to mention that I think a lot of our problem is our weight,
> which will typically be 3000 lb single pilot with full (93 gal) fuel --
> that's a lotta lard to push up to those high altitudes!
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Scott Derrick
> Sent: Tuesday, June 28, 2011 6:49 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: REFLECTOR: Hot oil
>
> I took off from Henderson(Las Vegas) this morning it was 95 degrees. By
> the time I rotated what with taxiing and waiting in line, the engine was
> pretty much hot.
>
> I climbed from 2500 ft to 5,000(clear of the surrounding dirt) and my
> oil temp was 230-240.  My Dynon has an irratting oil temp display that
> rapidly changes temps all the time. A smoothing function is needed o
> that sensor.
>
> Anyway I leveled off and pulled the power back to cool things off. The
> one thing I noticed immediately was the EGT's  were pretty high, high
> 1400's.  I would have expected 1200-1300's at full rich. This was the
> first time I've had this new engine at such a low altitude and I think I
> have the (idle) mixture or high pump pressure set to lean.
>
> I eventually gave up on it cooling down, climbed to 8500 and the temps
> started to drop, both egt's and oil temps.
>
> What temps do other big engines +500CI see on hot day climb outs..
>
> Scott
>
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