advice needed - weird temps

: Cyl 5 and Cyl 6 both hang out front but there is consistently about 70F
: difference between them.

Propwash (both in climb and cruise) affect different sides of the engine
differently. It's not uncommon to have different temps on different front jugs
because of this.

: Some of your suggestions I already checked.
: Possible causes that I hadn't considered that I got from your responses:

: - Timing,
Could do it, but should affect all cylinders the same.

: - miss-adjusted carb
Nothing to adjust on non-idle operations.

: - intake manifold leak.
Doesn't affect much at cruise power or above. Not enough relative pressure
difference between the intake ports and ambient pressure.

I'm not saying that these are impossible... they're worth checking. They're
just loosely related different CHT temps at cruise power settings.

Also mentioned by myself and a few others is improper break-in. Just because
there are 30 hours on the jugs doesn't mean they're broken in. Some people fly
engines to TBO on jugs that never broke in. High CHT's, rapid oil degredation, high
oil consumption, and oil-fouled plugs tend to plague such an afflicted engine.
Fortunately, it's not a big deal to pull off a jug or two, hone, new rings, and
re-breakin.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Hi Cory

Thanks for your response.

I don't have rapid oil degredation, high
oil consumption, or oil-fouled plug - don't know about the break-in - I
did it by the book but anything is possible.

The guy that rebuilt it is going to have a look - I'll let you know what
happens.

Thanks

Tony
C-GICE



In article ,
wrote:

: Cyl 5 and Cyl 6 both hang out front but there is consistently about 70F
: difference between them.

Propwash (both in climb and cruise) affect different sides of the engine
differently. It's not uncommon to have different temps on different front
jugs
because of this.

: Some of your suggestions I already checked.
: Possible causes that I hadn't considered that I got from your responses:

: - Timing,
Could do it, but should affect all cylinders the same.

: - miss-adjusted carb
Nothing to adjust on non-idle operations.

: - intake manifold leak.
Doesn't affect much at cruise power or above. Not enough relative pressure
difference between the intake ports and ambient pressure.

I'm not saying that these are impossible... they're worth checking. They're
just loosely related different CHT temps at cruise power settings.

Also mentioned by myself and a few others is improper break-in. Just
because
there are 30 hours on the jugs doesn't mean they're broken in. Some people
fly
engines to TBO on jugs that never broke in. High CHT's, rapid oil
degredation, high
oil consumption, and oil-fouled plugs tend to plague such an afflicted
engine.
Fortunately, it's not a big deal to pull off a jug or two, hone, new rings,
and
re-breakin.

-Cory




--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE