Gamijectors - problem probably solved

I sent the following note to the Cardinal Flyers Online. I repeat it
here in case it may help somebody, or if anybody has advice!

Here is an update on the problem I was having getting my Gamijectors
tuned on my engine. As I posted in #3311 in September, I had done a lean
test that indicated #2 was peaking at the lowest fuel flow and a spread
of 0.7 gph. John-Paul at Gami said great, we’ll get you a leaner #2 and
it was installed. Then the next lean test indicated that #2 had actually
gotten a little worse, with a spread of 0.8 gph.

There followed some discussion in digest #3314 with Paul and George
Braly that suggested investigating #2 for other problems such as
induction leak or cam lobe wear. Well, I finally got it into the shop on
Friday. First thing the AME did was measure the intake valve lift. He
compared #4 at 0.46 with #2 which was 0.25. So off came the cylinder and
what do you know? The #2 lifter has failed in such a way as to make it
pound against the cam lobe, which in turn is badly damaged. The camshaft
is ruined and my engine goes to Progressive in Kamloops this week for
teardown and repair.

This may explain a lot. Cylinders 1 and 2 share the same damaged cam
lobe for the intake values, so I believe both those cylinders have been
producing less power. CHT on #1 and #2 have always been significantly
less than #3 and #4; I assumed this was because they got more airflow.
The engine has always run smoothly.

This aircraft cruises at 130 knots or maybe slightly more. The previous
owner thought this was normal, but it has concerned me ever since I
started reading this digest and discovered most RG owners claim 140+
knots cruise, which of course is what the book says too. The flaps were
badly out of rig, but fixing this made little difference. The other
controls have been carefully re-rigged as well. Nothing has helped in a
significant way. The only other thing that should cause this is a lack
of power, but I always got full RPM and MP. Should have had the camshaft
checked a long time ago...

Cost to split the case and repair is C$6k (Canadian and US dollars are
about equal at this time). An additional $1k gets a bottom overhaul
accomplished, so this is a no-brainer. My engine is 750 hours and 13
years SMOH and this will zero the bottom end.

I have a few decisions to make. First, should I get the Firewall Forward
camshaft with built-in lubrication? Sounds like a good idea.

While the engine is off this may be a good time to get the Firewall
Forward Horsepower Plus STC. I’ve searched the digest and people seem to
be pretty happy with it. My only concern is oil temperature – mine goes
into the 220’s on a hot day (CHT’s are under 380.) The FF oil cooler STC
was installed this summer which helped a little but not much. The
Vernatherm also came off on Friday and there is some visible damage
where it seats. This will be machined and fixed. However, I’m not sure I
want to put the FF pistons in before I have solved the oil temperature
problem. This is a bit of a conundrum. Any suggestions?

One last thing. When the cam has been repaired should I continue to use
the existing Gamijectors that are currently installed? They have been
tuned for the engine in its slightly defective state. #1 and #2 may no
longer be appropriate.


randall g =%^) PPASEL+Night 1974 Cardinal RG
http://www.telemark.net/randallg
Lots of aerial photographs of British Columbia at:
http://www.telemark.net/randallg/photos.htm
Vancouver's famous Kat Kam: http://www.katkam.ca

On the Gami's, call Gami and take their advice... I suspect they will
want to go back to the original starting set they sold you...

On the lubed cam, it depends!

The problem the lubed cam solves is the delay in splash lubrication
right after starting when the engine has set for long enough for the
cam to drain dry... That the lubed cam gets oil faster than an
unlubed cam is good (very good) but whether it is worth the money is
your call...

The problem it does not solve is that the cam still rotates dry when
cranking and after initial start until the oil pump can get flow up
to the cam... The best of all worlds would be a lubed cam AND a
preoiler to have the oil pressure up before cranking... bucks &
pounds

Now the cheap solution is to fly the airplane twice a week and use
AVBLEND
those who don't like avblend, or similar, can just hit delete and
save us both aggravation
Outfits like American Flyers use avblend AND run the engines 7 days a
week and don't have major cam or wear problems..

cheers ... denny

Oh yeah, and I will be tearing down my 1600 hour factory new
starboard engine for fresh cylinders next week... We will be
inspecting the bottom end and I am holding my breath on the cam... If
the cam is good we just hang the jugs.. If not I do the bottom and
cough up another $7K...

denny - roll them dice

On Dec 10, 7:09 am, Denny wrote:

The problem the lubed cam solves is the delay in splash lubrication
right after starting when the engine has set for long enough for the
cam to drain dry...

A better way out of this is to religiously preheat in cold weather.
The cam won't ever drain completely dry. Rather the problem is that
it takes quite a while for the replacement lubrication fog to develop
in a cold engine/crankcase.

Think of it this way - many of the the most critical parts of an
engine are lubricated only by the fog. The design of the oil pump and
relief valve system is such that the sump oil has little access to the
heat of an engine if the oil is thick. As a result, the fog can be
very slow to develop. Any high power without having the fog, & the
cam can spall in a few seconds. It will never recover its surfaces
from this.

Pre oilers might help, but there is thermally a long way between a few
oil splatters and a true oil fog. The problem really isn't the
immediacy of oil pressure, it is the needed thinning so that oil is
generously spraying around the crankcase vs being congealed.

Further to my post in #3354 regarding my destroyed camshaft and oil
temperature problems, I have received some photos my mechanic took with
his cell phone camera.

These show the damaged camshaft lobe:
http://www.telemark.net/randallg/stu...ngine/cam1.jpg
http://www.telemark.net/randallg/stu...ngine/cam2.jpg
http://www.telemark.net/randallg/stu...ngine/cam3.jpg

These show where the vernatherm seats:
http://www.telemark.net/randallg/stu...gine/vern1.jpg
http://www.telemark.net/randallg/stu...gine/vern2.jpg



randall g =%^) PPASEL+Night 1974 Cardinal RG
http://www.telemark.net/randallg
Lots of aerial photographs of British Columbia at:
http://www.telemark.net/randallg/photos.htm
Vancouver's famous Kat Kam: http://www.katkam.ca

Hmmm, not good, kemo sabe....

Anyway, let us know what you decide on the fancy, schmancy cam...
Remember, we have been flying since 1912 without this cam...

Fly often, use avblend...

denny

"randall g" wrote:

Further to my post in #3354 regarding my destroyed camshaft and oil
temperature problems, I have received some photos my mechanic took with
his cell phone camera.

Oof; that's ugly.

What kind of oil did you use?

--
Dan
T-182T at BFM

"Denny" wrote:

Fly often, use avblend...

CamGuard

http://www.aslcamguard.com/antiwear.htm

http://www.aslcamguard.com/humiditycab.htm

Slick50 is more widely available and do the same for your
engine.....NOTHING!

"Dan Luke" wrote in message
...

"Denny" wrote:

Fly often, use avblend...

CamGuard

http://www.aslcamguard.com/antiwear.htm

http://www.aslcamguard.com/humiditycab.htm

On Dec 12, 11:50 am, "Dan Luke" wrote:
"Denny" wrote:
Fly often, use avblend...

CamGuard

http://www.aslcamguard.com/antiwear.htm

http://www.aslcamguard.com/humiditycab.htm

As the thread morphs:

That's interesting, Dan... I would like to know what additive A and B
are... I would also like to see the testing done by an unbiased
source... There are also other factors in real engines: drainback
resistance, anti rust, etc...

I am wary of additive claims... I use 15W50... I only came to adding
avblend kicking and screaming out of necessity... My port engine
(500 smoh) suddenly developed signs of morning sickness, culminating
in a stuck exhaust valve (during the flight to the mechanic for the
annual, no less)
This was quickly and smoothly solved in the usual fashion by an old
timey mechanic - who has done many of these over 40+ years in the game
- without having to take off the jug...
About 3 months after that it began showing slight signs of morning
sickness again (not necessarily the same valve)... I discussed this
with the mechanic I had purchased the plane from... He laughed, and
said they had fought with sticking valves for decades in their rental
aircraft (especially the C-150's)... When they finally made the
decision to try avblend (it is expensive, esp. when you are dumping it
into a half dozen airplanes) it was only after much discussion and
arguing... But, they never had a stuck valve on their planes after
that... So, I sprung for a case of the stuff and I have not had a
problem since...
Anecdotal? Yes.
But as one poster has on his sig, "Absence of evidence is not
evidence of absence."

denny