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Yes, too hot for that rpm, I agree.
Assuming you followed the good suggestions offered
by Al, Lynn and others regarding getting all the air out of the block - really
important! I almost cooked engines two times because of excess air in the
coolant system. Here is something that may quickly tell you
something about the air you may have in the system.
I can't recall what type of radiator set up you
have, but with the Two GM cores I use which are mounted vertically, you can
touch the side tank of the radiator and determine if there is air in the
system. In my case, if I do a complete drain and refill of the
system, on the first run up the core's tanks will be hot approx 2/3 of the
way up and then they are much cooler - indicating that the remaining 1/3 of my
core is filled with air. It generally takes me 3 runups reaching 5000
rpm before I can touch the core tanks and find them hot all the way
from top to bottom. So depending on your radiator set up that might be
something you can quickly check.
If the mixture is too lean, you can get a backfire out the
intake, too rich and its generally the exhaust - where unburned fuel cooks
off. So that and black smoke would indicate to me too rich a
mixture. I presume you do not have an Air/Fuel ratio indicator - strongly
recommend you get one, that tells you right away whether you are running rich or
lean. Even a cheap one can be a tremendous help in finding out whether too
rich or too lean.
One thing you may want to check is your ignition
timing. If using Tracy's EC2 you need to set the static timing around 35
Deg BTDC. The EC2 backs off 10 deg from that (25Deb BTDC) as its default
starting point for ignition timing. So if you set the static timing to say
25 Deg then the EC2 would be having the engine operate at a 25 - 10 deg = 15 Deg
BTDC which is pretty retarded timing for the rotary. OR if you set
it too far advanced then the timing might be too advanced.
So just recheck it when you get the chance.
Another possibility is your injection system might not be
staging properly. IF that were the case, the engine might work fine below
the staging point but not above it. Could possibly be a sticking secondary
injector (if too rich or lean). But, that is a bit down the likely
list. Something impeding the fuel flow might provide sufficient fuel and
low rpm but not sufficient to run at high rpm.
Hope some of this helps
Ed
----- Original Message -----
Sent: Wednesday, October 03, 2007 11:23
AM
Subject: [FlyRotary] Re: Problem?
[FlyRotary] Re: Coolant Water Pressure
Ed, this is at about
2000 rpm. Like a fast idle. I am getting all kinds of fuel cut
like stoppages if I try to run the engine faster. I haven’t seen more
than about 3700 rpm, but I just started it and have not tried to tune
anything. I figure I will have to run longer to get it tuned and the
cooling is holding that back.
Speaking of that, you
guys were talking a while back about the effects you see when the engine is
too lean, or too rich. Talking about backfires, etc and what each effect
represents. I have forgotten what means what…senior days, not
moments!
Do any of you
remember how that went? I am having some problems getting started and am
not certain if I am too rich or too lean. I am getting backfires out the
exhaust at times and smoke from the exhaust at that time.
(black)
I ran the batteries
down yesterday trying to get started due to this. When I originally
started the engine, I flooded it. I am trying to prevent this now and am
concerned that I may not be using enough mixture.
Bill
B
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Ed Anderson
Sent: Wednesday, October 03, 2007 10:05
AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Problem? [FlyRotary]
Re: Coolant Water Pressure
You indicate you get overheating
after 10-15 minutes run time. I may have missed it, but is this at idle,
max throttle or what. Also what is your OAT. If at idle or low
power then, yes what you are seeing is not what it should be. On the
other hand, if at WOT or high power settings, then 10-15 minutes run time
would be indication of a great cooling capacity. I can not run my engine
more than a minute or two at WOT on a 80F day without temps getting into the
200F range. But, that is at 5800-6000 rpm. At idle, the temps
stabilize and I can idle all day with safe
temps.
My coolant system runs with no air
cushion and yes, I get a hydraulic "lock" pressure reading of as high as 25
psi immediately upon engine start up. After a 30 - 60 seconds of running
the pressure drops down to zero and then after a few minutes
running builds back up as the coolant warms up to operating
temperatures.
Plenty of suggestion have been
made about what to check - all good.
----- Original Message -----
Sent:
Wednesday, October 03, 2007 9:30 AM
Subject:
[FlyRotary] Re: Coolant Water Pressure
Bill, the definitive test is the
one I described below. Really encourage you to do it as described. Resist
assumptions. Convert your ideas to
measurements.
----- Original Message -----
Sent:
Wednesday, October 03, 2007 6:08 AM
Subject:
[FlyRotary] Re: Coolant Water Pressure
I think that I
would see air under the radiator cap if I had a compression gas
leak? I never see any air.
To check a piston
engine for head gasket leaks, you would put the cylinder at TDC and
pressurize the cylinder to about 150 lbs with compressed air and check the
radiator for air bubbles…How do you check a
rotary?
I will check the
pressure sender against a mechanical gage.
There is
obviously a heating problem, but I think the pressure is higher than it
should be until just ready to boil. I shut the engine off at 210*,
and at 22+ lbs, the boiling point should be well above
250*??
Thanks for the
suggestions of where to look, guys…
Bill
B
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Al p Wick
Sent: Tuesday, October 02, 2007 7:49
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Coolant
Water Pressure
Your coolant reservoir should be above engine.
1) If it is, remove two cups of air from the
reservoir. Then repeat your test.
2) If you now see pressure rise above 22 psi
within 5 minutes of cold start, you clearly have compression gases leaking
into cooling system or bad gage.
3) Air in the block is 10 times more significant
than any other cooling factor. Make darn sure you don't have any. It
causes local boiling, high temps, strange
behavior.
Operating with two cups of air under cap is an
important safety and diagnosis advantage. Everyone should do it. With that
two cups, you only see 22 psi if you have a genuine problem. You only see
0 psi if you have genuine problem. The pressure is then a very fast and
reliable indicator of system integrity. So two cups of air has no negative
effect on system efficiency, just a substantial improvement in safety.
Only time it could be a negative would be if your reservoir was way too
small, way too low, or flowed way too much
coolant.
Since you describe high temps AND pressure, I
suspect you have temperature problem.
I deliberately overheated my engine many times so
that I was intimate with pressure and temperature patterns.
Then tested various concepts. Don't recommend you do the
same.
I just recently got my
Renesis started again after finishing my cowl. I seem to be
getting very high coolant pressures. I can only run the engine
about 10-15 minutes before hitting the redline at 210*. My water
pressure is at 27 Lbs at that time. I only have a 22 Lb radiator
cap, so I assume that I am blowing into the recovery tank, but I have
not confirmed that. My oil temp has never exceeded about
165*. It might have gone higher if I could have run
longer???
This whole water pressure
thing has me a little baffled. Since this is a closed system and
the only way pressure can build is due to the expansion of the coolant
after heating???, I am confused by some comments that have been made
from time to time. I remember something that Tracy said about
his pressure would build for a time, then go to zero. It seems to
me that the pressure should correlate to the temp pretty closely since
it is a closed system??
Can someone enlighten me a
little on the science of this pressure? It seems to me that there
could be some pressure build up on the positive side of the pump, but it
would go negative on the suction side, so the net effect of the pump
should be close to zero??
Also, my Renesis had only
1800 miles on it when I bought it, so I did not have to tear it
down. As a result, I am somewhat in the dark as to how the water
flows through the system. Could someone help me with that? I
had to remove the thermostat tower for height clearance , so I made an
adapter plate that takes water from the top outlet of the pump and sends
it to the radiator (double pass), then from the radiator, it returns to
the lower inlet of the pump.
Thanks,
Bill
B
-al wick
Cozy IV powered by Turbo Subaru
3.0R with variable valve lift and cam timing.
Artificial intelligence
in cockpit, N9032U 240+ hours from Portland, Oregon
Glass panel design, Subaru
install, Prop construct, Risk assessment
info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
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