In a message dated 11/3/2005 1:49:31 AM Eastern Standard Time,
JoeH@PilgrimTech.com writes:
I ran the engine for an hour
straight tonight. It seemed to run well but I do have a couple of questions
that maybe this esteemed group can comment on.
- Engine starts out
at about 1300RPM at idle when cold and Oil PSI briefly is 81PSI and then
drops to 65 or so after 15-20 seconds. Then as things warm up the RPM’s increase and oil pressure drops. RPM levels out at about 1550 and oil
pressure hovers around 30PSI.
Is 30PSI an OK oil pressure level at that RPM? I did increase the RPM briefly
toward the end of the hour and oil pressure did go up. At 1900-2000 RPM oil
pressure was around 50PSI.
- At the 1550 RPM the
MicroTech says manifold pressure is 9-10Hg
(18-20PSI). Does that sound
reasonable?
- EGT’s are
2000-2050F. Seems a tad high to
me!! My EGT probes are located
about 2.5” from the rotor housing.
When I shut it down my exhaust manifold/muffler was a very nice
glowing red. It’s made out of
Inconel and is .06 thick so it seems to hold up
pretty well. But if it’s like
this at 1600RPM what’s it going to be at 5800RPM??
Cooling seems to be OK at the
moment. When ever it gets to 212F
I’ve got the MicroTech setup to turn on my radiator
fan and it immediately heads down and goes to 180F in 1-2 minutes. Oil temps never got above 150F. But we are in Washington and the air
temp was between 45F and 50F so I’m sure that
helped.
Thanx
(rethinking fuel return and heater hoses)
Joe
Hull
Redmond
(Seattle), Washington
I think the EGTs are out of bounds for any condition. The exhaust system
color seems to agree with the gage.
Look for trailing ignition not working, or, total advance under 20 degrees
TDC, or, TDC mark on pulley wrong, or, way lean or way rich mixture. At light
throttle, my gages hardly move.
At best power I look for 1575 to 1600. This is rich of where you would want
an airplane engine, but is good for racing. A/F between 12 and 13.
The oil pressure is also out of bounds. It isn't even up to stock street
car engine pressure.
I have no clues on that. If it can get to 81 PSI under one condition, that
should be the oil pressure at full song.
In a warm-up from stone cold, I would expect to see high oil pressure to
the point that the relief valve lifts off and stops it at 80 PSI or
whatever yours is set at. Then as idle rpm increases a period of reduced
pressure as the suction side is the limiting factor because of the bug screen
and vena contracta at the pickup tube. Then as the oil gets some heat in it, the
bug screen and pickup becomes less of a problem, and pressure comes back up.
Maybe not to the relief pressure at idle, should go there smartly when the
throttle is blipped.
Water temps above 180 and oil above 160 cost a bunch or power. On a hot
day, water should be 180 to 185 and oil 190. That is on a scalding hot day at
full throttle. I would turn on the fans at 190 degrees.
I use an external pump that holds 100 PSI hot or cold. At idle (2,000 RPM)
I have a solid 80 PSI and a rock solid 100 PSI above 2,400RPM.
Your results may vary.
Lynn E. Hanover