Continuing V8 saga

[Mike Kimball]

I ran the engine a few more times yesterday and today. This time I had dye
in the oil. Here's what I discovered.

1. The head bolt oil leaks are gone. No sign of new oil on the head bolts.
One theory is that the preservative on the studs for corrosion resistance
for shipping and shelf life migrated up the studs and is now all gone.
Theory number two: I cranked down on the valve covers more than I would
normally do. Maybe the first time the source of the oil was indeed the
valve covers and I just didn't detect the oil path from there to the head
bolts. I am personally leaning towards theory number two. I also checked
everywhere else. Nothing else is leaking. Oil pan, front and rear oil
seals, etc., dry as a bone. Yay.

2. Ignition #1 on my dual MSD ignition is not working now. It was working
just fine the last time I ran the engine. I can't find anything simple like
a loose wire. Dangit!

3. I removed the thermostat for this test. Coolant ran out of the overflow
right away and then on and off while running the engine. The coolant
pressure never exceeded 5 psi. My cap is 16 psi. How is the coolant
getting to the overflow port past the cap seal? You guessed it.
Contamination on the cap seal. Whattaya suppose it was? Aluminum shavings,
of course. Must have gotten on the cap when I set it aside at some point.
Cleaned the cap and I didn't get another leak until the coolant pressure
reached 16 psi on my last run. My coolant temp was fluctuating all over the
place. I'm sure it was because I'm a bit low on coolant and the thermostat
housing is not a great place for the probe. I think the best solution is to
get an intake manifold with four point outlets. One on the "back" (front in
an airplane) to return coolant from there to the water pump and one for the
temp probe. Luckily, my water pump already has an extra return.

4. My mixture control doesn't seem to be working as expected except for the
idle cutoff position which will stop the engine. There is some thought that
it will respond more normally when the engine is under load, i.e., when the
prop is on.

5. On one run I saw very cold EGT, about 500 degrees! I could not
reproduce this. On most runs the EGT was solid at 1450 degrees F. On one
run it was a bit over 1600 degrees but I was messing with the mixture so
that could explain that. I adjusted the advance to 35 degrees at 2000 rpm
and the EGT settled in at about 1300 degrees and stayed there.

6. I put a -6AN to -4AN reducer in the oil line that feeds the gearbox. I
am still getting too much oil there since oil leaked out the breather. I
installed an in-line oil filter in the return from the gearbox to the engine
but I am not satisfied with the simple metal mesh that comprises the filter
element. It is clearly only intended to catch big stuff. I will probably
modify it with a smaller mesh. I wonder how small is too small restricting
the oil return?

7. Oil pressure was about 60 psi and oil temp maxed out at 200 degrees. I
shut the engine down when coolant temp reached 220 degrees. As mentioned
earlier, coolant pressure never got over 5 psi. The most I saw on a
previous long run (about 12 minutes) was 10-11 psi. My longest run this
time was about 5 minutes.

8. Despite all of these things, the engine runs and sounds awesome! I'm
going to upload a sound file that I collected during this testing to the
archives. Right now it's about 3 Meg as a .wav file. When I try to export
it from the program I used as an .mp3 it is only about 40K but it doesn't
sound right at all. I'll keep trying to get a reasonably sized sound file
that sounds right. In the mean time, you folks with high speed internet can
listen to the big file I uploaded.

Mike






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[Mike Kimball]

I found a sound file converter trial version online and converted the sound
file. I uploaded two files to the archives. One is about 600K and is
pretty decent quality. The other is 300K with reduced quality but is OK.
Can you imaging the heads turning when I fire up at the airport?! Have fun
you gearheads.

Mike

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Mike
Kimball
Sent: Friday, December 30, 2005 5:16 PM
To: Rebel Builder's List
Subject: Continuing V8 saga

I ran the engine a few more times yesterday and today. This time I had dye
in the oil. Here's what I discovered.

1. The head bolt oil leaks are gone. No sign of new oil on the head bolts.
One theory is that the preservative on the studs for corrosion resistance
for shipping and shelf life migrated up the studs and is now all gone.
Theory number two: I cranked down on the valve covers more than I would
normally do. Maybe the first time the source of the oil was indeed the
valve covers and I just didn't detect the oil path from there to the head
bolts. I am personally leaning towards theory number two. I also checked
everywhere else. Nothing else is leaking. Oil pan, front and rear oil
seals, etc., dry as a bone. Yay.

2. Ignition #1 on my dual MSD ignition is not working now. It was working
just fine the last time I ran the engine. I can't find anything simple like
a loose wire. Dangit!

3. I removed the thermostat for this test. Coolant ran out of the overflow
right away and then on and off while running the engine. The coolant
pressure never exceeded 5 psi. My cap is 16 psi. How is the coolant
getting to the overflow port past the cap seal? You guessed it.
Contamination on the cap seal. Whattaya suppose it was? Aluminum shavings,
of course. Must have gotten on the cap when I set it aside at some point.
Cleaned the cap and I didn't get another leak until the coolant pressure
reached 16 psi on my last run. My coolant temp was fluctuating all over the
place. I'm sure it was because I'm a bit low on coolant and the thermostat
housing is not a great place for the probe. I think the best solution is to
get an intake manifold with four point outlets. One on the "back" (front in
an airplane) to return coolant from there to the water pump and one for the
temp probe. Luckily, my water pump already has an extra return.

4. My mixture control doesn't seem to be working as expected except for the
idle cutoff position which will stop the engine. There is some thought that
it will respond more normally when the engine is under load, i.e., when the
prop is on.

5. On one run I saw very cold EGT, about 500 degrees! I could not
reproduce this. On most runs the EGT was solid at 1450 degrees F. On one
run it was a bit over 1600 degrees but I was messing with the mixture so
that could explain that. I adjusted the advance to 35 degrees at 2000 rpm
and the EGT settled in at about 1300 degrees and stayed there.

6. I put a -6AN to -4AN reducer in the oil line that feeds the gearbox. I
am still getting too much oil there since oil leaked out the breather. I
installed an in-line oil filter in the return from the gearbox to the engine
but I am not satisfied with the simple metal mesh that comprises the filter
element. It is clearly only intended to catch big stuff. I will probably
modify it with a smaller mesh. I wonder how small is too small restricting
the oil return?

7. Oil pressure was about 60 psi and oil temp maxed out at 200 degrees. I
shut the engine down when coolant temp reached 220 degrees. As mentioned
earlier, coolant pressure never got over 5 psi. The most I saw on a
previous long run (about 12 minutes) was 10-11 psi. My longest run this
time was about 5 minutes.

8. Despite all of these things, the engine runs and sounds awesome! I'm
going to upload a sound file that I collected during this testing to the
archives. Right now it's about 3 Meg as a .wav file. When I try to export
it from the program I used as an .mp3 it is only about 40K but it doesn't
sound right at all. I'll keep trying to get a reasonably sized sound file
that sounds right. In the mean time, you folks with high speed internet can
listen to the big file I uploaded.

Mike






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