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RV-8 IO 360 Wouldn't Start????

S

Skycrane

Member
After visiting the kids/househunting in Raleigh got in the RV to return to Pennsylvania and the engine (New IO360 Experimental Lycoming 85 hrs) would not start. With the help of my good friends at Cox Airport, we tried all the start procedures known to man. After pulling the spark plugs we found them to be wet. Not fuel (flooded) but wet with water. The RV sat for 5days in 95 degree heat/ 65 degrees at night with 90% humidity. We blew out the plugs and the engine started right away. Question is what caused this condition? Humidity & condensation on the plugs?
I use 20-50 synthetic oil. 30 hrs since oil change. Could it be because I only get about 165 degree oil temperature in cruise and not boiling off the water in the oil? Just looking for a way to prevent this from happening next time.

Maybe just a warning to Yankees coming South???
 
You Hit the Nail on the Head

Oil Temps Too Low!

I know a fellow here in Montana who runs a fleet of Cubs, and they had all kinds of cam problems (pitting & accelerated wear) until they starting blocking off their oil coolers until they reached 210 F in cruise. Cam problems went away.


Hans
 
Which induction?

Duane

Which induction do you have? I have horizontal induction and always use engine inlet plugs if it's parked outside. Otherwise rain can flow into the filter and down the snorkel. It should drain out the hole in the snorkel and also the sniffle valve. However before I started to use the plugs I had found water sitting in the inlet manifold. I think the water doesn't always active the sniffle valve.

Just a thought

Peter
 
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I typically open my oil sump filler cap after landing to let vapor (water?) out. This may have nada to do with your case.
 
Your oil temps are too low.

A rep from Lycoming visited our EAA chapter in the spring and he said that the oil temps in the sump are 20* warmer than where you oil temp probe is. You need to get to at least 212*F in the sump to boil off the water.
 
N941WR said:
Your oil temps are too low.

(snip). You need to get to at least 212*F in the sump to boil off the water.
Click to expand...

I'm pretty sure that's not true.

It's true that water boils at 212 degrees F at sea level, but it evaporates as long as the temperature of the water is above the dewpoint and the water has someplace to go. Even 1 degree above the dewpoint and the water will eventually leave the oil (assuming it has someplace to go) but it will take a long time. The problem with low oil temps is that the engine makes water as part of the combustion process, some of which finds its way into the oil. This can add water faster than it leaves.
 
"95 degree heat/ 65 degrees at night with 90% humidity"

Could moist warm air been drawn in through the vents? The moisture would condense as the temperature continued to fall putting water into the fuel tanks. Seems like a long shot but I know a significant amount of water can collect in mostly empty tanks over time in humid areas.

Were the tanks left partially filled? Did the engine fire at all when you tried to start it?

This does not address the problem, but the 165F temperature seems really low for any IO360 in the summer with an OAT of 95. Are you sure your temperature gage/probe is reading correctly? If so, what oil cooler are you using, and where can I get one? I have a 180 hp IO-360 and was just up in Wyoming where the OAT temperatures were similar and I saw temps in cruise of 225F at 2200/22" and 9500'.

I have the standard Oil Cooler II from Vans. I need to go to something larger but keep changing my mind as to what to go to! No hurry because I won't do it until winter anyway.
 
Thread drift??

Guys I think this thread has gone in a different direction.
Yes all the points about oil needing to get warm etc are correct, however I can't quite see how that's going to effect the spark plugs.
It's more of a question of how did mositure get into the top of the cylinder.
I posted an idea from my own past experience with the horizontal induction.
Any other ideas?
Bubblehead suggested water in the fuel? Did the fuel check show any?
Has anyone else found water collecting in the induction system?

Peter
 
Plugs are not going to get wet soaked to prevent starting from oil.
Water gets to the plugs in only one way, through the induction. Thats fuel or air.

Water in the induction either via snorkel or scoop intake is known to be a problem IF a hole is not drilled at the bottom of any induction to allow for water drainage.

Best,
 
Kahuna said:
Plugs are not going to get wet soaked to prevent starting from oil.
Water gets to the plugs in only one way, through the induction. Thats fuel or air.

Water in the induction either via snorkel or scoop intake is known to be a problem IF a hole is not drilled at the bottom of any induction to allow for water drainage.

Best,
Click to expand...

There had to be some fuel on the plugs also in addition to water. It just did not light off perhaps due to the presence of water or water vapor.

Recently, I put too much fuel into the combustion chamber on a cold start and nearly ran the battery down before the thing finally cleared itself and started. This with the horizontal AFP system. If you prime the engine with the throttle at idle, fuel pressure up to the flow divider is about 1 psi, at wide open throttle it is 4 psi. It does make a difference how much fuel is delivered for the start and the engine definitely likes less fuel as opposed to too much.

Until that event about a week ago, I though the learning curve with fuel injection had peaked, now maybe it has. I have not had any trouble since.
 
RV wouldn't start

Peter and the rest of the gang.
Thanks for the info
I have the Horizontal induction, not the snorkel. I did not have engine inlet plugs in and it rained quite hard the previous day.(Normally in a hangar) but I plan on getting the plugs. I have the K&N air filter but I guess rain could enter there. The engine did start for a second or two, so maybe it did swallow a bit of water.
The engine oil Temp is 165 at 8000 feet and about 10 C, but I will be blocking the cooler off to get the temps up. The 95 degree temp was the daytime temp while the RV was parked for 5 days. Thanks again for your comments and advice. Duane
 
In regards to the engine oil temp, I have talked to Lycoming and they tell me that there can be about 40 degree difference between the oil temp in the sump and oil cooler where the prob is installed. My engine temp is running a bit on the low side (180 degree) and building a restrictor so I can bring the temp up a bit.

Bavafa
RV7a- IO360
 
Drain Hole

Duane

Do you have a drain hole in the fiberglass in front of the Fuel Injection Servo? It allows any rain water that passes through the filter to drain out before going into the engine.
Sounds very much like that was the problem.
I also use my plugs when washing the plane.
165 oil temp is quite close to the recommended 180. See what the temp is like lower down and in the climb. I'd suggest a shutter type arrangement, so you can adjust for each day's conditions.


Peter
 
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Peter
Thanks again. I have plugs in the mail and will check on the drain hole but I don't rmrmber putting on drain hole in the intake. I'm quite sure the engine started for a second and then sucked the sitting water into it.
Duane
 
Yes water in induction

Yes the water comes from induction it happen to a bunch of RVs at Oshkosh, 2 years ago, 1 example was so bad the engine hydrostatically locked and the starter broke its mount. The drain hole is a must.....
 
67MK Larry said:
Yes the water comes from induction it happen to a bunch of RVs at Oshkosh, 2 years ago, 1 example was so bad the engine hydrostatically locked and the starter broke its mount. The drain hole is a must.....
Click to expand...
Perhaps it is a good idea to pull the prop through at least two full rotations if an aircraft with the horizontal induction has been outside in the rain. Of course you must assume the mags are hot, even if you have confirmed the mag switches are OFF, so keep all important body parts out of the prop disk.
 
Kevin

As the manifold is well below the cylinders I don't think pulling the prop through slowly will show up anything.
If you were really worried about water, put vacuum pressure on the sniffle valve and make sure that it has opened.
From experience I have found that water won't necessarily open the valve.
I would say suck on it but you risk inhaling a mouth full of fuel and vapour.

Peter
 
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