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First engine start

jtdehaan

Member
I am almost ready for first engine start and would like to know from those that are flying what all had to be done. I have some paperwork from Rotax that calls for pressurizing the oil tank and taking one of the hoses off the oil tank and capping that fitting. I don't have a cap, do I have to buy one? I thought the only thing required was to "burp" the engine. How many revolutions does it take to properly "burp" it the first time?

Jake - just a little nervous, but getting close.
 
Hi Jake,

Yes you will need the cap for the oil tank and if you have installed the return hose you may wish to buy a 90 degree fitting and hose for the bottom fitting as it is much simpler to just disconnect the real hose and add a short clear plastic hose so that you can see the oil come out of the engine. We used an air jet blower with the air pressure set to 6 pounds on the regulator of our air compressor. Take out the top spark plugs and have some one to watch the oil pressure gage.

With the oil return fitting on the oil tank caped off and two quarts of oil in the tank put the oil tank cap on and put air into the oil tank vent line while turning the engine over as fast as you can with the prop (no you should not use the starter) turn it for about 30 seconds and stop the turning and air pressure and check the oil on the dip stick, it should need about another quart (it is important to not allow the oil tank to empty as this would put air in the lines again). Restart the process above of turning the prop with the oil tank pressurized and check the oil level again at about thirty more seconds. During this last prop turning you should have seen oil pressure indicated on the Dynon and if you turn fast enough it will get to about 50 psi. When you see oil start to flow out the bottom of the engine and you have good oil pressure indication you have charged the oil system. return the normal oil return hose to its connections at the oil tank and bottom of the engine, check the oil level and fill the tank as required, you should now have about 4 quarts of oil in the engine.

Install the spark plugs and you can now burp the engine just to see how that works.

Best regards,
Vern
 
Oil System Purge - Rotax Service Bulletin SI-912-018

The above service bulletin which came with my new engine is very specific about this oil system purge. I, too, wondered (for about 2 seconds) why you could not just burp the motor or spin it with the starter to get the oil into all the lines and parts. Then, I said to myself, hmmm -- $20,000; and decided to be righteous and do it like the service bulletin says to.
Here is a picture of my fittings purchased at the hardware store to pressurize the oil tank. I bought the AN929-8d cap here: http://www.aircraftspruce.com/catalog/hapages/an929.php
[url=http://tonytessitore.smugmug.com/RV-12-Project-N577RV/Final-Assembly/11643775_hcft9#829766790_8zEcv-A-LB][/URL]
A click on the image will take you to my photo galleries.

I have not flown yet, waiting for Airworthiness, but have run the engine a few times and am very impressed with the quality and workmanship. I can see why it is expensive. It starts instantly, cold or hot, and feels and sounds stronger than its small size. The carbs seem to have been carefully adjusted at the factory and required no effort to syncronize.

Tony
 
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I am almost ready for first engine start and would like to know from those that are flying what all had to be done. I have some paperwork from Rotax that calls for pressurizing the oil tank and taking one of the hoses off the oil tank and capping that fitting. I don't have a cap, do I have to buy one? I thought the only thing required was to "burp" the engine. How many revolutions does it take to properly "burp" it the first time?

Jake - just a little nervous, but getting close.

Jake,
Congratulations, and don't be nervous, but do follow the recommended procedures as spelled out by Rotax.
I think the fittings on the tanks have caps screwed on them when delivered new. This plastic cap will work fine for the purging procedure. If you don't have / can't find that cap, you will have to get an AN style cap in the -8 size.
 
Tony, I hope you put coolant in your engine! The picture shows none in the holding tank. :D
 
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Thanks

Thanks to everyone that replied. I did the purging this morning, had the oil pressure up to 63 psi. This forum is the greatest! Now the fuel tank back in and make some noise.

Jake
 
Coolant...

Tony, I hope you put coolant in your engine! The picture shows none in the holding tank. :D

Actually, I still had the radiator off when this picture was taken in order to comply with Van's Service Bulletin 10-3-17. I ended up having not only trimming the cooler box ribs but had to replace the cabin heat door and hinge as I could not get the specified clearance otherwise. Happy to have the radiator issue fixed before flying :).
And then added the DEX-COOL before 1st engine start.

Tony
 
Actually, I still had the radiator off when this picture was taken in order to comply with Van's Service Bulletin 10-3-17. I ended up having not only trimming the cooler box ribs but had to replace the cabin heat door and hinge as I could not get the specified clearance otherwise. Happy to have the radiator issue fixed before flying :).
And then added the DEX-COOL before 1st engine start.

Tony

I was just giving you a hard time, I knew you would not start it without coolant. I had to replace the radiator. It had some pretty good cuts in it. I should have known better than to mount the radiator and not check it. I could have caught this issue way before the SB came out and let everyone know. :cool:
 
You also need to safety your air cleaners if you haven't already done so.
Larry

Their is nothing wrong with doing it, but I do not consider it a requirement (it is not specified in the KAI. It is critically important on an airplane with the engine in pusher configuration...not critical with the RV-12's tractor installation.
 
How not to:

I had a hard routing the oil return line back to the sump, so I put an adapter & clear hose on the top it and merrily spun the prop. Oil pressure came up but no joy in the clear tube. I then disconnected the 90 degree fitting in the bottom of the crankcase and found where the quart of oil had gone! On my tire :) The rotax service bulletin shows the hose snaking down into a bucket, gravity is all that gets the oil out.

Its entirely different when there is compression leaking past the rings to blow the oil back in the tank. I just am a bit thick sometimes....

How/ Where you get make a air powered reverse brake bleeder? I've been pumping the oil can like mad and not getting anywhere.
 
=okiejohn;428641How/ Where you get make a air powered reverse brake bleeder? I've been pumping the oil can like mad and not getting anywhere.

A cheap garden chemical sprayer (pump type) from Lowes or Home Depot. Mine has done brake bleeds for four different aicraft, at this point. Works great.

L.Adamson -- RV6A
 
Still Confused

I put oil in the engine, capped off the return line, put 10psi or so in the oil tank, turned the prop and got 35psi oil pressure. Put things back to normal. Rotated prop again until I got the 'gurgle' loud and clear. Topped off the oil level to the 'max' point.

What still puzzles me is why you are supposed to put the line from the bottom of the engine into a bucket. It took me an hour or so just to snake that line in place from the sump bottom to the "in" port on the reservoir, and I certainly don't want to go through that misery again. Why can't the oil just accumulate in the sump during pressuration and then be pumped back to the reservoir when burping the system?

I cannot see a reason to let the oil drain out. Can someone straighten me out?
 
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