VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.


Go Back   VAF Forums > Model Specific > RV-14
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 06-23-2016, 10:56 AM
TimO TimO is offline
 
Join Date: Feb 2005
Location: Wisconsin
Posts: 649
Default Engine Issues to Work Through

I wanted to post this to make sure that everyone has a good engine run experience and help eliminate some of the potential you may have for issues. I feel this is important for many reasons, but one big one is that I believe that Lycoming has been making a serious mistake on the engines they're shipping out.


First, this is an important one...
Check your engine data plate. The IO-390 has a timing setting of 20 degrees BTDC. At least on mine it is. In my case, I also am using a Lightspeed ignition, so I had to make sure that when I sent my flywheel to Klaus for drilling, it was drilled for magnets for a 20 degrees BTDC setting.

I've been finding that Lycoming is not properly setting the timing on the engines they're shipping.

Case 1: There is another airplane at our airport who just got a new factory IO-390 in his Mooney. He had high CHT's that went over 400. The mechanics did their troubleshooting and found that the factory had both his mags timed to 23 BTDC. Once they corrected that his CHTs dropped into the normal range. They warned me and I checked mine.

Case 2: My timing was set at about 22.5 BTDC, so I backed mine down. I had been ground running at 22.5 but before my first flight I made sure it was at 20 BTDC.

Case 3: I warned a fellow RV14 builder on this list about this today, because he experienced most everything I did on my first engine start. He checked his, and found his was at 22.

So that's 3 brand new from factory IO-390's that I've heard first hand about, in the last week, and all of them were off.

Invest in your own buzz box...it will come in handy.


This is simple but... Depending on your engine monitor, and your ignition choices, you may have RPM readings that are off by double or by half.
On my install I read my engine monitor guide and had my Lightspeed input set to the proper pulse per rev so it worked great on the tach but my mag I had set double so the rpm read half....and I had to change that setting. Everyone may have different experiences here due to the variety of igntion and EFIS, but just be aware that it's something you may see.


Regarding the propeller, don't expect it to cycle immediately when you start the engine the first time. You should all be pre-spinning your engine with the plugs out, to start pumping oil before start, but that isn't going to pump enough to fill the prop hub. Also, it won't cycle at low RPM's. I'd suggest getting it over 1800rpm (maybe over 2000) and cycling it 10 or more times. It will take a while, but eventually it will work. If it did not, think back and make sure you pulled the plug out of the engine crank. You need to do plug pull if you want oil to flow to the hub. When you got your engine (if from Van's/Lycoming) it should have had a sheet explaining this.


Next, my idle (and the other RV-14's) were both very rough on first engine start. Anything under 1000 and it wanted to die. Above that, on the Lightspeed it was good, but the mag was rough. At higher power it sounded great though.

You need to do the ground lean test and make sure it's set properly. I found if I idled maybe 1200rpm at full rich...let it stabilize in RPM, and then slowly leaned it until it wanted to cut off, I had maybe a 180 rpm rise or possibly more. That's way way too rich! You want 20 rpm min rise but 50 rpm max rise. On the throttle arm is a little star wheel in the middle of the 2 sections. If you look at the arm, it has an "R" with an arrow on it. Turn it the opposite way a couple turns and re-test. Both of my planes were very excessively rich from the factory. It did take me maybe 6 or 8 times in and out of the cockpit and starting before I got this just right. When you are close, even 2 clicks of the detent will make a noticeable change. But when you are done, you will improve your rough running. It may never be as smooth on the mag as an electronic system, especially under 1000, but mine idles well now. Surprisingly the mag drop is also very small and both ignitions run great. It sounded awful before I got done with that. The timing stuff may have helped too.


Finally, my engine almost hates any priming. If I prime even for one second, let alone 3, the only way to start it is to pull the mixture all the way back with about 1/2 throttle And crank. Then it fires right up and you quickly push the mixture to about mid travel and it runs well. I believe this engine really wants to be totally lean lean on the ground (which is what you should do for ALL engines) but it won't require much for priming.

I do find it runs great at full rich, in-flight, for break-in, so no problems there.

Hopefully all of the above will help you get your engine in shape for an awesome first flight. I had all of the above adjusted and tested before flying and it was super....but before it was all done it sure didn't run as nice. All just the normal engine check stuff...but it makes a difference.
__________________
Tim Olson - CFI
RV-10 N104CD - Flying 2/2006 - 1400+ hours http://www.MyRV10.com
RV-14 N14YT - Flying 6/2016 - 350+ hours http://www.MyRV14.com
Reply With Quote
  #2  
Old 06-23-2016, 11:59 AM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,659
Default

Idle mixture has to always be adjusted.
The required setting will vary with the what induction system is feeding the engine so the engine manufacturers and overhaulers seem to set it conservatively rich so it wont be too lean for any installation.
I have installed quite a few new and overhauled engines on RV's and they always require adjusting the idle mixture to a leaner setting.

Amount of prime required for start is not because it is an IO-390, it is likely because of the boost pump being used.
If you are using the recommended Andair pump, it is a very high flow volume pump. It comes up to pressure quickly and then seems to flow more fuel than many of the other electric pumps. The tail dragger prototype with an IO-360 is the same way.

I know that the actual amount of fuel flowed is controlled by the fuel servo, not the fuel pump, but I can assure you that there is a difference with the Andair pump.

I cold start both RV-14 prototypes by going mixture and throttle full fwd... pump on for about 1 second... pull throttle back to open 1/8", then crank.
They start quickly every time.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Hubbard, Oregon
Van's Aircraft Engineering Prototype Shop Manager
FAA/DAR
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #3  
Old 06-23-2016, 02:30 PM
Ron B. Ron B. is offline
 
Join Date: Nov 2007
Location: Yarmouth, Nova Scotia
Posts: 2,623
Default

Thanks again Tim, got all but my mixture fixed up. Had company today and I'm off volunteering for the COPA convention for the next two days in Yarmouth.
Thanks Scott for the explanation on mixture, it all makes sense now. Probably a reason for Lycoming to have the timing advanced beyond the 20 degrees, it's quick and easy to adjust to the 20 degree mark. Hope to meet you July when I visit your factory to thank you in person.
Ron
__________________
Thanks Ron
RV-10 SOLD
RV-14 Flying
AirCam flying
Reply With Quote
  #4  
Old 06-23-2016, 02:37 PM
TimO TimO is offline
 
Join Date: Feb 2005
Location: Wisconsin
Posts: 649
Wink

Ah sure, that makes sense on the ground lean mixture setting. That's why they all need adjustment. So there you all have it, plan to do that for sure.

Regarding the prime and boost pump, yes, I'm using the Andair. If I use it for even a second though, my engine will either require some cranking, or if I go to idle cut-off it'll fire right up. So it's definitely delivering enough fuel even with a quick flick on and off of the pump, to go past the best fuel/air ratio to get the engine running. My main point for people is, don't expect with this engine and fuel pump combo, to do the ol' 3-second boost pump and then crank. You'll always be starting a flooded engine if you do that. It's worth mentioning this characteristic to keep people from the head scratching moments.

I flew in to fuel up with another newer RV pilot last weekend and the whole idle-cutoff for a hot start was not familiar to him. I figure if we can educate people in the best ways to get an engine to fire, it'll help them in the long run.

I still haven't figured out why Lycoming wouldn't have proper timing set up on the engines they are putting out. I may have to call them on that. Maybe they're just trying to generate new cylinder sales, since apparently from what I hear the IO-390 cylinders aren't too cheap.
__________________
Tim Olson - CFI
RV-10 N104CD - Flying 2/2006 - 1400+ hours http://www.MyRV10.com
RV-14 N14YT - Flying 6/2016 - 350+ hours http://www.MyRV14.com
Reply With Quote
  #5  
Old 06-23-2016, 04:19 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,637
Default Starting

The procedure for starting a IO Lycoming is always mixture ICO after priming. Throttle cracked for cooler ambient temps is ok for cold start up to 1/4 throttle for warmer ambient.
For hot start try when the engine has been shut down more than a few minutes up to 2-3 hours, ICO and full throttle. If it doesn't fire after a few seconds, try a very minimal amount of prime and repeat. Just be aware that overpriming a hot start will sooner or later result in an induction fire.
To repeat the procedure hot or cold is always mixture ICO before engaging started.
I believe that most of the bogus Lyc starting procedures come from people who have been operating Continental fuel injected engines.
Reply With Quote
  #6  
Old 06-23-2016, 04:20 PM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,659
Default

Quote:
Originally Posted by TimO View Post

I still haven't figured out why Lycoming wouldn't have proper timing set up on the engines they are putting out. I may have to call them on that. Maybe they're just trying to generate new cylinder sales, since apparently from what I hear the IO-390 cylinders aren't too cheap.
My only guess is that it is caused by something I have seen in the past.
On brand new mags it seems that there is sometimes a small amount of initial wear that occurs with the points that causes the timing to drift from where it was when the mags were installed new. Once this initial wear has happened, the timing seems to stay correct for a long time.

We had this happen recently with the engine in the RV-10 prototype after overhaul.

I have heard that the design intent for the wear on the block that rides on the cam, is that it matches the wear rate of the contact surfaces on the points so that the internal timing stays relatively constant. This should result in the external timing also staying constant.
It obviously doesn't work perfectly or we would never encounter a need to re-time a mag.
I doubt that Lycoming sends the engines out with the mags incorrectly timed, but it is possible.
Regardless, I always check the mag timing on a new or overhauled engine as part of the install process. If future builders do that before first engine start, we may be able to get a better idea of what is going on.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Hubbard, Oregon
Van's Aircraft Engineering Prototype Shop Manager
FAA/DAR
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #7  
Old 06-23-2016, 04:23 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,637
Default Timing

IIRC the 20 degree timing goes way back, at least the mid 90's, for certain IO 360 angle valve engines. This was a change from the original 25 degrees. I suspect that many of the Reno racers are running 25 degrees and perhaps much higher on angle valve Lycoming's. Of course these are closely held secrets that few if any will talk about.
Reply With Quote
  #8  
Old 06-23-2016, 06:18 PM
Ron B. Ron B. is offline
 
Join Date: Nov 2007
Location: Yarmouth, Nova Scotia
Posts: 2,623
Default

Tim ,the manual recommends starting the engine with the mixture at idle cut off and slowly advancing as the motor starts. I do read some of that stuff you know, I just usually don't understand it.
__________________
Thanks Ron
RV-10 SOLD
RV-14 Flying
AirCam flying
Reply With Quote
  #9  
Old 06-23-2016, 07:56 PM
rv9av8tr's Avatar
rv9av8tr rv9av8tr is offline
 
Join Date: Dec 2006
Location: Portland, OR
Posts: 827
Default FI Starts

Quote:
Originally Posted by jrs14855 View Post
The procedure for starting a IO Lycoming is always mixture ICO after priming. Throttle cracked for cooler ambient temps is ok for cold start up to 1/4 throttle for warmer ambient.
For hot start try when the engine has been shut down more than a few minutes up to 2-3 hours, ICO and full throttle. If it doesn't fire after a few seconds, try a very minimal amount of prime and repeat. Just be aware that overpriming a hot start will sooner or later result in an induction fire.
To repeat the procedure hot or cold is always mixture ICO before engaging started.
I believe that most of the bogus Lyc starting procedures come from people who have been operating Continental fuel injected engines.
I completely agree with this! Mixture must be in ICO with the boost pp ON when you crank, that way fuel doesn't get to the intake if your start sequence is delayed, and you immediately have design fuel pressure to the distributor as soon as the engine fires and you bump the mixture IN.

Works EVERY time
__________________
Long-EZ built 1985 -> Sold 2007
RV-9A; N539RV First Flight: 7/2010
RV-8A N468DL 40 hr Flight Test Program
Building Log: www.mykitlog.com/n539rv
APRS Tracking: aprs.fi/n539rv
2017 Paid
Reply With Quote
  #10  
Old 06-23-2016, 08:31 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 7,855
Default

I checked my mag timing on the new Vans YIO-540 before engine start. It was off. (One at 27 vs 25 deg BTDC).
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 12:26 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.