Mailing List flyrotary@lancaironline.net Message #34708
From: Bob White <rlwhite@comcast.net>
Subject: Re: [FlyRotary] Re: MSD coils - Plug Fouling... again.
Date: Fri, 8 Dec 2006 08:13:24 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
On Fri, 8 Dec 2006 07:37:08 EST
Lehanover@aol.com wrote:

In a message dated 12/7/2006 9:37:29 P.M. Eastern Standard Time,  lors01@msn.com writes:

If the MSD coils are plug-in replacements for the stock LS1 coils they  will work with the EC2 as-is.  Having said that, I doubt that they would  help with flooded engine problems.   I'm running the Renesis coils on my 20B and not having any problems so  far.  The LS1 coils on my 13B Renesis have performed well and I have  not had a flooded engine problem in the last 9 years.
 
I changed my plugs to iridium type (stock Renesis parts) about 210 hours  ago and they have been wonderful.  Never a hint of 'SAG' but I have run  only a few tanks of 100LL during that time.
 
Proper priming and starting procedures are the keys to easy starting  and avoidance of carbon fouling.
 
Tracy (sending Blue Mountain EFIS back for  updates)

 
 
Keep saying that to yourself.
Proper priming and starting procedures are key to easy starting and  avoidance of carbon fouling.
 

The Renesis engine does not have the self purging feature of the earlier  13B with the peripheral exhaust ports. So it can be stopped cold (pun) by an  over rich starting attempt. It will reapply liquid fuel to the spark plugs with  each passing apex seal. Mazda had to re burn all of the Proms to help (but not  cure) this problem. So there is a mechanical layout problem involved in the hard  starting, that owners of older 13B's and 12As just have never seen or had to  deal with.  The early cars had a small container on the firewall that was filled with  antifreeze. When temps were cold enough, a spray of antifreeze would go into the  engine during cranking to remove frost that tends to form on the surfaces and  lock the seals into the rotors. This would reduce the compression to zero and  make starting impossible. The antifreeze would also add volume to the chamber to  increase effective compression and help seal around the stuck seals.  In carburetted cars just pumping the gas pedal would cure this problem, and  the peripheral exhaust port would dump out the excess fuel and frost as each  apex seal went by.
 
Those engines had a one piece 9MM carbon apex seal, and that seal ran about  .004" to.005" of end clearance, so as not to bind up when it was up to  temperature. But that gap and some sloppy end clearance on the side seals  assured that winter starting was a hit or miss project at best.  With the modern 2 piece apex seals this is far less a problem, as the  corner piece keeps the apex seal pretty much the right length (zero end  clearance) all of the time,  or it was, until the exhaust port was mounted up into the side of the irons  instead of on the peripheral housing where it should be.
 
When I first raced (I called it raced, It was just driving around fast) an  RX-2 Mazda with a stock junk yard engine with no compression, it could be  started by inserting an extra battery in the starter motor circuit to spin up  the engine extra fast to shorten the leak time, or by push starting the car  in first gear to do the same thing.  We used to run a race called the Great Pumpkin up near Akron Ohio and at  times there would be snow on the ground. The starting problem was profound  indeed. I poured in a cup of hot coffee and squirted motor oil into the  carb before attempting to start the engine. It drew quite a crowd and better  yet, it worked every time. There was a large smoking problem for a while after  startup (Like a big radial) but we got to race, and were very happy.
 
All of this was with the stock (Lame) points style (Kettering) ignition  system. We could get up to 9,000 RPM with points. Plugs were gapped to .012"  because secondary voltage was way down, and misfires were common with bigger  gaps.  If you are having trouble starting your rotary, in cold weather, or on cool  humid mornings, you are in a big club. Clean and properly sized conductors in  the starting circuit are a must, for the highest possible cranking speed. If the  engine has been overdosed with fuel, shut off the fuel and crank with the  throttle full open.  Do not do this from outside the plane.
 
Do this from inside the plane with feet on the brakes and full up elevator,  unless it is on the wrong end, in which case full down elevator. Tie the tail to  a fixed object. Because the engine makes best power at full throttle, and once  it blows out the excess fuel it will start from sort of a dead quiet to a scream  and jump those little tiny chocks you made, and rocket down the flight line into  my plane or Tracy's plane.  In any case this works for the Renesis but it takes a good long time  because of the exhaust port placement. The fuel wetted plugs will dry out if you  have enough battery. A clean dry set might get you going faster. A few blades  with no fuel at all might get some heat of compression into the cold iron parts  before the chilling effect of the fuel mist wets the plugs.  Do not spray any kind of starting fluids meant to start diesels into a  rotary. It is conductive and shorts the plugs worse than water. WD-40 used  to work great. It was an explosive fog and helped sealing as well, but they made  it much safer now and it is nearly useless.
 
If there is to be a high energy system added to the aircraft engine, I  would add it to the trailing plugs only until the system is proven with many  hours of service. You can fail the trailing system and loose very little power.  You will know immediately if you loose the leading system.  But the high energy system would still help with starting and fuel burn,  and you would still have two independent systems.  If Tracy's system mimics the Kettering system, it is likely that it could  be used to trigger an after market high energy system with no problem.  Otherwise, a transformer or shunt of some kind may be required to prevent damage  to his system. Ask Tracy.
 
This advice may be worth what its costing you.
 
Lynn E. Hanover
 


Hi Lynn,

Do you know if the MSD replacements for the LS1 coils are as hot as the
real MSD systems?  I've got a set of LS6 coils that the ad on ebay said
had a higher spark voltage than MSD, but haven't tried them yet.

Bob W.


--
N93BD - Rotary Powered BD-4 - http://www.bob-white.com
First Flight:  11/23/2006 7:50AM - 0.7 Hours Total Time
Cables for your rotary installation - http://www.roblinphoto.com/shop/
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster