Mailing List flyrotary@lancaironline.net Message #60337
From: Ken Johnson <kjohnsondds@yahoo.com>
Subject: Re: [FlyRotary] Re: help starting engine
Date: Fri, 25 Oct 2013 21:39:34 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
This is a new engine, not a rebuild. I will try the oil tomorrow. Thanks

Lehanover@aol.com wrote:

That was a fresh rebuild or crate engine? I have forgotten already.
I have only seen show room stock racers use the stock ignition system systems because the rules require it. All others use either a Mallory Hifire CD system or an MSD multi-strike CD system. It is not uncommon to have difficulty starting a fresh engine. The assembly lubes drain off or evaporate and good sealing is lost before the first start attempt. Thus the squirting oil idea. Also the street car being pushed after a rebuild is common. In 2nd gear fast enough to spin the engine well past starter RPM so that leak times are so short that high enough compression for a start is achieved. If you follow even the factory suggested rebuild clearances, you can be disappointed. Maximum end gap for side seal to corner seal is, .004" when anything over that is rebuild time. I start with zero end clearance. That will increase as the rotor comes up to temperature. So, there is no binding at all and a near perfect compression seal, and instant starts. The CD systems offer the
additional help by lighting a mixture so lean as to be a lean cut-off for the stock system, and also light a massively over-rich mixture that would foul the plugs with the stock system. Even if only installed to start rebuilds in the shop the CD system is a good investment. Once the engine has run in for a number of hours, it will start instantly.
 
Just as cylinder filling is affected by engine RPM. It is also affected by throttle position. In carbed engines we must keep the butterfly close by the idle drillings in the carb body, lest there be little to no fuel atomization. Poorly atomized fuel looks too lean to the engine and ignition (if any) produces a very low power explosion. So starts are done with the butterfly close to idle and an over rev on start up is unlikely. In injected engines any amount of fuel per cycle may be selected, and a start may occur with the throttle in the wide open position. It is a safety  must that a hand be on the throttle ready to close to the idle position instantly on start up.
 
Lynn E. Hanover    
 
In a message dated 10/25/2013 7:38:13 P.M. Eastern Daylight Time, kjohnsondds@yahoo.com writes:
Thanks Lynn,
It would seem that the reason the spark plugs fire every once in a while is because they are wet.
Ken
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