flyrotary@lancaironline.net Mailing List Archive

Chris,

One thing you might check - is your coolant "O" rings - if they are compromised - combustion pressures can push mixture into your coolant system during compression stoke lowering your chamber pressure. That could show up as bubbles in the coolant or you might notice "oily" sheen on top of your coolant if you can see it through your cap. You won't always get green coolant fluid in your combustion chamber if an O ring is compromised.

The O ring can seal on the intake stroke because at most you have a 14psi difference, but may not on the compression stroke where you can have a 100 psi difference between coolant pressure (ambient) and chamber pressure which could push past a compromised "O" ring.

Also, if you take you engine down - check carefully in the coolant "O" ring lans to make certain there are no cracks. I use a dentist pick (a needle would probably work) and gentle pull it around the inside corners - if it catches, examine that area closely.

Another thing you want to check is your rotors apex seal slots. They can wallow out through use (although you should not have that much use) such that the apex seals do not ride vertically in the slot and sort of lean over (as the supporting wall of the slot wallows out) and do not seal as well as they should. I think Lynn suggested sticking an apex seal in the slot (one end) and with the other end sticking 3" or so in the air - measure how much you can measure by wiggling that end from one side of the slot to the other. The far end of the apex seal should not move more than 3/8".

With new Rotors that again should not be a problem, but you are looking for stretches and this is one {:>)

Yes, it gets easier to pull and tear down an engine with practice - but, it gets to be less fun each time {:>)

From: Chris Barber

Sent: Monday, February 14, 2011 10:39 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: Low compression in rotor 2 ... still

Not sure how that would effect the lower compression though.

From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Chris Barber [cbarber@texasattorney.net]
Sent: Monday, February 14, 2011 9:35 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Low compression in rotor 2 ... still

Jeff,

I shall give that a try

Chris

From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Jeff Whaley [jwhaley@datacast.com]
Sent: Monday, February 14, 2011 9:28 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Low compression in rotor 2 ... still

Chris, try changing your spark plugs. If you’ve caused damage to the rotor springs from detonation, you’ve also exposed the plugs to the same force.

I have never had a problem starting my engine except for this past weekend … wouldn’t start, I was blaming it on the cold, so it got more pre-heat and eventually started exactly as you said, a lot of cranking and liking the starter assist. Yesterday, same thing wouldn’t start – more pre-heat, still no joy. Pulled the plugs and they were coated with black soot, so I went home, got a brand new set of plugs – engine started right away and with no additional pre-heat.

Jeff Whaley

From:	Chris Barber <cbarber@texasattorney.net>
Subject:	Low Compression in rotor 2...still
Date:	Mon, 14 Feb 2011 03:29:28 +0000
To:	Rotary motors in aircraft <flyrotary@lancaironline.net>

To remind y'all, following very hard starting, I discovered bad apex seal springs in my rotor 2 most likely due to detonation. I cracked the keg and replaced the rear apex springs and sealed it all back up. While apart, I did not discover any damage other than the bad springs.

I have been trying to tune the engine, however, even using BOTH my EC2's, I am still having problems with very hard starting. When I do get it to start it is at full lean and I believe only if I switch over to B. Once started I can take the mixture from full lean to a more moderate setting (even if the tuning is still lacking) and it will run on A or B about the same. I have reset A to factory settings. I do have a bit larger injectors, per Mistrals recommendation, but did crank her up to 22. MAP and adjust Mode 3 once started to just over the mid point per the EC2 manual.

It takes an extended period of time of cranking (maybe 50 or 60 seconds...betting my starter is hating me) before it starts and then kinda just starts running as a continuation of the starter being turned, instead of the engine actually "firing up".

I pulled the plugs to check inside and unlike before all the apex seals are nice and springy, HOWEVER, when I do a compression check I am only getting about 60 psi on the rear rotor. I am getting about 80 psi on the front rotor, which is what I expected.

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