---------------------------------------------------------- LycomingEngines-List Digest Archive --- Total Messages Posted Thu 03/12/09: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:14 AM - Re: Re: Converting IO-360 to O-360 (Rhonda Bewley) 2. 12:12 PM - IO-360 conversion to carb (Larry L. Tompkins, P.E.) ________________________________ Message 1 _____________________________________ Time: 06:14:31 AM PST US Subject: RE: LycomingEngines-List: Re: Converting IO-360 to O-360 From: "Rhonda Bewley" If they put 8.5:1 in it, that means they also changed the cylinders to parallel head taking it from 200 hp to 180 per your assumption. You cannot use the flat 8.5:1 piston in the angle head cylinder. Rhonda Barrett-Bewley ________________________________ From: owner-lycomingengines-list-server@matronics.com [mailto:owner-lycomingengines-list-server@matronics.com] On Behalf Of r falstad Sent: Wednesday, March 11, 2009 8:51 PM Subject: LycomingEngines-List: Re: Converting IO-360 to O-360 For what it is worth, the GlaStar kit I bought partially completed came with an engine that started out as a Lyc IO-360-A1A and was converted by an overhaul shop to an O-360-"A1A". Because of the conversion, it is no longer a type certified engine and can only be used in experimental airplanes. In addition to swapping out the fuel injection for a carburetor, it appears that they changed out higher compression pistons, which if memory serves are domed and produce about 8.7:1 compression to flat-topped pistons that provide 8.5:1 compression. Why do it? Two reasons: the original owner was an older gentleman who wasn't familiar with fuel injection/was more comfortable with carbs and, more importantly, "bumps" would have had to be added to the cowling to provide sufficient clearance for the fuel injector tubes -- a lot of fiberglass work. The engine was originally built in the mid-1960's and the log books are incomplete. But it has run strongly for the past ~170 hours. My best guess is that it puts out about 180 HP, which is plenty of power for my plane. Best regards, Bob ________________________________ Message 2 _____________________________________ Time: 12:12:19 PM PST US From: "Larry L. Tompkins, P.E." Subject: LycomingEngines-List: IO-360 conversion to carb I was not considering this swap, it has already been done on a flying kit plane that is now for sale. TTAF & E is over 300 hrs. My question was seeking input on issues to consider other than the carb icing issue that I mentioned. If it still has 8.7:1 pistons as represented, then it probably makes a little more than 180 HP but less than a FI engine since the FI engine, at least theoretically has more even fuel distribution. For the same reason, I would predict that the carbed version would have slighly poorer fuel economy. My question is really whether to live with it (as someone has for 300+ hrs.) if the alteration is reflected in the price or if the alteration should be viewed as something that absolutely has to be reversed. I apologize for not making a more detailed post in the first place. Hopefully, this post is clear enough that you don't need to do any mind reading. Larry ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message lycomingengines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/LycomingEngines-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/lycomingengines-list Browse Digests http://www.matronics.com/digest/lycomingengines-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.