Thorp Air Command - T18.net

Supporting Owners, Builders and Pilots of the Thorp T-18 and its variants.
It is currently Sat Nov 25, 2017 2:31 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 21 posts ]  Go to page Previous  1, 2
Author Message
Lou
 Post subject: Re: O-290 pistons
PostPosted: Wed Jul 12, 2017 5:06 pm 
Sr. Member
Sr. Member
User avatar

Joined: Sun Feb 12, 2012 4:04 pm
Posts: 370
Images: 3
Location: San Bernadino, CA
How are these pistons going to me made?
Any room for custom comp. ratio?
900 for titanium pins and total seal rings?

_________________
http://www.dixiefriedfabrication.com/


Top
 Profile Personal album  
 
DanaL
 Post subject: Re: O-290 pistons
PostPosted: Wed Jul 12, 2017 5:53 pm 
Newbie
Newbie

Joined: Mon Nov 09, 2009 9:39 pm
Posts: 39
Location: USA
The pistons will be CNC'd from forgings. What compression ratio you looking for? 9310 pins per the suggestion of my piston guy and Deves rings. Deves are more user friendly in our air cooled engines. Let me know what you are looking for. I'm also going to have the pistons and pins match up to standard O-290 parts weight wise so if you just want to top your engine balance won't be an issue. If you really want Ti pins we can do that but they are more $$, I didn't even price them.
I just ask for your patience and tolerance here as we are in the middle of horse show season and I do crop hay all summer.

Code name "Lizard Man"
The Possum Works


Top
 Profile  
 
DanaL
 Post subject: Re: O-290 pistons
PostPosted: Wed Jul 12, 2017 5:57 pm 
Newbie
Newbie

Joined: Mon Nov 09, 2009 9:39 pm
Posts: 39
Location: USA
Oh, just to be clear, $900, may be slightly more or less for everything, pistons, pins, buttons and rings.

Parts Department
The Possum Works


Top
 Profile  
 
Binder
 Post subject: Re: O-290 pistons
PostPosted: Tue Jul 25, 2017 5:59 pm 
Sr. Member
Sr. Member

Joined: Thu Sep 01, 2016 10:50 pm
Posts: 153
DanaL wrote:
Oh, just to be clear, $900, may be slightly more or less for everything, pistons, pins, buttons and rings.

Parts Department
The Possum Works



My compression numbers are getting lower so the AP wants to hone and do rings although we can't find rings. Can I get your source on rings in order to price them? I'll need 3 chrome and 1 non-chrome (I have 1 chrome cylinder). Depending what we find I might just take up that $900 package and just refresh the hole thing if there is piston wear.


Top
 Profile  
 
Jim Mantyla
 Post subject: Re: O-290 pistons
PostPosted: Wed Jul 26, 2017 7:59 am 
Sr. Member
Sr. Member

Joined: Wed Oct 21, 2009 6:57 pm
Posts: 169
Location: Barrie, Ontario,Canada
Guys,

What about the strength of the cylinder bases when you increase the compression ratio? I have a wide deck IO-320 and from what i remember about the O-290 is that the flanges on the cylinders are thinner than what is on my engine.

Jim


Top
 Profile  
 
SHIPCHIEF
 Post subject: Re: O-290 pistons
PostPosted: Wed Jul 26, 2017 11:56 am 
Sr. Member
Sr. Member

Joined: Tue Nov 29, 2011 9:05 pm
Posts: 389
Location: USA
O-290 are all Narrow Deck engines. Narrow Deck O-320 high compression and O-360 engines came with cylinder flange plates to add strength to the flange. They use special Barrel Nuts because the larger cylinder bore (than the O-290) causes the cylinder exterior to be closer to the cylinder studs, so a typical cylinder wrench won't fit over standard nuts.
The force applied to damage the flange would be 10.5% greater on an O-320 (5.125" bore) because the bore is greater than an O-290 (4.875"). An O-360 has the same bore as an O-320, with 1/2" longer stroke.
The question is: Do O-435 high performance engines, like GSO-435 (300 HP!) from an Aero Commander or a helicopter use cylinder base plates and barrel nuts? If so, get some. These engines use angle valve heads, which would require different pistons, so I'm just referring to the cylinder base.
http://canadianflight.org/content/lycoming-go-435-0

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 21 posts ]  Go to page Previous  1, 2

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to: