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Straight Bore Cylinders

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Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Wed Feb 22, 2012 1:16 pm Post subject: Straight Bore Cylinders

Any consensus here on straight bore cylinders?

http://www.chuckneyent.com/cylinderoverhaul.asp

flyv35b(at)minetfiber.com
Guest

Posted: Wed Feb 22, 2012 3:12 pm Post subject: Straight Bore Cylinders

On 2/22/2012 1:15 PM, 923te wrote:

 	  Quote: 	
		   



 Any consensus here on straight bore cylinders?

 http://www.chuckneyent.com/cylinderoverhaul.asp




	


You tryng to reduce the friction and increase HP, Ned? <G>



Chunk told me several years ago that he has run the big bore Continental 

cylinders with and without choke on a dyno and as I recall the straight 

bore produced a little mre HP.  He didn't think the choke is needed if 

the cylinder runs cool as it therefore doesn't expand as much at the top 

and remains pretty straight.



Another question for Ken at Lycon.



If you are talking about stock Lycoming cylinders all the nitrided 

cylinders have choke whereas the old 150 hp plain steel cylinders did not.



Cliff

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Wed Feb 22, 2012 3:58 pm Post subject: Straight Bore Cylinders

 	  Quote: 	
		   	  Quote: 	
		   Any consensus here on straight bore cylinders?

 http://www.chuckneyent.com/cylinderoverhaul.asp

 

 	
 

  Ned: 	




The requirement to Choke or not to choke is up to the cylinder manufacture and the STC.  Years back when I upgraded my O-320 there were two STC out there.  Bill Scott's STC is a choked cylinder. The other fellow was not.  

 The reason for choking is to keep the compression high as the cylinders heat up.

All cylinders expand as they heat up.  The most heat is in the area of the piston stroke.  SO... If you start with a Stright cylinder and say a compression ration of 8.5:1; when the cylinder heats up the cylinder/barrel will expand.  BEYOND stright.  So the compression ration will drop 8.45:1 who knows!!!  But it will and there will be room for the rings (top ring) to loosen up at the split.  Lower compression equals lower HP.

 So, if you know there is going to be an expansion why not compensate for it with a little choke.  REMEMBER the choke is there for a very short time.  Once the cylinder/barrel is hot it expands to stright.



 

Now...  What about the NAY NOZZLE?  I have them, anyone else?

Barry

"Chop'd Liver"



  [quote][b]

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Feb 22, 2012 4:15 pm Post subject: Straight Bore Cylinders

On 2/22/2012 6:57 PM, FLYaDIVE wrote:

 	  Quote: 	
		  

 Now...  What about the NAY NOZZLE?  I have them, anyone else?



 Barry

 "Chop'd Liver"

OK, I'll bite.  What's a NAY NOZZLE???
	


Linn

Discover

Joined: 26 Feb 2007
Posts: 429

Posted: Wed Feb 22, 2012 4:50 pm Post subject: Straight Bore Cylinders

Sprays oil on the cam

 http://www.chuckneyent.com/neynozzle.asp

 [quote]   ---

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Feb 22, 2012 4:59 pm Post subject: Straight Bore Cylinders

Ah yes.  Well, I have them in my Pitts engine (O-360-A4A).  When I     had the departing prop problem and rebuilt the engine I had the case     overhauled and they had to mod the case for them.  Mine are aimed at     the pistons for cooling though.  I suppose some oil is sprayed on     the cam.

     Linn

     

     

     On 2/22/2012 7:53 PM, 923te wrote:     [quote]                            Sprays oil on the cam

       http://www.chuckneyent.com/neynozzle.asp

       [quote]         ---

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Wed Feb 22, 2012 5:03 pm Post subject: Straight Bore Cylinders

Hi Linn:



I mentioned the NAY NOZZLE only because the link that Ned posted was to Chuck Nay.  It is a great idea.  Inside the engine case there are oil galleys.  When the engine is opened for OH you drill and tap into four of these galleys, two on each side of the engine.  Into these you thread a SPRAY NOZZLE (Nay Nozzle).

 The purpose is to SPRAY oil onto the Crank Shaft and the Cam Shaft.  This is because the engine is not what is called a Wet Crank... ONLY oil that is splashed around gets on the Crank and Cam Shafts.  The Nay Nozzle improves this oil spray tremendously.  The WORSE part of our engines next to the poor oil flow is the lack of oil flow to the cam.  The cam is a VERY high ware area of our engines.  I hope the Nay Nozzle solves some of this problem.

 



Thanks for asking Linn,

Barry

"Chop'd Liver"

On Wed, Feb 22, 2012 at 7:15 PM, Linn Walters <pitts_pilot(at)bellsouth.net (pitts_pilot(at)bellsouth.net)> wrote:

 [quote]--> TeamGrumman-List message posted by: Linn Walters <pitts_pilot(at)bellsouth.net (pitts_pilot(at)bellsouth.net)>

  

 On 2/22/2012 6:57 PM, FLYaDIVE wrote:

  	  Quote: 	
		   

 Now...  What about the NAY NOZZLE?  I have them, anyone else?

 

 Barry

 "Chop'd Liver"

 	
 OK, I'll bite.  What's a NAY NOZZLE???

 Linn

 

 

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n76lima(at)mindspring.com
Guest

Posted: Wed Feb 22, 2012 6:06 pm Post subject: Straight Bore Cylinders

Chuck Ney has an STC to add oil squirting nozzles in the case to flood the cam with oil.

--Bob Steward



Sent from Samsung mobile

teamgrumman(at)yahoo.com
Guest

Posted: Wed Feb 22, 2012 7:30 pm Post subject: Straight Bore Cylinders

Often wondered about that too.  Seems to me that with todays ability to machine to extreme tolerances, making a round cylinder with straight walls and compatible rings only makes sense.  

        From: 923te <923te(at)att.net>

 To: Team Grumman <teamgrumman-list(at)matronics.com> 

 Sent: Wednesday, February 22, 2012 1:15 PM

 Subject: TeamGrumman-List:  Straight Bore Cylinders

 --> TeamGrumman-List message posted by: 923te <923te(at)att.net (923te(at)att.net)>

Any consensus here on straight bore cylinders?

http://www.chuckneyent.com/cylinderoverhaul.asp

gt;

teamgrumman(at)yahoo.com
Guest

Posted: Wed Feb 22, 2012 7:32 pm Post subject: Straight Bore Cylinders

I asked Ken about these several years ago.  He wasn't a believer.

        From: Linn Walters <pitts_pilot(at)bellsouth.net>

 To: teamgrumman-list(at)matronics.com 

 Sent: Wednesday, February 22, 2012 4:59 PM

 Subject: Re: Straight Bore Cylinders

  

 

                     Ah yes.  Well, I have them in my Pitts engine (O-360-A4A).  When I     had the departing prop problem and rebuilt the engine I had the case     overhauled and they had to mod the case for them.  Mine are aimed at     the pistons for cooling though.  I suppose some oil is sprayed on     the cam.

     Linn

     

     

     On 2/22/2012 7:53 PM, 923te wrote:     [quote]                             Sprays oil on the cam

       http://www.chuckneyent.com/neynozzle.asp

       [quote]         ---

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