REFLECTOR: Franklin Engine

[Jerry Teitsma]

I battled high temps as well - both oil and CHT.  I have two oil coolers up front with two NACA scoops.  The oil coolers are in parallel.  I think the biggest change was installing fairly large (1 inch tall) vortex generators ahead of the NACA scoops on top but I also put in a heavier spring in the oil bypass at the same time.  Oil temps and cylinder head temps went down to acceptable levels.  I have not operated below 5,000 feet as our airport is at 8,300 ft. but have flown back and forth to Denver several times.  I have a new Franklin and had the cylinder heads relined with harder steel at about 26 hours.  JT  

----- Original Message -----

From: "WJ Wilbeck" <wjwilbeck at gmail.com> 
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org> 
Sent: Thursday, February 20, 2014 4:02:08 PM 
Subject: REFLECTOR:  Franklin Engine 



That's interesting.  How many hours on your engine?  What are the CHTs? 





Reply: 

  

Just over 500 hours on a new PZL Franklin 

Normal Cruise is lean of peak at +- 9 Gal/Hr. 

CHT 340 – 380 will go higher if too rich at LOP. 

  

In Summer can climb 15K+ at 100 knots & not break CHT red line of 390. 

  

Sure I fought High Oil & CHT. 

  

Fix for me: 

  

Set ignition no more than 32 degrees 

Added 2 nd oil cooler on top of engine with additional NACA& Plenum 

Added 3 additional exits to bottom cowl. 

  

CYL 5 &6 can get hot if mixture not set right. 

I believe cause is blow-by on rings & will hone and install new rings this spring. 

I have been told the PZL Franklin has chrome barrels & Rings and that it would never seat the rings until changed to Cast Rings 

We shall see. 

  

  


WJ Wilbeck 

620-727-3596 


  


From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of John Dibble 
Sent: Wednesday, February 19, 2014 9:10 AM 
To: Velocity Aircraft Owners and Builders list 
Subject: Re: REFLECTOR: Franklin Engine 


  


On 2/18/2014 5:13 PM, WJ Wilbeck wrote: 




One more thing to consider is the spark plug. 

  

In my Franklin, I have light speed ignition and run their recommended spark plug. 

  

It is DENSO X27GPR-U. 

  

It is a long reach and available from your local Honda Motorcycle shop for cheap. 

  

                Part Number 98061-59626 

  

The proper spark plug adaptor is available from Light Speed. 

  

I run the timing at 0 to start and 32 degrees for full power – Cylinder Temps OK. 



  

wj 

  


WJ Wilbeck 

620-727-3596 


  









	

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