T&L .40 How should it run???

[frank mccune]

        Hi All:

        I got an old Ringmaster Imperial out of  the attic to fly today and it had a Tom Lay .40 engine mounted.  This engine is one of the ones that he made by installing a ST .46 P&C into an OS .35 Stunt case.  Is this engine supposed to only run in 4 cycle mode or is it supposed to 4-2-4?? 

       I flew it in a wet 4 cycle and I thought that I would feel much better if it did a 2 cycle break through the manouvers. The plane flew very well and the engine  started first flip each time.  I have never flown this plane or started the engine prior to  today.  They have been both hanging in my attic since circa 1980.   I have no idea as to when the plane was built but the engine was put together circa 1977.  Even after all that time, the engine started first flip!!!!!!! It appears to hae great compression.

       Has anybody had any experience with the TL .40 in the past?  How about a RMI.  Thoughts comments etc.


                                                                                                                                         Be well,

                                                                                                                                         Frank McCune

[frank williams]

I had no idea that you could make that swap.  A ST46 piston and sleeve in an OS35 case.  Whats the timing like, I wonder.

[Bruce Hautamaki]

If it's a Tom Lay or Aldrich OS 35 they replaced the Con Rod to a Super Tigre. I don't think 46 p&l would fit. George did two for me and I had to send the con rod with it. He supplied wrist pin etc and did his magic.

[Air Ministry .]

Frank will have to do some pictures , with the head off . Is it a ringed Alumnium piston , Frank . The Port devider thingos , ( 4 small Ex port holes ?? ).

[frank mccune]

      Hello Frank, Bruce and Matt:
 
       Some information re the TL OS/ST .40 Stunt engine:

       Built 1977
 
       Cautioned not to remove the head and/or the backplate.

       There appears to be an aluminum piston with one conventual ring.

       Four square exhaust ports are seen in the exhaust stack.

       The cyinder was honed to make it straqight.

        Use an 10-6 Wide prop with 25% castor oil fuel.

        What modifictrions do you think were made to make this engine a first flip starter?

        Honing of he cylinder?
   
        Custom ring made to FIT the cylinder? Did the two together provide the outstanding compression? It leads me to think that a cylinder must be honed prior to fitting a ring! I have engines rebuilt by "experts" that had no-inadequate compression after they were customized!!!! Can one say,"Waste of time and money?"

       Any other questions and/or comments?

                                                                                                                                               Be well,

                                                                                                                                                Frank McCune