Author Topic: building the Frisco Standard Model  (Read 14894 times)

Offline gbritnell

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Re: building the Frisco Standard Model
« Reply #210 on: July 07, 2019, 12:56:32 PM »
Hi Craig,
Issue 1, heating. The only engines in my collection that will run for extended periods without overheating are my hit an miss types. If I override the governor they will get hot also. My multi-cylinder engines only have an operating period of about ten minutes, they get hot.
Issue 2, lethargic running. My best guess at this would be ignition timing. When I start one of my engines for the first time I usually set the timing somewhere between 10-15 degrees advance. I'll crank the engine over and once it starts I'll start adjusting the timing. Usually it takes more advancing.
Issue 3, igniters. I have built several engines with igniters. Generally the larger ones are more successful.
To try and eliminate any ignition problem with an igniter I have made an adapter that mounts in place of the igniter. I thread the adapter for a spark plug. I make up an aluminum disc to hold a magnet which is held on the crankshaft with a set screw. I make up a holder for a Hall transistor and super glue it to the block or crankcase. Using a conventional ignition sorts out quite a few problems. I know it sounds like a lot of work but it's not really and if the ignition isn't the problem everything is easily removed
Issue 4, just an observation. I noticed your fuel tank is higher than your needle valve height. Other than using a Lunkenheimer type carb with a check valve all my fuel tank heights are level with the needle valve or below. An engine with good vacuum will pull fuel from at least an inch below the venturi level.
 Hang in there Craig. It's a beautiful engine and deserves to be fine tuned. As an aside I tinkered with my flathead engine for over a year.
gbritnell
Talent unshared is talent wasted.

Offline Craig DeShong

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  • Raleigh,NC. USA
    • Lauson small engines
Re: building the Frisco Standard Model
« Reply #211 on: July 09, 2019, 07:01:04 PM »
 :LittleDevil:Im going to call this model complete at this time.  Maybe a little additional tweaking yet to do, but its running fairly well.

Id like to take a brief moment to thank those of you who have been following along, those that have commented, and especially those who have offered advice regarding a problem I was having.  Im not sure this engine would be running without it; so, a sincere thanks again.

For someone who follows along and builds one of these things, I hope this thread will have value for them.  Some things I might do different, in retrospect:
1-   I might think about boring, then pressing in the valve guides rather than threading them in as specified in the drawings; getting them in and sealed might be easier.
2-   When aligning the heads, Id pay very close attention to the head center line so that the valve rockers, as specified in the drawings, will fit.  Rotating the head just a fraction of a degree off center will greatly affect the dimensions of the valve rockers.
3-   PLEASE note that the measurement between centers of the cylinders as specified in the drawings is in error as noted in the above thread.   
4-   Id follow my lead and make aluminum pistons so you dont have to bore out the top of the piston and then silver solder in a false piston top.
5-   Check to make sure you have enough meat to drill all the holes in the top of the heads.  On my casting on one of the heads, the casting was too short; thus causing me to re-design the valve rockers on that head and alter the length of the valve guides and valves.
6-      Before drilling any holes in the base locate the crankshaft centerline by facing the jourrnal covers and the base where they lie; place the journal covers on the base where they center on the base boss, then locate the crankshaft centerline by the ridges on the two journal covers.

A video of the completed and running model can be seen at thi URL:
http://www.modelenginemaker.com/index.php/topic,9173.msg203447/topicseen.html#new
« Last Edit: July 09, 2019, 09:52:15 PM by Craig DeShong »
Craig