Longboy's "OVERTIME" I/C Twin!

[Longboy]

Tecumseh ignition points are located on the end plate and are camshaft driven. I like their compact size that wraps around the cam trigger. The coil stud attached to the tension spring is low and inside on the plate here. I want to bring that to the outside edge of frame for easy connect.



An eyelet over the stud with a brass rod encased in a Delrin tube threaded to a bracket mounted to the side of plate solves the location issue. Condenser to be mounted to opposite side plate edge.



When the bottom plate is joined to the end plate the stud sits on its top for a ground out. A relief area is milled out for the stud here for isolation.



Now ready to work on the "special feature"!   ....anybody see it yet? 

[Perry]

hmm would that be a fuel tank?

[Longboy]

Nope....sorry Perry. Fuel tank is the wrong answer...... but you do have this on your 2 cyl. engine!  Anyone else!

[Roger B]

As you are working on the ignition system I would guess that it is the distributor.

[Longboy]

You got it Roger B.

[Longboy]

On my "Gemini" twin, I have a dedicated dual fire coil and 6 volt battery ignition mounted with the engine on a oak board. For "Overtime",  I wanted a free standing engine and be able to use my traveling 3 volt battery pack & coil. To do so requires a distributor.



From Home Depot, I picked up both a 1-3/8in and 1 inch PVC end cap and bag of #8 brass machine screws & nuts. Used the 1 inch cap on the engine. Three drilled and taped holes located for coil and plug leads.



The rotor is Delrin with brass strap, stainless #4 screw. The coil screw is dished out to a ball & socket mate with the rotor screw head with a round nose tool bit on lathe. Threaded into cap from the inside, when placed over the distributor base it is threaded down till contact with the rotor screw and locked nutted in place.



Rotor brass is located on the camshaft for line up with the plug leads. Distributor base is machined with a wrap around to the side of the end plate and a matching piece serves as a timing gear guard at other end.





Plug lead screws are threaded in till contact and locked. Being a sweep contact, fine tune by finger rotating camshaft and feeling for it then. The screws where replaced with longer studs to fasten the wiring. Though a press fit to the base, a finger screw was added to hold cap in its base.......cuzz I like doo dadz on the engine!

[Longboy]

Overtime went to the cobbler last month. Some steel tabs, hood bumpers and custom nuts mounted to the bottom plate should make it as stable ....as a turtle! 

[Longboy]

Delrin intake is used with .10 to.15 size carburetor. Press fit brass tubes join intake to engine........I didn't like the looks with the carb jutting out from the engine too far and a duplicate was made at a right angle shown on engine here.



A gathering of parts for the fuel tank. I used the decorative steel tube with a nickel finish for both the tank & muffler.



Cutting off the neck of mini liquor or energy drink bottles make great fuel filler necks for fuel tanks.



Some fillister head bolts turned into studs by cutting heads off.





The exhaust port is threaded for them that is thru drilled and tapped for 4-40 socket heads to secure muffler. Stud is cross drilled to exit into muffler after spacing out with brass collars.

 .....Hey come back this weekend to the conclusion to Overtime's build with some tips, troubleshooting, the beauty shots and maybe a video!

[Roger B]

We're waiting for the happy dance  Tutus are available from various longstanding (or longsitting) members of the forum   

[Longboy]

Instead of a press fit for the lifter guides, set screws are used to secure them to the deck. The lifter heads are small enough to pass thru removing them with the guides otherwise, depending on how long the lifter stems are, you may have to pull the cam to drop them out the bottom.



The brass collar in front of the timing gear is the collet knockout. Pushing and twisting the flywheel, as it will ride over this collar pops the collet for removal then.



Flywheel retainer is drilled & tapped for a stud and brass acorn nut. Socket on the cordless drill for a starter drive!



One of Overtimes cylinders had no compression. To reveal the leak, some dish soap suds over combustion chamber, a blow off nozzle from your compressor set to 10PSI into port shows where. In this case some epoxy dried on the valve guide seat preventing the seal.

[Longboy]

With the valve train set up now, I see that my lift and duration on the lobes is too great. The valve keeper bottoms on valve guide stem. Re-profile the lobes and cut lobe lift back by .035 and I have a nice idle cam profile.



Checking the spark here. The distributor cap rocked some as the rotor made contact. Some filing of rotor tip and a spin of the camshaft with electric drill for wear in left some brass dust  under cap and proper clearances.


Some paint work in black and polishing the bright work...... and it looks like I'm ready to go! 
__________________

[Longboy]

     Welcome to the reveal of my new engine! Work on "OVERTIME" was started Sept. 25th and its first signs of life happened Dec. 15th.



I meet my goals & benefits of a distributor ignition, a stronger crankshaft and boxed open frame.



Pleasant solitude hours in the garage. A few trips to metal supply and hardware store.



And then its time!









....Well that about does it for Overtime........(not so fast LONGBOY.... .....WHERE'S THE VIDEO?  ) ...Geez you guys are a tough crowd!




<a href="https://www.youtube.com/watch?v=qh09Fsku3ZU" target="_blank">http://www.youtube.com/watch?v=qh09Fsku3ZU</a>

Hey thanks for following along on this project. "OVERTIME" is alive and well...........see my other model engine projects on YouTube, Longboy4.      Dave.

[Roger B]

Great runner and great video       I'm proud if I can get the video up without Jo having to fix the link 

[fumopuc]

Hi Dave, congratulations for this runner. I like the "open" design of this engine.

[Jo]

  Very nice, I wish mine did that 

I'm proud if I can get the video up without Jo having to fix the link 

I have my uses 

Jo