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An Onan Alternative?

Stan Somers first contacted me several months ago, stating he had successfully replaced the bad 16HP Onan CCKA engine in his Simplicity 4040 (AC 616 equivalent) with a used 16HP L-head Briggs & Stratton.  As many of you are aware, parts for the CCKA and CCKB (19.5 HP version) are getting harder to find, and are quite expensive...

But, before he shared the details, however he wanted to wait and test the results a bit more, so that he would not mislead anyone else.  Read his story and view the results below.  Click these pictures for a closer view.  WARNING:  The linked pictures are VERY large so that you can see the details.  They will load slowly.

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Stan Says:

This overview has been delayed for two reasons: 1) A couple of system crashes with file losses due to "Ditto" tape-backup system failures. 2) The realization that if this project turned out to be a failure after a few months of running the machine I might need a place to hide from those who followed me.  So far itís a success.  The only test left is to push a lot of snow this winter.

It suddenly came to me in the form of horrendous noises from the engine that it was time to replace it. Even a liberal Scotsman would not consider spending over $2,000.00 to rebuild a 26 year old 16.5 hp engine that has to earn itís keep year Ďround. (My deepest apologies to antique collectors and museum curators the world over but this is a limited budget production.) So, being a very cheap Scotsman I knew I had to find an alternative. It turned out to be the only reasonably horsepowered used engine I could find and was cheap to boot. A fantasy come true; sixteen horses, 16 years ($) old, and so few hours on it you could remove the factory installed muffler lock nuts with 10" channel-lock pliers. The only problem was to convince it to fit into the Simplicity 4040 without hiring an engineer and machinist.

Briggs and Stratton 1983, 16hp L-head, Magnetron IC. Model 402437, Type 066601, Code 83032912. Cost: $250.00.

Two major problems had to be overcome. 1. The engine would not fit in the engine well-deck. 2. The double pulley (from the CCKA) for tractor drive did not match the new enginesí flywheel-puller mounting holes. To complicate things the flywheel is a rather light weight aluminium.

The first major problem turned out to be not so major after all. The front engine mounts rest 1.5" onto the battery platform and the rear mounts rest on a large engine bed. Two "Z" clamps welded to the battery platform hold the front of the engine in place. The wood and metal engine bed is temporary and will be replaced (maybe) with a permanent metal stand after the whole system has finished proving itself.

The second major problem wasnít so major either, just took a little longer to solve. The pulley bolt holes were carefully filed to an ellipsoid-like shape and a rod (cut off bolt) was tack welded into the center hole for alignment assistance and added stability. Altered with care this pulley can be restored for use again on a CCK engine.

With the engine raised this means longer drive belts. I decided to go with 28" belts. That was the week that every machine using 28" belts in two counties were replaced. Iím using 29" belts instead. It may seem backwards but the belts appear to be at correct tension when the clutch spring is compressed to only 9" instead of the normal 8 inches. When determining the best tension for the new belts donít forget to continually check and readjust the clutch pedal free play or the neighbors may unintentionally learn a few new descriptive mechanical terms.

The electrical system for this engine is very simple and will integrate with the 4040 by just connecting a few wires. Donít forget a bonding strap. See closeup photo. If your ignition switch works odd like mine move one of the now useless wire ends from the bundle to a new grounded kill switch on the dash and the other end to the engine kill terminal. This will help keep the electrical switch-over as simple as possible. Make sure the wiring is electrically correct before inserting the fuses because, at least in this town, a new rectifier/regulator costs $61.90. Part # 691185. On the regulatorís heat sink I mounted an open fuse receptacle and attached the blue charge wire (from the wire bundle) directly to it. Then I attached the regulator red wire to the other side of the holder by means of a spade connector. This gives you a quick disconnect feature when jump starting, and the location is good for easily checking the fuse. I keep only a 15 amp fuse in this holder. A 20 amp automatic circuit breaker (12.6v) goes between the battery and the amp meter. Your local motor home/camper/RV dealer should have these for about $3.50. The engine PTO shaft inconveniently takes up space on the battery platform meaning you have to mount a smaller than automotive size battery. I use a size U1-7 with 230 cold cranking amps. Iím not worried about starting the tractor when itís 10 or 20 degrees. Iím worried about starting the tractor when itís 10 or 20 degrees below. The only sane way to handle that is to have a second battery kept in a warm place until itís time to start the show. Believe me when I say that the second battery makes life so much more pleasant at 4 AM on a Saturday morning in the winter.

A few days after the pictures were taken I got around to turning the exhaust pipe 90 degrees to the left and fitting a flexible extension to exit through the grill and the return fuel line was shortened. Itís now more than a few months since I took the pictures and Iíve still not replaced the muffler portion of the air guide. The hood doesnít like closing over the outside corners of the guide. See leading edge of air guide in closeup photo. An alternative is easy to fabricate with pinched corners. I used the tractor very hard for four hours during the worst heat wave of the summer with no loss of power or measurable overheating.

Speaking of the hood, the stiffening web will have to be removed or repositioned. The hood is a snug fit now and refuses to shake or rattle. To get this much accommodation I had to make a pair of hinge extension brackets that lift the hood 1.75" and push it forward 1.25". See close up photo.

By now Iím sure you want to know what that "thing" is on the front of the tractor. Itís a rock roller. It rolls rocks up and out of the ground. With two inches or more of rock sticking out of the ground press the beam down (very near the rock) until the front wheels begin to lift off the ground. Push forward until the beam is on the other side of the rock then pull back. Repeat until the rock rolls right up and out of the ground. Also itís pretty good as a general ram for pushing anything around. It scrapes a pretty mean trench in stony ground too! Itís on the same A frame that the Honda 54" snow blade will be mounted.

Stan Somers
December 4, 1999




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