Cub engine mods

[Puffie40]

Mental exercise: I was wondering if anyone has tried modifying the engine to get more power out of it. (Aside from rebuilding the motor of course)

Upping the compression to handle modern octane levels is one way to start - that would require shaving the heads.

A turbocharger would be another method- they make them small enough and there's enough space under the hood for it to fit comfortably.

[Eugene]

Short answer - - NO engine modifications. Why bother.

Reason, if you need more power on the ground, get a bigger tractor. Some larger tractors can be purchased for less money than a Farmall Cub.

Edit: And bigger tractors for less money than the modifications cost.

[staninlowerAL]

Some of the changes to the C60 engine in 1975 (and before) that resulted in higher hp for the "NEW" International Cub were Zeneth Carbuerator, larger manifold intake/exhaust ports, a slight change in timing, modified head identified by the R2 suffix on the part number, higher rpm/governor change. The changes resulted in about 18 hp as opposed to the approx 10 hp of the early Cubs. Take a look at Raymond Durban's database for Cubs, page 31. Others may chime in with other changes. Stan

[Eugene]

Actually the changes is in how the horsepower was advertised. The original Cub had and was advertised as having about 9 3/4 HP on the draw bar and 13 HP at the engine. The engine modifications rated the engine at 18 HP.

(Aside from rebuilding the motor of course)

Cheaper to buy a bigger tractor.

[KETCHAM]

Well....a v6 cub is neat along with Gary's Cubota....time and $$$$ on what you want to do...Why not....I like small power houses....take up less room....Kevin

[Lt.Mike]

A question like this brings Rick Prentice's cub to mind
Would a V6 cub work for you?

[bob in CT]

For a 48 Cub
Cam change in the mid-50's. BillyBob had a custom re-grind.
Pop-up pistons in 1968
There are lighter governor weights that push the RPM curve up. All numbered Loboys have them.
The later manifold has larger ports and the carb has a larger throat.
The heads changed, but there is not a lot of difference. I cced one of each and posted the info in an old thread. Clark Thompson posted some information on shaving heads and he probably is the best one for advice on getting the most out of a normally-aspirated Cub motor beyond putting the best of the factory components into a rebuild.

Port matching is always a good thing to do.

Pushing up the RPM and torque curve is good for mowing, which is probably why the numbered Loboys were set up that way since they were sold as estate mowers. However, for low speed work, it is desirable to have the torque peak at the bottom end.

[leerenovations]

It would be cool if there was a Funk v8 conversion for the Cub. Wonder why one was never made. I love the sound of the Funk conversions on the 8ns, especially with the foot feed.

[Puffie40]

I did a little looking around the forum for shaving/milling heads and it looks like the range is 0.04" to 0.08". the new style pistons will swap in no issue.

What I have seen regarding porting on flatheads is related to B&S engines: smooth out the intake and exhaust ports, and file back the 'Eyebrows" between the piston and the valves.

Looking at turbos, there is a lot more to do. one site actually stated the compression ratio should remain stock or be lowered in order for the motor to remain reliable. I believe I saw mention that the carburetor has to be able to do blow-through vaporization instead of vacuum vaporization, and fitting the turbo to the manifold will be a fabrication challenge (I would consider building a new manifold instead of using the old one). I dont recall if there are any external oil lines on the engine, so some drilling will be needed to plumb in a oil line.

It would be cool if there was a Funk v8 conversion for the Cub. Wonder why one was never made. I love the sound of the Funk conversions on the 8ns, especially with the foot feed.

hmmm...put a Harley motor on? The long stroke would mimic the sound of a V8.

[BigBill]

More power? Super A

That was my first mistake I didn't get a super A