what makes up a 1641 engine?

[drs1023]

I agree that the 1641 is an improvement over the stock 1500/1600. My 1641 and Schneider 275 cam (almost same as Engle 110), is 7 years old and still very dependable and strong. 6000 mile valve adjustments and annual plug changes (Pertronix ignition). I've built more than a half dozen of these, and I like 'em. The difference is noticeable driving up hills on the highway - not as much loss of speed (more torque).

The 88 mm slip in cylinders were a BAD idea. The part entering the block is paper thin, and the fins are brittle and break off. I only used these cylinders once for someone who insisted on them. Georgia summertime heat burned them up in a little over a year.

[nz fish]

[goober]

"...great thanks for info ..have you got a doghouse with the bigger fan cooling your system ? cheers fish"

I have the non-doghouse fan and housing with oil coolers under my rear window inside the cab. (not for everyone) I've had no problem with cooling in the hot weather and have warmer oil in the cold weather.

I have the stock non-doghouse cooler removed and replaced with an adapter for the cooler lines. I didn't go full flow because I wanted to save the coolers from undo pressure in the cold weather. The added resistance doesn't seem to present a significant delay to when the coolers come on line. (I use 10w30 in summer and 5w30 in winter)

The natural imbalance of cooling air from the OEM cooler being removed from the fan housing doesn't seem to be a problem. The stock SP 1600 radial fan with the non-doghouse housing works well putting all it's output over the engine fairly evenly. I'm guessing about 10% or so of the larger doghouse fan is going over the cooler to the outside anyway. Actual cooling air over the engine might be nearly the same.

Removing the coolers from the fan housing to the cab also allows me to better control the oil/engine temp in colder weather. When it's not too cold, it has the added benefit of more cab heat should I want it.