Info needed: Chevrolet 235 c.i. conversion for CMP

[Bob Carriere]

Bruce is right on target....

Far easier to find a CMP bell housing....... 0.05 cents each in Ontario and the SM420 will bolt on directly....... it would silly to pass the convenience of the synchros on the SM420.....and it's a straight bolt on.

You will in all probability need to find and adapter plate to instal a 216 water pump which will not only shorten the lenght of the engine but will also better align the fan blade to the center of the radiator......and to the changeover ofo the water pump BEFORE you install the engine in the CMP as you will require to drill and tap into the engine block......sounds scary but not so complicated.

We built a small drill guide using a flat plate and a piece of tubing welded to the plate.....bolt the plate on the block using the other existing water pump holes and drill and tap the hole by drilling from inside the tube as a guide.... it will insure near 90 degrees.... I used a heavily greased rag stuffed inside the engine block to catch the metal shavings from behind..........mark your drill bit so you ONLY drill deep enough to reach through the water jacket BUT not into the cylinder casting. Use pipe thread sealer on the bolt threads .....
When you install the pump with the backing plate you may have to use some washers as shims if you find that the new pump does not fit perfectly flush even with the block leaving a tinny gap that may cause some distortion when the pump bolts are torque properly........ not all blocks are exactly the same but on some we had to use washers made thinner with a grinding wheel......

I have a picture somewhere and will try to dig it up......

If you buy an adapter plate make sure you do a good tracing of its shape in case a friend in EU had a need for one......very easy to copy in 3/16 flat plate......

Cheers

[Bob Carriere]

....and while working on the water pump do not forget to install a bypass tube where the heater hose would connect to the pump.....best done with brass fittings and a flexible copper pipe prebent on the workbench ready to fit in place.....

Now for the pictures....... look at the new higher location of the new pump which is better centered on the rad....

Happy plumbing!!!

[Bob Carriere]

These are off the web but shows well the adapter plate in question and once instaled using the (old I hope) pump housing as a guide.

I also discovered that the true "CMP" elbow fitting that bolts onto the head is cast with a small flat area......which gives a tinny bit of additional clearance for the crazy throttle linkage of the cab 11/12 I eventually had to fabricate my linkage as a custom fit to get good free motion...... You do what you gotta do!!!

Cheers

PS 6 blade fan came from a C15a water truck

[Bob Carriere]

one is a web picture the other composite came from Phil. W. site....

[Bob Carriere]

Original 216 water pump is equipped with inlet / outlet to connect a water heater inside the passenger cab...... it is highly recommended to install a bypass to facilitate coolant flow....... read it somewhere did not want to risk over heating the engine..... so used a rubber hose temporarily while doing short running tests than replaced with solid copper pipe.

[Bob Carriere]

216 vs 235...... the adapter plate lifts the center height of the fan blade about 4 inches.

[Paul Singleton]

Here’s a link to the plate.

https://davisspeedequipment.com/prod...adapter-plate/