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

[Hanno Spoelstra]

This is a photo of a 1954 235 cu.in. engine.

What would it need to convert it to fit in a Chevrolet CMP?

Obviously it needs to be converted to RH drive: bell-housing and pedal linkage.

What else? Only repositioning of the water pump as per Phil’s instructions? Ref. https://www.canadianmilitarypattern....ifications.htm

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[Jordan Baker]

Make sure if has a front engine mount and not the side mounts. I do not remember what year the engines started using the side mounts.

You may also have to change the exhaust to match the engines exhaust manifold.

Otherwise I believe that is it.

[Phil Waterman]

Hi Hanno

As Jordan points out the front foot engine mount is needed. The front plate will swap from 216 to 235. Be sure to check on the cam gear lubrication nozzle, I have found them plugged or broken.

Now to the bell housing l had very good luck changing over clutch throw out pivot from left to right. Cut out for through side for the arm and then drill and tap for the pivot ball stud. As long as you have a CMP bell housing for measurement to copy not a big problem. In my experience the CMP bell housing should bolt up to 235 engine directly. You will need to check dowel per the manual. Also check that the transmission hole is truly centered on the crank.

On one of my conversions from 216 to 235 or 261 engines the centering dowel in the housing didn't match the dowel hole in the block. Strangely all of the mounting bolts did line up, I left the dowel out, torque all the bolts and nothing has move in 20 some years of driving.

I'll look for photos of the bell housing conversion.

Cheers Phil

[Grant Bowker]

I think it is covered on Phil's web info but care is needed to fit the throttle linkage across the front of the engine when using the water pump adapter plate. The commercial water pump adapter plate is made to fit 1942 or later water pumps that have 2 holes in their backing plate. The earlier plates (as used on all CMP as far as I know) had only 1 hole in their backing plate. I think I've posted on this but if you have difficulty finding let me know. The 235 is likely to have a distributor that uses a higher profile cap than the 216/CMP and it isn't quite as simple as just swapping the caps - better cap, rotor and distributor body ass a unit. Also, some people have concerns about early/late distributor gear to camshaft material compatibility.

[Hanno Spoelstra]

Thanks gents,

Looks like this one has the front engine mount, correct?
Sorry for asking, I don’t have my references at hand.

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[Jordan Baker]

Hanno, it does have the front mount so that is good.

The side mounted oil filter will need to be removed as well.

[Harry Moon]

three of my trucks are 1954 235's. water pump is perfectly situated but the pulleys and balancer should be swapped, not sure by your pictures if the water pump has a longer shaft but I haven't come across one that was different before.you do need to use the exhaust and intake from a 235 not the 216 and as always I recomend swapping the exhaust manifold for a set of Fenton cast iron duel exhaust. you can work out relocating the filter to the head bolts or delete it altogether.

[Bruce Parker (RIP)]

My understanding is that the block length and height are the same between a 216 and 235. The front mount is the same and both use the same bell housing. And since the bell housing also has the rear engine mounts it solves that problem. I agree with Harry that you need the correct RH drive bell housing which means you can also use an original transmission if you chose to. The only thing that may cause problems is if the water pump is too far forward and interferes with the rad.

It's a shame we live on the opposite sides of the ocean as I have a spare bell housing and transmission.

[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....