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

[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.

8C0FA675-50A6-4040-B2D7-8E3A284B2F0A.jpeg

[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.

[Grant Bowker]

The question on the front mount is (like so many things) a little more complex than it may seem at first glance. Yes, Hanno's engine has the plate with the lower edge flange for mounting the CMP style rubber mount. I can't see if it is punched with the two square holes for the carriage bolts that hold the rubber mount in place. As long as the flange is there, it would be possible to drill and file holes for the bolts and have a functionally identical mount to the CMP mount.
For the style cylinder head shown, the CMP oil filter mount isn't a direct bolt-on. It is possible to make head bolts with an extended hex and threads pointing up to engage the filter mount - weld two bolts head to head (and since my welding was messy but strong, clean up the surplus).
Concerning timing gear lubrication nozzles, there are several styles and I'm quite sure (should confirm...) that there were two different size holes made in the nozzles to allow different oil flows.
For more information on the water pump relocation (using either a CMP pump or one that looks close to the same) to raise the axis of the water pump and fan to be better centered on the radiator, take a look on the Stovebolt forum - it comes up regularly:
https://duckduckgo.com/?sites=stoveb...er+pump&ia=web is their website search for "water pump"
https://www.stovebolt.com/ubbthreads...elocation.html
https://www.stovebolt.com/ubbthreads...ater-pump.html

[Bob Carriere]

You need to make sure the various pulleys you use are all the same width for the belt to run properly. Sometimes you need to find a wide pulley groove on a 216 Harmonic balancer to match the wide pulley of the pump and generator.

Is this for a cab 11/12......... if so as Grant pointed out the 54 dizzy is too big and the whole dizzy assembly needs to be changed.....Pertronix now makes a magnetic device to eleminate the points and condenser witihareal hot spark. On a cab 13 the larger 235 dizzy should fit...... using the 216 harmonic balancer and a 216 water pump pulley will insure the pump does not turn to fast and induce cavitation.

One more thing the water pump will usually have on the rh side an outlet./intake location that should be fitted with a by-pass pipe.....rubber is easy but the 180 degree ebnd will eventually crack.....better to install a 1/2 inch flexible copper pipe soldered to threaded brass fittings.

My experience has been to buy an adapter plate that once fitted allows to use a rebuilt 216 water pump with the two holes at the back.....it does require to drill into the engine block water jacket and tape but relatively easy if the engine is on a stand.

If you need pictures for my set up let me know....

Cheers

[Bob Carriere]

..... would be nice to retro fit a 216 valve cover and a new thick corkgasket.....

Kits containing the necessary longbolts and acorn nuts a readily available....

From my memory....some 1954 and only 54 trucks valve cover had slits cut on the top for air intake for the PCV or draft tube.... and will allow dust/dirt to enter the engine. They can be brazed shut from the inside but then you will need to install a small 216 oil bath air intake filter on the valve cover as per a CMP 216 valve cover..... or the engine crank case will develop a vacuum.