Chevrolet CMP Engine variants

[BSM]

The few engines we have been working on in recent times were all single hole, narrow cross section (front to rear top) models per attachment 1. The 3 engine we have acquired in more recent times are all 2 hole water pump models with a wider front to rear cross section per image 2. This then causes a problem with the throttle linkage from the former model as there is insufficient room to mount same. Can anybody shed some light on the variations please. Have we got hold of a few car engines?? One of the latter came in the C60S tipper chassis. Regards.... Rod

[Phil Waterman]

Hi Rod

Which Pattern are you working on? I've worked around the later design 2 port water pump on both and can take some photos of how it was done. Really not difficult, just some fabrication.

I've got the water pump and throttle link age apart right now on my Pat 12 so can take detail photos.

Cheers Phil

[BSM]

Phil thanks much for the quick response and yes please I would appreciate the images and any advice. Not being expert in the field of Chev. 6's this one caught us out temporarily. We have taken the test run engine (2 hole pump) from the tipper after a few repairs and it is now sitting in the No 6, Arty Tractor. It was not until we got to that stage that we realised that we had a linkage problem with the 2 hole water pump variant. From what you are saying am I correct in assuming that both 1 and 2 hole (water pump) 216 engines were used in Chev CMPs. Thanks again..... Regards.... Rod
PS: the third image is the 2 hole block in one of the other spare motors.

[Phil Waterman]

Hi Rod

First my understanding is that the 2 port version of the 216 engine is actually post war. But as the engines are otherwise identical you will find them as replacement engines in CMPs.

My solution to the throttle link is simple it that I fabricated a new cross shaft bracket that moves the shaft forward about 1 1/2".

This picture is of the stock bracket
W 41 Pat 12 Throttle Linkage modified 017.jpg
W 41 Pat 12 Throttle Linkage modified 018.jpg

This is of the fabricated bracket

W 41 Pat 12 Throttle Linkage modified 007.jpg
W 41 Pat 12 Throttle Linkage modified 008.jpg

You also make new lever arms but it is all done from simple materials. You also have to check the arm angle on the shaft to be sure to get full throttle swing. Also check your side engine bell crank that connects the link age up to the carb. Be sure that it is free and allows the peddle linkage to over swing with out trying to push the carb past full throttle. (Carb will break if this happens.)

Little difficult to post all the measurements on MLU if it would help I can post all the photos on my web site I took 40 some photos of the two throttle linkages.

There is also a slightly different approach if you are installing a 261 or 235 because the thermostat housing is different shaped and I'll post pictures of that version as well.

Now to the coincidences of you asking this question while happen to have the bracket out of the truck. I'm in the process of swapping out bent cab frame on my Pattern 12 for a straight one (thanks to Santa Bob for the straight cab frame) also trying to solve an engine over heating problem so the whole nose is off the truck. Also plan to swap out the 216 for a freshly rebuild 235.

But the coincidence is even bigger because earlier this week when I start the project I came in from the shop to find a private message from Alex van de Wetering asking a question about how to tell the difference from Pat 11 and Pat 12 Cab Frame.

The wonderful world of CMPs and MLU

Hope the information helps.

Cheers

[cletrac (RIP)]

Phil, I don't think there's any difference between the 11 and 12 cab frame but there is a difference between the 4x2 and 4x4 versions.

[Phil Waterman]

Hi Rod

Probably no difference between Pat 11 & 12, but there are differences between Pat 12 and 13.

Here are a couple I've noted:

• Length of cross shaft
• Drivers side lever arm is different length.

But these differences are pretty self evident when fabricating. Trying to this with the nose sheet metal in place is very difficult but with the radiator remove and nose removed on Pattern 13 removed or the center sheet metal panels on the Pat 12 off it isn't bad.


Cheers Phil