New CMP owner

Eastblock · #1 14-07-10, 19:05

Hi,
My name is Michael and I live in Harpenden, UK. I just acquired this 1945 C15A. It has a later Chevy engine and the radio box from an Austin K9. It runs OK but tends to spew water at full revs. I need to find out why. No history on it so far but I hope to find out more about it. It's my first WW2 vehicle so I'm thrilled to bits with it. I have a "thing" for Eastern Block vehicles and own a Gaz69M, Robur LO1801 and a Trabant. I also have an Uaz 452 but that must be sold because I bought the CMP.

malcolm erik bogaert · #2 14-07-10, 20:57

Michael welcome to the club....seeing that picture again makes me think it could be my old machine...we did fit many years ago a body from a Humber 1 Ton ex Otterburn Army camp to a chassis cab...could be the same truck...I will check out the registration number and see what I can come up with....I may have swaped this for a mint Gaz 69...small world indeed!cheers malcolm

Phil Waterman · #3 14-07-10, 22:43

Hi Micheal

About your water problem first question does you truck have an over flow recovery tank? Should be on the left in front of the side vent above the fender (non-visible in your picture) or on the left in the wheel well.

Cheers Phil

Eastblock · #4 14-07-10, 22:51

Phil, I'll have to check. Some changes were made when the newer engine was fitted. There wasn't room for the fan so it has a pair of electric fans mounted on the front of the radiator. I've read that it can be a pulley size issue making the water pump spin too fast. I only just bought the CMP so I have not had any time to tinker with it yet.

Phil Waterman · #5 16-07-10, 21:43

If it does have a tank check to be sure that radiator cap and all the connections to the radiator are air tight. If any of them leak air then as the engine cools the coolant in the tank will not be drawn back into the radiator.

Mismatching the pulley sizes can do a number on how the cooling system works. Take a look at my web site in particular http://www.canadianmilitarypattern.c...ifications.htm which shows what can happen with engine change mixing of parts.

The thermostat, can also cause the problem you mention, it needs to have a little by pass or the back of the block gets hot before the thermostat starts to open.

Take a few pictures of how the cooling system is set up. I sure the collective heads full of knowledge will help spot the problems. Then you make a list of the solutions and put them in order of easiest to hardest.

One other quick check is how thick is the core of the radiator. I've seen one with a Chevy car radiator instead of truck.

Cheers Phil

Eastblock · #6 25-07-10, 19:34

Here are some pictures. First one shows that there is no expansion vessel. That might explain why the water squirts out.

The bypass tube is kinked. That probably doesn't help

Anyone know what this plug does?

I need to get a hold of an air filer. Any suggestions where to get one?

Because the engine has been replaced there wasn't enough room for the fan. Two small electric push fans have been mounted to the outside of the rad but they a cheap, inefficieint ones. I'll mount a 16" Kenlowe instead. The rad istself is in good nick (no gunk in it).

Can anyone tell from the pictures exactly what engine I have? All I know is it says "Cheverolet" on the engine cover.

Hanno Spoelstra · #7 25-07-10, 20:14

Quote:

Originally Posted by Eastblock

this 1945 C15A. It has a later Chevy engine and the radio box from an Austin K9.

Hi Michael,

Welcome to this forum. That is a purposeful looking truck. Judging by its wheelbase, I think this a C30, rather than a C15A. The radio box must be very usable for camping when going to a show.

Regards,
Hanno

Eastblock · #8 25-07-10, 20:57

You are right about the wheelbase. I'll have to remember to measure it the next time I'm at the barn.

Phil Waterman · #9 25-07-10, 21:20

Hi Micheal

Your 1st picture showing the top of the radiator - shows the over flow pipe coming out the driver side, so I don't think the radiator is the correct/original CMP no mater if it works. Measure how thick the core is though so we can compare it to known good cooling CMPs might be under sized. A temporary fix for not having a coolant recovery tank is a gallon plastic jug with a rubber hose to the over flow tube and all the way to the bottom of the jug. Fill the radiator start the engine and see how much coolant is pushed out once the engine is war let it cool see if it sucks the coolant back in.

2nd Photo shows two things some one has put a by pass from the thermostat housing to water pump, this is not necessarily bad as it actually allows the water to circulated around the block and that way actually get the thermostat up to temperature. About the thermostat is there one? In the 2nd photo I can see the crank pulley but from the looks of it the water pump and crank are mismatched causing the water pump to turn much faster than it should which can cause cooling issues depending on which water pump.

3rd Photo that plug you circled is the temperature gauge sensor. Which instrument group do you have 5 gauges or single large unit?

4th Photo showing carb I've attached some photos of how I worked around this issue. Big oil bath like the original is my desired solution but what I've done for now keeps the dust and small animals out of the intake. The throat of the carb you have look larger than a CMP.

Hope this helps

Cheers Phil

Eastblock · #10 25-07-10, 21:47

Phil, the rad core is 35mm thick.

Here is a picture that better shows the size of the pulleys. If the pump runs too fast cavitation can become a problem. It does have a thermostat.

The engine may well have a larger displacement than the original engine which could explain the larger carb. I have been told that the truck came with this engine ready to install and that the original engine was not included.

I should add that it runs very well but previous owner has had issues with overheating.

Here is a picture of the instruments.

maple_leaf_eh · #11 25-07-10, 22:00

Quote:

Originally Posted by Eastblock

...

Anyone know what this plug does?

...

You'd be wise to seal up that 1/2 dia hole on the valve cover too. No doubt it spits oil and vents fumes to the atmosphere. My M38A1 has a rebreather tube from the crackcase to the air intake just to burn that particulate matter.

Eastblock · #12 25-07-10, 23:49

I have the elbow joint for the cover and will fit it once I've got an airfilter sorted.

Harry Moon · #13 26-07-10, 00:29

I'd agree with Phil that the water pump is cavitating with the small Pulley. Check out Phil Wattermans web site to see the differences in water pumps and pulleys. I can't say how often I have gone through Phils site to get on top of issues that come up. The motor in all likelihood is a 55-62 235 chevrolet.

Grant Bowker · #14 26-07-10, 02:07

Your temperature sender (circled in photo) is of the electric style rather than the original capillary tube design, not necessarily a problem since it looks as if some of the guages are also later replacements and the two could be properly matched.
You have said the engine is a later replacement, it is definitely NOT an original 216. It is a later 235 or 261. Indicated by the style of water pump, completely in/on the front of the block, not covering the block/head joint and also being inset in the block rather than completely on the front of the block. I am not sure, but think the unequal size pulleys may be normal for that style of water pump. Others can confirm. Also ndicated by the valve cover being held on by screws at the lower rim rather than 2 acorn nut on top. The Rochester B carb is consistent with these comments. Its smooth inlet is suited for the CMP slip-on air cleaner (compared to the later variants that were set up for an air cleaner held down by wingnut). Have you looked at www.stovebolt.com and www.inliners.org for engine information?

Bruce Parker (RIP) · #15 26-07-10, 02:29

Quote:

Originally Posted by Hanno Spoelstra

Hi Michael,

Welcome to this forum. That is a purposeful looking truck. Judging by its wheelbase, I think this a C30, rather than a C15A. The radio box must be very usable for camping when going to a show.

Regards,
Hanno

Note the 6 bolt rims, the narrow fenders, the wide channel under the driver's door and the vertical tow shackles on the front bumper. I think it's a HUP.

Bob Carriere · #16 26-07-10, 03:43

Hup rims..... frame looks smallish like a HUP......engine is at least a 235 late 50s or even better a 261...... that hole in the valve cover should be connected to the air filter inside the paper element..... my guess is a 1957-59 261 truck engine....... give away is the large 6 sided brass fitting on the intake manifold just below the carb......

See if you can read the serial number on the head just between the valve cover and the carb....

also..... just above and almost behind the starter motor.... see if you can find the "captain"s" bars...... two one inch long raised vertical bars about one inch apart....... just like the Captain's bar......

Best solution for the water pump is to go back to a regular cone shape... or flower pot shaped pulley that was there originally for the 235 or 261.....

Too bad you are so far away........

Try taking some pictures underneath of the front axle/rear axle to see if they are HUPs....

Also..... above the rear axle.... is the frame straight and horizontal or do you have a curve up on the frame over the axle......

Parts for the water pump may be hard to find inyour location but plentifull here in Canada.... shipping will be a pain but if we can help you just holler..

Boob

Bob Carriere · #17 26-07-10, 03:47

Can you read the serial number on the flat surface next to the distributor...stamped in the machined surface....

..... and how is the throttle connected between the gas pedal and the carburator........

I still think you may have a very desirable 261 truck engine....

Boob

Grant Bowker · #18 26-07-10, 04:09

Quote:

Originally Posted by Bob Carriere

Can you read the serial number on the flat surface next to the distributor...stamped in the machined surface....

..... and how is the throttle connected between the gas pedal and the carburator........

I still think you may have a very desirable 261 truck engine....

Boob

I wondered about that, but didn't want to say so because I saw that the oil lines to the filter were the smaller lines like the bypass setup rather than your large lines for full flow. The other puzzle is now the air filter that you say should be a paper element, were the paper element ones made for the slipon carb or only the screwdown carb? I wondered about the throttle linkage not passing just below the water outlet from the head, possibly removed for maintenance but I didn't see mounting holes when I first looked (I didn't notice 6 bolt rims so perhaps wasn't looking carefully enough).

Hanno Spoelstra · #19 26-07-10, 10:11

Quote:

Originally Posted by Bruce Parker

Note the 6 bolt rims, the narrow fenders, the wide channel under the driver's door and the vertical tow shackles on the front bumper. I think it's a HUP.

Yes, you must be right! But it had it's chassis lengthened, didn't it?

H.

Hanno Spoelstra · #20 26-07-10, 10:49

Quote:

Originally Posted by Eastblock

You are right about the wheelbase. I'll have to remember to measure it the next time I'm at the barn.

The 8-cwt and 15-cwt have a 101" wheelbase, the 30-cwt has a 134" wheelbase.

See http://www.mapleleafup.org/vehicles/.../chevspec.html for other specs.

Eastblock · #21 26-07-10, 19:50

My engine has the bars. The number stamped on the machined surface is F1031L.

The only picture I have of the underside is this one:

Thanks for the advice so far. It will be nice to find out what this "hybrid" really consists of. It only cost me £2500 and I'm not concerned that it isn't fully original. If it was the price would have been much higher I'm sure.

Bob Carriere · #22 26-07-10, 20:12

You have a desirable 261 cubic inch engine...... will check the serial number for dates...

....but you have HUP axles...... and probably a modified HUP frame......

Now don't let it worry you...... the truck looks good... and if it drives half as well ....just enjoy it.

Still puzzled how they got the gas pedal linkage from the right side to move the carb on the left side...... maybe a flexible throttle cable.....

Bob C.

hrpearce · #23 26-07-10, 20:31

Bob post #8 picture 3 shows the cable for the accelerator.

Bob Carriere · #24 26-07-10, 21:02

You are right Bob..... not sure I would want to trust a simple choke cable to stop and go traffic..... although I find the setup interesthingly simple.....

Now from the serial number of F1031L.... the engine is 1957 to 1961..... and decoding WILL require the casting numbers raised from the block..... should be 7 numbers like.....3769716...... seems that the serial number coding was abondonned after 1957 and you need the block casting number plus the serial numbers and possibly the head casting numbers (xxxx50)to sort out the puzzle.

Interesting vehicle......

Boob

Eastblock · #25 26-07-10, 21:15

I'm not too keen on that cable but mainly because it is frayed and the return spring is quite weak. The loud pedal is also very worn and wobbly so I'll have to replace it. The clutch uses Land Rover master and slave cylinders.

I don't mind paying for postage if I can get a suitable pulley for the pump from Canada. What diameter should it be and how would I get the old one off the pump?

The engine runs sweet and is mechanically very quiet. I read up on the history of it and was delighted to discover that it was designed by a Dane. I'm from Denmark myself.

I can make out some of the block numbers in a picture. It looks like 38368 and 5 or 7.

Eastblock · #26 26-07-10, 21:32

Looking at this it would appear I should have a much deeper core on the radiator.

Bob Carriere · #27 26-07-10, 21:56

Hi Michael

You will need to check that casting number.....should be 7 digits..... the begining of 3836XXX is the proper sequence for a late 57-58 261 engine....

As for the pulley I may have one sitting in the barn... we never use them because we usually change the water pump.... we use a 216 water pump with an adapter plate. Your water pump looks like a typical in block 261 water pump BUT the pulley has been removed and replaced by a 216 pump pulley. Now on a water pump there is a machined adapter that is pressed on the pump shaft..... then the pulley bolts on by 4 1/4 bolts onto the adapter.

Note that the bolt pattern of the pulley you have is different from the original 261 larger pulley. You would have to obtain not just the original pulley but also the adapter backing....... you woudl no doubt need an hydraulic press and some serious ehat source (oxy-acet. torches) to remove the existing pulley..... unless you have a fully equipped garage, I would take the pump to a competent machine shop to do the change over.

I will post some pictures from home of the 261 set up..... or you can check Phil Waterman's excellent web site for tons of pics.

Meanwhile check those casting numbers.

Boob

Eastblock · #28 26-07-10, 22:06

Located this on Phil's site. I guess I need a pulley like the one in the picture on the left.

We have a workshop by the barn where I store the CMP. There is a hydraulic press so getting the pulley off should be possible. As long as I can get a hold of the required bits I'll get it sorted. No parts came with the vehicle.

Seeing how big the pulley should be I'm not surprised the cooling systems isn't efficient. It must be making bubbles rather than moving water around.

Phil Waterman · #29 26-07-10, 22:16

Well I've tried to post a response, about the 35mm thick core twice and neither of them has posted so I'll try again.

Measured the core on the original radiator on my C60S it is 3 inches or 76mm thick. This radiator has no problem cooling the 261 engine with the original 7 bladed fan and using all the pulleys from a 216 engine.

I suspect that the 35mm thick core man just not have enough heat radiating area particularly if it is not being operated with antifreeze and 15 psi cap, if the radiator was designed as a pressure system. CMPs originally were not a pressure system.

Cheers Phil

Eastblock · #30 26-07-10, 22:26

My radiator does have a pressure cap but it does not state any value. I guess I'll have to get in touch with someone who can add a bigger core to the radiator.