The Stovebolt Site Forums The Shop Area Engine Shop 1943 Chevrolet Canada (CMP) - 261 from 1960

I have had a 1943 Chevrolet Canada C15A (CMP) for 3 years which I am restoring. The original engine for this truck is a 216 but this one has a post-war engine in it, a 261 from 1960. It has been partly rebuilt like re-flatten the motor head and new oil filter and lines. I still have some questions about the engine. One is about how to connect the temp sensor to the gauge. What is the size of the hole where to put in the sensor. The gauge is mechanical. I put some photos of the Gauge as a sample.

Hope you can help me with it and also hope to learn al lot from this forum.

Neat truck! You'll find the 261 makes that a much more driveable truck Somebody did you a favor.

Welcome to our site!

I know this is for the technical stuff (THE SHOPS) but you may get a kick out of checking in at the International Zone of the Side Lots. You Bolters from "out of town" have some unique perspectives and issues that only a "local" can help with.

Good job on doing your image attachments. Was impressed on the PDF even!! Way to go.

Welcome Chevrolet Canada

Agree with John that your truck qualifies as "Neat"! Also, you are not the only member with a C15A. There has actually been some recent discussion about some difficult to find steering tie rod ends for the C15A and looking for possible sources.

On your temperature gauge question, need to know if the gauge with sensing bulb (from your picture) you are looking to install is the one meant for the original 216 engine?

If yes, it is designed to fit the earlier 216 head probe opening. You will need an adapter fitting (usually brass) to fit that gauge bulb into the larger 261 temperature probe hole.

That adapter fitting is available on this side of the pond from a number of suppliers. Below are links to 3 of those sources:

https://www.napaonline.com/en/p/BK_7011798

https://www.classicparts.com/1941-54-Temperature-Sender-Reducer-Bushing/productinfo/24%2D811/#.UP9MwXy9KSN (must copy and paste this link)

https://store.fillingstation.com/detail/FS-1001/Chevrolet_19301962_TEMP_GAUGE_FITTING_IN_HEAD.html

Not sure if you have sources in the Netherlands for fittings with these specifications???

From what I have been able to learn, these fittings (normally brass) have an internal thread size of 3/8" NPT (National Pipe Thread) with a beveled seat that your existing probe/collar nut would thread down into, and the external thread size is 1/2" NPT (National Pipe Thread) which is threaded into the temp probe hole in the drivers side of the head towards the rear. Picture attached below to show older probe installed in head with adapter.

Hope this information is helpful.

Once again, Welcome!

Greetings from across the pond.\

********* last caution.....when fitting the adapters into the head of your 261////DO NOT overtighten the adapter....used liquid sealant of white teflon tape,,,,, you can actually crack the block you can never
a tell how much rust has weakened the inside of the water jacket you are screwing into.

Very nice cab 13. Your new registration to Stovebolt was brought to my attention.

You are very lucky to have the 261....which gives you about a 50% increase in horsepower and it is a direct bolt in...... exception being the water pump which needs to be a 216 water pump to save space.

Some general suggestion....... the ENGINE section is very good for motor related issues........ I am currently in the Drivertrain section trying against all odds to find a source for the tie rod ends....
Over the years I have learned a lot from Stovebolt members and still learning....... amazing how the web has shrunk the world.....

First of all I am a die hard CMP nut with a totally rebuilt cab 11, 1940 Chev.....purrs like a kitten...... You are very fortunate to be in Holland as you have the largest part dealer Stefan at LWD CMP Parts.
There are a lot of other CMPs in Europe and you have the best and largest flea market, gatherings that exist....... and do not forget your friends in Australia who were supplied by Candaina made trucks and USA vehicles.
Do a search for Maple leaf up and you will find the MLU Forum......... lots to read and lots to ask questions from.

First if you do not have one already get yourself a GM shop manual and eventually a parts manual MB-C2

Now on MLU you will find me under restoration.....The Hammond Barn....... and for ease of exchanging photos I will eventually give youo my personal email address....... I have thousands of pictures on the "Puter.........

This is not an attempt to short circuit the Stovebolt forum....... I tend to use both.... the more is posted on either Forums the more people will benefit from the now rare to find information.....

Lets tackle your first question of the oil gauge sender......... the problem started when the engine was switched...... the location of the oil sender/bulbis correct fromt he last photo you sent...howeever the odd thread size of the original 4 sided nut that hold the bulb in the head will not fit the 261 head and you need a brass adapter...... and it is not metric..... I will need to measure up what Ihave on my truck.

Another consideration is that the original army 216 had a special fitting in that location and itis referrd to as a steam line that connects to the filler neck or tank of your radiator. In very rough cross country driving up steephills and down steep slopes the head would sometimes develop steam pocket in the head at the rear section....... having that steam line allowed the steam to purge itself. Now yoour 261 has had some engineering improvements by GM as the drilled 2 steam holes between cyl. 2 and 3 and between 5 and 6 which was done for a similar purpose. On my 261 I did instal as steam line with t fittings etc. and added a quarter turn brass valve...... as a test.....drive around for a while with the steam valve closed...... then open the valve and watch the bubbles run to the radiator tank. I had installed a clear vinyl line for the test. Repeated the process and has the same results...so I concluded I was better to have one and installed a permanent steel line ( brake line tubing) to the radiator. I run a 160 thermostats and the engine Summer and Winter and never gets up above 165 F.

You may have some difficulties finding the proper British Imperial size brass fittings but I am sure that some of your fellow Dutch have already resolved that issue....... if not we can certainly send you some by mail. I can count on my fingers they items that are exclusive to CMPs ....such as the tie rod ends..... Master brake cylinders...... but in most situation we....the CMP nuts ... have found practical solutions.
Remember that the design was British....so overbuilt, super heavy and awkward to work on...... the production was a collaboration between GM and Ford........ so some of your brake parts are Ford... except for the engines which were unique to each almost everything else can be interchanged...

I will find pictures of how I connected my steam line...... and refresh my memory (failing) on how to post pictures. On the same picture you will see, no doubt, a very different carburator I am using a recommended YF Carter thanks to CarbKing...... and I have a rebuilt spare Zenith from a 270 GMC.

Hang in there..... from Canada

Bob C.

Some pictures worth a thousand words..... 3000 in French.....

just realized that none of the captions got attached to the pictures....

This picture was to caution you that the water pump on your 261 has to have a bypass line installed ....or risk damaging the engine.. The two outlets/ inlet were meant to accommodate the heater core in modern vehicles........ A rubber hose is fine while testing the engine but should be replaced with a solid copper pipe

So it works lets try again

Again as a word of caution....... the steering arm from the steering box to the steering linkage is a weak area..... after 80 + years worthwhile checking. The one pictured was brokenand rewelded....when I got the truck I replaced it ....... a short while later the one that I had thought to be in good shape broke just at the ball joint going into the steering linkage... I was testing the truckat low speed and ditched it on a snow filled ditch.... no injury or damage.........but on closer inspection the arm had a number of microscopic cracks...metal fatigue??? replaced with a tested one that was good.

So the next pictures are not as critical.....

Pictures of what I started with in 2004...... what I eventually got safetied and licensed and the finish product whizzing by my wife's camera cruising at a comfortable 31 Miles per hour or 2000 rpm.

some more on the steam tube....

About the steam tube...... notice that my truck is 3 years older than yours and the rad set up is different but you should have an "expansion tank" for coolant overflow on your pass. side fender or under the nose of the truck. I eventually installed one on my truck but had to hide ti fro view as the 1940 early models did not have one..... I used a S.S. hot rod tanks that was tall and slender and hidden in the side of the radiator/fender area..... it saves a lot of coolant leakage. All the temporary rubber tubing was eventually replaced by proper steel lines.

some more... air filter oil bath found to be spilling oil all over during rough wild rides.... now sporting a Chrysler slant 6 paper filter...works great fits great.

Lots going on there......first of all I sued the stock intake exhaust manifold of the 261.......however the engine compartment and engine cover was so tight that I had to remove the original 1959 GM truck vacuum fitting...... there is only 3/4 inch of clearance between the engine cover in the pass. side and the sheet metal get burning hot....kids getting a ride in short can be seriously injured. Not an issue in your model....... Originally the inside of the engine cover was lined with a 1/4 inch asbestos pad which was all carried away by mice for nesting.... so I cleaned what was left and installed a 1/4 inch of ceramic cloth.......... inside is still hot but bot skin burning hot.; Some of the plumbing I had done to fit the temporary steamline is visible.........

Next picture is the engine running at a fast 900 rpm during the earlystageofraod testing as a driveable self powered frame..... no body or license yet but I use my back field as a test track.
I have added a tachometer since...... I use a tach, oil pressure, temperature gauge and vacuum now permanently installed just below the cowling that carries the steering wheel. Not original but I like to see what is going on under the hood while driving...... I have about a 400 miles of back field running/idling and 700 miles on the new civilian instrument cluster that I eventually installed.

The next picture....lots of info....

The new YF carburator, I mean ebuild by a pro, model suggested by CarbKing....out performs the new army surplus Rochester carburator...... Rochester leaked everytime I did rough off roading and gas leaking ontop of a red hot exhaust manifold isnot good. It also has good response purrs like a kitten. The oil bath air was modifed based on Stovebolt postings...... found that the Chrysler 6 cyl. sland 6 iof the mid 50s fitted perfectly well within the original black GM box...... added some green foam for a tight fit....... engine loves it...... no more oil spilling over my clean engine while jumping logs.....

Onemore thign to notice..... remember my earlier picture where Ihad toget rid of the vacuum pickup fitting from GM ..... well I plugged up the hole with a brass plug...... then and made a 3/4 inch thcik spacer, copying the shape of the phenolic spacer...... then drilled and tapped the spacer for brass fittings for the vacuum gauge, the wipers, and for the line from the Positive crankcase valve tubing. The littel sectoin of red foam was to keep dirt out of the vacuum intake line that was connected to the side of the original 1959 GM truck air breather assembly.. I now have installed a slightly modified 216 valve cover which uses itsown small oil bath air cleaner as intake for the PCV system. Most original 216 valvecovers have been serioulsy abused and the nuts over tighten and distorted that they leak like an old bucket.

Solution by a new valve cover from China fully chromed....... makeusre it is a straight one.... sand blast the chrome finish lightly to make it satin finish and now the engine paint will stick real good. Call me crazy but the recommended GM grey blue paint in spray cans is not the real cololor tomy eyes....... so I use regulary available Ford six cyl. Bluel in engine hi temp spray cans........

Final issue,...... your steam line or just fitting the temp bulb of your new gauge may be a head ache. You mentioned that you had installed an "oil filter" on your engine..... did you use the original CMP GM oil filter installed on a bracket bolted to the head....... it is usually a headache fitting the sender in such tight proximity to the back side of the original oil filter bracket..... I really need to see your oil filter set up....... the 216 had a by-pass filter.... that could be removed... or in fact early engines did not have one and were retro fitted...... yoou can run a 216 without a filter but will burn your engine ifdriven extensively with out a filter and the oil ports plugged.

You should include in you next posting picturesssssss of the oil filter arrangement you have or propose to install on your 261..... also need to establish if your engine came from a GM truck and might have solid valve lifter ( you were lucky once maybe lucky again) or a car Pontiac or Chevrolet which would have hydraulic valve lifters and your oil filter set up maybe totally different

My truck engine has two large 1/2 steel line outlets and inlet just behind the exhaust pipe underneath the exhaust manifold..... or you may have two small 1/4 inch or 5/16 linecomng oout ofthe blcok at the same place going to a remote filter....of some sort.....


Catch a glimse at the plumber nightmare to fit the temp bulb into that location.....the bulb is actually within the coolant inside the T fitting..... after fitting the valve was removed and copied a steelline topermanentlly finish the set up.

On my truck I have piped my 2 large 1/2 oil lines to a bracket that accepts two PH-8 screw type cartidges full pressure filters..... those double filter brackets were used in the early 50's on hot rod race cars and are found used cheap at flea markets....... the bracket is installed vertical on the inside of the frame below the pass. seat....... totally invisible........ it provides additonal cooling of the oil and increases the capacity of the engine crankcase by about one and a half quart ( almost 2 lts) of nice clean oil.

Please do not be shy about asking questions as they arise... you are surrounded by good help with Hanno, Alex and others.

Here a picture of the cylinder head with the temp sensor I want to replace so I can use the original (repro) gauge.

Is this the same adapter fitting Gdads51?

https://www.prinstruckshop.nl/a-605...ture-sender-reducer-bushing/#description

This company is in the Netherlands.

Yes sir. Same item and I see locally available so no import fees and such.

Only thing will be to double check fit of the gauge probe collar nut to make sure no issues.

Both this adapter fitting and the probe collar nut are slightly tapered pipe thread which when tightened properly become self-sealing. No need for any added sealant.

Looks like we got this question if yours pretty much wrapped up! 😁

Hi Dan, I have already asked the seller about the size of the probe collar nut. Thanks for the tip!

Hello Bob C.,

Thanks for the info! Very nice truck do you have. You don't see this much in the Netherlands either.

I am already a member of the MLU forum and met Hanno last summer at a sale of CMP parts. It's a very useful forum with a lot of info. I used the thread Jordan Baker a lot because it's the same truck as I have. He put's a lot of pictures in his thread which I used as example. The books I have are the MB-C1 and 2 and the spare parts list.

I'll look up your "The Hammond Barn" on MLU. I think I've seen this before but I'm very curious. I am also curious about the photos.

You are lucky in having guys like Hanno, Alex and others in your backyard

Look me up on MLU sometimes.

Here are some pictures of the oil filter and the bracket that I mount on the engine.

Hello Bob,

Above you ask the following:

"Also need to establish if your engine came from a GM truck and might have solid valve lifter ( you were lucky once maybe lucky again) or a car Pontiac or Chevrolet which would have hydraulic valve lifters and your oil filter set up maybe totally different"


How can I find out which vehicle the block comes from?

A picture of the water pump and fan. I don't know what type the pump is. It's not the one what's on a 216 I believe.

Here a picture of the full flow oil filter mounted on the engine.

I had the hoses made at a local company that specializes in making hydraulic pipes. The original oil filter had thin pipes but I have read that this is not good for the engine.

Here's a better picture of the water pump that is currently mounted on the block.

The goal is to get the truck running first and then to install the right water pump and the original radiator. I managed to get hold of the original radiator a while back, but still have to find out if it leaks too.

Richard,

Before you go changing that water pump, take a look at member RAC1812's post here https://www.stovebolt.com/ubbthread...e-1943-chevrolet-canada.html#Post1483989 which has a picture clearly showing the 216 with a water pump looking very much the same as yours.

You might want to send him a PM to see if he can share more details about this.

Dan

Hi Richard

Will try to answer your ?? as they appear....... there is so much information and nice to know information that I am worried about covering all aspects.

First you have a commercial oil filter....full flow....usually found on large truck engine...... your engine block is drilled for the larger 1/2 inch oil lines.

Check for a serial number....on the flat ground surface near the base of the distributor.....post here and we can determine the year it was made.

Check the engine head.... same side as carburator...... serialnumber shouldread XXXX848...... if you are lucky it will be a 848 a better head for your engine.

Your picture of the head on a work bench..... as the engine been taken apart???? ....if so you may have casting date inside....same side.... that may tell you the date of the casting.....

Your filter bracket will need extra bracing or will crack eventually due to vibration..... you need a small welded side bracket near the base...like a 45 degree angle brace......

Have you found a source for replacing the filter element of your set up???

Do NOT try to start your engine without a oil filter connected or you will destroy the engine........ at ALL times you must have a connection between the two holes in your block....even it is just a temporary fitting with a short by pass hose......

My engine had a similar large filter but couldnot use it due to tight space in the engine compartment.....so I installed longer hoses connected to a dual screw on car filter that I bolted to the inside ofthe frame under the passenger side.

Here is an repro original oil filter set up on a 216 engine....

The filter is referred to as a by-pass filter.....only part of the oil is oushed by the pump into the filter and it drains back into the oil pan.....

Your filter is a "full flow" filter where the oil pumps ALL the oil through the oil filter and the clean oil is returned to the engien oil galleys to continue lubricating the bearings....a.k.a full pressure system.

Now for the Vater pump......

Is the 261 in the truck..... as it been running in the truck with the 261 and the existing 2561 water pump??????

Reason for asking..... the overall lenght of the 261 is looooonger than the 216 and the water pump needs modification.

Your 261 has a water pump partly inside the block and located higher on the block........ unless the radiator has been moved forward 3 to 4 cm......or the total engine moved backward.

Check the technical section of the forum library ofr detailed info.

Basically you have to remove your 261 pump and replace it with a 216 water pump with the aid of an adapter plate...... sounds complex but one step at a time and you get a finished professional installation.

While doing the plumbing check your thermostat...... worth getting a new one..... I run a 165 degrees Fahrenheit has the engien compartment on the earky cab 11 is very HOT.....

Care will be needed to insure your 3 pulleys align up properly...... and that they all match teh same width belt ....... early belts were 3/4 in. but your truck crankshaft belt will be modern and take 1/2 belts. in some cases we re install the 216 harmonic balancer to maintain same rpm of pump to crank ratio.....prevents cavitation and over heating.....

Here is a photo of my valve cover...... its a 216 valve cover made to fit the 26i with the military crankcase mini oil bath air breather needed for the PCV valve to function properly.

Now for the Vater pump......

Is the 261 in the truck..... as it been running in the truck with the 261 and the existing 2561 water pump??????

Reason for asking..... the overall lenght of the 261 is looooonger than the 216 and the water pump needs modification.

Your 261 has a water pump partly inside the block and located higher on the block........ unless the radiator has been moved forward 3 to 4 cm......or the total engine moved backward.

Check the technical section of the forum library ofr detailed info.

Basically you have to remove your 261 pump and replace it with a 216 water pump with the aid of an adapter plate...... sounds complex but one step at a time and you get a finished professional installation.

While doing the plumbing check your thermostat...... worth getting a new one..... I run a 165 degrees Fahrenheit has the engien compartment on the earky cab 11 is very HOT.....

Care will be needed to insure your 3 pulleys align up properly...... and that they all match teh same width belt ....... early belts were 3/4 in. but your truck crankshaft belt will be modern and take 1/2 belts. in some cases we re install the 216 harmonic balancer to maintain same rpm of pump to crank ratio.....prevents cavitation and over heating.....

Here is a photo of my valve cover...... its a 216 valve cover made to fit the 26i with the military crankcase mini oil bath air breather needed for the PCV valve to function properly.

A suggestion........ make sure you install a new or rebuilt quality water pump including the pulley....... too much trouble doing the same job twice.

Can we see some photos of the engine compartment.... both sides of the engine and whether the nose has been modified so you can install your newly acquired radiator.... make sure it is tested for 5 to 6 pounds of pressure not any more....... as your system is really running at O pressure but it helps to detect leaks and to run an overflow tank later.

My water pump as installed on my 261.....front view.....notice the 216 pulley and the adapter plate showing below the pump.......... last photo shows the little spacer to make the plate fit tight on the block.

Photo of an original cab 13 rad

Photos of a 261 pump to be compared with the second one for a 216

Also photos of the adapter plate

Front end of a 216 with two hole water pump removed.........

Water pumps are going for about $85 US dollars up to 145 currently on Ebay.

I would suggest you try contacting other CMP lover in Holland to find out where good prices fro good pumps can be had.......

Composite picture tells everything....

Don't forget the bypass tube.......EBay pictures

My grandson was asking me "What was a buckboard" buggy.......... as opposed to a dune buggy or a go Kart......

Here was my answer...... first drive under its own power in 2008.....notice the rear axle shafts are not yet installed but brakes do work....

Hello,

in answer to Bob's question; according to the data, it would be an engine from a truck. The block was made in Flint Michigan on September 16, 1960 and the head was produced on July, 22 1960

Here some pictures of the engine from different angels.

Last summer I found an original radiator for the CMP. One of the photos shows the radiator in question on the CMP it was on.

It looks like the radiator was manufactured by Chrysler.

Hi all,

I have question about the fan belt. What size is correct for the 261 engine I have? The engine is build in 1960.

Chevrolet Canada,

If your 261 has only the water pump and generator pulleys to run off the crankshaft, a web search I did says an "ACDELCO 17440" (commonly known belt size C50) should fit your 1960 261 engine.

That's assuming (yes we all know what that means - lol) that the generator mounting point and brackets on the engine are the original 1960 261 units and not something else.

Others will be along to add info or correct me if I have strayed on my advice.

Let us know what you find and works please and thanks.

Dan

EDIT: After going back and looking at earlier posts in this thread, did you add a relocation plate to the water pump??? If yes, that will cause the suggested belt to be too short.

Hi Dan,

Thanks for the info! I keep the same water pump and pulley. I had it adjusted by shortening the shaft of the water pump and the pulley by 4 cm. This way I create enough space for the radiator.

This was easier than adjusting everything and putting a different water pump on it