Pat 12 gets a nose job

[Phil Waterman]

Hi All

My `41 Pattern 12 C60L has been a long term project it has been on the road for a number of years. But the nose frame on the truck has always been bent despite using a porta-power the bend meant that things didn't fit correctly, and the right fender had been badly crushed. A number of years ago, Bob brought a straight cab frame and front fender down to the Weare Rally.

Well I finally decided it was time to swap out the cab frame and replace the front fender, the side of the originally cab frame was so bent that a good fender could not be mounted.

The other part of this project is to try and solve a chronic engine overheating problem. Which I think is being caused by crud in the engine water jacket, despite repeated flushing. This engine was a running replacement that can work all day at low gear with no problem. But try to drive it over the road at air temperatures above 70F / 22C and it would start boiling. I've had a freshly rebuilt 235 sitting on the engine stand so with the nose all disassembled seems like this is the time to swap the engines out.

Here are a series of photos from the first day of work.

w C60l Cab Work 001.jpg w C60l Cab Work 003.jpg w C60l Cab Work 006.jpg w C60l Cab Work 039.jpg w C60l Cab Work 049.jpg

[Phil Waterman]

New Cab Frame in place
C60l Cab Work 055.jpg

Bringing the 235 down on the elevator from the loft of the barn

w C60l Cab Work 057.jpg

235 Hanging on the leveling bar getting it ready to lift up to put in on an engine test stand.

w C60l Cab Work 059.jpg

If you have any questions about how something is mounted on a Pattern 12 Chev now is the time to ask.

Cheers Phil

[Phil Waterman]

Hi All

This post is in response to a question asked by Alex van de Wetering who happened to send me a message asking about part numbers or a way of telling Pattern 11 from Pattern 12 Cab Frame.

His message came in the day I was swapping out cab frames. I have not found any part number stamped on the cab frames. But it occurred to me that one of the major differences was Pat 12 have a hinged hood so the holes for the hinge and there location should be a give away.

So the photos below are looking down on the top rail of the cab frame, with a tape measure stretched from one end to the other.

Pat 12 Cab Frame 003.jpg

The center of the top frame is at inch 26 the driver side hinge outside mounding bolt hole is 16 inches in from the end and the other 18 inches

Pat 12 Cab Frame 004.jpg Pat 12 Cab Frame 005.jpg Pat 12 Cab Frame 006.jpg Pat 12 Cab Frame 007.jpg

Alex I hope this is of help, because otherwise these are probably the dullest photos I have ever posted, not photo contest stuff.

Cheers Phil

[Tony Wheeler]

Originally Posted by Phil Waterman

This engine was a running replacement that can work all day at low gear with no problem. But try to drive it over the road at air temperatures above 70F / 22C and it would start boiling.

Sounds to me like a partially blocked radiator Phil, perhaps from the crud in the water jackets getting into a few tubes. You'll soon know when you swap the motor.

[Phil Waterman]

Hi Tony

I've look at the radiator with an IR gun to see the change in temp across the radiator, left to right and up and down on both sides of the radiator (You can only do this on the test stand without the fan mounted) fairly consistent readings left to right. and a good 20F-40F degree delta from top to bottom, moderate airflow from a fan.

Reason I thing it is trash and crap in the water jacket, is when I removed the water pump and look in there was an acorn. Then when I started pushing a tube probe into the block and head with vacuum attached kept getting sandy or rusty grit out of the block.

I've got the radiator mounted on the test stand with the 235 engine so tomorrow I'll start doing some run tests with airflow and see if I keep getting a good delta temperature drop across the radiator.

Will say one thing about 235 it has hydraulic lifters and boy is that a quiet engine without a fan mounted. The loudest think is the mechanical fuel pump which I've bye past for an electric one.

One thing I am going to check is the thickness of the radiator as compared to the Pattern 13.

With the 235 or the 216 I have noticed one thing you need to have a bypass from the thermostat housing down to the pump housing because modern thermostats don't have enough bypass to allow the hot water to actually get to the thermostat to get it to open. Also these engines I think originally had 140F thermostats which are no longer available the lowest being 160F.

On the test stand I have one temperature gauge reading the normal position at the rear of the block and another in the pump housing reading the return temperature. Then I use the IR gun to read the temp at the top of the radiator and the bottom.

If this radiator doesn't work I'll order a aluminum hotrod radiator.

More to follow.

Cheers Phil

[Tony Wheeler]

Very interesting post Phil. I had similar issues with my F15A when I first put it on the road. It was mid summer and the radiator kept boiling. I tried four different radiators before I found one that worked satisfactorily. Some of them worked on the flat but they boiled uphill. There's a long hill near my place where I could test them, using a digital thermometer probe in the top tank. The one that worked best has been recored at some stage, with the usual thin core seen on recored Ford CMP radiators. The others had the original "tropical" core, which is much thicker, having an extra row of tubes across the front.

Naturally I examined each radiator before fitting them. The tubes appeared to be clear, insofar as I could see them through the filler cap hole. I tested them for leaks by plugging the bottom outlets (using small lemons off my tree) and filling with water, and when I removed the plugs the water gushed out under gravity, which would seem to indicate no major blockage.

In the course of this radiator swapping I decided to test the flow through the system, by running the motor with the top hoses disconnected and the radiator level maintained via a 3/4" garden hose from the tap (there are no thermostats in this motor). I don't know how much it's supposed to flow but it sure pumped out a lot of water at around 2000 rpm. It gushed out in front of the truck through both hoses and the garden tap was flat out keeping up. The water pumps are brand new and have the improved impeller design, ie. helical vanes instead of the original straight vanes.

Based on these tests I'm satisfied that the radiators are all clogged to varying degrees, despite appearing to drain quite rapidly under gravity. Your IR gun may pick this up, although if the tubes are randomly blocked I suspect it may not, as there are multiple rows of tubes which may average things out from side to side. Also if they're all partially obstructed, or most of them, the effect would be the same. I guess that could result from small particles of rust lodged in the tubes, or perhaps a coating of residue internally, although chemical flushing should remove that if done properly.

One thing I've noticed is that the recored radiator has much larger tubes than the original ones, which are flat and thin. Obviously these would be far more prone to blockage/obstruction, and would also flow much slower. On the other hand they allow more airflow, which is also a factor in cooling efficiency. However if you look at modern radiators you'll see they have large diameter tubes, so I imagine these are an improvement.

That said, we know these CMP cooling systems worked in hot climates during the war, often in heavily loaded trucks grinding up long hills at full throttle. I'm told Fords had a reputation for boiling sometimes and Chevs were preferred in this respect, so you shouldn't haven't any boiling problems in New Hampshire with the stock Chev radiator, even on peak summer days. Which brings us back to your present problem!

Let's consider the physics. Boiling is caused by one thing and one thing only - insufficient heat loss through the radiator. Heat input is determined solely by the rate at which fuel is being burned. It can't be increased by blocked water jackets, because they're not generating heat energy. Only combustion gases can introduce additional heat energy to the coolant, via a leaky head gasket or cracked head. Blocked water jackets may cause overheating of the surrounding metal, but they can't add heat energy to the system. All very obvious of course but worth covering nonetheless, as it helps us to focus on the real problem, namely heat loss rather than heat gain.

Heat loss occurs through the radiator and is a function of coolant temp and flow rate, cooling air temp and flow rate, and heat exchange surface area. We're not concerned with cooling air temp and flow rate, and we've fixed the coolant temp at say 170F, which leaves only coolant flow rate and heat exchange surface area. If all the radiator tubes are clear, then the heat exchange surface area is maximum, so the problem has to be insufficient coolant flow rate. Obviously if the radiator tubes are clear it has to be in the block! It seems unlikely that all the water jackets could be so badly blocked as to restrict coolant flow rate sufficiently to boil, but if the acorn was restricting the flow out of the water pump it could conceivably be the problem on its own. At that point in the system the effect on flow rate could be similar to a partially closed thermostat. Not having seen its position I'm unable to judge.

Alternatively, if some of the radiator tubes are blocked, then obviously the heat exchange area is reduced proportionately, and also the flow rate. That's the usual cause of overheating, however there's usually no acorn in the block to consider! Of course, it could also be a combination of these factors - acorn, partially blocked radiator, and badly blocked water jackets. If that's the case, then the radiator may be adequate with the new motor after flushing, and it won't be subject to subsequent blockage from crap in the block. Whatever the case I'd persist with the Chev radiator myself, even if it needs recoring.

I look forward to future instalments. My blitz mate down the road is putting a 235 in his C15A project so I'll post some pics when he gets to that stage.

Cheers,
Tony

[Phil Waterman]

Hi Tony

Interesting thoughts on cooling issues, takes a bit of careful thinking to nail down the causes and issues. Agreed with what you are saying but still trying to figure out what is going on with my Pat 12.

Concerning flow testing, when I did the water pump conversion on the 261 engine before putting it my C60S actually did flow testing both with the stock 261 water pump and with adapter plate and the 216 water pump.
261 eng water pump 03.jpg
Set up the engine test stand with a large tank at level of the standard radiator so the water came out the top outlet and dumped into the tank with 22 inches of standing water in the tank same as the radiator. Of course with the thermostat installed the flow rate is control by temp and RPM. Results with the two water pumps came out almost identically so it probably the thermostat throat that controls the flow rate. The at 500RPM flow is 2-10 gallons per minute at 1000RPM flow rate is 8-20 gallons per minutes.

After two hour long test cycles to day with the 235 I'm getting strange results. I have two water temperature sensors one in the normal location at the rear left of the block and the other into the water pump housing. At 500RPM the engine seems to stablize with the rear reading 170F and the return reading 150F good 20 degree delta for the radiator. But when you bring the engine up to 1500RPM rear is reading 170 and the return is reading 170. To further confuse things though at 1500PRM the water going into the at 200-210F (read with IR gun) and returning at the bottom of the radiator 198-175

The other thing that was going on during these test was the air temperature in the shop went from 74-80F.

I knew there was a reason normally do engine testing and break in running in the winter heats the shop up nicely.

Will have to figure out how to display the data so you can take a look.

Cheers Phil

[Bob Carriere]

When you're hot you are hot.

How can you tell if it is the engine that is being overheated by a plugged passageway or the radiator that is not flowing in all tubes.

I would try to test the radiator with a known temperature water going in and measure the delta.... actual drop in water temp..... and by this I mean off the engine completely...... but may be cheaper to run it to the rad shop to have it boiled out and the tubes rodded which means taking(unsoldering) the top and bottom tank off.

On the engine...... without taking the engine apart.... would it be possible to remove the water pump, all frost plugs, temp sensor and drain petcock and flush and fish in there with a coat hanger and/or pressure washer until all that flows out is clear...?

How worn out are the impeller blades on your water pump..... I have seen even rebuilt pumps with very eroded impeller blades.

Can the engine be run with no rad but with a garden hose with controlled flow X amount of water volume and measure water temp going in and going out at various RPM...... hard to simulate load on the engine without some braking device on the output shaft......

On the other issue raised by Alex...... in the Chev parts manual dated Jan 1941 they list the cowl as a separate part from the ARCH BARS...... and the cowl is common to all sizes of cab11/12...... on the other hand they also list the ARCH BARS right and left ( confusing because to us restorer they are all the same once welded to the cowl angle iron) and shows that the arch bars are all the same part number for RH and LH for all C15, 15a,30, etc. size trucks....BUT the C8 has a separate part number which would reflect it own peculiar BAR shape due to the different frame, steering configuration, etc.

I have two sets of C15a spare arches at the barn ....... I could not find any numbering on them at all.... mind you all are rusty.

Phil .....US radiator makes an aluminium rad that is a copy of the cab 12 and includes the off set 90 degree filler tube.... only issue with the AL rad is you will need special coolant compatible with AL...... U tube has a few clips on their manufacturing process and they sell regularly on EBay.

Good luck.

Bob C

[Tony Wheeler]

Originally Posted by Phil Waterman

Results with the two water pumps came out almost identically so it probably the thermostat throat that controls the flow rate. The at 500RPM flow is 2-10 gallons per minute at 1000RPM flow rate is 8-20 gallons per minutes.

After two hour long test cycles to day with the 235 I'm getting strange results. I have two water temperature sensors one in the normal location at the rear left of the block and the other into the water pump housing. At 500RPM the engine seems to stablize with the rear reading 170F and the return reading 150F good 20 degree delta for the radiator. But when you bring the engine up to 1500RPM rear is reading 170 and the return is reading 170.

Phil, you won't detect any delta once the motor speeds up with the thermostat open, because the water passes through the radiator far too quickly to cool down measurably. At normal flow rate it's only in the radiator tubes for an instant, you'd need quite sensitive equipment to measure the temperature drop from top to bottom. The cooling system relies on the huge volume circulating every minute, so it only needs to cool down a few degrees through the radiator.

We can do a rough calculation based on your 8-20 gallons per minute result at 1000 rpm, choosing say 16 gallons per minute, which is 16 x 3.8 = 60 litres per minute = 1 litre per second. I don't know what the total volume of all those skinny tubes would be, but if we estimate it to be 1 litre, then the water passes through in 1 second. It just won't cool down much in that time, esp. stationary with modest fan rpm. Different story at idle when the thermostat is closed and you're only getting 2 gallons per minute flow. That's 8 times slower, which means the water spends 8 times longer in the radiator, ie. 8 seconds by this calculation. That would account for your 20F delta at idle.

Of course, the delta will also be greater at speed when you're getting maximum airflow. We can do a rough calculation based on a CMP at cruising speed, let's say 50 HP engine output. Petrol engine efficiency is about 25%, which means there's another 150 HP being lost in heat. About half goes out the exhaust and half into the cooling system, which means the radiator is operating at 75 HP (x 0.746) = 56 kW. That would heat your workshop nicely Phil, and it also explains why the engine cover gets so bloody hot!

56 kilowatts = 56 kilojoules per second, and since the specific heat of water is 4.2 kilojoules/kilogram/degree Celsius, and a litre of water = 1 kilogram, the delta will be 56/4.2 = 13 degrees Celsius. However...that's based on our 1 litre per second figure, ie. 16 gallons per minute, which applies to 1000 rpm. If the flow rate is 3 times higher at 3000 rpm, the delta will be one third, ie. 13/3 = 4 degrees Celsius. Also, if the volume of all those skinny tubes turns out to be 1/2 litre, the delta will be halved, ie. 2 degrees Celsius.

It's a fascinating experiment you're running Phil, I don't think I've ever seen it done before, and it gives a lot of insight into how cooling systems work, esp. the thermostat. We tend to think they're only for cold start up, but in fact they're constantly varying the flow rate. It would be interesting to set one up in a perspex tube instead of the housing, so it could be seen operating. It would also be interesting to have a delta gauge on the dashboard, I'm not sure what earthly use it would be but the same could be said of vacuum gauges!

[Phil Waterman]

Hi All

Have you ever taken a Chinese Puzzle apart an had problems putting it back together, well I'm convinced the Patter 12s are more challenging.

With all mechanical work done I'm finally finishing reinstalling all the body panels on the cab and was just about done when I discovered that the last two panels could not be installed because other parts are in the way.

So here is a tip I learned then forgot then learned again the hard way.

For those of you who are working on Pattern 11 and 12 Cab CMPs remember the order in which the various body and panels are removed. Many of the panels and parts can only be assembled in one sequence. If you don't follow the same sequence that they were removed you suddenly discover that the last panel or part will not fit with out removing other parts.

In particular the inner fender wells and the engine side covers are problematic.

Once you have worked on worked on Pattern 11 & 12 you realize how much of an improvement the Pattern 13s were.

Next time I disassemble the cab on my Pattern 12 I plan to have a paint pencil in my pocket and plan to number each part as it comes off.

Cheers Phil

[Bob Carriere]

HI Phil

I am currently going through the smae frustration. Grants keeps laughing at me for putting on 2 pieces remove one installing two more and then thebolt hole do not line up.

Fortunately I have other less molested cab 12 to refer to. Yes ...... their is a specific order to installing the sheet metal andnow I think I know.

First of all the 3/16 floor panels that have been in place for years have to be loosened up ....only to realize that the nice hole I cut into the floor plates for the 2 speed T case was too tight and gave me no flexibility at all...... so I removed about 5/16 of an inch on two sides and that made a whole difference. Having removed all the sheet metal panels previously installed Grant and I started to pull, pry with alignment bars and tapered punches and in some cases with 4 inch long bolts to pull everything together...... now all of this work is ONLY for a trial fit..... it all has to come off for the official 5/16 domed slotted fine thread screws...... and also to fit the antisqueak/rattle tape on all metal to metal surfaces.

I don't know how you do it all alone particualrly some fo the frame/floor bolts as I was glad to have Grant work the top side while I crawled underneath to hold the other end of the bolt/nut. Your name did come up many time deuring the difficult fitting.

So it is round bulding inner fender, front inner panel, then remove half the inner fender bolts and do the top inner foot well,....oops forgot to insert the front fenders at this point......yeck !!! then the nose vent panel without forgetting to install the funnel and short peice of duct macterial then over the radiator cross piece then the outter nose panel..... and that is only for one size.

Now I do have a few bolt holes I cannot instal a bolt as the fender support bracket is now in the way.... not sure I can take ther backet off now... and all of this is for one side only..... and the engine cover has to be remembered...

I am sure I will have to remove some panels to get this job done.

Wish you where closer Phil.

Cheers

[Bob Carriere]

Chinese puzzle....

Holly manure...... now I can't post pictures as the system says I need "security tokens" and I think Bill Alexander bought them all last time he had to post pictures.

Any one has a nickle for me to buy a security token???

UN - Cheers

[Ian Johns]

I guess I have lots to look forward to with a cab 11 and 12 to do.

[Bob Carriere]

Lots of pictures Ian...... and then some more.....before...during and after.....
None of the shop manual gives you those details.

Cheers

[Phil Waterman]

Hi Guys

I've been trying to learn how to upload video to YouTube and here is the first test. What I was trying to show was the process of double clutch shifting but what is here is a shorter video from this morning.

Here is the link https://www.youtube.com/watch?v=PCX3...ature=youtu.be

Cheers Phil

[Bob Carriere]

A pleasure to see a pro at doouuble clutching both in the upshift as well as down shifting.

Now for the general comments...

Looks like you were driving in the narrow streets of Europe...

seems like you were going really fast but could not read the speedo...

...and no wonder you were cold you forgot to put the top on...... and you worry about the draft coming from around the pedals and steering shaft.....duh!!!!

Are you using a Go Pro???

Joyce's comments on seeing the new coat of paint was....WOW !!!!!

Cheers

Bob C

PS///do you need any particular measurements for the pass. side engine panel...? Or I could send you mine next week for the UPS store in upper NY.

[Mrs Vampire]

Those Gear changes are sweet even a nice down change....

How fast were you going it looks Montecarlo F1 from the video

[Ganmain Tony]

Phil that is fantastic! Really terrific to be able feel like I was in the truck with you.

She is running like a swiss watch and clearly has an excellent operator behind the wheel.

Really enjoyed getting a tour of the town - is that part of Temple you were driving through?

Beautiful part of the world where ever it is.

Congratulations on a big effort.

[Phil Waterman]

Hi All

To Bobs questions - Video is next town over, streets are narrow and actually in the main part of town were made narrower a couple of years ago as a traffic calming effort. The speedometer only goes up to 30MPH and then stops, probably a dead bug inside. Speedometer may not be accurate anyway as this truck originally had the 16 inch rims which have been replaced with the 20s you brought down for me years ago.

Yes the video is shot on a GoPro I have a lot more video to edit down and make a couple of videos out of. One problem I'm having with YouTube is extremely slow up loads, got to check my computer and internet connection to figure out why.

Gina- yes this transmission shift very nicely now, before I replaced the clutch plate and got some sticky stuff of the pressure plate during the recent work it shifted horribly because half the time it would not disengage completely. The clutch was so unpredictable once the truck was in second gear it was often just as easy to not use the clutch shift, instead just use the throttle to load and unload while going through neutral.

Tony- This particular video is driving around in the Town of Peterborough, NH which is the Big town near Temple, NH where we live. I've got some really good video of driving around on the back roads of Temple which I will try and upload.

Like having the Pat 12 without the roof, call it my 3 ton roadster. The truck drew a lot of attention at the car show that I was going to in the video. I have before, as found pictures of the truck along with a lot of photos from the Australian Archives, they're mounted in plastic sleeves with magnets put them on one side of the truck. People find them quite interesting.

Cheers Phil