Pat 12 gets a nose job

[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 Tony

Your giving me some interesting things to think about with this which is making it into both an interesting test but a quest for more information. I'm rethinking my testing logic and data collection methods. One thing for sure next test will set the Go-Pro Camera to capture the engine instrument panel through the whole test. Need to move it closer to the instrument panel this next time, so the gauges are easy to read.

vlcsnap-2014-06-24-17h46m17s34.jpg

At the end of your post you said " 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"

Your comment about being able to see the thermostat in a prespex tube how about thisl
Clear View.bmp

Here is their web site https://coolviewthermostat.com/ not sure I want to spend that much for a single test but it would provide an interesting diagnostic tool. I just check and they have one that fits 216 https://coolviewthermostat.com/products/chevy-products/ and they have ones that fit the Ford Flat Head.

Here is the first round of data collection for this test
Test Data June 20 2014.JPG

I'm going to do one more engine flush on the radiator tomorrow then do another round of testing.

Bob, your thoughts on cleaning are running along with mine. I did back flush the radiator with it upside down but surely did not reach the flow rates my flow test (on the 261 at 1000RPM) showed of 20GPM. Had thought about mounting the radiator upside down running the engine but with no way of catching any trash that might come out decided that might be counter productive.

One of the things that running the engine from cold to full hot showed was the value of the coolant recovery tank over a Half Gallon of water goes out into the tank and is drawn back in as the engine cools.

Cheers Phil

PS In the 1990s worked on a couple of large Co-Gen setups for hospitals we were using 545 Cat engines which put out a lot of heat at full power, the system was recovering the heat from both exhaust and from the cooling systems and using the heat to heat the hospitals. As owners rep on the project part of my role was to make the various engineers and suppliers explain how the system and components worked. If they could not explain it they generally did really understand it themselves.

[Tony Wheeler]

Originally Posted by Phil Waterman

I'm rethinking my testing logic and data collection methods.

Phil, I think what you're doing is fine. That's really good data you've collected, it tells the whole story when it's plotted. You can see the thermostat opening at t = 10, then the radiator works perfectly for the next 20 minutes at idle, but when you increase the revs the engine temp starts to soar, giving every impression it would boil if you continued. Perhaps you could let it go a few minutes longer next time and see if it boils. It can't hurt the motor provided you switch off immediately.

09-12-1949_06531-Aanrijding---Flickr---Photo-Sharing!.jpg

There's only one improvement I can think of for this test regime, and that would be a coolant flow meter. It would be very useful to know what the flow rate is doing in response to RPM increase, because it would tell us if the radiator is partially blocked. The temp graph doesn't tell us much there, because although it shows a huge drop in delta when the revs increase, which indicates greatly increased flow rate, it doesn't mean a great deal if the baseline flow at idle is being restricted by the thermostat. We need to know absolute flow, not relative flow, and only a flow meter can tell us that. They're dirt cheap nowadays, eg $57 US for 1.5" diameter: http://www.aliexpress.com/item/Free-...572166866.html


On the subject of flushing radiators, I recall using a kit back in the '70s which had a tyre valve on the hose fitting, the idea being to introduce a burst of air into the backflush flow to help dislodge particles. I don't know if it's still done that way but it makes sense to me. However I only used it in a servo for routine servicing, so I don't how effective it would be on a problem radiator. I haven't had much luck clearing blocked radiators over the years, despite using some very savage chemicals at times. Last year I put a whole bottle of phosphoric acid in a blitz radiator and left it for a month! It was bright green when I emptied it out but when I stuck it back in the truck it made no difference. You'd think by now there'd be a chemical on the market specifically designed to dissolve that brown stuff that clogs radiator tubes. Unfortunately it seems mankind has yet to come up with a way to unblock long skinny tubes except by poking things into them. In that respect we don't seem to have progressed beyond the monkey poking sticks into ant holes.

I was amused by the Coolview thermostat, I thought only someone like me would think of something so weird! I love it as a dress up item and it would be very instructive to see a thermostat working, however apart from that I don't really see the value. My query would be replacement thermostats, ie. do they sell the thermostat separately or do you have to buy a complete new unit.

Look forward to your next data set Phil.

[Phil Waterman]

Hi Tony

Your graph came out giving more information than mine because of the way you ordered the data to be graphed. Did you have to type all this data back in because or did you capture from the picture? (Will add a photo of location of measurements)

Well this afternoon, did flush the radiator with radiator cleaner, because of the right angle filler neck you can not see in to see if it really cleaned. But what came out was nearly clear. The engine had been hot tanked when it was rebuilt so it was clean inside.

As to air burping radiator while flushing, yes I did this when back flushing the radiator upside down. Shop vac to what would be the in pipe water to the out pipe and a flex tube fed in through the drain cock hole with the engine upside down ran the water at full tap flow in and kept moving the flex tube in and out of the tank so that it would move the stream of bubbles around no crap came out.

Ran the engine for nearly an hour today. Air temp in the shop when I start was 80F/26C (hot day here) very quickly the shop air temp jumped to 90F/33C. Ran the engine for 30 minutes with the cleaner in then 30 minutes with drain out and cold tap water going into the top tank to make up what was coming out to clear the flushing agent out. Running the engine at 2000RPM it climbed to about 190F and on the water jacket sensors and about 205 on the top tank with IR gun, but no higher.

Interesting to watch the temp gauges with the engine not running but the blower fan still on the engine continues to circulate, thermosyphoning causing good circulation. (to insure some flow with the thermostat fully closed I have added an 1/8" hole to thermostat body.)

Was going to do more testing but by then I was pretty well cooked standing around in the hot air blast coming through the radiator.

Think the next step will be to finish the conversion of water pump from the low mount position to the high mount to match the original fan location.



More details on pump swap from doing it on the 261 http://www.canadianmilitarypattern.c...ifications.htm

Looking at these photos, it reminds me that I need to check the pulley sizes back to the original engine on the Pat 12 engine just to be sure that in the process of swapping out the original unusable 216 engine for the one that is in it now that I didn't in inadvertently mess up both the water pump and fan speed.

Ah the mysteries of CMPs.

Thanks everyone for taking time to read this thread and add thoughts and suggestions.

Cheers Phil

[Tony Wheeler]

Hi Phil

I haven't learned how to split posts on MLU so I'll have to do it manually:

re: Your graph came out giving more information than mine because of the way you ordered the data to be graphed. Did you have to type all this data back in because or did you capture from the picture?

Something else I haven't learned is how to use chart functions on MS Excel. I'm still using the old school method - graph paper! Other times I just use plain paper and construct my own axes, which means using a ruler to mark scales and plot data, but for presentation I do it on MS Paint, using the cursor pixel position instead of a ruler. It means using a calculator to convert figures to pixel position, but I'm pretty handy with a calculator so it's a very quick method, esp. with my scientific calculator which stores data. I've had it for 20 years and I'm always using it for something or other, in fact I rarely leave home without it! It's a bit tragic, but I'm one of those people with numbers rattling around inside my head all the time! I daresay you can relate to that Phil. Unfortunately though I don't have the patience or aptitude to learn computer programs, and unless I use them regularly I soon forget.


re: Running the engine at 2000RPM it climbed to about 190F and on the water jacket sensors and about 205 on the top tank with IR gun, but no higher.

That's very encouraging Phil, hopefully it will do the job on the road.


re: Interesting to watch the temp gauges with the engine not running but the blower fan still on the engine continues to circulate, thermosyphoning causing good circulation.

I hadn't realized you were running a constant speed blower fan, I had assumed the engine fan was fitted. That's why I was disturbed by the temperature spike at 1500 rpm. It's a good idea though as it allows you to load up the cooling system. If the fan was fitted it would just maintain a steady 170F, which doesn't tell you much.


re: I need to check the pulley sizes back to the original engine on the Pat 12 engine just to be sure that in the process of swapping out the original unusable 216 engine for the one that is in it now that I didn't in inadvertently mess up both the water pump and fan speed.

If the radiator is in good condition you may find you can get away with the larger pulley, which would be highly desirable in terms of fan noise. However I suspect it may overheat in summer, because it's reducing not one but two variables, ie. fan speed and water pump speed as you say. It would be an interesting experiment though.


re: If the radiator is big enough there will be a delta change and should be a delta. There is also the obviously, as Tony points out, a speed through the radiator at which fluid is moving to fast for heat exchange to take place.

As you say Phil there HAS to be a delta, and there always WILL be a delta. However, my reference to high coolant speed through the radiator core was not to suggest it's a bad thing, but merely to indicate the difficulty in measuring delta when the value is small. That's actually a GOOD thing. Believe it or not, the aim with radiators is to MINIMIZE the delta, which is done by MAXIMIZING the flow rate, so the coolant spends the LEAST possible time in the core. This is why our brain hurts when we try to get our head around cooling systems. It's entirely counter intuitive, because we've learned from everyday experience it takes time for hot water to cool down! However, it's the RATE of cooling we need to consider, because it needs to keep up with the RATE of heating in the motor. We need to forget about TEMPERATURE LOSS, and think about HEAT LOSS, which is a different thing altogether.

I'll try to elaborate in a separate post, or maybe even start a separate thread, as it's highly relevant to flatheads.

Cheers,
Tony

[Phil Waterman]

Hi Tony

Going old school on graphing the data makes it even more interesting.

Agree on splitting the thread to put the cooling system discussion in one thread and the rest of the nose job in another makes senses, will see if I can figure out how to do it.

Worked yesterday and hope to finish today the water pump conversion. The directions with the conversion plate spend a lot of time on the fan/water pump speed. When I did this conversion on the 261 I did run the engine on the test stand with big pulley on the crank and a small one water pump. That combination seriously over speeded the fan. Particularly with the 6 blade CMP fan, which when you cracked the throttle sounded like a plane, with a really strong prop wash. Air flow was so strong that it was sucking oil out of the oil breather. Was really concerned about the fan failing from being overspeeded so swapped the pulleys around from engine to engine to get the speed down.

Now out to work on the truck.

Cheers Phil

[Bob Carriere]

I have a recorred 3 rows of tubes with the six blade fan..... no sheet metal yet except for the front fenders.

Not sure if I have the 216 I have the large 261 crank pulley front pulley but the engine maintains a steady 161.005 degrees F with the 160 thermostat. Double PH-8 spin on oil filters.

This Spring when we first took it out of storage is ran at about 900 rpm for nearly an hour to cook off any condensation then the oil was changed.

I drive it in the back field exclusively in low range ( t-case was changed to a 2 speed). Low range allows me to cycle/crash in all 4 gears when travelling on the paved road from the house driveway entrance to the back field lane.

On wide open throttle the heat damper on the exhaust manifold vibrates the little coil spring like crazy...need one of the antirattle spring..... the Carter YF carb sounds like a vacuum cleaner trying to suck tennis balls. Filling the bowl of the air filter with oil has toned down the sucking sound somewhat.

Never gets up above 161 F.

Cheers

[Alex van de Wetering]

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, Bob, once again thanks for all your comments and ideas regarding the arch bars. And what a coincidence that you were right in the middle of arch bar replacement, Phil!!

My main question was how to tell a C8 arch bar assembly (trying to find a suitable name here for the weld assembly of the three parts....) apart from a C15A one....or a Ford one for that matter. As usual such a question results in an interesting query.....with new questions arising along the way....what's the difference between Ford and Chev?. Is there a difference between cab 11 and 12......what's the difference between the C8 and other Chevs?
My intention was to find out if the arch bar assembly in the yard at LWD parts was from a C8.... and possibly a suitable replacement for mine...which is pretty rusted. Dirk and Stefan were very helpful as always and it was enjoyable to talk about the hobby. Sadly for me the assembly they had available proved to be from a Ford, so I have decided to try and repair my rusted example.



Maybe this info is useful for others, otherwise it might be the dullest info ever posted

- Ford vs Chev Arch bars....the Chev RH arch bar has an extra bend/bulge, to give some extra space for the pedals. I guess Ford's don't need the extra clearance (?), as they lack the extra bend.

- The cowl as mentioned by Bob is listed in the Chev parts list with a Chev part number, as well as a Ford number, so I presume the cowl is the same for all(?). I don't have a Ford parts list here, so I can't check if all Fords used the same....nor can I check if the F8 used different arch bars (compared with F15 F30 etc.) as seems the case with Chev.

- I have to check Phils pictures closely, but the parts list seems to suggest the cowl is the same for the cab11 and 12. Usually there is a mention of "before serial...." if there is a part difference between Cab 11 and 12....or a mention on using up old stock, before using the new part(number), but that doesn't seem to be the case here.

- Also interesting.....in the Chev parts list you will notice that it takes 2 bolts and nuts less to assembly the fenders on a C8, compared with it's bigger brothers......so, could that be a way to tell a C8 arch bar assy from the others?

- The fender itself are definitely different in width between a C8 and the sisters....we compared my C8 fender to a fender of the F60H....wow....a considerable difference!



Phil, please keep the pics of your work coming....never dull....always useful! good luck with the engine.

Alex

[Bob Carriere]

Hi Alex

I have mixed and matched parts from both cab 11 and cab 12.... they all interchange. Except for some minor adjustments between the cab 11 engine cover lid and the cab 12. For example I have transplanted a cab 12 brace to my cab 11 to make the nose stronger...less saggy !!!. Took some sheet metal from the inside alligator cab 12 nose piece to replace sheet metal torched by the previous owner.... and arches are absolutely the same.

The C8 has the cab sitting lower on a civvy frame therefore the bends would have to be different to join the regular sheet metal to the civvy C8 frame.

It's amazing what you can fix with patience, a MIG welder and a back up copper plate.

Phil

After looking at your data chart...... would an oil cooler for the engine be part of your solution..? they now have an oil spin-on filter with a thermostat that will cool the engine ONLY when required..... and you can use a double PH 8 spin on for approx. 2 more liter of oil.

Have you considered installing side panels on your engine stand to simulate the engine compartment air flow and large fan in front of the engine.........

Interesting read.

[Phil Waterman]

Originally Posted by Bob Carriere

Hi Alex

...

Phil

After looking at your data chart...... would an oil cooler for the engine be part of your solution..? they now have an oil spin-on filter with a thermostat that will cool the engine ONLY when required..... and you can use a double PH 8 spin on for approx. 2 more liter of oil.

Have you considered installing side panels on your engine stand to simulate the engine compartment air flow and large fan in front of the engine.........

Hi Bob

Strange you should mention Oil Temps as part of the equation. When I was testing the 261 engine prior to putting it in I ran some long test on the engine stand hour plus one of the things being checked was the inlet and outlet temp of the oil filter that was mounted in the airstream from the fan.

What I was testing for was oil pressure drop as the oil and engine temp went up. You will notice that there is a significant delta temp across the filter from the cooling area of the big spin on filter.

261 oil pressure to temp.JPG

Once the engine was installed with the longer lines to and returning from the filter and the filter mounted lower more down in the airstream under the truck the delta got even larger. The cooling effect on the oil means that you have to drive the truck pretty hard for at least an hour to get the oil temp and the engine temp to equalized. If the outside air is much below 70F it never does, which means the valves can only really be adjusted in hot weather.

As to adding an oil cooler/ oil warmer wonder which would be better an air flow cooler or one that runs through the bottom tank of the radiator? But will over cooling the oil just add to the problem of vapor condensation in the oil not getting boiled out? Or is the internal air temperature through which all the oil must travel at some point get high enough to boil of the water vapor. But maybe that is why they have the thermostatically control oil cooler?

Now as to adding side panels to the test stand, that will raise a whole another set of study questions. I do know that if you run the Pat 13s with out the front side shield it makes the cab a lot hotter. Managed to over heat the driver (me) on the recent long convoy I think because didn't have the drivers side shield installed. The guy riding with me used the IR gun to read the foot well temps and the drivers side (no shield) was 20F higher than the passengers side (with shield) now how much of this was also the air spaces around the pedals I don't know. Since have fabricated a two piece drivers side heat shield which is easy to instal and remove for service and I put rubber flaps around the clutch pedal which is inboard of the shield.

Now to Tony's comment on delta on the radiator at full throttle, believe he is absolutely correct if the radiator is at all undersized. If the radiator is big enough there will be a delta change and should be a delta. There is also the obviously, as Tony points out, a speed through the radiator at which fluid is moving to fast for heat exchange to take place. This gets into the problem of no thermostat no flow restriction may make an over heating problem worse. With the CMPs though I don't think we are at that point because the top hose is so small.

This afternoons work will be to use a radiator flush and do another long engine run to see if the temperatures change.