Cooling system design Flatheads

[Bryan]

After I cleaned my engine out and looked how the water passages are designed, I can only assume they wanted to cool the valve seats and head area.   The distribution tube has holes only in the top. If installed according to the manual, it should be flared at the front to allow no water slip around the front.  The water goes up to the head towards the thermostat. They didn't even have the distribution tube holes on the left side towards the valve area to make flow go up along the valve area then to the top. Directly goes to the seat area. There are no feeds at the bottom of the cylinders.  Reckon there's some kind of convection current that moves flow up to follow the flow across the top of the head.   You would think hey would have made holes progressively larger towards the rear of the motor.  Well, when clean it works, but strange.

[kencombs]

That distribution tube is genius engineering.  Look at the issue Henry had with his flatheads.  Cracks at the seat by the jillion.   Nothing in the  design to assure the seat area was cooled first and the exhaust from two cylinders exiting the engine between cylinder was a recipe for overheating.

 

I recall removing the heads from 24 said blocks looking for a good one back in the 60s.   Finally found one after taking out 1152 bolts, with hand tools! That is 24 per head, two heads per block and 24 blocks.  Dad had a salvage and a stack of exchange engines.  The 24th one had a scored cylinder wall and had to be sleeved, but not cracked.

 

I can't recall ever seeing a 218/230 cracked in that area.

[James_Douglas]

One thing I will be doing on the new 265 is fitting it with a Davies Craig electric water pump. I have only had heat issues with the fluid drive engaged in traffic at a stop or crawl for extended period of time.

 

If fact, Chrysler stated that one should not have the fluid drive engaged at a dead stop for more than 5 minutes.  I have noted that stop and go speeds, like waiting to merge at bridges here in the SF Bay Area or out at freeway chock points, causes the same heat build up issues as a dead stop with the coupling.

 

The internal drag of the weight of the fluid couplings causes the heat to climb on these engines. If one clutches it, it does not heat up.

 

I am hoping that an electric water pump and fan at stop and go speeds will do the trick.

 

James

[Bryan]

1 hour ago, kencombs said:

That distribution tube is genius engineering. 

Even more so..I modified the drawings after thinking about it more.  There may be a reason why there are gaps between certain cylinders. Might be to direct more flow around the exhaust valves. The holes to the head are also larger in those areas

[kencombs]

Yep. Note the paired exh valves get the added flow. 

[keithb7]

Each pair of cylinder is “Siamese’d”. Water does not flow between each pair. Connecting rods are also offset in pairs to match. As all rods are not spaced evenly apart across all 6 rods. 

Having the coolest water from the water pump, directed at each exhaust valve is pretty nice. From each exhaust valve it flows across the block. Pretty cool design I think. 
 

In my experience it works but it does border on not being quite cool enough. Regular driving around town, on the hiway too. No problem. 160 easily maintained. Climb a long steep 11% grade hill. 2nd gear 25 mph steady.  She gets warm. 200 F comes up fast, at 35 ambient air temps.  This is with a fresh serviced cleaned rad. New thermostat. Newly flushed and rebuilt engine. Very clean block. New water-pump. New belts. Good original fan. Air shrouds in place. 

It all works, it’s just borderline sometimes. Under hot summer, heavy load, lower speed drives. To be expected I suppose for its design age. It hasn’t boiled over (bwry close) so I guess its all good. 

 

I used a round punch and a lighter ball peen hammer to flare the edge of the water distribution. Ensuring it was sealed tight against the block. 

[Sniper]

I am not sure the stock fan moves enough air for marginal situations.  Heck, I don't even see water moving in the radiator cap opening.  I think a smaller water pump pulley, or a larger crank pulley, or both, would help with both issues.  Though in my case I am going with an electric fan.

[kencombs]

1 hour ago, keithb7 said:

Each pair of cylinder is “Siamese’d”. Water does not flow between each pair. Connecting rods are also offset in pairs to match. As all rods are not spaced evenly apart across all 6 rods. 

Having the coolest water from the water pump, directed at each exhaust valve is pretty nice. From each exhaust valve it flows across the block. Pretty cool design I think. 
 

In my experience it works but it does border on not being quite cool enough. Regular driving around town, on the hiway too. No problem. 160 easily maintained. Climb a long steep 11% grade hill. 2nd gear 25 mph steady.  She gets warm. 200 F comes up fast, at 35 ambient air temps.  This is with a fresh serviced cleaned rad. New thermostat. Newly flushed and rebuilt engine. Very clean block. New water-pump. New belts. Good original fan. Air shrouds in place. 

It all works, it’s just borderline sometimes. Under hot summer, heavy load, lower speed drives. To be expected I suppose for its design age. It hasn’t boiled over (bwry close) so I guess its all good. 

 

I used a round punch and a lighter ball peen hammer to flare the edge of the water distribution. Ensuring it was sealed tight against the block. 

I think we worry about temp too much.  I would prefer mine to operate from 190-200 at all times as it increases fuel efficiency and eliminates oil sludge as well as keeping rings and pistons cleaner.   Electric fans can be very beneficial in controlling low speed temps. 

[Bryan]

1 hour ago, kencombs said:

I think we worry about temp too much.  I would prefer mine to operate from 190-200 at all times as it increases fuel efficiency and eliminates oil sludge as well as keeping rings and pistons cleaner.   

Now that we're on the subject, there are 195F thermostats out there, above 180F. Any opinion on using these?

[kencombs]

That's what I plan to use, after I upgrade my radiator to a new one that can be run pressurized to 8-12psi.

[Bryan]

What about with a non-pressurized standard radiator?   Little too close to 212F?

[LazyK]

Is it the radiator or the disc style freeze plugs that are the weak link?

Edited April 22, 2022 by LazyK

[kencombs]

1 hour ago, LazyK said:

Is it the radiator or the disc style freeze plugs that are the weak link!

Well I look at this way,  the core plugs are 1 5/8" in diameter, an area of just over 2.5".  So at 10psi the total 'push' is 25 lbs, less than you can generate pushing with your thumb.  IMO, that is way below the pressure needed to unseat a properly installed plug.  

 

The original radiator would probably be fine if it wasn't 66 years old!  So it will get a new one before bumping the pressure up.

1 hour ago, LazyK said:

Is it the radiator or the disc stle freeze plugs that are the weak link!

 

[Dodgeb4ya]

Those core plugs will not come out if installed properly.

I would be more concerned about the OE heater core or OE design water pump seal leaking before good core plugs at 10-12 lbs.

[allbizz49]

I live where 110 isn't uncommon and 100-105 is the norm in summer. I never, ever have any overheating, percolating or any other problems that guys seem to have. My car is as stock as can be, fan, radiator and water pump. 

[Go Fleiter]

well, I have had thermal problems even though having installed a new waterpump plus high performance 2- layers radiator core. (The 3. layer would not have stayed in between the original radiator frame) plus an additional electrical fan (12 V driven)

We travel a lot with the Plymouth, so - heavily loaded with bagages- he encounters hot summers, traffic holdups, heavy mountain gradients or all together ...

 

Thy didn´t mind interruptions to cool down in the 50ies, but I do - although I have to wait for the brakes to cool down some times. I´m planning to add a booster waterpump.

 

With normal duty, the original system works perfectly.

 

Greetings from Düsseldorf!

Go

 

[Bryan]

49 minutes ago, Go Fleiter said:

well, I have had thermal problems even though having installed a new waterpump plus high performance 2- layers radiator core. (The 3. layer would not have stayed in between the original radiator frame) plus an additional electrical fan (12 V driven)

 

 

Has the engine been rebuilt and water passages cleaned out?  I found a lot of sticky sand in my block.

[Sniper]

Back when these engines were designed and used it was common to use just plain water in the summer and alcohol in the winter as the coolant.  Water has better thermal transfer properties compared to ethylene glycol.  Might be the difference?

 

I, too, live in the desert and don't really have cooling issues.  Nor do I have issues with vapor lock or fuel percolation.  But I generally fart about in the city and my longest drive is maybe a half hour.  So I might not be getting a good heat soak.

[kencombs]

7 hours ago, Dodgeb4ya said:

Those core plugs will not come out if installed properly.

I would be more concerned about the OE heater core or OE design water pump seal leaking before good core plugs at 10-12 lbs.

Quite right.  my heater is toast and was likely the cause of the huge hole in the right side floor,

and will be replaced along with the pump when it goes back together.

[Bryan]

1 hour ago, Sniper said:

Back when these engines were designed and used it was common to use just plain water in the summer and alcohol in the winter as the coolant.  Water has better thermal transfer properties compared to ethylene glycol. 

That's how my old 1948 Dodge block ended up being a 1949 Plymouth block. The previous owner before my father let it freeze a year after he bought it, and cracked the block. Probably forgot to change the pure water out from summer.

[Sniper]

Well, well.  I was surfing Youtube looking for info on the M4/M transmission and this popped up.

 

 

[James_Douglas]

Like I said above, I do not have any problems even in 110F heat. As long as the car is moving at more than 15 MPH. One thing people need to keep in their mind when talking about this is the very big difference between cars that have a fluid coupling and those that do not.

 

When stopped the drag on the inside of the coupling equipped cars puts a load on the engine. The heat generated from that load is more then the cooling system can take unless the car is moving well.

 

My '47 Desoto is one of the more heavy cars to be using a flathead six, so it is a good benchmark on such things.

 

I climbed out one summer from Yosemite to the north and even though the temp hit 205 or 210 it did not boil over. At at 6000 feet it should have boiled over below 200F more or less. I do run water wetter and soluble oil. No antifreeze.

 

If in stop and go traffic I clutch it the engine does not over heat. If let the engine "buck" against the fluid coupling for 10 to 15 minutes it will overheat.

 

That is why I am going to replace my mechanical water pump and fan with an all electric set up. If need be it can emulate driving down the road at 50 MPH when standing still. Not to mention the HP saving be getting rid of the mechanical fan.

 

James

 

 

[Bryan]

Today besides other things I took the old plate off my original water pump since it doesn't have the internal bypass hole.  I like redundancy.  I'm going to swap it to the new water pump. ANYWAY, I mounted the plate to the front of the engine to see how everything lines up.  The water pump distribution tube hole is slightly smaller than the block hole.  The other unknown small hole is half covered by a ledge at the edge of the block hole.  Looks like someone didn't like the narrow width of metal near the top of the block

[DJ194950]

I do not think that I would open the plate hole up. It just may have an effect on water pump pressure produced and making it bigger may make water flow situation worse?

 

These pumps do not move major water volumes as I always thought they would  (or pressures in 0 pressure systems)  as seen in the radiator top tank .

 

Not sure I explained this well, but.

 

Just my thought on this subject

[OUTFXD]

Doing some cooling work on Jacquiline at this very moment!  I will reference this over and over!  Quick question,  How snug is the Distributuion tube supposed to be?  I cant get mine out and it appears to have been pushed through the block.