Re-routing cooling system at SOHC?

[stayros32001]

First of all my setup
1500cc engine (custom EFI) 1.6 Head from Lancia
On a Fiat 128 / Zastava 101
With custom A/C setup


Thoughts about outdoor temp and outdated water cooling mechanism on our engines.

When our engines designed in Italy at late 60’s the max temperature was 32 Celsius (90F).
Now the top temperature in Italy is 40 Celsius (104F).

These temperatures are measured under a shadow and not at the road and at the asphalt. Also, at the summer traffic jam, when all the cars try to cool their radiators, more heat is produced. At 70’s there were no A/C cars (extra heat exchange from other cars).

Comparing the circumstances, our cars have to work in a very different and much more difficult world, than they used to.

So the past 50+ years everything changed. Our little cars and SOHC engines not at all.
I think that we should start considering how to cool our cars with a more efficient way.
I saw one other topic that someone used an electric car pump using the same routing to push cold water to the engine.

And in my honest opinion this routing is the first of our problems.
When the car idles at traffic, hot air is trapped between the back of the engine and the firewall. Exhaust Manifold placed between the end of the engine and the firewall ( FWD cars) increases more and more temp at the surrounding steel and after some time there is a no return point. Because even if the cars starts to roll out of the traffic, and engine block tries to cool through radiators fresh air, the buildup heat from the surrounding steel stops the engine compartment from really cool down.

This means that the pipe that is placed under the exhaust manifold and supposed to deliver cool water to the block, now delivers hot water, because hot air is trapped there and exhaust manifold can’t really drop temperatures. In reality exhaust manifold due to this builtup heat will be unable to cool down. This problem of course is huge when car is idling at the traffic jam.

So, pipe now pushing hot water instead of cold, in our engine block. None water pump, electric or mechanic will solve this problem.
Is it possible to change routing?

Maybe!
Most of cylinder heads have at the belt side an water port ( I believe for heater core, I do not use heater core) ( 1.4 and 1.6 heads do not have this port )

So the real question and the purpose of the topic is:

If someone places an electric pump at the lower radiator hose and push cold water through this port of the cylinder head (of course routing the pipes from the spark plug’s side of engine) and completely remove the mechanical water pump, will have better cooling results?

* mechanical water pump could be replaced with just an electric impeller like this:

 

[carl]

How about a thermo wrap for that steel pipe between the water pump and the thermostat? How about a bigger aluminum radiator?
Louvers in the hood over the exhaust manifold to help cool the engine bay while sitting still?

Is this a theoretical discussion or are you actually experiencing over heating issues?
Electric water pumps have been discussed here a lot for X1/9s as they are more prone to running hot as the poor little water pump from a 128 now has to push coolant the length of the car to the radiator....and back.

 

[Dr.Jeff]

I agree that these engines could benefit from a improved cooling design...even more so on the X1/9 where the engine is trapped in a small box behind the passenger cabin. And I agree the location of the "water return pipe" is very poor. Perhaps even a simple rerouting of that pipe away from the exhaust manifold would help some? Or insulating it like Carl stated? But ideally your thoughts for a better overall configuration would be ideal. A electric pump of some type seems to be the best approach. Now the question is as you stated, how to route the water flow. Additionally some removal of the heat from the engine bay in general would be good.

 

[Rupunzell]

Stock cooling system is fine as is long as the cooling system is in proper condition.. why, we have endurance raced (24 hours of LeMons) the exxe with a uprated engine (aprox 120 Bhp at the flywheel) in 100+ degrees F for Many Hours.. with no cooling issues.. This means coolant temperature less than 212 degrees F under all conditions with ambient temperatures of 100+ degrees F..

The stock exxe simply will not produce nearly as much heat loading as a race car running at near 100% output hour after hour.. At idle in traffic, long as the cooling fans are operating and cooling system is proper, the thermoswitch will effectively fix the coolant temperature to just over 212 degrees F..

Don't think running the engine at a lower temperature is beneficial as the oily bits need to reach a proper operation temperature range to (typically 180 to 210 degrees F) function properly.

A non problem.. long as the stock cooling system is in proper condition.

 

[stayros32001]

Of course bigger radiator, dual fan set up etc, are always under discussion, but every attempt to make these kind of changes end up to this problematic set up.

Actually Aurelio Lampredi understand how problematic is the trapped heat at FWD cars with sohc engines and he redesigned the engine. The Fiat Fiasa Engine ( known as Brazilian ) has «same block» and cylinder head but is twisted 180 degrees so as the Exhaust manifold be in front of the radiator.

To be honest I have minor overheating issues when I am in traffic jam and using the A/C. ECU checks the water temperature and closes the compressor.

I would like to get opinions about this re-routing that I am thinking off.
The plan is to do it someday. Not this summer. But I want to hear opinions first. Is actually a good way to poor water from the head? Is there any: No way, you must not do that because…. Terrible things …?

 

[Rupunzell]

Cooling "issues or problems" in the x1/9 are nil compared to the cooling system problems in the NA/NB Miata.. Where the folks at Mazda did two fatal design decisions. The engine used in the NA/NB came out of the FWD 323 which has a transverse layout typical of many FWD cars. This engine was rotated 90 degrees in the Miata (MX-5), but the cooling system was not properly modified for this revised engine position. Coolant flow is hideous as only cylinders# 1 & 2 circulate coolant to the radiator in front, cylinders# 3& 4 rely on the heat core for their primary source of cooling.
This is why NA/NB Miata tend to fry head gaskets at cylinders# 3 & 4..

Adding to this problem, the folks at Mazda were well aware of what they were doing, then altered the coolant temperature gauge to have a dead zone between 160 degrees F to 220 degrees F to halt any customer complaints for a moving temperature gauge.. As your Miata is slowly frying the engine, there is no way the driver knows about what is happening.. Except the fuel injection system does and does with it can to reduce power output and such to reduce coolant and engine operating temperature. The fuel injection system knows this due to the coolant temperature sensor being located at the back of the cylinder head where the operating temperature is highest..

The correct fix for the cooling system problem in the Miata NA/NB is coolant re-route.. This modification is well known within the Miata community but prohibited in SCCA spec Miata racing...

 

[stayros32001]

haha! I didn't know about miata! It has a point, but it is a completely different case to comparing racing cars to stock ones.
Racing cars have big aluminum radiators with very noisy fans, oil cool radiators etc.
Cost of these changes vs just two hoses and one thermostat housing is incomparable if it really have some effect!
Also no one said about operating engine at lower temperature. I just want to make the system more efficient.

 

[ng_randolph]

So the real question and the purpose of the topic is:

If someone places an electric pump at the lower radiator hose and push cold water through this port of the cylinder head (of course routing the pipes from the spark plug’s side of engine) and completely remove the mechanical water pump, will have better cooling results?

The proposed change would not improve cooling for several reasons. The port in the head you are referring to is very small; much smaller than the radiator hose ports, and would seriously limit flow. Also, coolant would enter the head at the timing belt end and exit the head at the transmission end, bypassing the block entirely.

As others have said, the colling system in the X1/9 is very good as long as it is well maintained. Things to look at are:

• Radiator. Is it in good condition, no partial blockage etc.?
• Radiator fans; cars with A/C got dual fans from the factory. If your car has only one, a second fan can be retrofitted.
• Radiator thermoswitch. Does it work? Mine failed, and would turn on the fans for a second or two only. Easy to replace.
• Water pump. Is the impeller in good shape? Impeller to housing clearance within spec?

 

[dllubin]

I bought my X1/9 49 years ago and I can count on one hand the number of times the fan has come on while driving (only when in bumper to bumper traffic on extremely hot days). If the cooling system is in good condition, it should have plenty of capacity to cool the stock engine as well as one that has been modded a bit.

As far as the coolant return pipe goes, I'm sure it is picking up some thermal energy from the exhaust but while moving it could help some, more of that thermal energy will get absorbed by the block instead, which is no longer shadowed by the pipe. It may be an improvement but I'm not sure how significant it would be. Better insulating the exhaust heat from the engine might be a preferred approach.

 

[stayros32001]

Alternatively if not using the inlet at the c.Head, we can poor water from the water block plate that is behind the flywheel.
Using heavy duty e.pump will ballance the differrent between big port from stock pipe VS smaller port elsewhere (I believe)

Also we can ceramic coat the Exhaust Manifold and wrap it, but topic is not about suggesting cooling solutions but about re-routing.

 

[kmead]

Alternatively if not using the inlet at the c.Head, we can poor water from the water block plate that is behind the flywheel.
Using heavy duty e.pump will ballance the differrent between big port from stock pipe VS smaller port elsewhere (I believe)

Also we can ceramic coat the Exhaust Manifold and wrap it, but topic is not about suggesting cooling solutions but about re-routing.

The engine has one coolant input and two coolant outputs. The input is approximately equal to the two outputs. The flow of coolant is driven by an engine rpm dependent pump. The pump output at higher rpm is sufficient to move enough coolant through the system to the radiator to shed the heat generated by the engine. At low rpm the pump output is less than ideal to deal with the heat built up in the engine after a good run which is why we see temps spike after coming off the highway.

Here in the US we had X’s in large number from the start of production and many of them were sold into our fair weather states which are as hot or hotter than Italy. Most of our regular cars have had AC since the late 1970s, some of our X’s even have AC. In general X’s do well regardless of the temperature if in good repair.

The X cooling system can be improved upon of course. A larger aluminum radiator, two fans, a two temperature thermo switch for those fans, some additional shielding/insulation on the cross tube and likely the biggest improvement being to use an electric pump which can drive sufficient coolant flow at all engine speeds to carry whatever heat generated away from the engine to the radiator.

 

[Dr.Jeff]

I am intrigued to see what @stayros32001 can come up with in terms of a redesign. I'm always interested in modifications to any stock component...if for no other reason than it's just fun to do. Who knows, he may find something revolutionary. That being said, I tend to agree with Karl; a few simple upgrades to the stock components, plus the swap to a electric pump should be more than enough for pretty much any conditions - without redesigning the coolant pathway / routing overall. But I'll hold off on that view until we see what develops here.

 

[kmead]

I am intrigued to see what @stayros32001 can come up with in terms of a redesign. I'm always interested in modifications to any stock component...if for no other reason than it's just fun to do. Who knows, he may find something revolutionary. That being said, I tend to agree with Karl; a few simple upgrades to the stock components, plus the swap to a electric pump should be more than enough for pretty much any conditions - without redesigning the coolant pathway / routing overall. But I'll hold off on that view until we see what develops here.

One of the biggest issues relating to this approach is the head being cooler than the block. From a design perspective the head gasket interface was designed for the head to be in a particular temperature range relative to the block. Given the expansion coefficient of aluminum being markedly higher than cast iron one could get a very negative effect from a reversed coolant flow. Additionally one wonders if you would get some other deleterious effects from the way the passages are in the head relative to the passages in the block. The openings in the head are all the same size whereas the block’s internal manifolds likely are created to ensure a similar amount of cooled water from end to end by adjusting the passage size from end to end. I would also be concerned by the number four cylinder receiving the coolest water and over cooling that part of the head

The aluminum head with the combustion chamber and upper area of the block are where the heat is, the lower part of the block where the main bearings are is generally cooled more by the oiling system given the water jacket is above there and transfers heat to the rest of the block by conduction.

I know there are reverse flow cooling systems which intentionally push the cooled coolant into the head first, I believe those are clean sheet designs and not modifications of existing engines, the GM LT1 being one example.

 

[Rupunzell]

Higher coolant circulation rate alone might not improve cooling, there is a time element for the heat from internal engine surfaces to transfer into the coolant. Essentially, more is not better, there is an optimum for any given situation and specific need. Unless you're willing to do the math, design, extensive testing and all related, why alter the cooling system when it is simply not a problem?

Given the lack of cooling problem history with the X, it simply not rational or logical to alter a design that has been well proven to be effective beyond the stock engine power output. If you're stuck in traffic on well over 100 degrees F or 38 degree C, that is what the cooling fans with the thermo switch in the radiator is for.. as the heat load on the cooling system at idle is just not that high and the OEM cooling system with properly operating thermo switch and fans should be more than good enough.

~Yes, if the coolant pump impeller to housing clearance is too large, coolant flow at idle is lower, but that in itself is usually not an issue.

This is completely different for a endurance race engine producing much greater than OEM engine power output run at over 100 degrees F on the track.

There is simply insufficient evidence, case history to justify radically altering the OEM cooling system in any way.

Know the reasons for many modern cars to have electric coolant pumps is much to do with lower engine power losses which translates to lower fuel consumption. Electric coolant pumps is not about better cooling.

Bernice

 

[Dr.Jeff]

One of the biggest issues relating to this approach is the head being cooler than the block. From a design perspective the head gasket interface was designed for the head to be in a particular temperature range relative to the block. Given the expansion coefficient of aluminum being markedly higher than cast iron one could get a very negative effect from a reversed coolant flow. Additionally one wonders if you would get some other deleterious effects from the way the passages are in the head relative to the passages in the block. The openings in the head are all the same size whereas the block’s internal manifolds likely are created to ensure a similar amount of cooled water from end to end by adjusting the passage size from end to end. I would also be concerned by the number four cylinder receiving the coolest water and over cooling that part of the head

The aluminum head with the combustion chamber and upper area of the block are where the heat is, the lower part of the block where the main bearings are is generally cooled more by the oiling system given the water jacket is above there and transfers heat to the rest of the block by conduction.

I know there are reverse flow cooling systems which intentionally push the cooled coolant into the head first, I believe those are clean sheet designs and not modifications of existing engines, the GM LT1 being one example.

Agreed. However maybe he has other ideas on how to reroute the cooling system in general, that aren't necessarily a reverse flow layout?

 

[carl]

I was going to say to just convert the car to plug in electric but apparently even electric cars have cooling systems for the batteries?

 

[Dr.Jeff]

I've heard the argument before that reducing the circulation rate (slow it down) to allow more time for heat transfer will work better than increasing the flow rate. Simply not true, as learned by studying some physics to understand the science behind it.

Exploring creative thinking, developing new designs, altering a factory system, modifying stuff is great fun. I'm never one to try and strangle someone's unique / innovative thinking and willingness to try new ideas. Afterall, that's how progress is made and why we aren't still in the dark ages.

 

[kmead]

Higher coolant circulation rate alone might not improve cooling, there is a time element for the heat from internal engine surfaces to transfer into the coolant. Essentially, more is not better, there is an optimum for any given situation and specific need. Unless you're willing to do the math, design, extensive testing and all related, why alter the cooling system when it is simply not a problem?

Given the lack of cooling problem history with the X, it simply not rational or logical to alter a design that has been well proven to be effective beyond the stock engine power output. If you're stuck in traffic on well over 100 degrees F or 38 degree C, that is what the cooling fans with the thermo switch in the radiator is for.. as the heat load on the cooling system at idle is just not that high and the OEM cooling system with properly operating thermo switch and fans should be more than good enough.

~Yes, if the coolant pump impeller to housing clearance is too large, coolant flow at idle is lower, but that in itself is usually not an issue.

This is completely different for a endurance race engine producing much greater than OEM engine power output run at over 100 degrees F on the track.

There is simply insufficient evidence, case history to justify radically altering the OEM cooling system in any way.

Know the reasons for many modern cars to have electric coolant pumps is much to do with lower engine power losses which translates to lower fuel consumption. Electric coolant pumps is not about better cooling.

Bernice

Agreed in terms of excessive flow, my point was just around appropriate flow at high heat but low flow conditions due to low engine rpm. Folks often see excessive heat needing to be shed after coming off a highway run or other higher rpm activity and then coming into traffic or a light. A system which responds to temperature inputs can meter the flow to maintain an appropriate temperature. Jonohh has a thread around using a PWM controlled Pierburg pump which would meet this need: https://xwebforums.com/forum/index.php?threads/cooling-system-build-thread.42322/page-1

 

[Dan Sarandrea (Phila)]

First of all my setup
1500cc engine (custom EFI) 1.6 Head from Lancia
On a Fiat 128 / Zastava 101
With custom A/C setup


Thoughts about outdoor temp and outdated water cooling mechanism on our engines.

When our engines designed in Italy at late 60’s the max temperature was 32 Celsius (90F).
Now the top temperature in Italy is 40 Celsius (104F).

These temperatures are measured under a shadow and not at the road and at the asphalt. Also, at the summer traffic jam, when all the cars try to cool their radiators, more heat is produced. At 70’s there were no A/C cars (extra heat exchange from other cars).

Comparing the circumstances, our cars have to work in a very different and much more difficult world, than they used to.

So the past 50+ years everything changed. Our little cars and SOHC engines not at all.
I think that we should start considering how to cool our cars with a more efficient way.
I saw one other topic that someone used an electric car pump using the same routing to push cold water to the engine.

And in my honest opinion this routing is the first of our problems.
When the car idles at traffic, hot air is trapped between the back of the engine and the firewall. Exhaust Manifold placed between the end of the engine and the firewall ( FWD cars) increases more and more temp at the surrounding steel and after some time there is a no return point. Because even if the cars starts to roll out of the traffic, and engine block tries to cool through radiators fresh air, the buildup heat from the surrounding steel stops the engine compartment from really cool down.

This means that the pipe that is placed under the exhaust manifold and supposed to deliver cool water to the block, now delivers hot water, because hot air is trapped there and exhaust manifold can’t really drop temperatures. In reality exhaust manifold due to this builtup heat will be unable to cool down. This problem of course is huge when car is idling at the traffic jam.

View attachment 75077


So, pipe now pushing hot water instead of cold, in our engine block. None water pump, electric or mechanic will solve this problem.
Is it possible to change routing?

Maybe!
Most of cylinder heads have at the belt side an water port ( I believe for heater core, I do not use heater core) ( 1.4 and 1.6 heads do not have this port )

View attachment 75078

So the real question and the purpose of the topic is:

If someone places an electric pump at the lower radiator hose and push cold water through this port of the cylinder head (of course routing the pipes from the spark plug’s side of engine) and completely remove the mechanical water pump, will have better cooling results?

* mechanical water pump could be replaced with just an electric impeller like this:

View attachment 75079

I re-read what you have posted so far 3x, and I did not see any mention of:
1. Your coolant temps
2. Your cap pressure rating
3. Your coolant type/mix

Rational evaluation and advice is impossible without the above information.

 

[Stuartc]

My previous’81 X1/9 never had any cooling issues and as I’m in Australia and one of the hottest capital cities don’t really see any point to looking to improve its capacity on my current Bertone.
I had twin carbs, extractors and running higher compression and better camshaft timing as it was a euro spec vehicle.
Only modifications I’ve/will be doing is twin fans as it’s A/C model, 2 speed fan settup and aluminium radiator.
Apart from that completely stock.
I think the biggest factor here is to ensure the cooling system is in good condition.