Removing the cooling lines (intake manifolds)

[mlc240z]

I kept my coolant lines.

I used a cheap water valve from the hardware store to set up a system where coolant could pass through the manifold, if required.

I don't drive regularly in truely cold weather but I have. If I do in the future, I don't need to worry about letting the thing idle to warm up properly before I drive off or things like throttle plates icing up. I like the idea of having an 'option'.

As far as performance goes, volumetric efficiency is improved in summer when the ambient temps are already high, the setup can be turned off. In winter, as I mentioned, there is some benefit to retaining something!

Excellent solution, OZ

Don't think I'll be driving too much in the winters here (road salt will awaken the rust monster), but this is a good option.

[ozconnection]

Only during start-up.Once the engine is up to temp,the water in the manifold is completely redundant.Where you live and how much cold weather driving should be a factor in the "removal equation".

Sure at start up with a cold engine and a cold day, everything is cold.

Once the engine cranks and fires, the coolant will begin to heat and immediately begin to warm the intake manifold and the induction charge. Its at this time, in cold weather, that this kind of setup is valuable. Obviously, its the time it takes to get the engine to full operating temperature that is different with both setups and the amount of potential engine wear that also takes place during this time, especially since the choke is on supplying a rich mixture, washing the cylinder walls of oil, causing wear and soiling the oil with excess hydrocarbons........ Warm up the engine quickly to minimize this!

So, it's not 'start up' where there is a difference, its 'warm up' where the advantages are. Didn't I allude to this in my last post?

Edited May 29, 2010 by ozconnection

[Z train]

Sure at start up with a cold engine and a cold day, everything is cold.

Once the engine cranks and fires, the coolant will begin to heat and immediately begin to warm the intake manifold and the induction charge. Its at this time, in cold weather, that this kind of setup is valuable. Obviously, its the time it takes to get the engine to full operating temperature that is different with both setups and the amount of potential engine wear that also takes place during this time, especially since the choke is on supplying a rich mixture, washing the cylinder walls of oil, causing wear and soiling the oil with excess hydrocarbons........ Warm up the engine quickly to minimize this!

So, it's not 'start up' where there is a difference, its 'warm up' where the advantages are. Didn't I allude to this in my last post?

Start-up/warm up-you're talking semantics.

Bottom line-the manifold water system is NOT needed in warmer climates.It is also part of the emissions sytem.once the motor is to temperature,the manifold water is a DETRIMENT to performance.IF this is what you're after.

Taking a diverging route for a minute,the FI on teh Z cars has it's version of a choke.It's called a "cold start injector".It's a "7th injector" for all purposes and it is mounted in the plenum of the manifold.So techically speaking,even the FI "washes" the cylinders during warm-up.

The clyinder wall "washing" you speak of while technically you are correct,is negligible in actuality.

From a performance point of view.The colder the intake manifold is,the better the car performs.

They guy with the shut-off valve has a good idea.But i would take it one step further and install a petcock to drain the lines.Air make a better insulator than water.

[ozconnection]

Start-up/warm up-you're talking semantics.

Bottom line-the manifold water system is NOT needed in warmer climates.It is also part of the emissions sytem.once the motor is to temperature,the manifold water is a DETRIMENT to performance.IF this is what you're after.

Taking a diverging route for a minute,the FI on teh Z cars has it's version of a choke.It's called a "cold start injector".It's a "7th injector" for all purposes and it is mounted in the plenum of the manifold.So techically speaking,even the FI "washes" the cylinders during warm-up.

The clyinder wall "washing" you speak of while technically you are correct,is negligible in actuality.

From a performance point of view.The colder the intake manifold is,the better the car performs.

They guy with the shut-off valve has a good idea.But i would take it one step further and install a petcock to drain the lines.Air make a better insulator than water.

Are you in too much of a hurry to post a reply to actually read what or who wrote what? I'm the guy who suggested the water shut off valve. :stupid:

Maximum engine wear occurs in the first few minutes after start up. This is fact. Why do taxi cabs have engines that run for over half a million kms? Because they hardly ever cool down!

EFI inlet manifolds are very different animals to carb style inlet manifolds. The weakest link in the carb induction system is the carburettor itself. Design features that are built into the factory style carb induction system are there for very sound engineering reasons. The 'performance' you speak of is only part of the overall big picture. If you were to specify 'top end performance' as the only design critera, then yes, remove the coolant lines to the manifold. This is fact also. However, the word 'performance' can also be used as a much broader term that encompasses such things as 'start up', 'warm up' and 'fuel efficiency'.

Besides the faster warm up times and less engine wear, the factory warms the carb manifold because it allows for a sustained induction system temperature regardless of the ambient temperatures the car engine sees. What this means is that by knowing how dense the air is based on temperature, a much more precise AFR can be achieved through finely calibrating the carburettor. A carby engine requires air temp stability since there are no air temperature sensors that can send an electronic signal to determine how much fuel has to be added under varying conditions (including altitude) when managed by an efi computer. Basically, when it comes to emmisions, carbs have a much harder time meeting emissions than efi do. No contest really.

A 7th injector is a warm up device. It was deemed to be somewhat inefficient since the cylinders closest to the injector ran richer than those further away. Recall that an efi manifold is a dry manifold and isn't designed specifically for wet mixture flow....here is the compromise. With more modern setups, the duty cycle of the port injectors is increased to allow for richer warm up mixtures and the 7th injector was deleted. With either system, carb or efi, warmup still exists and significant wear takes place but the efi management system works more quickly to get the engine to proper operating temperatures.

Oh, and using a petcock to drain coolant should be something found at the bottom of the radiator only. You don't want to potentially allow air leaks into your cooling system at any time between flush and refills. Even removing the radiator cap should be avoided and coolant levels should be checked in the overflow tanks/recovery system only. (Just like modern cars bro!)

I'm done

[Z train]

1)Are you in too much of a hurry to post a reply to actually read what or who wrote what? I'm the guy who suggested the water shut off valve. :stupid:

2)Maximum engine wear occurs in the first few minutes after start up. This is fact. Why do taxi cabs have engines that run for over half a million kms? Because they hardly ever cool down!

3)EFI inlet manifolds are very different animals to carb style inlet manifolds. The weakest link in the carb induction system is the carburettor itself. Design features that are built into the factory style carb induction system are there for very sound engineering reasons. 4)The 'performance' you speak of is only part of the overall big picture. 5)If you were to specify 'top end performance' as the only design critera, then yes, remove the coolant lines to the manifold. This is fact also. 6)However, the word 'performance' can also be used as a much broader term that encompasses such things as 'start up', 'warm up' and 'fuel efficiency'.

7)Besides the faster warm up times and less engine wear, the factory warms the carb manifold because it allows for a sustained induction system temperature regardless of the ambient temperatures the car engine sees. What this means is that by knowing how dense the air is based on temperature, a much more precise AFR can be achieved through finely calibrating the carburettor.8) A carby engine requires air temp stability since there are no air temperature sensors that can send an electronic signal to determine how much fuel has to be added under varying conditions (including altitude) when managed by an efi computer. 9)Basically, when it comes to emmisions, carbs have a much harder time meeting emissions than efi do. No contest really.

10)A 7th injector is a warm up device. It was deemed to be somewhat inefficient since the cylinders closest to the injector ran richer than those further away.11) Recall that an efi manifold is a dry manifold and isn't designed specifically for wet mixture flow....here is the compromise. 12)With more modern setups, the duty cycle of the port injectors is increased to allow for richer warm up mixtures and the 7th injector was deleted. 13)With either system, carb or efi, warmup still exists and 14)significant wear takes place but the efi management system works more quickly to get the engine to proper operating temperatures.

15)Oh, and using a petcock to drain coolant should be something found at the bottom of the radiator only. You don't want to potentially allow air leaks into your cooling system at any time between flush and refills. Even removing the radiator cap should be avoided and coolant levels should be checked in the overflow tanks/recovery system only. (Just like modern cars bro!)

I'm done

1)I couldn't be bothered to look back at who posted it.THis observation is irrellevant

2)True.Because they are maintained better.

3)No kiddin'

4) no it is not.It is THE only thing.

5)WRONG

6) WRONG again

7)Semantical bullsh!t.No water in the manifold equals lower intake charge temps P.E.R.I.O.D.

8)Air temp stability?In a car?Out in the real world?No such thing.

9)Finally-yes-you are correct.But not on point.

10)But it works

11)Again not on point

12)True-but none of which applies to any part of this discussion.

13)True-but it is not the "earthshaking event"that you claim it to be.

14)Wrong-fuel management has no effect on how fast a engine comes up to operating temp all other factors being equal.

15)O.K.-make sure you have a good petcock or line valve that doesn't leak.Again-this is not an issue.

The FSM lists the manifold water piping/tubes as an EMISSION CONTROL DEVICE.

Since no-one here gives a Rat's arse about emissions during warm-up,it is NOT needed.

[DaveBonds]

If someone wanted to, in a race application, they could seriously benefit from running a race coolant through a coil in an ice canister with an inline pump through the intake manifold, separately from the block and head's antifreeze system.

[ozconnection]

1)I couldn't be bothered to look back at who posted it.THis observation is irrellevant

2)True.Because they are maintained better.

3)No kiddin'

4) no it is not.It is THE only thing.

5)WRONG

6) WRONG again

7)Semantical bullsh!t.No water in the manifold equals lower intake charge temps P.E.R.I.O.D.

8)Air temp stability?In a car?Out in the real world?No such thing.

9)Finally-yes-you are correct.But not on point.

10)But it works

11)Again not on point

12)True-but none of which applies to any part of this discussion.

13)True-but it is not the "earthshaking event"that you claim it to be.

14)Wrong-fuel management has no effect on how fast a engine comes up to operating temp all other factors being equal.

15)O.K.-make sure you have a good petcock or line valve that doesn't leak.Again-this is not an issue.

The FSM lists the manifold water piping/tubes as an EMISSION CONTROL DEVICE.

Since no-one here gives a Rat's arse about emissions during warm-up,it is NOT needed.

Too bad you live too far away for me to lend you some books from my own automotive library. You would find some of the information contained within those pages very informative.

Oh well....

[Pop's Z]

Boys, boys, calm down. This has gotten a bit out of hand. Deep breaths everyone. I didn't envision a shitefest with my simple question. We're all friends here, right? FWIW I went ahead and removed the system which had been cobbled together by the previous owner. I don't normally run the car here in Colorado in the winter, and I let it warm up until I see the needle move in the temp guage. Problem solved. Thanks for all the info, though, it adds to the store of knowledge here on the site.

Cheers, Mike

[Z train]

Too bad you live too far away for me to lend you some books from my own automotive library. You would find some of the information contained within those pages very informative.

Oh well....

So you got your in-correct info from books.I see.My info comes from wrenching since 1966.

However,the FSM trumps all.

Point,set match.

Mike-you'll be fine with what you did.

Edited June 2, 2010 by Z train

[Zed Head]

Your page is for a 1978 EFI engine. The discussion is about coolant lines on a 1973 carburated engine.

Replay point...

[Zed Head]

This has turned in to an interesting technical discussion (aside from all of the extra stuff).

Here is a paragraph from the 1972 FSM, in the Emissions section (page EC-13), but it seems to be a general statement that the coolant lines are there for consistency in fuel supply, by keeping the gasoline at a constant temperature through heating of the carburetors. I could not find a comparable page in the 1973 FSM. Draw your own conclusions.

[ozconnection]

This has turned in to an interesting technical discussion (aside from all of the extra stuff).

Here is a paragraph from the 1972 FSM, in the Emissions section (page EC-13), but it seems to be a general statement that the coolant lines are there for consistency in fuel supply, by keeping the gasoline at a constant temperature through heating of the carburetors. I could not find a comparable page in the 1973 FSM. Draw your own conclusions.

Thank you for posting this!

Thank you also for pointing out the relevance of Z trains attachment.

Hmmmmm, it seems what I said about temperature stabilization may in fact be fact!

For all intents and purposes, what I say here in these forums is based on my own personal experience and technical research. I will not make comment on something that I'm unsure about or have no experience on, that's where I'll sit back and read what other people have written. If I think something is awry, then I'll look it up and post my point of view. That way, I'm sure that others who are interested and read our posts get accurate information.

After all, isn't this what it's all about Z train?

Edited June 3, 2010 by ozconnection