Should I worry that there is a crimp in this red air tube?

LexZ

Daily Driver
12CFB9BC-7B79-4EC0-83F1-914D2F791FD9.jpeg
 

Jefco

Easily Amused
It's a crankcase breather, it willnot work well with this much crimp. Shorten the hose (an inch or so at a time), it may need to be rerouted in front of the fuel line to straighten adequately.
 

bbrown

Bob Brown
Moderator
I wouldn't worry that it will actually hurt anything keeping it like it is, but its function is to route crankcase vapors back into the carb for burning, so I would fix it to function as intended. It's part of the emissions lowering setup. Personally, I would make it right by replacing the hose and insuring it doesn't kink.
 

carl

True Classic
If your dip stick is sitting loose it was pushed out of it's socket due to crankcase pressure that couldn't vent out that tube. That kink will be hard to undo as it's a set in the hose now. Get a new hose.
 

LexZ

Daily Driver
It's a crankcase breather, it willnot work well with this much crimp. Shorten the hose (an inch or so at a time), it may need to be rerouted in front of the fuel line to straighten adequately.
Thanks. Will do.
 

LexZ

Daily Driver
If your dip stick is sitting loose it was pushed out of its socket due to crankcase pressure that couldn't vent out that tube. That kink will be hard to undo as it's a set in the hose now. Get a new hose.
Thanks. I will follow the forum’s guidance: try to shorten existing one, then either buy new hose or order the part from MWB
 

LexZ

Daily Driver
I wouldn't worry that it will actually hurt anything keeping it like it is, but its function is to route crankcase vapors back into the carb for burning, so I would fix it to function as intended. It's part of the emissions lowering setup. Personally, I would make it right by replacing the hose and insuring it doesn't kink.
If I will not put too many miles on it, do I need to get the emissions lowering on my ‘74 fully operational? I appreciate that every little bit helps, but any additional complexity is one more thing to maintain
 

JKIDD

True Classic
Some coolant hoses contained a metal coil or spring to keep them from kinking & collapsing.
 

kmead

Glutton for punishment
If I will not put too many miles on it, do I need to get the emissions lowering on my ‘74 fully operational? I appreciate that every little bit helps, but any additional complexity is one more thing to maintain
There aren‘t many emissions controls on a 74. Personally I would remove and plug what few there are (Air pump if fitted, EGR). I would leave anything related to engine blow by and gasoline fumes/vapors as neither of these have a negative performance effect.

On your red hose, which is likely just coolant hose two things: if it is a coolant hose it will break down over time as the rubber isn’t formulated for resistance to oil products; it should have a flame arrestor inside it another thing you can add to your next order with MWB or similar.
 

fiatfactory

Steve Cecchele
If I will not put too many miles on it, do I need to get the emissions lowering on my ‘74 fully operational? I appreciate that every little bit helps, but any additional complexity is one more thing to maintain
Unkinking the hose (by fitting the correct part for the job) will lessen complexity and require less maintenance.

A blocked breather hose and increased crankcase pressure that follows, in the worst case scenario, can blow oil past the seals / blow out the crank seal / pop the dipstick and pump oil out of the engine, creating a huge mess and potentially running the engine low on oil.

So yes, you should be worried about the hose being kinked.

SteveC
 

LexZ

Daily Driver
There aren‘t many emissions controls on a 74. Personally I would remove and plug what few there are (Air pump if fitted, EGR). I would leave anything related to engine blow by and gasoline fumes/vapors as neither of these have a negative performance effect.

On your red hose, which is likely just coolant hose two things: if it is a coolant hose it will break down over time as the rubber isn’t formulated for resistance to oil products; it should have a flame arrestor inside it another thing you can add to your next order with MWB or similar.
Thanks. Really appreciate the guidance as I try to stabilize this newly acquired ‘74
 

EricH

Eric Hamilton
Moderator
If I will not put too many miles on it, do I need to get the emissions lowering on my ‘74 fully operational? I appreciate that every little bit helps, but any additional complexity is one more thing to maintain
There are arguments both ways, and of course if you live in a jurisdiction that requires the emissions equipment to be in place you won't have much choice. But as far as helping with the environment....

There are three emissions control systems on your '74.
One collects fuel vapor from the tank and the carb bowl when the motor is off, routes it to a charcoal canister that captures the vapor. The canister is heated by the exhaust when the motor is running; this cooks the vapor out of the charcoal and another hose sends it to carb so that it can be burned. This is a passive system - if no one has been messing with it about the only thing that can go wrong is that heat shield over the exhaust manifold can rust out so that the hose carrying hot air to the canister cannot be attached, or the three-way valve that vents the tank may stick. If this system is not working your garage may smell of gas but nothing else awful will happen (we've already told you to check tank venting).

The second is the crankcase vent system which sends vile and disgusting blowby gases back through the intake to be burned. This what your kinked hose is for, and you want that to be working properly. If you look underneath the air cleaner housing where that hose connects, you'll see another line that goes to a nipple on the driver's side of the spindle for the primary butterfly - that's there to keep negative pressure in the hose and crankcase. As long as you have the stock air cleaner housing making this work is just a matter of keeping two hoses connected and cleaning the cyclonic trap at the bottom of the big hose once a decade. Do this - you don't want blowby gases gunking up every surface in the engine compartment, contaminating your oil, pushing the dipstick out, and blowing out your crank seals.

The third system is the one that really distinguishes the US-spec from the European cars of the era. US emissions controls at the time required that carbon monoxide (CO), unburned hydrocarbons (HC), and nitrogen oxides (NOx) be limited. Note that carbon dioxide, the greenhouse gas that everyone is thinking of when they say "carbon emissions" was not considered a pollutant back then - it and water vapor are what you get when gasoline burns completely. Those early emissions control standards were also measured at idle because it wasn't technically feasible to measure anything else.
HC and CO are basically unburned fuel; they are products of incomplete combustion caused by low cylinder pressures and temperatures and rich mixtures. However NOx is produced by the lean mixtures and high temperature and pressure conditions that also promote complete fuel combustion and maximum efficiency, so these goals are in conflict. Modern engines use computer-controlled electronic fuel injection, oxygen sensors, and a bunch of other high-tech magic to get exactly the right air/fuel mixture and ignition timing and then use catalytic converters to remove the NOx and residual CO/HC from the exhaust, but these technologies weren't available in 1974. So Fiat (and all the other manufacturers did something similar) detuned the engine by reducing compression ratios and retarding idle timing to lower the cylinder pressure and temperature to reduce NOx formation. However, these changes increase the CO and HC in the exhaust; to fix this they added a belt-driven air pump to inject fresh air into the exhaust stream so that the waste HC and CO would burn to water and CO2 before it left the tailpipe. The effect is that some of the energy from burning your gas goes into heating up the exhaust manifold instead of turning the wheels - less NOx produced, less CO/HC emitted, but higher fuel consumption and higher carbon footprint. It's not clear how much environmental benefit there is keeping this system operational, as opposed to tuning for best fuel economy.
 
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kmead

Glutton for punishment
There are arguments both ways, and of course if you live in a jurisdiction that requires the emissions equipment to be in place you won't have much choice. But as far as helping with the environment....
Well stated.

Passive systems have no effect on performance and weigh very little.

The air injection system is more problematic given how it is driven and that it is indeed parasitic. The pump being driven off the cam, has been known to break by locking up and causing the timing belt to fail. Not something you want on an interference engine.
 

LexZ

Daily Driver
There are arguments both ways, and of course if you live in a jurisdiction that requires the emissions equipment to be in place you won't have much choice. But as far as helping with the environment....

There are three emissions control systems on your '74.
One collects fuel vapor from the tank and the carb bowl when the motor is off, routes it to a charcoal canister that captures the vapor. The canister is heated by the exhaust when the motor is running; this cooks the vapor out of the charcoal and another hose sends it to carb so that it can be burned. This is a passive system - if no one has been messing with it about the only thing that can go wrong is that heat shield over the exhaust manifold can rust out so that the hose carrying hot air to the canister cannot be attached, or the three-way valve that vents the tank may stick. If this system is not working your garage may smell of gas but nothing else awful will happen (we've already told you to check tank venting).

The second is the crankcase vent system which sends vile and disgusting blowby gases back through the intake to be burned. This what your kinked hose is for, and you want that to be working properly. If you look underneath the air cleaner housing where that hose connects, you'll see another line that goes to a nipple on the driver's side of the spindle for the primary butterfly - that's there to keep negative pressure in the hose and crankcase. As long as you have the stock air cleaner housing making this work is just a matter of keeping two hoses connected and cleaning the cyclonic trap at the bottom of the big hose once a decade. Do this - you don't want blowby gases gunking up every surface in the engine compartment, contaminating your oil, pushing the dipstick out, and blowing out your crank seals.

The third system is the one that really distinguishes the US-spec from the European cars of the era. US emissions controls at the time required that carbon monoxide (CO), unburned hydrocarbons (HC), and nitrogen oxides (NOx) be limited. Note that carbon dioxide, the greenhouse gas that everyone is thinking of when they say "carbon emissions" was not considered a pollutant back then - it and water vapor are what you get when gasoline burns completely. Those early emissions control standards were also measured at idle because it wasn't technically feasible to measure anything else.
HC and CO are basically unburned fuel; they are products of incomplete combustion caused by low cylinder pressures and temperatures and rich mixtures. However NOx is produced by the lean mixtures and high temperature and pressure conditions that also promote complete fuel combustion and maximum efficiency, so these goals are in conflict. Modern engines use computer-controlled electronic fuel injection, oxygen sensors, and a bunch of other high-tech magic to get exactly the right air/fuel mixture and ignition timing and then use catalytic converters to remove the NOx and residual CO/HC from the exhaust, but these technologies weren't available in 1974. So Fiat (and all the other manufacturers did something similar) detuned the engine by reducing compression ratios and retarding idle timing to lower the cylinder pressure and temperature to reduce NOx formation. However, these changes increase the CO and HC in the exhaust; to fix this they added a belt-driven air pump to inject fresh air into the exhaust stream so that the waste HC and CO would burn to water and CO2 before it left the tailpipe. The effect is that some of the energy from burning your gas goes into heating up the exhaust manifold instead of turning the wheels - less NOx produced, less CO2/HC emitted, but higher fuel consumption and higher carbon footprint. It's not clear how much environmental benefit there is keeping this system operational, as opposed to tuning for best fuel economy.
I truly appreciate this Great response. Helps me think through tradeoffs going forward as to maintaining “the third system”.

I had noted from previous advice the importance of checking the tank venting. I bought the Haynes manual but it is unclear to me what am I checking for? Thank you for your patience as I ask must be very questions.
 
My air
Well stated.

Passive systems have no effect on performance and weigh very little.

The air injection system is more problematic given how it is driven and that it is indeed parasitic. The pump being driven off the cam, has been known to break by locking up and causing the timing belt to fail. Not something you want on an interference engine.
Hopefully, the skinny air pump belt goes first!

I've seen those air pumps go bad when somebody disables the system by just removing the belt. The hot exhaust gases back up through what Fiat calls "the non return valve" and trashes the pump. Removing the plumbing and plugging the air injection ports (M12x1.25) is the way to go and removing the pump probably saves about 10 pounds.
 

kmead

Glutton for punishment
My air

Hopefully, the skinny air pump belt goes first!

I've seen those air pumps go bad when somebody disables the system by just removing the belt. The hot exhaust gases back up through what Fiat calls "the non return valve" and trashes the pump. Removing the plumbing and plugging the air injection ports (M12x1.25) is the way to go and removing the pump probably saves about 10 pounds.
Need to find a non air pump timing belt cover as well for a 1300 or modify a 1500 cover.
 

EricH

Eric Hamilton
Moderator
Need to find a non air pump timing belt cover as well for a 1300 or modify a 1500 cover.
Not really necessary to change the belt cover, although leaving the old cover in place does make it very obvious that a belt has been removed.
 
I got rid of the cover and backplate when I removed the air pump on my 1300. It makes it a bit easier to work on things and I found that nothing was getting any dirtier without the cover and backplate.
 
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