EGR / WTF / AND OTHER DRIVEL....

[maytag]

So while I've got it all off.... and all taken apart... and I've identified some of the marginal parts in the system (the diaphragm holds vacuum, but nothing seems to be moving in the valve), I'm wondering why I need it? Why wouldn't I just remove it in a "factory-appearing" manner?

[So Cal Mark]

removing it depends on whether you need it to be installed for a visual or functional emission test. Generally if the diaphragm holds vacuum and the valve won't open, then it's gotten stuck with carbon. Usually the thermal vacuum valve fails so no vacuum gets to the valve and it gets full of carbon from the exhaust.
It's used for a very specific purpose; to lower combustion cylinder temperature under light load. High cylinder temps create Nox, the most deadly of auto emissions and of course detonation which can destroy pistons

[majicwrench]

Engine was designed by some very smart Italian guys to run well with valve. I would leave it on. Not sure how much money I would want to spend to keep it on however. Not familiar with Fiat EGR valves, but if diaphram hold vacuum, and you are sure nothing is moving, it can probably be freed up, as Mark said, it may be stuck with carbon.
Keith

[So Cal Mark]

actually the engine wasn't designed with the valve. The egr was an add-on to meet Nox standards that were imposed. The valves caused some driveability problems initially, mostly off-idle lean conditions that resulted in a sag in acceleration.

[majicwrench]

I'll respectfully disagree. Some Fiat engineer sat down and designed a system that would work with that engine. FI system was probably tweeked as well to work with EGR. I will give you that in '67 (or whenever engine was first designed) they had no thoughts of putting on EGR.
Worked thru the 70s and 80s in various dealerships, even a brief stint in a Fiat dealership, mechanics and the public LOVE to blame the EGR for running issues. Can't tell you how many plugged EGR vacuum hoses I used to see. USUALLY something else is wrong, and the EGR is just amplifying the problem. Plug the EGR on most cars, now they ping. Then people retard the timing, now they REALLY run like crap.
I vote to leave valve on, but it ain't my car.
Keith

[So Cal Mark]

your disagreement is slightly offbase. Of course the egr was designed for the engine (although they did use a Volvo egr valve). The engine wasn't designed for egr. It was a hang on system stuck on the engine when Nox restrictions came in the early 70's. Those systems that opened as soon as the throttle opened caused lots of driveability problems, mostly a sag in acceleration off idle. Many owners discovered the steel ball trick in the vacuum hose would cure the sag, and increase fuel mileage 10%.
Current engines are designed for egr, and they still had driveability problems until they became computer controlled. When emission standards were first imposed, it was only CO and HC. Engineers found that running high engine temps and lean mixtures reduced both of those levels. The trouble was that those conditions sent Nox levels off the scales. Once research showed that Nox was the most unhealthy pollutant, they rushed restrictions into law. The mfgs didn't have too much lead time to meet the levels, and hung egr onto engines. By taking a small amount of exhaust and introducing it into the intake stream, cylinder temps dropped significantly and Nox levels fell. As computer controls came into play, and with the advent of FI, operating conditions could be met to reduce all emission levels through efficiency.

[mbouse]

'scuse me. what was the original question?

need will be determined by your local authority and his/her demand on engine pollutants, and very possibly on visible inspection of "original" equipment.

design of the engine was not accomplished with the emission equipment in mind, the emission equipment was designed around the engine, and USA ever increasing and tightening demands on allowable pollutants. think back to about 1965-66 when the original Fiat Spider dual overhead cam engine was first put in place..there is your design origin... not the pre-F.I. emissions laden, two litre.

USA federal and local laws were changing faster than anyone could keep up with, especially and including the best in the field of controlling emissions, and certainly the former big three, Fiat, and anyone else attempting to sell cars here. frequently laws had to be repealed or revised because they were just too stringent for any manufacturer to adhere to in a competative manner. that is why you will see every year from 1974 on having ever increasing pollution equipment devices added and modified on our engines.

this is the environment that created the Spider two litre engine that could not get out of its own way.

[majicwrench]

Again, to disagree respectfully,   The engine was not originally designed for EGR, that is a given. By same token, was not designed for FI either.    To say valve was an "add-on" makes it sound like something they put on as the boat was nearing our shores.  Not true.    Some very smart Italian guys figured out how to make all that stuff work together.  The engine itsellf, it's compression ratio, the camshaft design, WAS changed to help lower emissions, and work together, as best they could under the rather trying circumstances.   It is not just some '71 engine with a bunch of emmisions stuff added.       To the original question, i'll stick to my original response
" I would leave it one. Not sure how much moneyI would want to spend to keep it on however."
Keith

[manoa matt]

"To say valve was an "add-on" makes it sound like something they put on as the boat was nearing our shores. " Yes, exaclty!

The smart Italian engineers never designed emissions equipment for Fiats because there were no emissions requirements in Europe either prior to, or after the American standard in 1974. The "add on" systems were designed so that the cars could meet US standards. They were rushed into production, and hence why they use GM components for the air pump and check valve.

I'd consider myself a pretty smart Italian guy, but I'd never design an emissions system for an Italian car with GM components.

[majicwrench]

Again, to disagree, are you saying they put the EGR on as the boat was chugging across the Atlantic?? If some Italian guy didn't design the emmisions stuff, who did?? The Italian guy may not have actually designed the air pump, (GM) or the EGR valve ( VOLVO) but he sure a heck put it all together. Somebody made the exhaust manifold to accept the EGR, and it wasn't GM. Someboy made the intake to accept the feed pipe from the EGR, and it wasn't GM. Somebody designed the brackets for the air pump, and it wasn't GM. Somebody lowered the compression, and it wasn't GM.

All car companies use part supplied by other vendors.
Keith

[amsiegel]

Here is my 2 cents. I am not a mechanic I just tinker with cars.

Point 1 Just because someone is an engineer does not mean they know what they are doing.
Plus was it really a design or just copying what the companies where doing
I have seen smart people design dumb things.

Point 2 The orininal engine design did not have all that stuff on it it was added on later.

Point 3 Maybe 30 something years ago when the stuff was added on to the engine everything might had worked well
but know this stuff might be clogged, broken, or impossible to find. If it is not needed in the state you live
in and it is not working remove it.

Point 4 My car (1977) had emission on but was not operable. I removed all the pieces. If I remeber correctly there was
2 copper tubes with mulitple connextions points, the 4 ports on top by sparkplugs, the temperature thing on intake manifold, the 2 senor things, the countless rubber hoses going back and forth accross the engine. Plus the pump which was already off the car. In that list if things in one item got a small hole in it than something would not run right. Plus if the pump locks up there can be a big problem.

I like to try to keep things original but sometimes older things need to be modified.

[mbouse]

wow! lots of other Drivel....

wonder if we ever answered the original question? near got to fist-i-cuffs, but the original question is still out there, me thinks.

maybe the originator of the post could sift thru all this and restate the question at hand..in his garage..for his car.. despite and except for the definition of the word "IS", cuz in my book nothing we just got done typing has anything to do with maytag's situation.

[So Cal Mark]

I think the question was whether to remove or not. IMHO, I'd remove it, but that isn't the federal legal answer or perhaps not the ethical answer either if we are responsible, earth-loving adults. As mentioned earlier, if the stuff isn't working at all, or malfunctioning to the point the engine runs poorly (thus raising the emission level even higher) remove it.

[bwilson27]

Sorry, I can't answer the original question, but I have a related issue myself; I have a '74 without the cat, but it has the smog pump. I know I'll need this on to pass the visual test, and possibly the smog test itself.... But when I've passed the test, and have two years between tests, can I remove that pump, and if I do, will it affect performance? Would I just plug all the hoses and holes? Or is there pointers on this?
Sorry to threadjack.

[So Cal Mark]

you won't notice any change in performance if you remove the system. Don't just take the belt off the pump though, they have a habit of locking up if left on the car for exhaust gases to work their magic