egr valve

[sikoticnaz]

what yr did chevy trucks start having an egr valve? i am looking around at trucks right now and want one that doesn't have an egr valve or cats
thanks

[old Rusty C10]

my 86 with a 4.3 has no cats i know for sure i dont remember having an EGR either

[PHOENIX]

You in AZ?

Not sure what year, I think it may have changed depending on what state the truck was for. Someone could probably answer better. There is a sticker under the hood near the hood latch. The sticker shows what emissions equipment should be on that truck. Something to look at when buying a truck. This sticker is the same thing the inspectors look at here in AZ for visual inspection during emissions testing.

If you are trying to stay away from as many emissions components as possible get a '73-'75 ?

[rfmaster]

My 1975 3/4 ton heavy duty with 350 has no EGR or cats in Cal, but I have A.I.R.

Light duty (1/2 ton) have EGR and cats.

AR

[sikoticnaz]

what is this A.I.R. system u speak of?

[old Rusty C10]

AIR is the air pump that pumps cold air into the exhaust
i stand corrected tho my 86 has an EGR in it although it is broken and my air pump isnt operating either i figured that id fix it in march when i need to get past emmissions unless i can get someone to overlook it

[sikoticnaz]

i guess i should focus my search to 73-75
i really don't want cats and if i don't have to have egr i could do without that also, but i still need to pass emissions. thanks for the help

[Russell]

My 1980 3/4 ton doesn't have the AIR system, but does have an EGR valve, I actually want it on there so the engine heats up a bit quicker...

[Fletch]

Emission controlls such as Catalitic Converters , EGR and A.I.R. were determend by GVWR, gross vehical weight rating. I know in 1977, Pickup Trucks with GVWR under 6400 lbs. had Emission Controlls. Trucks over 6400 GVWR had none. I believe it was the same for 1978, but after that, started putting controlls on trucks under 6400 GVWR.

[Fletch]

Originally posted by sikoticnaz
i guess i should focus my search to 73-75
i really don't want cats and if i don't have to have egr i could do without that also, but i still need to pass emissions. thanks for the help

1973 to 1975 tucks did not have cats, some of the under 6400 lbs. GVWR may have had EGR valves. As far as passing Emissions tests, you have to meet the Emission Standards that were in place for the year of your vehical i.e. 1974 truck must meet 1974 Clean Air Standards.

[Grim Reaper]

About the only place you need to worry about emissions on anything older then 78 is the Republic of Kalifornia on a Cal emissions truck. I know a Cal 1/2 ton truck was running EGR in 74. Waxer over at CK5 had a hell of a time getting his 74 K5 past emissions. Ended up having to change intake manifolds and some other junk. I hear that some 76's had Cat's there as well. The rest of the country didn't get cats till 78 or later. My 75 doesn't have anything but a PCV valve. Not even a canister. My 79 had no Air junk but did have cat's, Evap, restricted fill neck, Thermac.

Now EGR's were used by GM well before the emissions crap. My 70 Burb had a 64 327 with EGR. EGR is not the evil monster everybody thinks it is. In a higher compression motor it helps control detonation. I had a hell of a time getting my 75 to quit pinging. I was ready to drop a EGR intake on it. I ended up having to run it a little wet and back out of the timing, Get it freash air (it had the restrictive under hood aircleaner with no Snorkle) by throwing a 85 Aircleaner on it with a snorkel.

Whay did I have such problems?....THe motor was setu up for leaded fuel. Leaded fuel is less prone to detonation.

[swervin ervin]

No 327's ever made came with a EGR. Some must have stuck a later year EGR intake on that thing.

But I do agree, with a EGR, you can run more timing.

[mike reeh]

Originally posted by Grim Reaper
THe motor was setu up for leaded fuel. Leaded fuel is less prone to detonation.

what was different being that it was setup for leaded fuel?

mike

[swervin ervin]

As far as I know, the only thing different in a leaded fuel motor and non, is the valve seats.

[Grim Reaper]

Originally posted by mike reeh


what was different being that it was setup for leaded fuel?

mike

Compression. You can run more compression at a lower octane on leaded fuels. The Lead has a simular effect as Octane and rasies the flash point of the fuel. So you can run more advance on the timing without getting into a ping problem. At High RPMS or heavy load the fuel ignights bbefore the sparkplug goes off. That's when you start having spark knock/ping/detonation/woodpecker infestation problems. Carbon build up can cause a simular problem. It raises compression and it can have a hot spot that will light the fuel.

The EGR actually can help becuase it pumps a little no oxygen gasses in there. Sound counter productive I know but it helps raise the flash point enough to stop ping and let the ignition be all spark plug.

[bigd65]

what do you hook the vacuum to on the EGR. i am getting a new tomarrow and need to know, PORTED or MANIFOLD

[swervin ervin]

Ported. You only want it working above idle.

[784X4GUY]

I have a 78 3/4 4X4 (Arizona Truck) and it never had cats or egr or AIR Injection

[alf4444]

My 78 blazer has nothing on it (cats, egr, air) its a 1/2 ton originally had a 400 in it but i haven't got it to the point of taking it in for inspection hopefully it passes, I think it shoud with the new engine, i'm thinking it probably will only be street legal for the first year anyway.