Smog specs ???

[karl]

i have a 77 heavy half chevy. im guessing this is federal heavy emissions. no cat, no egr. but a smog pump and other little B.S. does anyone have a chart that shows the smog layout for a 77 350 4 barrel heavy emissions. or know where i can get this info? thanks.

[7387chevys]

Originally Posted by karl

i have a 77 heavy half chevy. im guessing this is federal heavy emissions. no cat, no egr. but a smog pump and other little B.S. does anyone have a chart that shows the smog layout for a 77 350 4 barrel heavy emissions. or know where i can get this info? thanks.

I take it that the sticker is gone from the core support?

[rfmaster]

I have 75 C-20 350/350. For '75 heavy duty (over 7500 GWVR) did not use cats - dual ex, AIR, PVC, no EGR, and hot stove for CA/Fed certification. BTW label is on air cleaner, and half damaged. I am also looking for replacement label as well. I'll take a picture over weekend.

RF

[7387chevys]

try lmc for repo label

[rfmaster]

OK

I check my smaog labels and this what I have. My 75 C-20 was built in July 1975 - probably one of the last units of the line. It is equiped with 113 family emission 350 heavy duty

The second label lists three different engines:

4bbl 350
4bbl 400
4bbl 454

RF

[72C203503ONTHETREE]

The 73 C10 I just got doesnt have a sticker anymore. It has a 350 with the turbo 350 trans and it has an EGR valve thats been torn apart and the passenger side manifold has the air injection system thats been removed. The drivers side is the non air injection manifold, one has been replaced at some time but dont know if the truck is supposed to even have AIR. The EGR is held down with a clamp and bolt, almost like a distributor hold down peice not the normal 2 bolts that I have seen. Im wondering if the engine is even original or not. I didnt think trucks had EGR's or air back then. My 76 K20 with the 350 and SM465 didnt have any smog crap at all and the 76 K10 with a 350 turbo 350 didnt have any either but it had been messed with before I got it. I wish I had kept the K20.

[rfmaster]

72 3 on the tree

In the eyes of EPA and CARB, back in 1973, C10 was considered to have car like emissions. C20 on the other hand were considered to be heavy duty, industrial – commercial vehicles. The ¾ and up gas powered vehicles were smog exempt well into 1977 when federal loophole for heavy duty commercial vehicles was closed. At that time EPA and CARB finally brought the emission regulations onto heavy duty commercial vehicles as well.

With respect to 1973 C10 – I am assuming that you have a 50 state vehicle (CA included). For 350CID (Y) with 4 bbl combination I would expect the following equipment requirement:

AIR – Air Injection Reaction - requires Air Pump and special exhaust manifolds or headers as well as temperature controlled vacuum switch.

EGR – Exhaust Gas Recirculation valve usually includes a temperature vacuum switch (TVS) or solenoid to block or bleed vacuum until the engine warms up.

CCP - Controlled Canister Purge, also known as EVAP, - Charcoal canisters and sealed fuel to eliminated fuel vapors.

EFE - Early Fuel Evaporation system includes heated air intake. It’s a very simple system that draws warm air from a "stove" around the exhaust manifold into the air cleaner to reduce emissions during warm-up. Fuel vaporizes slowly when it is cold, so heating the air before it enters the carburetor or throttle body improved fuel vaporization and allows the engine to more easily maintain a balanced air/fuel mixture.

PVC - valve siphons blow-by vapors from the crankcase into the intake manifold so the vapors don't escape into the atmosphere.

No Catalytic converters – these became requirement on all 1975 model year cars and light duty trucks.

I hope this helps

RF

[7387chevys]

Originally Posted by rfmaster

72 3 on the tree

In the eyes of EPA and CARB, back in 1973, C10 was considered to have car like emissions. C20 on the other hand were considered to be heavy duty, industrial – commercial vehicles. The ¾ and up gas powered vehicles were smog exempt well into 1977 when federal loophole for heavy duty commercial vehicles was closed. At that time EPA and CARB finally brought the emission regulations onto heavy duty commercial vehicles as well.

With respect to 1973 C10 – I am assuming that you have a 50 state vehicle (CA included). For 350CID (Y) with 4 bbl combination I would expect the following equipment requirement:

AIR – Air Injection Reaction - requires Air Pump and special exhaust manifolds or headers as well as temperature controlled vacuum switch.

EGR – Exhaust Gas Recirculation valve usually includes a temperature vacuum switch (TVS) or solenoid to block or bleed vacuum until the engine warms up.

CCP - Controlled Canister Purge, also known as EVAP, - Charcoal canisters and sealed fuel to eliminated fuel vapors.

EFE - Early Fuel Evaporation system includes heated air intake. It’s a very simple system that draws warm air from a "stove" around the exhaust manifold into the air cleaner to reduce emissions during warm-up. Fuel vaporizes slowly when it is cold, so heating the air before it enters the carburetor or throttle body improved fuel vaporization and allows the engine to more easily maintain a balanced air/fuel mixture.

PVC - valve siphons blow-by vapors from the crankcase into the intake manifold so the vapors don't escape into the atmosphere.

No Catalytic converters – these became requirement on all 1975 model year cars and light duty trucks.

I hope this helps

RF

Thats a lot of smog crap ........thankfully we have no emissions testing round here.....and that it was a diesel