stevekk

I need help to take all the smog crap off my 74 small block.

I have already taken the smog pump off and plugged the holes.

What about the rest of the crap? Can I do this? Should I do this?
Am I wasting my time? Better performance? Yes or No?

Can I buy a book to guide me through it?

I am In California and my 74 is exempt from the smog laws.

Please advise. Or am I being a weenie for not being a greenie???

Thanks

72LS1Vette

You're not likely to find the Environmental Police on this forum!

You can also remove your old exhaust system and put on a true dual exhaust with no cats. Your carb could go into the parts box also. The biggest problem with the mid-70's engines is the low compression ratio. Since crate engines are so reasonably priced you are probably better off removing and storing the original engine and dropping in a new motor.



Rick B.

1974slcvette

1974's had true dual's..... last year before CAT's were installed by the factory.

SIXFOOTER

Keep the evap recovery system, thats the black canister in the drivers side fenderwell, Add on some nice headers instead of the manifolds, good breathing mufflers or side pipes. I would keep the egr if it has one. There may be some stuff on the air cleaner you won't need, its there to warm the engine up quick if it works. If it works, keep it, if not a better breathing air cleaner is in order. Tune the engine to run instead of for emissions and economy.

enkeivette

Unless you're going to redo the exhaust you won't notice any performace gain. Just pull the belt off the AIR pump and be done with it, otherwise-> long tubes.

The3

I know your 74 is exempt from smog testing but not sure if that includes inspection. Some questions for you.
Have you registered the vehicle in California yet? If so did they look at the car or just give you a sticker.
Is your vette a Cali car or federal? I think this might make a difference at some point in time.
I would at least save all the smog equipment. I'm also willing to bet there are some members here willing to buy or rent your old smog gear. There was thread a while ago with some likely candidates.

SIXFOOTER

i WAS CURIOUS THE OTHER DAY AND FOUND 3 80'S SMOG PUMPS ON EBAY FER $50

stevekk

Thanks for all the input.

I am mainly interested in cleaning up the engine compartment of all the smog hoses and stuff, rather than performance.

I know I have seen books on taking smog stuff off. Does anybody have any sources.

And yes I would save and label everything. As for CA smog, if you live in certain low population counties, they do not require the 2 year, I think, smog certification. CA enforces that by making it a requirement on your annual licence registration.

Also I do not think sidepipes are legal in CA, because of the flow thru muffer rather than a baffeled muffler. Does anybody know for sure about this??

Easy Mike

Since it's illegal in lots of places to remove emissions crap, the odds of finding a How-To in a book somewhere are slim unless the thing was published way back. Why not purchase the assembly instruction manual (AIM)? It shows how all that stuff was installed at St. Louis. Ought to be a piece of cake to remove it if you've got a picture of how it was assembled.

My .02, but get a box and keep everything you pull off. Come resale time, a future buyer might have to have it.

63 340HP

I do not think you will find a book on removing emissions controls because it is a federal crime to get paid to remove the equipment (you can do it yourself, but hiring a shop places the shop owner at risk).

Your vehicle is exempt from testing in CA (under the old 30-year exemption by one year). You will not be inspected or required to test ever again, the car is exempt from either requirement (unless your elected congress votes otherwise and the Gov. signs agreement).

Sidepipes are legal on an exempt vehicle up to the noise law (95db, IIRC) and a citation is a purely subjective call by a LEO.


Removing some of the emission controls required in the old visual inspection requirement will not always increase the smog forming emissions produced by the vehicle. A modern high performance engine does not have to pollute more than the technology in 1974 could achieve. Modern oxygenated unleaded fuel is much cleaner than what was available in 1974, giving you an advantage. The challenges of poor fuel and limited experience controlling NOx emissions for 50,000 miles forced many compromises in emission controls that have been eliminated by improved technology.

The PCV function helps emissions and power (keep it).

The EGR will only hurt power if the valve sticks open (causing a lean condition). It was/is controlled to only open the valve under cruise and hot idle. It's mission is to dilute the available oxygen in the intake charge by mixing burned exhaust gas into the intake, to result in a lower combustion chamber temperature and lower NOx emissions. The EGR valve is closed at WOT. Keep it if it does not leak and the controls work (leave it closed if the vacuum controls have been removed).

The air pump was a bandaid fix to clean up the unburned fuel in the exhaust manifolds before the exhaust left the tailpipe. The intent was to add air to the exhaust and dilute the overall mixture, and hopefully add enough oxygen to complete the reaction of any unburned fuel to drop the CO emissions. A modern 3-way catalytic converter is a much more effective reactor (and the impact of a modern cat converter's minimal backpressure on power is much less than the air pump friction drag). Dump the smog pump (and install dual cats if you really care about emissions).

The carbon evap canister is intended to provided a filtered vent for the fuel tank (clean the gas fumes). It has zero impact on power (so keep it).

The canister has a similar vent hose running to the carb to clean the fuel vapors in the float chambers, and it's highly likely the carb's idle mixture screws originally had tamper proof caps. Getting the A/F mixture correct with modern fuel will reduce emissions, so jet the carb for power and tune the idle properly (or install a carb that will allow you to tune it properly). The air filter snorkel was designed to reduce noise and provide heated intake air to reduce the warm up time where emissions run high (needed to boil the vapor in the poor 1974 fuel to leave less unburned fuel to add smog in the exhaust). With modern fuel and quality ignition timing the heat is not needed (so fit the least restrictive filter you can buy).

The 1974 ignition timing & advance curve map was detuned to reduce emissions. With points and limited coil power the ignition map was detuned to meet the 50,000 mile duty cycle (simulate worn points and still pass emissions). Again, a modern ignition system will provide more spark discharge power and lower emissions. Look at the ignition tuning recommendations posted for the early C3's for the vacuum and centrifugal advance curves, and total advance, and apply it to your car. This mixed with an MSD or other high energy CDI ignition system and an electronic trigger (points eliminator) will add power and reduce emissions (you will not have point wear to force the compromise on timing and way better combustion).

Look at the camshaft timing. The camshaft is probably timed with a few degree of retard (compared to the same cam in a 68-70 car). This was done as a quick fix to reduce emissions (hang the exhaust valve open late in the intake stroke and suck back exhaust gas, just like the EGR, to lower chamber temps and emissions). Timing the cam to the earlier year specs will restore power, and with modern fuel a minimal increase in emissions. Swapping the cam with a properly timed L82 grind would probably reduce emissions and increase power. There is considerable power to be added with the proper camshaft and a minimal emissions penalty (again, if you care, run 3-way cats and it will be way cleaner than the 74 specs).

The heads are the place to add power, and adding compression is a major benefit (besides the potential airflow gain). The fuel available in 1974 did not burn well enough to offer detonation resistance and low emissions. Detonation increases heat and NOx emissions, and the factory 50,000-mile solution was low compression (those 76cc chambers and flat top pistons). Swapping higher compression heads will increase power, and proper ignition timing with modern fuel will resolve the detonation and NOx problems leading the 1974 emission control challenge.

Since the smog pump is not needed (and the air tubes on the factory exhaust manifolds) headers will help power with no further negative impact to emissions.

The fuel available in 1974 and the pre-converter emissions reduction technology combined with the 50,000-mile test cycle really compromised the performance the factory could design into the vehicle.

Your car will receive way better care than what the 50,000 mile test requirement was based upon, you have better high-octane low-emissions fuel to burn, better ignition technology, and can pay more attention to air/fuel mixture tuning than what was common in 1974. A few $$$ dyno tuning with an exhaust gas analyzer as a tool will benefit reduced emissions and increased power significantly better than what was available for a similar expense in 1974.

Beating the 1974 emissions with better power (and no air reactor smog pump or heat stove riser) using modern tools is much easier now than in 1974 (even without the real-time A/F tuning of MPFI and/or the reactive exhaust cleaning of a 3-way cat). This fact is the basis for SEMA's demand to allow CA cars in the future to be tested on only the measured tailpipe emissions and visual fuel leak requirements for the year of manufacturer. This is the basis of the newer rolling 35-year CA law relaxing the visual testing requirements for the 1976 and newer cars. The 1976 and newer cars will never be exempt from emissions testing like your 74', but thanks to SEMA and many people writing letters to the state congress they will be able to eliminate the obsolete emissions controls that the factory was forced to use as a compromise to clean up old fuel formulations with old technology.

Technically, it is illegal to add a 3-way catalytic converter to a pre-converter vehicle in California, regardless of the resulting reduction in smog forming emissions (at least it’s illegal until the car is 35-years old). You can clean up a lot of emissions problems with modern technology, it’s just against the law in California to do so before the car is 35-years old. Changing this catch-22 is one reason to keep up on what SEMA and other motorized enthusiast organizations are doing, and one question to ask your candidates at election time (and ask loudly).

Good Luck.

Little Mouse

Damn enviromental *****

onaqwst

how long would i have to have to register a car if i move into cali and do the smog laws emply if i bring a non-cali car in?....

b

Joes80

I have an 80 with true duals, no cats, and I asked about A.I.R. removal on the general forum, it seemed like I recieved the environmental police answer, no big deal. All I wanted to know is if there were headers that would accomodate the A.I.R. provisions(interested in hugger headers mostly), if the A.I.R. was part of smog equipment, and if I could/and did remove it, would I just plug the holes.
Still unsure of the answer...

wes weigle

What Ever You Do Dont Throw The Smog Equipment Away. California Modifies Its Smog Laws About Every Couple Of Years And The Age Exemption Is Threatend Every Time They Do, Dont Be Supprised If The Age Exemption Disapears In The Future. For A Couple Of Years It Was A 30 Year And Older Rule Which Would Have Had All Cars 30 Years And Old Would Be Exempt, So A Year Was Added Every Year. Last Year They Screwed Us Going Back To The 1974 And Older Rule.

Chuck-75

on my 75 I havent had to get smog checks ,here in calif. this is the last year that dosent have to be checked. (as far as I know). im running a ZZ-383 crate motor with Hooker side pipes.
Ive heard that here in CA. you dont have to go through smog checks but you must have all the original smog / emmissions stuff working?
the 75 year is the first year of Cats. so if yr pulled over and the cop has had a bad day he can have yr car towed?
I dont have a daily driver and Im 43 so I take my chances and if that time ever comes Ill show the officer that I only drive the car 1 or 2 day a month. and he will see that the car is for show and not for street raceing.
I hope I will never run into Mr by the book with no compasion.
other wise I have saved all my original engine and trans and smog. wiill have to bust my *** and just do a quick engine swap and get the fixit ticket sighned off.(what a pain in the ***)
but thats the price I will have to address one day?, (hopefully not.)
chuck-75 vert

breathial

I think you should dump all the smog junk... Get some good headers, true dual exhaust... A better induction system and a nice cam...

And LAUGH at the idiots being "green" in their Toyota PRIUS's...

stevekk

Thanks for all the ideas and help. I started removing some of the smog stuff. Like EGR and smog pump. I made a 1/4 inch steel plate to take the place of the EGR and used the original clamp to hold it in place.

Will let you know how it turns out.

Any more ideas???

Dracule

I guess I'm lucky where I live... I could say...... that my guy at the inspection station would get a Radio Flyer Wagon to pass. I could say that, but I won't. Were I anywhere else, I'd have to follow the rules or fall into the year exemption law. I feel a motor can 'look' all hooked up, but be in camouflage mode. Having everything present will certainly keep a zelous Highway Patrol officer at bay. Just saying.

Alwyn678

Indeed! You car REALLY make your 74 move with the right changes

cv67

DONT listen to the nonsense of "throw it out!!"
(wont make any more power youll feel anyway)

Listen, you dont have to smog test or inpect-yet

However you MUST have it on the car (even if it doesnt function)

Down here in LA the police have the authority now to have you pop your hood and check for smog euiptment.
They take some lame-o quickie class and now are qualified to check. Sure its BS but some will play the role

Not on there car gets impounded on the spot
If its there and they dont know what they are talking about same thing. If they have a hard on for you.....get the picture
Refuse to pop the hood ...bye bye car.

Its real , its CA law be careful.

Just know other states tend to follow our screwed up leads.
Look at Arizona all those musclecars are getting smoged.
Matter of time

This is no BS youve been warned.



on mine (67)I have a pcv..going to find the crustiest non working smog pump I can find and hang it by the bottom bolt by the fuel pump not hooked up. It is now legal. lol