ericupnorth

Hello
I recently asked on a previous thread for some information regarding reinstallation of emission equipment on a 1975 Corvette L82. The PO has installed an Edelbrock intake and carb. Although I have the original receipt for the work no part numbers were included. I just wanted to upload some photos in order to see if they are clear enough for a member to determine if this intake is a Non-EGR version and if so if someone can determine whether or not that carb. is compatible with the Edelbrock intake that is available which accepts an EGR valve in the event I need to switch intakes. I have a rough idea where the EGR goes from previous information provided however several angles are included.
Thanks

ericupnorth

Here are a few more.

Mike Ward

That's a non-EGR manifold. I believe that Edelbrock makes an EGR equivalent. In your shoes and if you want to keep the smog police happy, I'd track down a stock manifold and carb. In addition to lack of EGR, the existing set up uses a rubber hose for the fuel supply to the carb. That's a fire hazard.

cobrachuck

Bought this car not running it sat for 19 years, original 31,000 miles.
Touched for the most part. Stock should look like this, i

n Ohio we do not have e testing so I removed
most of the this.

Stock set up it does not look like this now

ericupnorth

Thanks guys.
Mike, I have seen the Edelbrock intake which allows for the EGR valve installation online. It is essentially the same price as this one I currently have. Do you figure that one allows for the installation of all the emission equipment or even with that I will still have issues. I also will try and go and go see the shop where the PO had the work done and get their input.

Mike Ward

We're talking about the Ontario Smog Police here. Who knows how picky they can get?

DUB

I know you did not ask:

BUT....if you are not under the hood checking things all the time to make sure 'things'a re all good. I know if you brought your car into my shop for an inspection...I would HIGHLY recommend that the rubber fuel hose going to the carb...and coming from the line at the front of the engine be REMOVED...and a new set-up installed.

I am not and NEVER will be a fan of or endorse a fuel system that uses hose clamps...AND YES...I still do not like the 1969 fuel filter set-up.

DUB

ericupnorth

Sounds like good advice. Doesn't take much convincing as soon as the word "fire" is used. Off topic but replacing anything rubber which is in contact with fuel to metal was something I wanted to look at with regards to ethanol in fuel. At the moment We have access to ethanol free fuel at a couple of stations however there is no telling how long into the future that will last. My service manual indicates that my engine was ok with 87 octane. I would like to eventually be able to burn fuel containing ethanol without worrying about damage to anything rubber or whatever else ethanol harms.

DUB

VERY WISE! I do know I have read in the past that Edelbrock carbs do not want a hard line attached to them...for some stupid reason...I think it is due to the amount of casting material around the fitting where the fuel enters is so minimal...UNLIKE the material on a Quadra-Jet...which is hard lined...and is STOUT.

NOW...I have hard lined them and also installed a fuel filter also that uses a 6An fittings and have not had a problem...and I have also used 6AN braided hose and the correct fittings also. I also made custom line clamps and holders. so the line was solidly mounted at and near the carb.

DUB

Mike Ward

Ethanol compatible materials have been standard issue in Canada for almost 30 years, since we've had E10 for almost that long. This issue should be the least of your worries.

ericupnorth

Thanks Mike. While I bought this car to have fun with not worry about so I will just try and knock off these issues one at a time. That is good to know about the fuel. Do you figure then that C3 people in Ontario are ok burning the 87 octane fuel with I believe is 10% ethanol with no difficulties ?
I did speak to the shop earlier today where the PO modified the engine. He claims he can swap intakes and then restore the emission equipment if so desired. As the vehicle has headers a modification would be required where the line goes from the A.I.R. pump to the exhaust manifold....but they could do it. I thought it was interesting. I think I understand your point however where the smog police might still have some difficulty with it as although the emission equipment is there and functioning the engine does not appear original....assuming that is what you were alluding to in your previous post.

Mike Ward

I've been running all my cars on E10 for 20+ years, no problem. The 'sky is falling ' crowd sometimes gets a little excited.

As for the smog police, I don't know how exacting their standards are and whether the regs. permit a custom made set up. I've never figured out how they can keep track of hundreds if not thousands of configs. that were around in that era.

Paul L

They kept their database pretty well concealed. And won't disclose it to those who have asked for disclosure. But I have not seen them for about three years. They certainly have not put in an appearance in local shows last summer or the former. Perhaps passe. No real reason for their existence given that old/vintage cars are perhaps 0.01% of the population. And are rarely driven.

They waste more gasoline attending our charity events than we do being there.

ericupnorth

Thanks Paul
Now that the province is broke perhaps they have to limit themselves to constructive activities. I got a lot of good info. on the thread though.

DUB

ericupnorth,

NOT meaning to ADD more to your list...but I noticed something and just want to point it out.

REGARDLESS if you do emission repair issues or not.

I noticed that your VACUUM ADVANCE pod on your distributor has no vacuum going to it. I know many engines where the distributor runs off of strictly centrifugal advance...so that is not so much of a big deal if the performance has been verified and it runs great that way.

Early cars used PORTED VACUUM operating the VACUUM POD.

THEN....GM went to CONSTANT VACUUM....BUT.....what they did was use a Temperature Vacuum Switch (TVS). AND what this switch does...is that when GM wanted 'something' that they controlled by VACUUM to be controlled.....they used these TVS'. In some cases...there were three of them.

If you look at the engine in POST #4. These TVS' are located in the thermostat housing and one is just below it to the right where you see the two black hoses connected. This TVS with the 2 hoses is controlling the EGR.....so when the engine coolant temperature gets high enough...it will open this switch and allow the vacuum to operate the EGR when needed....BECAUSE GM did not want the EGR operating too soon when the engine was cold. MAKE SENSE????

WELL..what I am getting at is that the other TVS was used for the VACUUM going to the distributor. SO when the coolant temp got high enough...the vacuum would work the ADVANCE pod as designed....BUT would not work when the engine is COLD.

The reason I wrote this is that I get numerous Corvettes yearly In my shop that are so screwed up and the owner wants me to get it 'running right'. BUT the problem is that someone has already slapped aftermarket parts on it.... NOT taking into consideration any of the critical dynamics that will make the engine run correctly and these parts actually fit under the hood.

From what I have encountered....when an engine has its VACUUM ADVANCE pod connected directly to a full vacuum port...when it is cranked cold...it is hard to get to run right UNTIL it warms up. Many customers do not like this inconvenience and want it working correctly so they do not have to 'baby' the engine to keep it running. And YES....that is even if it is set correctly on a high idle RPM's.

Just thought I would mention it if you come across having and issue when it is at the mechanics shop.

DUB

ericupnorth

Ok...I have been reading a bit about the emission system from various sources so I think I follow. Actually i just had the Assembly and Service manual delivered however I can't have them until the 25th.
What I am confused about regarding my aftermarket intake as it has been determined now to be a NON EGR type. There appear to be the two holes at the forward section for the EGR TVS switch and the EFE TVS switch. Some form of a plug has been threaded into the two holes. Perhaps I am wrong and they are for something else however they look close to the right position as depicted in the emission diagram. If this is indeed correct then why would they sell an intake with provisions for these two switches ( I assume they are considered part of the emission system ) and no provision for the EGR valve. I don't understand why you would want the two without the other.
I haven't had my car long however to me it seems to start and then initially idle a little on the high side. It seems to idle at about 1800 RPM for thirty seconds or so...then sometimes the idle falls back to about 1300 RPM and sometimes you need to nudge the gas pedal a bit and then the idle drops off. I have no idea if that is normal or not or how it compares to the stock set up.
Thanks for the detailed info.
Eric

Mike Ward

Yet GM and other OEMs built hundreds of millions of cars just like this. And they started and ran just fine. Mine always have (?)

Jim Shea

FYI, all 1975 (both L48 and L82) Vettes came with an AIR pump. So if your smog police make a visual check, you will have that problem as well.

There should be an emissions label underhood that calls out AIR and other required tuning and emissions equipment.
Sorry,
Jim

DUB

The ports in the top of the intake can be used for a temperature sensor for the temp gauge. Some early Chevrolet's did not have an area in the cylinder head for the temperature sensor. So it was installed in the top of the intake manifold....hence...the ports being there.

https://www.google.com/search?q=phot...27%3B300%3B210


Eric..the high idle is doing what it is supposed to do. I would have to verify the actual number...but with it dropping in a 30 seconds...and when you tap the gas pedal it drops and idles...you seem to be fine. Fine tuning may be needed when you get your book and look.

NOW...without me getting my head chopped off for mentioned it...If you plan on doing the emission repairs....and IF you TRY and connect a vacuum hose to your VACUUM ADVANCE pod and connect it to the carb WITHOUT using a TVS...You may be fine and then again....you may need a TVS for the EGR and distributor....but as I wrote before...it needs to be checked. I do not know the reason no vacuum is going to your vacuum advance pod....so your mechanic or having the car on a chassis dyno can aid in determining this reason.

As for a EFE TVS...you do not need one due to having headers.

LUCKY YOU!!!

I am aware of what GM did ( don't care about other makes)...and YOU do AGREE GM used the TVS' for a reason...or am I just making this stuff up????

And as you know NOT every engine is the EXACT SAME....and I KNOW this from experience...and I am sure you agree. There is NO HOLY GRAIL of set-up's that works for every engine.

I can get an engine to perform and run GREAT and when at operating temp...it is a bullet..or as close to a bullet as the engine will allow. The I come in the next morning and do a COLD start and it is 'having issues' that 'self correct' themselves when it gets warmer.

DUB

Mike Ward

No need for sarcasm. You inferred that a car with full time vacuum to the distributor would not start and run properly. This is false, GM built millions of them before ported vacuum was introduced around the beginning of the 'smog era'.

The OP's engine can be set up similarly.