Hoping you guys can help...I've been driving my car for about 3 months now, it failed smog for the second time yesterday and that is probably related to tuning.

Background: I upgraded the L48 in my '77 by upping the CR to 9.2:1, AFR 195 streetfighter heads, hedman long tube headers, and I modified the Rochester carb per Cliff Ruggles Recipe 2 ( I had help on this from someone who is knowledgeable and has done it before). The cam is a Lunati, duration 262/268, 219/227 at .050", lift 468/489 lobe separation 112 deg. Timing is set at 8 deg per the requirement on the firewall sticker and I have the vacuum limiter plate on the MSD dizzy at the lowest position, 5-8 degrees. Compression in all cylinders is 160-170 psi. I have a borrowed SMART air/fuel meter and both idle and fast idle readings are in the 14-15 range. Idle is below 1000 in Park when fully warmed up, it's around 700-750 after startup but increases after a couple of miles driving. At this point there are about 200 miles on the engine.

First attempt at smog failed visual because of an illegal cat and no EFE. It also failed emissions slightly high on HC and CO.

So I had the cat replaced and installed an EFE valve. I also had to reinstall the headers, they were leaking at the flange gaskets.

The second shot at smog passed visual although the guy really struggled with it, he didn't understand the details of the car - didn't even know what an EFE was. But to my surprise it failed the emissions test miserably on HC.

I'm attaching photos of both smog tests and the carb mods.

There are some clues, first of all gas mileage is really bad, under 9 mpg and looks to be worse after redoing the headers and installing the EFE - which I noticed is not opening up all the way. It is thermally controlled, there is a torsion spring that relaxes as it heats up and the flow of gases pushes against the offset flapper assisted by a countereweight.

So I am looking for some help. I am willing to take it in to a shop but everyone who works on these things is booked for 2 or 3 weeks, it could get to that point though. What do you guys think? Fire away...

 

Remove the flap from the Heat Riser....I believe this is what you are calling the "EFE".....it will still function to the test techs eye.....but nothing in it.....not only that, the heat riser does absolutely nothing after warmup.
Secondly......your timing is WAY off......your hydrocarbons are high because there is not near enough advance....late or retarded timing leaves unburnt hydrcarbons because you didn't light it early enough for a complete burn.
Timing needs to be set at 36 degrees @ 3000 rpm.....or something close to that. E-mail Lars for his timing paper: V8fastcars@msn.com Follow the instructions to a tee. The limiter needs about 10-12 degrees of vac advance. You have the timing set at "initial" and I would be willing to bet that your timing isn't but 28 degrees total.
Start there.

Jebby

 

Ok, those are two things that are easy to do. But the reason for the way I have it timed now is to get it past smog, I don't think those settings will fly. I did see that the tech had a timing light hooked up yesterday and he was going by the sticker. Does anyone know about that? I do have Lars' paper and after getting it smogged I was going to set it at 32 degrees initial + vac. Mechanical on that distributor is 22 deg and all in by about 3500 rpm so that would be 52 degrees total at 3500.

 

Set the mechanical to 36 total....let the initial fall wherever it falls......the can should pull 10-12 at idle.
You CANNOT set timing proper by setting it at idle......you just can't......and for 50 years, those who swore by those numbers on the sticker didn't know what they were talking about. Some of us are not sure what GM or the other big two were thinking back then.....but it had a lot to do with lawyers and warranty.
Timing and jetting affect emissions......not much else.

Jebby

 

It just occurred to me, the firewall sticker says for timing to be set with the distributor hose disconnected and plugged. That means I can put more advance in with the restrictor plate, doh!!

 

Can we back up a second to make sure I understand this, correct me if I am wrong which is always a possibility:

Initial timing: set by rotating the distributor at idle with the vacuum line plugged. This is the 8 degree number on the sticker and I am stuck with that, the smog guy needs to see it.
Vacuum advance: comes from manifold vacuum and on the MSD limited by the stop plate (A, B, C, or D position)
Initial + vacuum = Total timing
Mechanical (also called centrifugal): Controlled by the spring and weights in the dizzy, the MSD states 22 degrees

So I am a little confused by what you are calling mechanical, the 36 that you refer to would that be what I am calling initial plus vacuum, or "Total"? The 22 degrees that I am calling mechanical is not adjustable but how it goes in can be affected by changing the springs.

 

Mechanical advance is the actual advance that the distributor achieves at a pre-determined RPM.....it will rise as the RPM’s increase until it will pull no more. After 65 years of different people building, racing, and dynoing small blocks....we all agree that the number for best performance is 36 degrees. You check this with a dial back timing light set to 36 and rev the engine until you reach max advance....adjust to 36.....it may come all in at 2500 or 3500....but generally 3000 is the best baseline....
Forget about initial.....check it and write the number down for reference....but if you set for 36 total....your initial will be about 17-18. This is fine. Now hook the vacuum advance up and see how much more it pulls at idle....it shoul ideally pull 10-12 more.....for a total of 28-30 at idle.
Once again.....forget the sticker. We are talking about total mechanical advance....this is what the engine wants and is one half of the tuning aspect....
If you have Lars timing papers....read them again.
The MSD instructions have different curves in them....use a light blue and light silver spring with the 18 degree bushing.....that will give you 18 initial and 36 total at 3000 rpm.
Total timing and total mechanical timing are different and the mechanical must be done first.
Consequently....if the tech needs to see 8 on the timing light....you may never get it to pass.....without cheating or using a vac can that pulls like 20.
How much the MSD pulls is by all means adjustable....unless you have a Street Fire HEI which is not....

Jebby

 

The first part of your message is pretty much what I did before turning my attention to passing smog. Thanks for the info on the springs and bushing, I do have the MSD 8362 Street Fire so not adjustable.

I talked to another smog guy, this one recommended by the Corvette Shop (the one that is booked 3 weeks out). I'm going to see him on Thursday and find out what he says, seems to know what he is talking about. Also reserved a spot on March 23 at the shop if needed.

Thanks for the input Jebby.

 

In Ca., smog techs have to verify timing set to smog sticker within 2* of factory setting.

 

If that is so....this engine will never run efficiently enough to pass a smog test....it’s like an oxymoron.....
A lot of this has to do with the cam overlap....which is considerably more than stock....more cam overlap requires more initial timing....and 8 degrees is not going to do it.
I don’t have a good answer for you at this point I am afraid....

Jebby

 

Right. The max advance on the restrictor plate is 14-17 degrees so that with 8-10 deg initial gets me to somewhere between 22 and 27 degrees maybe that will be enough to make a difference. I hope it doesn't bump up the idle too much, that's another thing the smog test doesn't like.

 

That would not be good. But I was so close on that first test, I gotta get back to that point and a little more.

 

I feel your pain.
Back in 97 I picked up an 86 Camaro base LG4 car down state in a rural area for really cheap money. I was going to fix it up and give it to my wife. Could not get it to pass smog in Cleveland area Cuyahoga county Ohio where the testing was stricter. The car had passed and was certified in the area I bought it. Made no difference. Turns out the car had a cam replacement that was not exactly like the original. I had it tuned, etc. Nope. Nothing. Ended up selling it to a friend whose son lived in a state that did not smog test cars, and it got retitled there. He made more changes to it and it really has some kick to it now. I would have had a hard time selling it here if I could not get it registered.

My advice - Sell it. You will probably never get it to pass unless you replace the engine with an unmodified original engine.

 

Not giving up yet but I'll keep that in mind. I am sure your wife would look great driving it around Cleveland, the car looks great, interior is awesome.

 

Which shop?

Also was the second test uploaded to the DMV or was it a pre-test. If it uploaded you are now tagged as a gross polluter. A STAR station ot State Referee is the only place you can get smogged now.

If base timing calls for 8 you can increase it to 10 but I don't think that's going to help here.

Was it passing before the cam swap?

 

Kevin at Corvette Connection in San Jose, the smog shop is Adems Smog

Yeah I am wondering about that too. It probably was uploaded but the funny thing is when I went in for the first smog I talked to the guy a bit who did seem knowledgeable and he told me that CA did away with the gross polluter tag. I'll ask the guy on Thursday about that. I don't want to go to a referee, I would think hard about putting it on ebay before I do that. This car has lots of upgrades, along with the engine...a Bowtie Overdrive 700R4, Borgeson steering, Vintage Air, Retrosound w/4 JBLs and the interior almost looks brand new. Not to mention the car has been in California its whole life and there is no rust or corrosion anywhere. I put a lot of effort into this beast.

It was much more than a cam swap (see the OP), the only parts from my original engine are the block and the timing chain cover. But yeah it did pass way back in 2014 before I tore it all apart.

Sheez I thought you guys would come up with a golden bullet for me, this is depressing. But my gut feeling is something is not right somewhere. Might not be obvious, I just need to find it. Why is the gas mileage so bad?

I'm going (one at a time) to reposition the restrictor plate to the position with the most advance, wire the EFE (heat riser) wide open, and check the air pump output.

 

Your 1st test nitrous was way down. 2nd test nitrous was off the charts high. Are you sure your EGR valve isn't caked up with Gluck and not closing correctly?

 

Well you are in CA. My take is that you should have known that you would probably not get away with an engine upgrade like that in the Socialist Republic of California. Yep, you have probably been classified as a GROSS POLLUTOR, shame on you for not toeing the line. And of course now you will not be able to legally sell it to anyone in CA because of this, you will have to sell it out of state. Is that even legal in CA?
Sounds like the car is really nice. Good mods. It would be happy in another state, free to roam and all that....

Sure am glad I left CA (Sunnyvale) in 74-75.

 

I dont think you are reading the test correctly

in your second test, the column you have circled for "gross polluter" on the far right are not your measurements, they are the limits set by the state, the "MEAS" column is yours, and its way low.

it looks like you are actually failed for 3 items- both HC readings, and the bottom CO% which is at 25 mph.

 

Heads are not going to make it pollute......compression is not going to make it pollute. The overlap of the cam will make it pollute.....so will a rich mixture. You may have done the carb exact but after thinking about it now, you need to get an A/F meter and drive around with it to figure out if you are running rich, which is what I suspect, because your fuel mileage is so poor. Also, stick a vacuum gauge on it and tell us what you see......is the needle steady at idle? How much vacuum do you have.
I will repeat myself on the fact that more cam overlap requires more timing and you cannot do that....sooooooo.......
Here is an option......the real Pro-Billet HEI has a 28 degree bushing in it like their small cap units.......you could dial in 8-10 degrees initial and end up at 36 degrees total mechanical. https://documents.holley.com/8365.pdf There is also a 25 degree bushing so you could run 10 degrees initial and 35 total which is ok for your fast burn chambers in your AFR heads. I like this solution...only downside is that the distributor is expensive.
Let's switch gears for a second......an LS7 ZO6 2013 Corvette has a rather large cam and big heads...lots of compression....etc..... The computer that runs this engine uses timing and A/F to make it pass emissions......yes it has a lot of sensors and things but they are all there just to tell the computer what to do. So on an engine like yours......timing and A/F are critical....don't chase your tail thinking it is the engine build.....it is the engine management.....get it right....and your are good to go.....but the timing has to be done first......
I suspect that your Ruggles "recipe 2" is causing the mixture to be too rich at part throttle....
But anyway.....
Timing
Vacuum
A/F meter

Just some ideas........the A/F meter will answer a LOT of your questions......
BTW....do you have a stock Q-Jet you could put on it?

Jebby