e3pres

Please no Q-Junk, Q-Crap, Q-Bog, etc. jokes. I kinda like the old beasts. :)

This is my first attempt at a rebuild, and everything seems to be going well at the moment. But I do have a couple of questions. The carb I'm working with is supposedly from a '79 L-82. That seems reasonable since it appears to be identical to the one off of my '79 L-48. So here goes:

Question 1:

The idle-mix screws were sealed from the factory so the person I bought it from had drilled holes in the bottom of the carb apparently to drive out the caps over the screw heads. Will this hurt the carb? It doesn't look like it will cause any trouble, but I want to make sure before I finish the work.

Question 2:

The Primary Jets are 12C? (May be 72C)
The Primary Metering Rods are 40K
and
The Secondary Metering Rods are CH

Will this combination be a good starting point for my engine? (See Sig for Specs) Any other suggestions, comments, or advice will be appreciated.

TIA,

SteveG75

1. Not sure about the idle screws.

2. Seems like a very small rod. I am running a 74/47 combo on the primary side. All rods have the same tip size (.026) so the size of your jet controlls WOT mixture and the difference in AREA between rod and jet controls part throttle mixture.

The knowledge bought to you by the letter A and Lars Q-jet tuning paper (available at http://www.corvettefaq.com). :jester

clem zahrobsky

post the carb # and i will tell what was stock in that carb.

EarnIt

I had a 79 Trans Am with the 403 Olds, and we knocked out the caps to get to the mixture screws. As long the break does not go the width of the gasket you will be fine.

lars

In 1979, Carb# 17059203 ('79 Federal Vette with & without A/C, 4-spd) was jetted with #72 main jets, #40 Primary rods, and "CH" secondary rods. The L-82 engine was jetted with #77 jets and #53 rods, but retained the "CH" secondary rods. The 72/40 combo actually produces a richer cruise and idle metering area than the 77/53 combo, so this should work well on a stock or near-stock '79. Float levels were kept low and lean at about .450". If the car seems to run lean for any reason, you can raise this up to about .400 - .375". Keep your secondary airvalve windup spring at 7/8 turn windup initially, and then slacken it up 1/8 turn at a time until you get a bog going into the secondaries. Don't run it slacker than 1/2 turn windup or the airvalves may not return promptly.

It's no problem with the modified idle mixture casting area: the entire area can actually be broken out with no adverse affects.

e3pres

Lars,
The number on this carb is 17059206. It doesn't exactly match any of the numbers on you chart, but I'm not really to concerned about it as long as it works. :)

I'm glad to hear that. :) I went ahead and cleaned up the drilled area with a cutting wheel on a dremel. I figured I wasn't going to hurt anything worse than it alredy was. :D The holes in the bottom were the reason I didn't send you the carb to begin with. I thought it was ruined, but I don't really like the Edelbrock that I bought, so I figured what the heck. I might even learn someting in the process. :)

You know, you're the only person I know who will tell someone how to do something that he charges for. :). What's up with the carb scrapheap idea? I remember reading something about you paying shipping for old carbs to use for parts. What's the deal? I may have an old one to send your way.

Thanks,

clem zahrobsky

17059206 is 1979 350 light duty truck carb 52 pri rod, 72 jets

e3pres

Thanks. :)

lars

The 17059206 is not a Vette number, so I haven't included it on my "list." 17059206 uses the same jetting as a 17059203: 72/40/CH. I don't have the application handy here right now, but I can get it for you if you'd like.

I enjoy showing and telling people how to do this stuff themselves. Since this is just a hobby for me, I treat it as such and just have fun with it...

I have the first 2 carbs in the carb donation pile all put together and ready to test. "Flareside" sent 3 carbs out to me. He wants a good one back as a spare for his '68BB. "Pedro74" is getting one to replace the Frankenstein Buick carb on his Vette, and the third becomes the CorvetteForum Loaner Carb, tagged with Flareside's name. Whichever carb comes out looking and running the best is going back to Flareside - I have 2 out of 3 put together right now, but I have to fabricate some parts to make the choke pulloff systems work right on 2 of the carbs before I test them. One of the fuel bowls needs a little machine work, so I'm doing that this week, too. As soon as I've tested all 3 of them and shipped the 2 carbs out, I'll post a notice of the service in a new topic folder for all to see. I'm even going to fabricate a good shipping box for the loaner so it won't get damaged after repeated shipments.

oger

Lars do you have any idea why an L82 would need that much more primary jet? The two engines are not much different except for the slightly stronger signal of the L48 at lower rpm.

clem zahrobsky

the air bleeds could be a difference size or does the L-82 have different style air cleaner?

e3pres

In '79, the L-48 and the L-82 shared the "dual-snorkel" setup.