Bought a 73 280 a week or two ago, trying to tackle some issues. Chiefly, I want to get rid of the Solex. Don't convince me to keep the Solex, not going to happen.

Anyways, I snagged a q-jet off of a 79 El Camino at the junk yard, $10, 17058582... M4MC. Ordered a rebuild kit, but I need to grab some other pieces as well. From reading previous posts in this forum I gather I need something around .072 jets and 0.041 metering rods for the primaries. No idea what I should get for the secondaries.

Anyways, my carb knowledge is pretty much limited to SU's (1 barrel, 71 Mini Cooper). Looks like I'm going to have to drill new mounting holes and have some fun fabbing up the linkage. Also, the q-jet I have has a hot-air choke, but it looks like electric conversions are available.

I'm going to have a million questions as I do this, but I'm also going to take as many pics as possible so perhaps future members can benefit.

A couple of things you need to do.

There is a vacuum line tee on the bottom rear of the carb. Remove it and replace it with a plug. Do not overtighten the plug as it will crack the base plate. It touches one of the bolts for the acc. linkage and creates a hidden vacuum leak.

Don't change out the metering rods until after you test the running of the car. You might not need to change them. Ignore the secondary metering rods. You aren't going to flow enough air ever to consider increasing them and the stock ones are pretty skinny in the '79.

I don't think changing to an electric choke is going to work. The housing will still hit the valve cover. You might be able to rig something up. I just installed a manual choke and mounted the inside handle to the right of the steering wheel out of immediate sight.

I made a "L" bracket and clamped it onto the existing linkage. I drilled a hole into the Qjet's existing linkage and the bracket and used a pair of ball pivots and a short length of threaded rod for the connection.

You want to keep the "at rest" position of the linkage as close as possible to the original stock. The acc. linkage controls the transmission shift points and if you have it way off it makes the tranny do some weird stuff.

I don't think you can keep the stock air cleaner. I used a standard 9" X 2" chrome aftermarket replacement. Flip the top lid upside down and don't use the fancy retainer which comes with it. Use a standard 1/4" nut. Check for clearance BEFORE you close the hood.

You need to fab up a connection for the valve cover blow-by hose. I think you just need an elbow connection for the air cleaner.

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Thats what I like about this forum. Not the off topic stuff, but the real world advice of those that have done the job and made the mistakes before you.

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Oh, yeah. If you look at the picture in my previous post notice the allen head bolts holding the rear of the carb to the manifold. You might need to use a dremel tool to remove a bit of the throttle plate housing. It all depends on the year of the Qjet. I had to do it with the one I adapted but I saw one which didn't need it.

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Thank you very much for chiming in Mike. Going to the part store to pick up a re-build kit right now, guess I grab a manual choke cable as well.

Hard part about this is the 280 is a couple miles away, so I can't constantly check measurements at the moment.

I've done some more disassembling, the metering rods say 52k which I assume means .0520. Main jets are size 76. I'm thinking that they will work fine.

If you haven't put the carb back together, look on the bottom of the bowl (middle) section. There will be two brass or steel plugs. J-B weld or epoxy where they meet the pot metal casting. This is a known weakness on Q-jets. They leak air everytime! Be skimpy with the epoxy as they sit into recesses in the throttle plate.

True up the mating surfaces of all three pieces with a piece of very fine grit (800 or better) sandpaper on a sheet of glass.

Have you read the Buick White paper article on Q-jets? Excellent article and it tells you exactly how to rebuild the Q-jet to peak performance.

The plugs have been jbwelded, I'll give them a few hours to dry so they don't end up bonding to the throttle plate. I grabbed a book at borders on Rochester Q-Jets, so far so good. Plus there are a million online guides, so if one doesn't make sense, I can just check another.

Took the secondary throttle plates off to clean em, all four screws snapped. Looks like I need to drill them out and find new screws, or just pocket the parts I need from the junkyard. I can still continue rebuilding without this part though, as it looks like it can be inserted at a later time. Wish my digital camera I ordered will get here quick, I need to take pictures as I do this. Old camera was stolen out of friend's car, and my camera phone is just pathetic.

I'm glad you mentioned the secondary throttle plates. It reminded me of something. When you install the carb on the car have the throttle wide open with the secondary flaps open. This allows you to center the carb onto the manifold. Make sure you have free movement of the secondaries. I didn't the first time and the secondaries stuck about 3/4's of the way open. Gets the old pulse rate way the heck up there.

Finished rebuilding the damn thing (two base plates later), at first it seemed daunting but now I could probably do it in 20 minutes. Hardest part is trying to remember where all the springs go. Also need to find what baggy the accelerator pump linkage is in.





Installing tomorrow, wish me luck. I will take a lot of pictures.

Well shucks! No wonder you had trouble. That hammer is waaayyyy too small!

Be careful with that piece of all-thread you have for the filter mount. It looks too long. Is that a "flash" line down by the vacuum plug you installed or a crack in the base plate?

If I remember correctly the front mounting bolts are 8MM X 95MM. Try to use a flat washer between the head of the bolt and the carb. Do NOT use a lock washer! It cuts into the soft metal of the carb. I got the bolts at my local ACE hardware store. I believe I got the swivel mounts at carquest.

For my intial throttle set up I just used a thin cable (1/8"?) and a couple of cable clamps.

Actually, you probably should both a flat washer and a lock washer. The flat washer goes against the potmetal and the lock washer goes between the flat one and the bolt head. The flat washer distributes the pressure from the lock washer uniformly on the casting that way.

On a different, thread, I made mention of a suitable ball stud for the linkage assembly. I just found the one I purchased some years back (been meaning to do this conversion to my old 280C for about 9 years now). The part number is 601-991-02-15, which has a threaded end (you can thank Dan Penoff for finding that part). The lever arm on the holley gets tapped (metric) to receive the ball stud and the rest is supposed to be simple.

One of these days, I have to do this to that 280C and get it back on the road. It's one of my favorites and has been sitting far too long.

-CTH

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Damn, that is a 601 part number... there was a 190d at the junkyard yesterday wit the 601 engine.

That is not a crack in the case where the vacuum plug is, that is a piece of Teflon tape sticking out (I panicked and ran outside when I saw your comment).

Thanks for all the help so far.

Ummm, wouldn't it have been easier to re-drill the mounting holes BEFORE you assembled the carb?

No it was just as simple assembled. Drill press helps a lot.

Solex removed:


The hot air port wouldn't clear the valve cover so it had to go. Dremel to the rescue.




Fits!


Very little clearance, going to have to install a manual choke.



Coolant lines joined together to bypass the old choke:



Drilling new holes in the throttle plate:



This pot metal is EASY to drill through, like butter.



Everything lines up:


Had to cut off the nut on this fuel tee so I could still retain use of the return line.