Quadrajet have to change metering rods

[AdamB]

Well, I have been having problems with my Quadrajet bogging during accel and have purchased a rebuild kit some time ago. Well, after the boat left me sit on the ocean and I had to get towed in, I've decided to rebuild the carb.<br /><br />Anyhow, while doing the job, I somehow managed to bend one of the primary metering rods (cause I was rushing) and can't find an exact replacement. Mine is a 42, and the closest I can find is a 43.<br /><br />Does anybody know what difference the 1 point change will do?<br /><br />BTW, you should have seen how bad the gaskets were inside the carb. The gaskets around the accel pump were all but dissolved... and I'm hoping my bog problems will be gone upon completion.

 

[AdamB]

Re: Quadrajet have to change metering rods

Well, I'm guessing the 1 pt change won't hurt much... anybody else?

 

[Bonus]

Re: Quadrajet have to change metering rods

I'm "geussing" no to. I say that as I live, work on cars at 5-7,000 feet elevation, and to be tuned right we should rejet carbs; But most don't. (now that most are EFI, it's not as big o deal)....but it's my Geuss

 

[Bondo]

Re: Quadrajet have to change metering rods

I Don't Do Rottenchesters Either,......<br /><br />So,.. I'm also Guessing..........<br /><br />A Higher # would be a Larger needle,.... Which would Lean it out........<br />Do you need it Leaner ???

 

[AdamB]

Re: Quadrajet have to change metering rods

Don't know, haven't gotten to pull the plugs. However, I do know that whomever rebuilt the carb last has the idle screws messed up. One was like 6.5 turns out, the other was only 4. So, I could probably run leaner rods, and turn the screws in some (and keep them the same).... any thoughts?<br /><br />The boat didn't seem to run rich, but the marina I got the rods from said they didn't think the 1 point would be that bad. I couldn't find 42's anywhere.<br /><br />Guess we'll see...

 

[Buttanic]

Re: Quadrajet have to change metering rods

The world will be a better place when all the quadrajets lie at the bottom of Davie Jone's locker. They can be real good, problem is most aren't and trying to get them real good is dam near impossible.

 

[AdamB]

Re: Quadrajet have to change metering rods

Going from the comments on here, I take it you guys don't like Rochester Quads huh?<br /><br />What carbs do you recommend for my set up, 1985 21 ft Cuddy cabin with 350 Chevy coupled to alpha one. Boat weighs ~ 4000 lbs.

 

[Buttanic]

Re: Quadrajet have to change metering rods

Holly makes a quadrajet replacement that matches the Quadajet manifold. Much easier to tune and get parts for. Holly is the carburator of choice for most forms of motorsports using Chevy and Ford V8's. Qudrajets were born in the 70's to try and meet emission and fuel economy standards of the time before electronic fuel injection came into use. The old Rochester 2GC 2 barrel was a great carburator but the Quadajet is junk.

 

[AdamB]

Re: Quadrajet have to change metering rods

Thanks, if I can't get rid of my bog problem I'll look into a Holley. I'd really like to convert to MPI like on the mid 80's corvettes... Just need to work out the programming for the ECU.

 

[jimmbo]

Re: Quadrajet have to change metering rods

The 43s will be leaner. How it will affect ther engine? It will only be leaner during low speed high vacumun conditions, once the manifold vacumn drops the rods will rise and meter fuel on the tips which are the same as the 42s. How high above sea level do you boat? It might actually be benifical being a little leaner.<br />The Q-jet was introduced in 1965, while the basic design remained it went thru many updates/redesigns to meet stricter emission levels as it passed into the 70s and then the 80s. In the late 80s GM finally halted production. It was a very good and versatile design, used on engine as small 3.8litre V6s and as big as Cadillacs 8.2 liter( 500 cu.in.).<br />It also was an excellent marine carb.<br />Holley does make a 650cfm spreadbore model to replace the Q-jet http://www.holley.com/HiOctn/ProdLine/Products/Marine/FMS/FMSC/0-80552.html <br />I have this carb. It isn't any easier to calibrate than the Q-jet, in fact it is far less adjustable.

 

[AdamB]

Re: Quadrajet have to change metering rods

I usually boat anywhere between 240' above sea level, and when on the ocean of course I'm at sea level.<br /><br />I will try it and see, since I now have the 43's in my possession.

 

[Mahoney]

Re: Quadrajet have to change metering rods

depending on how bad you bend the rod, you can try and bend it back straight? I am assuming you probably tried that and it is beyond hope or broke. One thing to also make sure and check is that the primary metering rod hanger is in the power piston per specs. If you removed the hanger assembly and didnt get it seated all the way down when rebuilding, it will cause the primary rods to sit too high in the jets leading to a rich condition as well.<br /><br />Another thing to watch out for on those quadrajets is where you have the float needle attached to the float arm. It should NOT be attached in one of those 2 offset holes in the hanger. I have had rebuild carbs where they even do this. It should be hanging right in the middle to insure the float needle doesnt get stuck in the up position when the float drops(also leading to a bog as well)

 

[Buttanic]

Re: Quadrajet have to change metering rods

Jimbo quote "Holley does make a 650cfm spreadbore model to replace the Q-jet http://www.holley.com/HiOctn/ProdLine/Products/Marine/FMS/FMSC/0-80552.html <br />I have this carb. It isn't any easier to calibrate than the Q-jet, in fact it is far less adjustable."<br /><br />In my opinion the main problem with the quadrajet is the fact that it has so many adjustments that it is difficult to get them all right. That why I said that when they are good they are very good but getting them very good is difficult. Folks fiddle with them and they turn into junk. Hollys are far simpler with less ajustments and most speed shops have every jet. spring, power valve or any other partyou might need to tune them. The government is responceable for the design of the Quadrajet to meet emission standards. Prior to that GM was using Hollys on almost all its preformance engines.

 

[AdamB]

Re: Quadrajet have to change metering rods

I still have the 42 metering rods, the one I attempted to bend back straight is a little crooked but not too bad. In fact, the one 43 rod I received isn't perfectly straight either. I wonder how bad it would get screwed up if I use 1 42 and 1 43 LOL j/k.<br /><br />I did put the float needle in one of the holes from the underside (started under one hole, up over the hanger and into the other hole). Kinda of puts it right in the middle. I will change it and just place it over the edge, but that didn't seem as secure. I guess the plastic piece on top will keep it all together.

 

[Scaaty]

Re: Quadrajet have to change metering rods

Ebelbrock has (I did this last year on my 350) a Marine 600cfm with carbplate kit for adapting it to a Q-junk manifold. Bolted it up in a few minutes, and haven't touched it since, after tossing the Q-jet on ebay for $40

 

[jimmbo]

Re: Quadrajet have to change metering rods

Buttanic, I'm not trying to start a pi$$ing war but the government didn't design or mandate the design of the Q-jet. As for emission standards, the Q-jet was introed in 1965 3 year prior to exhaust emission controls being law federally. Holley was used on a few GM engines, usually the ones that were all out race engines, in the mid to late sixties. Prior to the Q-jet, GM used a carb called a 4G on most of its engines, including the dual quad models. On the ledgenary 409 a Carter 4bbl was used, an AFB I believe. Ford made greater use of Holley<br /><br />What I dislike about the holley, while it isn't too hard to calibrate the primary side for max power or max economy, it isn't easy to set it so you have both without resorting to drilling out the power metering orfices next to the power valve. And on the 4160 and 4175 models changing the secondary mix requires the purchasing a not-so-cheap metering plate instead of jets<br /><br />AdamB, with one 43 and one 42, only 4 clynders will be lean

 

[Buttanic]

Re: Quadrajet have to change metering rods

Jimmbo ,you miss my point. I said the Quadrajet can be a great carburator but the complication of it is why most tinkers should not mess with it. It takes a good understanding of how any carburator works and a means of veryfing that the changes you make are correct. On the Holly if room is available you can always change the secondary metering plate to the jet plate so you can use regular jets.

 

[Olds Eddie]

Re: Quadrajet have to change metering rods

I probably have the metering rod you need in my collection if you are interested.

 

[AdamB]

Re: Quadrajet have to change metering rods

Oldseddie,<br /><br />Hey, if you have one (or two) I'll take them off your hands.<br /><br />My email is adamborz@aol.com if you want to contact me about shipping and $$ etc.

 

[Manipulator]

Re: Quadrajet have to change metering rods

I don't favor a Q-Jet over a Holly or the other way around. I just happen to have a Q-jet and rebuilt it a while back. It was simple and so were the adjustments. Although I didn't like those funky heads on the the mixture screws.