When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I want to go over the carb a bit to see if all the things are where they belong, among other things.
The only issue I'm currently dealing with is that the choke pull-off doesn't seem to pull off as much or as soon as it should. Runs very rich for too long. Can confirm that butterfly isn't opening as much as I'd expect it to once running. This is all seat-of-the-pants - I've worked on a lot of other carbs to dial everything in correctly for cold starts.
However, the q-jet seems to have plenty of contraptions over there, and I'd rather do things correctly, than just go at it and become one of those "Previous Owners". On some carbs the instructions tell you to bend the rod till it's right. I don't want to go there till I know exactly what's wrong. I didn't see a general q-jet tuning guide on the site.
Have you looked inside the 1966 GM Oldsmobile Chassis Service Manual (CSM) for the Quadrajet tuning diagrams? I suspect the 1966 CSM contains also the same diagrams as do other years of the CSM.
EDIT: Well, not the EXACT same diagrams for all years; but, diagrams pertinent to the 1966 CSM.
Last edited by Vintage Chief; November 5th, 2023 at 07:04 PM.
The 66 QuadraJet had its share of "advanced" (read weird) design features.
If the car has its original carb, if you're lucky it's had the redesigned needle and seat installed. These carbs had a very poorly designed fuel inlet too that stripped the threads easily, so be careful fooling with it.
If you're really lucky it's had the complete updated 1967 service carb installed.
This is a 66' Qjet, see if it matches mine. They got much better after the 1st year so hopefully you have a later Qjet on there like Rocketraider said. I've got mine dialed in pretty close currently, you can see if your behaves similar to mine in this clip:
On these cars, the thermostatic coil mounted to the intake (little gold box on mine) gets warmer and pulls on the choke until it's completely pulled off. After about 5 mins mine has got the butterfly pulled completely open. The easy way to spot a 66' or earlier Qjet is the long arm on the secondary air valve. They did away with that for 67 and onwards. On mine you can see it just beyond the air cleaner stud.
Don't mind the long crank. The car had been sitting at least a month when I took that video so it needed to fill the bowl.
The 66 QuadraJet had its share of "advanced" (read weird) design features.
If the car has its original carb, if you're lucky it's had the redesigned needle and seat installed. These carbs had a very poorly designed fuel inlet too that stripped the threads easily, so be careful fooling with it.
If you're really lucky it's had the complete updated 1967 service carb installed.
Rocketraider, don't suppose you know what PN they used for the service carb on the 67'? I'd sure love to get my hands on one but I just went through all my parts catalogs and never did find a service #. The original 67' Qjet is 7027131. Could it be a 7036690 I wonder?
Watching that video gave me nightmares from the 80's. That Toro has the 1st year California-only AIR (Air Injection Reactor) anti-smog device that made my '66 425 run terribly.
Crap power, backfiring, carbon everywhere. Eventually I came across a guy who recommended I pull the equipment and plug up the head holes with pipe plugs.
It was a brand new day for that engine there after. I've kept the stuff in my crawlspace though, just in case I ever needed to put it back in.
Good on that owner for keeping the system and for how nicely that car started and idled!
Keep it for nostalgia if you like it and it’s not harming anything. Heck it might even be good for the environment. I’ve never been convinced it did anything more than dilute exhaust gases with fresh air, but I’m no chemist.
But to remove it would be a good learner level project.
The job is plugging the holes in the heads with pipe plugs, then capping off the huge vacuum ports on the intake, then removing the AIR pump and gulp valves.
I did this as a real novice and it wasn’t too bad at all. If you’re comfortable with carbs and engines, I’d guess you could do it start to finish in a couple of hours - even with a run to the auto parts store for the necessary plugs & vacuum caps.
A byproduct is you’ll love how simple the engine compartment looks with all those doodads removed. Once that stuff is gone, it looks like somebody really planned the Olds V8 425 very carefully. It makes so much more sense simplified.
way to spot a 66' or earlier Qjet is the long arm on the secondary air valve.
I have the long arm, so i guess mines a 66.
i messed with the choke vac puloff, rod lengths, and found the "gold box" was not mounted correctly at all. Got it all sorted now, works like yours now 👍. One more item off the list.
Yes, 7036690 is '67 Toro carb number per my 1973 Olds part book - Good luck.
Ok thx, wow not much on the ol' interwebs on that thing. I guess it's a pretty niche carb. I'll keep my eyes open for one but it's not looking good LOL.
If you’re not going for originality swapping to a 170-series (1975 & up) gets you 800 CFM vs 750 for originals and a center fuel inlet which was a good safety improvement. If you put in a later carb, you can switch the choke to electric instead of rare mechanical. Ignore this if you’re going for 1966 correctness.
My other favorite 1966 improvements are an HEI distributor, internally regulated 12SI alternator and front disc brakes. Again, if you’re going for originality, ignore these suggestions, but in sum they bring the car up to about 1975 in terms of safety & reliablity.
Carb acting up again. Bogging if I give it more than part throttle, it dumped some fuel out onto the manifold for no apparent reason, then stopped doing that (?), and the idle mix screws do nothing. So, generally questionable overall.
I may as well just do a rebuild.
There seems to be consensus that this is the book to get (amazon link): https://a.co/d/cp7C4Ay
Is there a PDF?
Pictured are the numbers on my carb. What rebuild kit do I need for this, and what do we learn from these numbers, if anything?
Also, is purchasing a complete bolt-on unit an option? From where?
Thanks!
Last edited by mike 66 toro; November 12th, 2023 at 04:29 PM.
Wow, what a score! You have the official 1970 service replacement carb. It's not the original troublesome 1966 version that many of us are stuck with. How cool is that!
The one you have is the one to stay with. However, if you're gonna get a replacement get the 1967 Qjet for the Toronado (7027131). I suppose you could order one up from Quadrajet Power but I think you have a really good core there as it is.
Finding the rebuild kit for the rare service replacement carb could be tricky. I'd contact Cliff Ruggles through his website and he should be able to put together the correct kit. He also wrote that book you posted earlier.
Last edited by ourkid2000; November 12th, 2023 at 04:52 PM.
That's a great find. Should have everything you need in that kit. I think the only wildcard would be the quality of the accelerator pump. I know Cliff sells the best quality pumps on the market but I'm not 100% sure about Qjet Pwr's. Some of the accel pumps out there don't seem to last. Might be worth grabbing one from Cliff just in case.
Qjet Power are a great resource though. The website is fantastic and they have wonderful Qjet rebuild videos on Youtube. The really great thing about the carb you have is that the troublesome well plugs, inlet fitting, and needle/seat design of earlier 66' carbs were dealt with by the time the service carb came around. The only leftover issue is the crappy secondary air valve damper that they still left in place. It's a great find and definitely worth rebuilding.
Things to watch out for would be leaking primary rod shafts and stripped inlet threads. The repair for these is installing bronze bushings for the shaft and helicoiling the inlet.
Last edited by ourkid2000; November 13th, 2023 at 05:12 AM.
The really great thing about the carb you have is that the troublesome well plugs, inlet fitting, and needle/seat design of earlier 66' carbs were dealt with
Provided the expert electrician and plumber didn't do something wonky with it. Fingers crossed.
I have the rebuild kit on the way, and Cliffs book in front of me.
$187 after coupon. Don't worry, I'm not going to do it. Just morbidly curious...
That Amazon carb.....getting something like that to work on your Toronado would be a bit tricky. The throttle arm on the Toronado is unique to the 66-67 so you would have to figure out a way to get that to work with the kickdown switch, etc. Also that choke linkage is a different geometry that ours and would also need some "engineering".
From what I understand though, these aftermarket rebuilds get a pretty cruddy generic "treatment" to make them work for all cars, but not well. Various ports are blocked off, etc which screw with the overall calibration. Unfortunately, these modifications end up making the carb almost impossible to rebuild correctly and the core itself is pretty useless. I look at these carbs as excellent backup carbs to have on hand while you get your original one rebuilt properly. No sense in wasting big cash on a backup carb. I myselft have a back up Frankencarb installed so I can use the car while I get my original fixed up. Not that I am an expert by any means, I'm just not dogmatic in my stance on these things.
Word to the wise, don't go on the QJet forums asking about these reman carbs expecting any kind of sane discussion. It usually turns toxic within minutes. Most of the big shots in the carb business are pretty passionate about them and will rake you over the coals if you even bring up the remans. Now, some of the folks are pretty good and can be reasonable to deal with but others.....wow, not so much. Jesus himself could have re-built your carb and these fellas would be like "a hack clearly worked on that thing"......"this persons work is hopeless"......"looks like it was amateur night".....etc.
Last edited by ourkid2000; November 14th, 2023 at 04:48 AM.
Word to the wise, don't go on the QJet forums asking about these reman carbs expecting any kind of sane discussion. It usually turns toxic within minutes. Jesus himself could have re-built your carb
So what you're saying is I should drop that link there and grab my popcorn. On it.
I abandoned generic rebuilds and Holleys and boneyard carbs decades ago. If you want a good running car, you want a carb that’s been carefully rebuilt by people who understand them.
Not associated, but I have been happy with carbs from SMI (Sean Murphy Induction) for a decade or so.
Now over $600, but they’re done right & safe. I go for Stage II 170-series 800 CFM carbs which work great. More CFM than the original 70-series, safer design, fantastic tuneability (thanks EPA emissions!). You give them details about your engine & they build up a carb for it. When they jet it, they err on the rich side which will keep you from burning valves, but you may have to tune it (probably lean it out) on your car after receipt.
I think their backlog (aka wait time) is a couple of months. I say this as a mild qjet geek. I’m not ignorant. I’m no guru, but have found their quality very good as a basis to get my cars really dialed in.
I aim for power, but with gentle throttle in ‘66 big cars with 455’s I’m getting 10-12 mpg around town & 14-15 mpg on the highway. My cars may not be perfect, but they’re reliable, powerful and smooth at idle.
Oh - forgot about the ‘66 Toro throttle cable. In these later carbs there will be a throttle rod hole or several connection points.
Google up “1/4” throttle ball joint” for throttle cable-to-carb connection options. You’ll be able to create something that works well.
If you need/want to, one of the rules of qjet land is that if you remove the throttle plate & properly support the vertical throttle arm, you can drill a 5/16’s hole where ever you want to get your gas pedal connection working. If you need to, pick your spot carefully, drill a pilot hole and don’t put too much pressure on the primary throttle rods.
Usually GM left a lot of good factory options that gave great throttle response and finely metered control, don’t drill unnecessarily.
That hex-head set screw holds the orientation of the slotted and spring loaded pivot post. You want just enough spring resistance holding the upper air door closed so that it doesn’t just flop open, but not so much that it never opens.
This is very much a get-in-the-car with a 3/32” Allen wrench and a small flat blade screwdriver and try different settings. Also take a flashlight or headlamp so you can see these parts clearly.
Find an empty straight stretch of road and nail the throttle from idle and also try opening it up wide (WOT) when at speed.
If it bogs when you nail it, you need to tighten the spring resistance - the upper door is opening too soon or too much. If it opens too slowly for your liking, loosen the spring by 1/8 or 1/4’ turn.
When tuning, I think of the set screw slot as a clock face. Mine seem to work best between 3:00 and 6:00 when seen from the passenger fender. However that method is very much dependent on the age and condition of your secondary upper air door spring.
Finally, be aware that you may be able to find fast and slow opening (and very misleadingly named) choke pull offs. These are the vacuum pots on the passenger front of the carb which hold the secondary upper doors closed (up) until you nail it. GM used various methods to control the opening rate on those vacuum diaphragms including restricting the size of the vacuum line and varying spring rates. If you get into this, consider getting a few different ones and playing with how fast that diaphragm opens.
holding the upper air door closed so that it doesn’t just flop open,
I guess it should come as no surprise to anyone here when I say that it flops open and stays open as received from previous owner. And yeah, the engine responds accordingly.
I'm going to need some close-up pictures of the springs related to the choke. There are two springs, and both of them currently have attachment points onto non-moving parts.
So that has to be wrong, unless the factory was looking to get rid of surplus springs by hanging them decoratively onto things...
The previous owner used his expertise on the carburetor too, it seems.
Is there an assembly diagram? I have to assume that my "rebuilding" is going to involve putting things back together potentially not as they are coming apart. I have no point of reference.
.
Last edited by mike 66 toro; November 15th, 2023 at 01:40 PM.
Years ago when I did my own carb rebuild, between the '66 Shop Manual and the carb kit instruction sheet, I was able to figure out what I was doing, and everything turned out okay. Both had adequate instruction as well as good pictures/drawings.
Helicoil is new to me. I understand the premise, but could someone drop a link here to a kit or everything I need to do this? And will I be re-using the part that screws in?
On phone hopefully link works. If you don’t have the appropriate bits/tools you should likely send it out or have a friend do it. Really not much to it. If uncomfortable w/ the process, have someone else do the install. Also, lots of videos demonstrating helicoil installations.
Send it off to Greg Kalkhoff www.sparkyscarbs.com. He can heli-coil it and rebuild it to specs, and refinish it to show quality if you want to go that far.
Sparky understands both QuadraJets and Toronados.
Carbking over on the AACA Forums enlightened us on the 1st year QuadraJet. Apparently the very first ones had only about three threads in the fuel inlet and the leaks showed up quick. Like the first time someone changed the fuel filter.
Rocket man has provided excellent information, as have others. This comes down to your comfortability & skill set. Do what is best for you now and in the future. I think I may own 5 or 6 helicoil sets, but that’s taken me 50 years to accumulate.
November 5th, 2023, 06:54 PM
