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I bought a very nice 1983 short bed 4x4 (with over 150K miles) about 6 weeks ago. It was originally sold in California and has tons of smog control junk added to the engine. It runs very rich, gets really poor gas mileage and has a very hard time idling when cold. I have adjusted/tinkered with the Aisin carb (I have the shop manual) as much as I can without removing/rebuilding it, and the improvement(s) were minimal.
After reading the really long thread on this site about de-smogging a 22R, I really want to get rid of the Aisin carb AND all the smog junk as I live in an area where smog inspections are not required. I've contacted LCE and am interested in the Weber 32/36 conversion kit (with manual choke) they offer and some of the block-off plates for EGR, etc. Seems to be a good way to go, and while a bit expensive, I feel I could easily spend an equal amount on the Aisin carb and have to keep all the smog junk.
So, please give me your opinions on whether you think this conversion is a good idea or not. I know there are some Aisin carb supporters out there, and also some Weber advocates. If you don't like the Weber carb, please explain what's wrong with it. To me, it seems the Aisin carb is overly complicated because it has to work with all the smog control add-ons and I would really prefer a simple old truck that runs better and is easy to maintain.
I too feel the same.
I don't have as much smog as a CA truck though.
A manual choke would be better imo. Less to go wrong. The simpler the better.
my truck seems to idle high at like 1100-1200. And it has not been going to much of a high idle or it takes awhile after starting to slowly creep up in idle speed etc.
Go for it! Aisin carbs were great. At this point there are too many parts clogging up, becoming brittle, failing. And being a pretty complicated system, like you mentioned, makes trouble shooting hard. The typical backyard mechanic has a LOT of trouble with them. There are some carb experts who do ok, but I've even had a lot of trouble with professional carb rebuilders not being able to get it right.
I put a 32/36 on my 78 20R and it was great. I also went with the manual choke. It's fun.
When I raced in SCCA the 32/36 was the required carb so I became familiar with them by taking them apart and reading (and seeing) about how they work. I think they are great piece if you understand them. They are simple once you understand what part does what job. Problem is, many people who have put them on don't know much about them and think they are plug and go - they aren't really. The other equipment, or lack of, an engine has, effects how you tune it. That takes time.and you should not expect the vehicle to run like a nitro funny car.
I had to deal with a poorly maintained Aisin when I got my 84 it wan't all that big of a chose really. Not it runs pretty well and I get around 20 - 24 MPG. So I'm not going to change it. But on some other vehicle I would rebuild one of mine and do the other upgrades (exhaust, timing, etc.) that a complementary to a 32/36.
If you want to save money you can get used manifolds and 32/36 on eBay. I think they're usually about half of the price of new. Then get a rebuild kit (about $25 on eBay) and familiarize yourself with the carb.
"Problem" with that is what 22R do they tune it for? A brand new or rebuilt one? Or a 22R with 190,000 miles? Of course before you carb trouble-shoot you always want to make sure the truck is well-tuned first, but...take your buddies Weber off his 22R and throw it on yours and it will not run exactly the same, or even necessarily well.
Before putting the new carb on, adjust the valves, put on a new fuel filter, make sure you don't have an exhaust leak, set the timing. And probably be prepared to set the timing again after getting the Weber on.
But yeah, it'll get you in the ballpark to have it "pre-tuned". In the end, though, you've got to tune it. You read the instructions and learn how to tune it, then you're good. No matter what LCE does, it's not going to be "plug & play". It's going to be plug, tune, play. Then regular tuning after that. For me, though, with how simple the tuning was, it was fun. I liked getting in there every few weeks (sometimes more often when I was traveling around in different elevations) and tuning it.
"Problem" with that is what 22R do they tune it for? A brand new or rebuilt one? Or a 22R with 190,000 miles? Of course before you carb trouble-shoot you always want to make sure the truck is well-tuned first, but...take your buddies Weber off his 22R and throw it on yours and it will not run exactly the same, or even necessarily well.
Before putting the new carb on, adjust the valves, put on a new fuel filter, make sure you don't have an exhaust leak, set the timing. And probably be prepared to set the timing again after getting the Weber on.
But yeah, it'll get you in the ballpark to have it "pre-tuned". In the end, though, you've got to tune it. You read the instructions and learn how to tune it, then you're good. No matter what LCE does, it's not going to be "plug & play". It's going to be plug, tune, play. Then regular tuning after that. For me, though, with how simple the tuning was, it was fun. I liked getting in there every few weeks (sometimes more often when I was traveling around in different elevations) and tuning it.
Yeah this, plus . . . what 22R do they tune it for? and is it for a stock or modified 22R? And, altitude, temperature and/or humidity extremes affect air to fuel ratio.
I've got an 83 4x4 with all the California emissions stuff intact. It takes awhile to go over everything, I'd recommend downloading the fsm in the stickies if your gonna go that route, it'll cover everything and how to test it. But the Aisin carb works well when it's properly tuned/functioning. It's also known for its off road performance. I've never fiddled with a Weber on the Yota but I've read if you re-jet and tune you should be good to go. Think lce makes a spiral adapter for it too.
The other thing to consider might be switching to Canada 4x4 emissions. It still runs aisin carb but with much less emissions equipment, looks like this:
I had an 83 FSM, 83 pickup. I also downloaded almost a dozen images from online of carb diagrams. NONE matched my carb. I could never find a diagram that could tell me where each hose, each connection went.
My 83 with the aisin worked fairly well with as many emissions ports plugged off as I could get at without doing a full de-smog.
I've used both the 32/36 and 38/38 on my 22R and would say go for it. They've both been manual choke which I like but takes some getting used to.
I have to tinker with them more than the stock AISIN carb depending on the season and what altitude I'm at. A fully functioning stock carburetor and the maze of vacuum lines and sensors tends to handle that stuff for you where the Weber carbs do not.
I know OP mentioned that he doesn't have emissions testing but I passed here in Colorado with a 32/36, single catalytic converter, and the visually required smog equipment bolted up; not reducing my emissions.
So long as you don't expect to transform your truck into a hot rod you will be pleased. The 32/36 is better on gas mileage but the 38/38 is almost as good if you keep your foot off the pedal.
Buy a Spanish-made carb from a reputable dealer like LCE and not a knock-off like 99% of what's sold on eBay. The true Webers are just better in every way.
Not having the Weber yet, there's still a lot I don't know. Would someone be kind enough to briefly explain what is meant by tuning for different elevations? We live at about 4700 ft elevation, but anticipate trips into the mountains and up on the Grand Mesa, which is 10,000 ft. Does the carb need to be disassembled, or can altitude adjustments be made from outside?
BTW- I fully expect to buy a jet kit and anything else I may need from LCE or elsewhere. Years ago I worked on Webers when we owned some 1960s Fiats. I got pretty good at tuning those tiny, sewing machine engines (<500cc), which needed monthly attention to run right.
Basically the altitude difference is just a matter of maintaining a proper air/fuel ratio. I would also add that for shorter trips into higher elevations this isn't as big of a concern, but rather for where you live and do your daily driving.
The higher in elevation above sea level you go, the thinner the air gets. So, with a mechanical carburetor that uses brass jets to maintain air/fuel consumption you will need to install larger air corrector jets to maintain your engine within the proper stoichiometric (air/fuel) ratio.
There is no perfect calculator for determining the correct jet settings to keep your engine producing adequate power at higher or lower altitudes. There are a number of guides and Weber and LCE will be happy to help set you on the right path.
But yeah, to get to the air corrector jets or main jets you will need to unscrew the top cover of the bowl. It's not hard and after you've done it 5 or so times it only takes about 5-7 minutes to get in there and another 5-7 to button it back up. Then you are supposed to go through setting the "lean best idle" procedure again but I have found it's not always necessary when changing mains or air jets.
For the most part you just want to jet your carburetor for the altitude you and your truck live and work at and forget it. If you went up to 10,000 ft from say 5,280 and were hanging out there for a week, starting your truck on cold mornings at altitude, then maybe consider putting smaller fuel jets or larger air jets in for the time being.
In winter I don't have to mess with jets, but occasionally a tiny twist of the idle speed or air/fuel mix screws are in order to get it to purr on extremely cold mornings. A properly set choke starts it right up 95% of the time though.
Yep. I just noticed that if I went from where I live (around 5,000ft) down to sea level, I'd need to turn some screws a little. Accessed by just opening the hood and using a screwdriver on the outside of the carb. For general driving in a +/- 2-3,000ft range, you shouldn't have any problems.
When I was tuned for the Minneapolis area one winter, then drove back west, I was going over Vail Pass (something like 10,000ft, right?), and I had very, very little power. But I made it up over the pass and back down. In the west, going from the valley up into the mountains shouldn't really be noticeable.
Like Punjab said, when you're first setting up the carb, the jet kit you get needs to match the elevation you live at. If you're going to move from a 6,000ft elevation down to sea level, long-term, you'd want to re-jet. But for just traveling around, messing around with the screws on the outside of the carb is all you'd need to do.
And yeah, the manual choke allows you a little more wiggle room to put off the proper adjustments. It's not the right way to do it, but you can kind of "tune" the carb with the choke, in a pinch.
Not having the Weber yet, there's still a lot I don't know. Would someone be kind enough to briefly explain what is meant by tuning for different elevations? We live at about 4700 ft elevation, but anticipate trips into the mountains and up on the Grand Mesa, which is 10,000 ft. Does the carb need to be disassembled, or can altitude adjustments be made from outside?
BTW- I fully expect to buy a jet kit and anything else I may need from LCE or elsewhere. Years ago I worked on Webers when we owned some 1960s Fiats. I got pretty good at tuning those tiny, sewing machine engines (<500cc), which needed monthly attention to run right.
Some, not sure if all, Aisin carbs have a altitude compensating vacuum devise. With a 32/36 you can adjust mixture and idle externally. To change jets all you have to do is remove the top screws. Most street vehicles can stand temporary altitude changes, but experience some degree of power loss.
One of the cars I raced was a Fiat 850. If you can adjust / jet their lil Weber you can do a 32/36.
Thanks for all the "tuning" info guys. Given my experience with 3 Fiat 850s (1 with a race engine) and all my tinkering with Holley 4-barrel carbs back in the day (before the Fiats), I think I'll be fine--maybe with a little help from LCE.
Since our '83 was originally sold in California, it doesn't have that extra altitude compensating device (with 10 more feet of vacuum line). Could be a partial reason I'm having difficulties with that Aisin carb (?), since we live at nearly 5000 ft.
We lived in Boulder County (CO) for 15 years, and bought a brand new 1986 SR5 4x4 truck when we first moved there. While I don't remember whether it had a carb or EFI, I really remember how slow it was climbing up I-70 into the mountains. Lots of staying in 3rd gear for miles and miles.
I drove my old 95 22re pickup across country 3 times and once I had a Honda xr650L and a bunch of other stuff in the bed and had to drop to 2nd going up the 70 near the middle and top by Eisenhower tunnel.
01-26-2018, 04:49 AM
