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Converting 1984 240 to Carb

jbirdyurd

jbirdyurd

New member
Joined
Oct 21, 2021
Location
Raleigh, North Carolina
This is my first post so I don't know if I will get shunned for asking about n/a cars but ya'll know the motor harnesses and ignition systems on these cars pretty well. I have two 1984 Volvo 242 DLs both n/a lh 2.1/2.0 cars. I do not want to boost one of them because the B23F in it is quite healthy and I want to do something a little less common. I want to get two Weber DCOE 45 carbs and run it like that. My current plan is to get a new motor harness for the EFI motor and close the circuits to the EFI stuff. Firstly, I do not know if I could just get a motor harness for a carved B23A car, or just close the circuitry on the EFI harness. If I was to do the carb harness, how would I control the fuel pump relay since, I do not want to do switches and what not. The ignition system I plan on just getting a MSD box and doing it that way. But I am really stumped on what to do with the motor harness.
 
I'd just unloom the harness and take out all the fuel injections stuff. It will be a large percentage of it.

You'll need a different fuel pump, the fuel injection pump puts out way too much pressure, you wouldn't want a pressure regulator to try to knock that ~50 psi down to 2 or 3 psi (DCOE's like very low pressures).

The current relay is triggered by the ECU, so you'd need something else. Could just hook it (the relay) trigger up to switched 12V+. Since the carbs have fuel bowls, doesn't even matter if the pump shuts off while cranking (many switched 12V+ circuits do that).
 
I would suggest some reading up on how to tune and adjust carbs. They require some understanding of balancing the airflow and adjusting the idle and overall mixture. The Haynes manual for Webers is a good start. A wideband O2 sensor can help with this. Air flow synchro tool from Germany is the one to use.

Another suggestion I have is to use a kjet fuel pump relay. That way you can have the safety of the engine shutting off the fuel flow if the engine isn't running. An electric fuel pump rated for carbs would work well with that relay.

Lastly going carbs is way more expensive than it seems. You'll have to have a decent budget for this as you'll need most of a thousand just for the carb setup. Good luck with the project. :)
 
I would like to do this too, my mechanic says the jetronik-k is impossible to fix when it breaks and he cant get parts anymore. In our state we dont have to keep the car the factory same onec it gets old like mine a 978 242 but she runs good.

Do we have some insruction for guys like me who are learning but want to put carb on? Why do you choose Weber, isnt that from Italy and expensive? Why not Holly carb like on V8 motors?

You say up there it costs $1000 for Weber?
 
CarlosGato said:
Why do you choose Weber, isnt that from Italy and expensive? Why not Holly carb like on V8 motors?
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I can't think of any way to use a 4-barrel carburetor (like on a V8) with a redblock without a custom manifold or a lot of really sketchy adapters - they just aren't available, and I'm not sure why you'd want one. It's a lot of carb for a relatively small displacement motor.

Webers are usually the carb of choice because they're available (and widely supported) and dependable. There's a lot of cheap Asian-made carbs out there on eBay or AliExpress, but they're almost always junk. Usually good to stick with name brands.

2-barrel DGV and DGEV (and DGS and DGES) carbs are a pretty common swap or upgrade for a lot of European cars - you can get kits for Volvo engines fairly easily as well. They're more of a budget/economy-minded carb versus the more performance-oriented (and pricy) DCOEs.
 
You're mechanic is a boomer, Kjet isn't hard to fix if you know how to read a few manuals and have the right pressure gauge
 
James M said:
You're mechanic is a boomer, Kjet isn't hard to fix if you know how to read a few manuals and have the right pressure gauge
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Is that bad to be a boomer, I dont know what it means. He said its a parts problem mostly, I think he is a good guy but he is still young and his shop is at homer.
 
CarlosGato said:
Is that bad to be a boomer, I dont know what it means. He said its a parts problem mostly, I think he is a good guy but he is still young and his shop is at homer.
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Boomer = Baby Boomer. I don't think NA K-jet parts are hard to find. Everything that can't easily be rebuilt is available, at least when I had my '80 242 a few years ago. When things start acting weird you just need to smoke the system to check for any vaccum leaks, and then start checking and adjusting fuel pressure down the line. The mechanic just doesn't know K-jet and sounds unwilling to rebuild warm up regulators and fuel distributors. You'll spend thousands to get a car that runs worse.
 
Ok well he it too young for that. But yes may be you are right he desnt want to learn about it now. He keeps talking about micro spurt too but all that custom electronic stuff scares me, I am old and dont even have a loptop computer he says you need to ajust it.

I saw a guy on youtube who said the Jetronik parts are not there any more but another guy who is scotish and he has lots of videos about fixing the injectionK system, his works great is seems. Iwill try to find his channel for you guys, maybe it can help, he seems to know alot.
 
OVERDRIVE said:
Boomer = Baby Boomer. I don't think NA K-jet parts are hard to find. Everything that can't easily be rebuilt is available, at least when I had my '80 242 a few years ago. When things start acting weird you just need to smoke the system to check for any vaccum leaks, and then start checking and adjusting fuel pressure down the line. The mechanic just doesn't know K-jet and sounds unwilling to rebuild warm up regulators and fuel distributors. You'll spend thousands to get a car that runs worse.
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If someone doesnt rebuild the kjet parts, they'll have to pay a lot of money. 300-400 for rebuilt wur, $700 for fuel distributor, add engine harness/ignition harness, and fuel injectors. Not including fuel pumps which he'll more than likely need. You're getting close to 2k. Not everyone is interested learning to rebuild/repair parts.
 
No yes you are right, $2k is more than the 242 cost and its for my sister not me but I did buy a 1980 GL too for parts but now maybe Iwill keep both and fix up the 1980 after yiou guys told me the wiring advice that after 1980 the wires all go bad by themself!

So what you say is may be double costs to fix the Jectronik or get a Weber carb for less than $1k well that choice is easy, I know carbs from when I was a kid, they are not hard to work on if your ears still work to here it running and tune it. I dont need a meter if there are adjustment screws on there. Speaking of Holly carbs they come in 2 barrel 500 cfm too, I had one on a Ford 351 and got a rebuilt kit from Summit before the virus stuff hit. My mechanic was scared to do it, he is too young
 
white855T said:
If someone doesnt rebuild the kjet parts, they'll have to pay a lot of money. 300-400 for rebuilt wur, $700 for fuel distributor, add engine harness/ignition harness, and fuel injectors. Not including fuel pumps which he'll more than likely need. You're getting close to 2k. Not everyone is interested learning to rebuild/repair parts.
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The poster said his car runs good. It's very unlikely he will have to do any of that. When I revived my '80 242, I just needed a new main fuel pump, filters, and to clean and adjust the WUR. K-jet doesn't like sitting, if the poster's car runs currently and only needs occasional fiddling then going carbs is going to net him the exact place he is now but with a lighter wallet and a car that runs worse.
 
CarlosGato said:
No yes you are right, $2k is more than the 242 cost and its for my sister not me but I did buy a 1980 GL too for parts but now maybe Iwill keep both and fix up the 1980 after yiou guys told me the wiring advice that after 1980 the wires all go bad by themself!

So what you say is may be double costs to fix the Jectronik or get a Weber carb for less than $1k well that choice is easy, I know carbs from when I was a kid, they are not hard to work on if your ears still work to here it running and tune it. I dont need a meter if there are adjustment screws on there. Speaking of Holly carbs they come in 2 barrel 500 cfm too, I had one on a Ford 351 and got a rebuilt kit from Summit before the virus stuff hit. My mechanic was scared to do it, he is too young
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K-jet is only a big problem if it has sat and won't fire up. Setting it right is a big effort. But so can carburetors.

I know you can get carburetor manifolds for the B21/23/230 family of motors, both for the two barrel downdraft and the DCOE sidedraft carbs. The tricky part will be jetting them so that they run nicely. You'll want a book to help you through that process.

You can also source parts for an OEM volvo carburetor, which I think is a zenith stromberg. Those operate differently than the standard holly that all the American mechanics love. I think that constant velocity carbs like the ZS or SU are simpler to understand.
 
It's unfair to give a young mechanic a hard time about not wanting learn outdated technologies for the one car he'll work on in a couple years that uses them. Unless he plans to lose money as a specialist mechanic, it's far easier to work on more modern cars that are in line with his training. Makes more money that way too, because the hours spent rebuilding Kjet stuff are hours he can't charge for.

Like it or not, K-jet is the area of an old-school mechanic, a specialist volvo shop (provided they still know how), or self maintained.
 
spock345 said:
You can also source parts for an OEM volvo carburetor, which I think is a zenith stromberg. Those operate differently than the standard holly that all the American mechanics love. I think that constant velocity carbs like the ZS or SU are simpler to understand.
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Truth. The OE B21A single zenith stromberg setup would be the way to go for anyone new to them. They just run. No fuss, no muss. I've done most carb setups on a redblock that someone can think of, and the best one was the dual ZS one I made.
 
OVERDRIVE said:
The poster said his car runs good. It's very unlikely he will have to do any of that. When I revived my '80 242, I just needed a new main fuel pump, filters, and to clean and adjust the WUR. K-jet doesn't like sitting, if the poster's car runs currently and only needs occasional fiddling then going carbs is going to net him the exact place he is now but with a lighter wallet and a car that runs worse.
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I don't see where he said the car is running good. It seems he won't be doing the work on car. If you leave this to a mechanic, all he's going to want to do is swap parts(more billable hours). I don't recommend a carbed setup unless you're willing to spend the money and learn how to do it. He's looking for an instructional which you won't find here. At best, we can recommend parts vendors. Either way, if he's not doing the work, it won't be cheap. If you like kjet, great. But it's not for most. There's a reason Volvo went to efi.
 
Broke4speed said:
Can't charge the customer for time spent learning. Being a mechanic is a business, unfortunately :-(
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You can roll that knowledge into the next job, younger you are the longer you have to use that knowledge too. I don't blame the guy, if he'll never see another Kjet car it may not make sense to invest the time and money into learning and a pressure tester. But "I can't get parts, you can't fix it" is a cop-out excuse.

$20 says I'm younger than his mechanic anyways
 
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