Carburetors - I think I've learned to like them

[JeffKeryk]

Originally Posted by Malo83
Originally Posted by supton
I can accept that, but still, there doesn't seem to be a large number of other owners that can claim that kind of lifespan. Daily driving I'm sure does help.

My 83 Silverado with the 305 and Qjet is still my daily driver, bought the truck new, the carb has been rebuilt, the carb outlasted the engine due to leaky valve guide seal and piston rings, don't concern myself with gas mileage or HP ratings, she's been my daily driver for the last 35+ yrs and the Q jet just keeps chugging along.

Beautiful truck. And still in service. Bravo!

 

[caprice_2nv]

Originally Posted by supton
I can accept that, but still, there doesn't seem to be a large number of other owners that can claim that kind of lifespan. Daily driving I'm sure does help.


Most vehicles from the era have rusted out or otherwise worn out since then. Mine has disintegrated weatherstripping everywhere and the vinyl roof is cracking, etc. It is driven daily for the winter but sits weeks at a time all summer.

 

[supton]

Originally Posted by caprice_2nv
Originally Posted by supton
I can accept that, but still, there doesn't seem to be a large number of other owners that can claim that kind of lifespan. Daily driving I'm sure does help.


Most vehicles from the era have rusted out or otherwise worn out since then. Mine has disintegrated weatherstripping everywhere and the vinyl roof is cracking, etc. It is driven daily for the winter but sits weeks at a time all summer.

True but I've long associated EFI with advent of long-life engines. I can't argue with 240k on the clock but it sure doesn't seem typical of that vintage.

My vehicles sure have been sitting a lot lately!

 

[caprice_2nv]

Originally Posted by MCompact
Originally Posted by JeffKeryk
There are fewer and fewer people who know how to rebuild a Quadra Jet which is the best street carb ever made.
And next to zero quality carbs left to rebuild. I have 3: the one on my Vette, the one on my 4-4-2 and a spare.
And Lars Grumsrud is a friend. How's that for name droppin'?


I agree; I ran a Quadrajet on my SBC back in the ‘70s during my misspent street racing youth. They are almost infinitely adjustable. The people who disparage Quadrajets usually lack the time, patience, or aptitude to understand how and why it is designed the way it is.
I still get called on to rebuild a Q-Jet every so often. Some older European BMW M30 motors were fitted with a four barrel Solex carburetor; when I had my 1973 Bavaria I was tempted to get a Euro manifold and see if I could adapt a Q-Jet to fit.


Between my Caprice and cutlass and my friend who has a 442, Delta 88 and a 79 Cadillac Seville (converted from problematic EFI), we have 5 quadrajet vehicles that all run fine. I guess I could also count my 78 Chevy k10 from my childhood, needs complete restoration. We start it once every few years. I wouldn't say it runs well but it does start up and idle.

Even my lawn equipment hasn't given me trouble, besides the 81 b&s 3hp that was parked for about 10 years before I got it going again.

I
The only bad memories of carbureted cars were a 77 Toyota Corolla and 84 Plymouth reliant my parents had when I was a kid. Both would randomly die on the road or fail to start sometimes. I don't even know if it was carb issues because they both fell apart in other ways before ever figuring out the running issues. Those were both hated cars. But the 79 Impala wagon, 79 Chevy k10, 83 Grand Prix my dad had all worked good. In his younger years my dad had a 78 international scout, 81 Jeep, 72 Plymouth satellite and a 70 Dodge Monaco. He never really complained about the days of carburetors.

 

[caprice_2nv]

Originally Posted by supton
Originally Posted by caprice_2nv
Originally Posted by supton
I can accept that, but still, there doesn't seem to be a large number of other owners that can claim that kind of lifespan. Daily driving I'm sure does help.


Most vehicles from the era have rusted out or otherwise worn out since then. Mine has disintegrated weatherstripping everywhere and the vinyl roof is cracking, etc. It is driven daily for the winter but sits weeks at a time all summer.

True but I've long associated EFI with advent of long-life engines. I can't argue with 240k on the clock but it sure doesn't seem typical of that vintage.

My vehicles sure have been sitting a lot lately!


My opinion is long life engines started when compression ratios dropped, rear axle ratios dropped, leaded fuel went away, better oil came out etc. EFI would have a small advantage as far as having a more optimized fuel mixture, but the biggest reason it would help is less people ignoring carb issues, flooding engines and diluting the oil and just driving alone like it's a normal thing.

However EFI can mess up and dump raw fuel in just the same. My friends EFI Seville was doing exactly that before we replaced the EFI with an intake and 4 barrel off an 83 Oldsmobile, no more issues. A failed fuel pressure regulator can flood an engine the same as a bad choke, or sunk float, sticking needle and seat etc.

IMO it comes down to when it's broken, you should fix it.

 

[supton]

Originally Posted by caprice_2nv
My opinion is long life engines started when compression ratios dropped, rear axle ratios dropped, leaded fuel went away, better oil came out etc. EFI would have a small advantage as far as having a more optimized fuel mixture, but the biggest reason it would help is less people ignoring carb issues, flooding engines and diluting the oil and just driving alone like it's a normal thing.

However EFI can mess up and dump raw fuel in just the same. My friends EFI Seville was doing exactly that before we replaced the EFI with an intake and 4 barrel off an 83 Oldsmobile, no more issues. A failed fuel pressure regulator can flood an engine the same as a bad choke, or sunk float, sticking needle and seat etc.

IMO it comes down to when it's broken, you should fix it.

That's an interesting take--usually people take the position of, engines lasted longer when EFI with precise fuel metering, and more likely, no cold start washdown on the cylinders. Interesting counter argument about lower rpm and lower compression (although... 70's engines?). Now engine oil improvements, no doubt that has had something to do with it.

Now that I think about it, the wife did have an '86 Olds with a carb 305 (307?) with 240k on the clock, it was starting to use oil but it was still plugging along in 2001 (when it was traded in).

 

[grampi]

Replacing carbs with fuel injection may be the single biggest improvement to the internal combustion engine...

 

[caprice_2nv]

Originally Posted by supton
Originally Posted by caprice_2nv
My opinion is long life engines started when compression ratios dropped, rear axle ratios dropped, leaded fuel went away, better oil came out etc. EFI would have a small advantage as far as having a more optimized fuel mixture, but the biggest reason it would help is less people ignoring carb issues, flooding engines and diluting the oil and just driving alone like it's a normal thing.

However EFI can mess up and dump raw fuel in just the same. My friends EFI Seville was doing exactly that before we replaced the EFI with an intake and 4 barrel off an 83 Oldsmobile, no more issues. A failed fuel pressure regulator can flood an engine the same as a bad choke, or sunk float, sticking needle and seat etc.

IMO it comes down to when it's broken, you should fix it.

That's an interesting take--usually people take the position of, engines lasted longer when EFI with precise fuel metering, and more likely, no cold start washdown on the cylinders. Interesting counter argument about lower rpm and lower compression (although... 70's engines?). Now engine oil improvements, no doubt that has had something to do with it.

Now that I think about it, the wife did have an '86 Olds with a carb 305 (307?) with 240k on the clock, it was starting to use oil but it was still plugging along in 2001 (when it was traded in).


Well they don't wash down the cylinders unless something is really wrong. That occurs from flooding or running really rich. I agree that it's a problem that occurs less often with most EFI, but it's just not the way a carburetor is supposed to work.

Ive had several 307 olds, 305 Chevy's and my 350 Oldsmobile. I know of lots of people getting a ton of miles out of all 3 engines. I got 332k miles out of my last 305 Caprice, it was the first year of EFI, but I know of others that got 300-400k out of the carbureted lg4 305 also.

I do appreciate how the EFI works on my 05 Silverado, it adjusts for what I suspect is a slightly leaking intake manifold gasket (fuel trims slightly high), but when I go on a long trip I do worry slightly about the aftermarket fuel pump failing without warning. There's not much I worry about with the carbed cars. I keep an ignition module, cap and rotor in the tool box just in case (never had one fail but one day maybe).

 

[caprice_2nv]

Originally Posted by supton
Originally Posted by caprice_2nv
My opinion is long life engines started when compression ratios dropped, rear axle ratios dropped, leaded fuel went away, better oil came out etc. EFI would have a small advantage as far as having a more optimized fuel mixture, but the biggest reason it would help is less people ignoring carb issues, flooding engines and diluting the oil and just driving alone like it's a normal thing.

However EFI can mess up and dump raw fuel in just the same. My friends EFI Seville was doing exactly that before we replaced the EFI with an intake and 4 barrel off an 83 Oldsmobile, no more issues. A failed fuel pressure regulator can flood an engine the same as a bad choke, or sunk float, sticking needle and seat etc.

IMO it comes down to when it's broken, you should fix it.

That's an interesting take--usually people take the position of, engines lasted longer when EFI with precise fuel metering, and more likely, no cold start washdown on the cylinders. Interesting counter argument about lower rpm and lower compression (although... 70's engines?). Now engine oil improvements, no doubt that has had something to do with it.

Now that I think about it, the wife did have an '86 Olds with a carb 305 (307?) with 240k on the clock, it was starting to use oil but it was still plugging along in 2001 (when it was traded in).


And yes 70s like 73+ is when I'm talking although my experience is 76+. Very low RPM engines obviously and low compression.

 

[PimTac]

Carburetors were simple until somewhere around the mid 70's. Then they got cheaper and EPA regulations made them harder to work on.

Fuel injection was a Godsend.

 

[caprice_2nv]

Originally Posted by PimTac
Carburetors were simple until somewhere around the mid 70's. Then they got cheaper and EPA regulations made them harder to work on.

Fuel injection was a Godsend.

Luckily in Canada emissions regulations weren't as strict so in 1981 when all quadrajets in the US were computer controlled us Canadians still got old style carbs without the ECM/o2 sensor's etc. Most of ours didn't even have air pumps (gm full size cars anyway).

 

[caprice_2nv]

I didn't feel like pulling the air cleaner off for a picture of the actual carburetor, it was hot from the 1.5 hour drive, but I was taking pics for the guy who is likely getting the car from me. I'm trading it for a paint job and cab corners and rockers on the truck, plus fixing a dent on the quarter on my cutlass. My paint and body guy really wants my car. Probably going to ls swap it.

 

[Malo83]

Yup looks like my snake pit under the hood of my 83.

 

[JeffKeryk]

Waaaay to much plumbing for me. Past the very early 70's I'm done.

 

[caprice_2nv]

Originally Posted by Malo83
Yup looks like my snake pit under the hood of my 83.

Half of it is for the broken cruise control. As you know, it's not a big deal. The biggest issue is when I work on something else and I'm thinking "why isn't there at least half a foot space to get around this"?

 

[meep]

Carbs gave me a couple of opportunities to meet girls. Either someone else's car wasn't starting and I'd go lend a hand, or one day I was pulled over in our ‘57 Chevy (I was 17 in the late 80s) and she pulled over and offered to drive me home for tools.

I was such a dimwit. I knew I could fix it with what I had and turned her down.

M

 

[tomcat27]

motorcycle carbs can be simple, or a pain. they definitely dont like old gasahol and dont like sitting. some are forgiving. others are finicky. I have a Yamaha Radian that goes bonkers if it sits for a couple of weeks - those carbs are haunted. our snowmobile carbs, simple. in a plane? eh, I'm not sure which is better or worse: carbs or FI. either way you do not want a problem!!!
I am actually in the process of swapping the Quick Fuel carb off the Cougar and installing FI. It ran good, although always ran rich, even after alleged dyno tuning. We will see how the conversion goes. installed fuel pump, ran new fuel lines: feed and return, installed the O2 sensor and CTS. need to finish up the fuel connections, wiring, linkage.

Anyway, carbs are usually simple. glad that you're having fun with it!

 

[02SE]

Had lots of experience fixing carbed vehicles for a living back in the day. Learned about their limitations and idiosyncrasies quickly.

Give me a good FI system any day.

Glad you got it figured out.

 

[supton]

Originally Posted by meep
Carbs gave me a couple of opportunities to meet girls. Either someone else's car wasn't starting and I'd go lend a hand, or one day I was pulled over in our ‘57 Chevy (I was 17 in the late 80s) and she pulled over and offered to drive me home for tools.

I was such a dimwit. I knew I could fix it with what I had and turned her down.

M

 

[bunnspecial]

I'm a young guy(32) and grew up driving and mostly riding in FI cars. My only real exposure to carbs was on small engines, which of course even though they are the same in principle are often a totally different beast.

5 years ago, I bought my MG, and what followed over the next few months was learning the ins and outs of constant velocity SU carburetors, and also learning how to sync/balance 2 of them! A lot of people fuss about SUs, but I've "bought in" to the superiority of the design and aside from a few weakness in early models(throttle shaft wear that causes vac leaks) they really are an excellent and reliable carb. An SU metering needle is designed with 8 "stages" to reflect varying speed/load conditions. The needle is used to change the size of the jet, which means that an SU has the equivalent of 8 jets vs. your usual 2-3 on a fixed venturi carb.

Right now, there's a set of HD6 SUs sitting on my bench that I want to at least spruce up, if not rebuild, and maybe see if they will run decently on my MG. With some recent performance improvements, I MIGHT be able to take advantage of the larger 1.75" carbs(the ones on it are 1.5"), but I need to experiment.

BTW, pull the choke out, turn the key, and my car starts right up. Leave the choke all the way on for a few seconds, then slowly push it in over the next couple of miles of driving. I much prefer that to the water choke fitted to the later MGs that can go out of adjustment and has a bad habit of corroding.