Carb/Distributor Swap?

Discussion in 'General Automotive Tech' started by TheSafariKidd, Aug 3, 2019.

  1. TheSafariKidd

    TheSafariKidd New Member

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    Damn, that runs hard in my opinion! I really want to stay Olds powered if at all possible. Everybody and their illegitimate cousin drops a Chevy engine in their rides because they are too narrow minded for a challenge.

    Im going to list that Vortec engine on Craigslist to see if i can trade for a good 350 Olds engine. I ran across a old school engine builder by the name of Joe Mondello, Looks like he has some pretty good build options that won't break the bank.
     
  2. Poison_Ivy

    Poison_Ivy Dogzilla Fan

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    I don't know about the 350s. But, the 330s had factory forged steel rods and cranks, if it matters
     
  3. KevinVarnes

    KevinVarnes Well-Known Member

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    Does everything work and run fine or is the previous owner just one of those people who thinks everything that is controlled by sensors evil? If it runs fine I would just leave it alone. If there is something wrong then I would get a factory service manual and go through their troubleshooting process to get it running properly.
     
  4. HotRodRacer

    HotRodRacer Well-Known Member

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    Joe died in 2011, but his business is still going. I second Kevin's thoughts above, if it runs fine I would leave it alone and only worry about replacing it once I had driven it until it no longer ran fine. :)
     
  5. cammerjeff

    cammerjeff Longroofs Rule!

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    Not true Ivy, the 2nd usage of Q-jet was actually for the 1966 Pontiac OHC-6 that only displaced 230 CI or 3.7 Liters. The secondary air horns make them very good carbs for a wide range of engine sizes, as the secondary air horns only open far enough to let in the air the engine is using. They were even used on 252 Buick V6's & some early 231 Buick Turbo's. Same basic carb was used all the way up to 500 CI Cadillac's. Almost all the 307 Olds used them after 1980. As did Pontiac 301 & Chevy 305 V8's.

    I agree the easiest way to make the original posters wagon perform better would be to put in a 350 or 403 Olds, almost a straight bolt it. Just will have a few issues with accessory drive brackets.
     
  6. Poison_Ivy

    Poison_Ivy Dogzilla Fan

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    It's true that those smaller engines were factory equipped with them. However, they were jetted and otherwise acalibrated to suit a wide range of applications.
    Initially, GM needed a replacement for the aging Carter AFB, since it was essential that GM was to keep its cutting edge. Meanwhile, Pontiac got the green light for experimenting with their new six. For them, using the Quadrajet was simply a matter of convenience. In other words, they simply grabbed whatever happened to be on the shelf, that day. If it wasn't planned to modenize every division's horsepower palate, Rochester wouldn't have bothered to develop this carburetor for only a handfull of smaller engines. Vaccuum-operated secondaries took out the rest of the slack. That's still not to say that a Quadrajet delivered on an OHC six will be able to satisfy the appetite of a 500 Caddy and vice versa. Here, you're dealing with one engine being more than double the size of the other.
    The same basic Rochester two-barrel on a '56 Chevy 265 was also found on big block GMs of every division, except on Cadillacs. For just getting from A to B with a trunk full of sand and bags of cement, a big block's inherent torque was sufficient to do the job, regardless if two or four barrels were doing the feed

    https://www.motorstate.com/Quadrajet.htm


    https://www.chevyhardcore.com/tech-stories/choose-your-quadrajet-number-identification-guide/



    [​IMG]
     
    Last edited: Aug 7, 2019
  7. TheSafariKidd

    TheSafariKidd New Member

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    Hey Guys thanks for all the great information! For some reason my alerts stopped going off to let me know you all responded, sorry.

    Another question, my temp always seems to be hovering right at the 220° mark, sometimes a little less when i let off the gas a coast down hills. Seems too hot ?
     
  8. Poison_Ivy

    Poison_Ivy Dogzilla Fan

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    185° should be right, if I remember correctly. I think, 195° was an alternative availability. If your guage or sender isn't out of whack, I'd start with trying a different thermostat. If it still runs hot, there might be a hot spot in the engine or the radiator's calcium blocked
     
  9. TheSafariKidd

    TheSafariKidd New Member

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    Ok, the thermostat was the only thing i didn't change so that will probaly be it Lol.

    I just installed a new radiator, clutch fan, hoses ect because the radiator shop said if i was going to replace one item i might as well replace everything so im not hunting gremlins.

    I made sure all the air was out of the freshly filled system too.
    Took it out on the highway and same problem, the faster i go the hotter it gets.

    Slower i go the cooler it gets.
    Hoses don't collapse and when i take the radiator cap off and let it come up to temp, its circulating like crazy. I'll try a new thermostat tomorrow.
     
  10. Silvertwinkiehobo

    Silvertwinkiehobo "Nothing is foolproof as fools are ingenious."

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    Having an engine in that temp is fine when you have a 195* t-stat...if the temp stays constant. But yours rises during freeway driving, cools down as soon as you are at street speed. That could be a bad T-stat, or a few different things. Drive it in the middle of the night, see if its behavior changes.
     
  11. TheSafariKidd

    TheSafariKidd New Member

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    Thanks Silver, I'll do that and let you know my findings. I hope its just a thermostat. Everything else is new now.
     
  12. joe_padavano

    joe_padavano Well-Known Member

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    I realize I'm coming into this discussion late, but you are seriously misinformed. The 1980-1990 Olds 307 ONLY came with a Qjet. Nearly all of these (from 1981-on) were the computer controlled Qjet. The ECU controls both the timing in the distributor (there are no advance mechanisms in the distributor body) and the mixture ratio on the primary side of the Qjet. The seller said to replace the carb and distributor because apparently he was incapable of reading the factory Chassis Service Manual and following the instructions as to how to properly adjust this system. Replacing the carb and distributor with older non-computerized versions takes the ECU out of the loop. People who lack the skills or patience to properly adjust the computerized system often do this. As for the DualJet with the back two barrels blanked off, that was only used on the Olds 260 motors in the mid-1970s. Real 4bbl Qjets were used on motors as small as the 4.1 liter (252 cu in) Buick V6 in the 1970s and the 230 cu in version of the Pontiac OHC six in 1966-67. Rochester limited the amount that the secondary air valves could open on these smaller motors (as well as on the Olds 307), however the air valve design of the Qjet tailors carb airflow to match the needs of the engine.
     
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  13. TheSafariKidd

    TheSafariKidd New Member

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    Joe, interesting information thank you. The original owner actually gave me a repair manual specific to my wagon and its still in the plastic wrap Lol.

    I'll give it a read here in the next day or two. The original owner told me to replace the electronic carb and distributor because they were useless for performance or towing purposes. The secondaries come in WAY late when WOT is needed.

    I tried this at different speeds and and even when manually shifting, still the secondaries barley opened before i had to let off of it.
     
  14. Poison_Ivy

    Poison_Ivy Dogzilla Fan

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    He should have advised changing the Gremlin instead. Doing what he previously told you to do would be like burning down the barn in order to rid of the annoying fly. After the fly's gone, you've ended up replacing the cows, chickens and ducks also
     
  15. TheSafariKidd

    TheSafariKidd New Member

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    Silver, i waited until around 10pm last night to go fill the wagon full of gas and to see if it ran cooler at highway speeds and in town.

    It did, it stayed right around 198°@60mph and well below that @35mph. I know the cooler temperature outside would have some effect but not that much!

    So is that a thermostat issue or just normal for these older vehicles?
     

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