I recently finished an almost two decade restoration process on my 67 with a 400 engine which involved replacing or rebuilding everything. The car was missing a lot when I got it. I replaced the 326 with a 400 and rebuilt that. It already had a TH400 so I rebuilt that. Bought a stock type intake and carb on ebay. Carb is a quadrajet off a 1969 428 Bonneville which I've rebuilt and think it's working pretty well. It idles well with like 19" vacuum and drives great. Stock type mechanical fuel pump. Engine runs well and I can spin the tires pretty easy which is fun.
The engine cranks fast and easy hot or cold so no issues there. I put in a high torque starter, 750 CCA battery, and 2awg cables which all together completely fixed up the slow/no-cranking-when-hot problem I had before.
My carb is one with a divorced choke coil in the intake manifold exhaust crossover which you can see in the attached pic. Accelerator pump works. Choke works. Generally the carb is all good I believe. It idles at like 900 in Park fully warmed up which drops to maybe 750rpm in gear while holding the brakes.
This is the only carbureted car I've ever owned so I have very little experience. To start I'll give the accelerator pedal a press or two to the floor then release and crank the engine with foot off the accelerator pedal. When cold it fires right up immediately to like 1500 rpm high idle. Sounds robust, engine speed flare up when it fires off is great.
My issue is actually when the engine is hot. I do the same procedure pump the accel pedal once or twice then crank with my foot off the pedal. As I said the starter spins the engine over very well so no problem there with cranking speed. It will light off right away but engine speed only rises for a second to like a few hundred rpm then it falls back down to cranking and will start after a few seconds of cranking. When it does start it's like a very weak start that does not flare up at all. The engine sort of sputters up to idle speed but it is not a robust start. You know on a new car whenever you start it the engine will flare up over like 1000rpm then fall back down to the idle speed, that flare up is really what I'm missing here but I don't know what is normal operationally or behaviorally for an old car like this.
My question is what do you all do with the accelerator pedal when starting cold and hot? Should I expect a robust engine start when hot with the engine speed flaring up to say 1000rpm before falling down? Am I supposed to be holding down the pedal halfway when hot or something to make up for the high idle speed cam not engaging when it's hot?
The wiring circuit shows +12 coming from the fuse box to the reverse switch to the bulbs in the rear.
- It appears from that the backup light shares a fuse with the turn signals. So if they are working, I don't suspect the fuse.
- You don't say what trans you have but each have backup/reverse switch specific to them. I would test the switch. In my TH400 with console, the switch mounts on the shifter lever assembly within the console. Search in this forum for "backup switch" (use quotation marks) for discussions of manual trans.
- I would still check the rear bulbs and their holders. Bad bulbs and a bad ground to the bulb holder are common failures. They are easier to test and cheaper to replace or clean then the switch. I would take a multimeter and see if you get +12 at the light green backup wire by the light with the trans in reverse.
Awesome advice on the bar reinforcement and the linkage kit. I will do both. Will let you know what happens next month when I get my hands on her. Car is in Maine and I'm in Florida for the next month. Great to hear the components will fit - I'd rather use the factory mechanical linkage if I can. Appreciate the encouragement !
I finally have my issues fixed thanks to being laid off and without a job for a month haha.
The car forever has had a really hard time starting when hot. Sometimes wouldn't crank at all. I put in a high torque starter, larger battery, and larger battery cables and that's fixed.
There were a number of driveability issues. It would take a long time to start. It had a vibration when accelerating onto the freeway. It idle'd rough. The engine would box down and nearly die when accelerating away from a stop. From a cold start it would usually die and need to be restarted again.
I found quite a few issues when I took apart everything. I pulled off the intake and rebuilt the carb again. I had originally done that in like 2006 with the help of Cliff Ruggles book. Well I bought the Doug Roe book and have been just reading those over and over the past few weeks.
Here are the issues I found: -distributor vacuum advance canister was leaking -carb accelerator pump was not working at all since the seal had fallen off -accelerator pump check ball was not sealing well -main fuel metering rods were stuck in the full lean position! There's a little metal twisty thing that holds them to the hanger which was bent and being pushed down by the air horn when bolted together. This pushed the jets fully down all the time. I think the vibration I felt was actually knock due to being lean -the throttle body plate was missing holes drilled for fixed idle air bypass because that was a mismatched part I got from a local carb shop many years ago since my original throttle body had stripped out idle screw threads -the choke pull-off vacuum diaphram was leaking -hot idle compensator was leaking open all the time I think
I rebuilt the carb and fixed all those things. Had to get parts from a few sources to get through it. Finished assembly yesterday and just got back from driving and it's all better!
The car actually drives with confidence which is new. I bet someone other than me could even start and drive it, lol. Pretty easy to squeel those tires now
Yes on the 4 bbl but a cam change will make it sluggish down low with that 2 speed automatic. My opinion but unless you just want the choppy idle noise, the car will be more enjoyable with the stock cam.