QuestionHey Don
I am trying to get this vehicle roadworthy.Here I my biggest problems-i hope you can help.
1.Overheating:I flushed out the rad,put on new hoses and thermostat,and water pump.Still it overheats.The temperature gauge on the dash doesnt work,but the rad is super hot after only a few minutes driving.
2.Three in the tree:I dont know if the linkage is worn or even how to adjust,but sometimes I have to struggle to change gears.
3.Carb:I replaced it with another used one,cleaned up the linkage,but it still seems a bit sluggish and I get the odd backfire.I know how to adjust the idle,but not the choke set screw-is this supposed to be closed or open or what?
Thanks!
AnswerBarry, As an American Pontiac car guy (my dad's first new car was a 58 Super Chief), I know of and appreciate the Canadian versions which looked like the American cars with a little different trim/grill sometimes and names, but Chevy drivelines. So here goes:
1. Overheating, Without a temp gauge you really have no idea how hot the engine is getting. Buy an aftermarket gauge and sender and screw the sender in where the factory unit goes. This is easy to do, you can just run the wire through the window opening and tape the gauge under the dash for a while if you don't want an aftermarket gauge in the car (some people just don't like that look). Find out how hot it really is.
If it IS running hot, then you need to check that the radiator isn't plugged with bugs/junk, blow it out with an air gun. straighten the fins if they are all bent over so air can flow.
By the mid-60's most cars had a round shroud that allowed the fan to more effectively pull air through the radiator. Sometimes in the process of working on cars for a couple decades or more, these get thrown away. If it had one and now doesn't, get one. Double check the cap, make sure it holds pressure and is the right speck. Double check the thermostat, put it in a pot of boiling water to see if it opens and closes ok. make sure the hoses aren't collapsing as coolant is pulled through. There should be a wire coil keeping this from happening in the lower hose I think.
Sometimes overheating is caused by a leaking head gasket, but it usually take more than just a few minutes. BUt check for air bubbles in the radiator (cap removed carefully) that is one of the signs. Even rebuilt water pumps can sometimes be bad. Make sure it is working and the fan belt is tight enough.
If and when the engine was re-built, was it boiled out? There might be a build-up of crud on the lower portion of the block keeping the coolant from working right. Maybe pull a freeze plug or two and see what is in there?
2. Three in the tree. Everyone loves the floor mount four-speed, but I love a three in the tree. I still know exactly how to hold and shift one of those. The mechanism was sometimes balky when nearly new. They tend to hang up between 1st and second and in my old Chevy (51) I would have to get under the hood and align the levers on the steering column by hand to get it un-hung.
Clean and lube the mechanism on the steering column, it gets road dirt and other crud in there. Spray some WD 40 in to clean it, and then some spray lithium grease to lube it.
Check that the bushings at the tranny and those levers under the hood are in good shape. They are probably rubber and in bad shape if there at all. Replacements should be available about anywhere. Remove the shift rods from the gear box while checking/replacing these bushings and by hand try to shift gears. Have someone shift the car while you are under it (use GOOD jack stands and be SAFE while under the car) and watch how the levers move into each gear. You can do this by hand and feel how easily it moves. you should be able to move them by hand, should click into place easy, if not, you may have a problem inside the tranny. Again parts are easy to find and not expensive. I can probably still bench strip and rebuild a chevy 3-speed tranny blindfolded as I did it hundreds of times when 15 and working on my first car, that 51 chevy. (I was amazed at how a tranny worked and loved watching the gears move with the side cover off.) As a last resort, you may have to remove the steeering column and rebuild the levers inside it.
3. Carb/choke. First, does the choke close when cold and open by itself when hot? Visually see if this happens. By choke set screw, do you mean the plastic cover that sets the choke spring tension? There is a little pointer on it, and you need to assemble the cover with the proper tension and set the pointer straight up to start with. You can turn the cover a little forward or back to adjust how aggressive the choke is. It really is pretty simple. Get a MOTORS manual for your year, they are better than Haynes in my mind, but a Haynes should work.
Make sure the float is not filling with fuel, and that it is set right for both drop and for the top point. Make sure the seat of the needle valve is tight. These tend to work lose and leak. Check for a vacuume leak by spraying a little carb cleaner at the base of the carb with the air cleaner on, with the engine idling (caution! The spray is flammable, so be careful). If you get a rise in rpm, you have a vacuum leak. Most likely place is the butterfly rod in the cast iron base, or an incorrect gasket when putting the carb back together.
With carb kits being really cheap, if in doubt, do another carb rebuild, making sure ALL passages are clean and all parts are put back in. Visually inspect that the accelerator pump is squirting when you press on the gas, you should see a squirt into each venturi (front two on 4 bbl carbs, both on 2 bbl, and the one on 1 bbl carbs like on your six).
To adjust the idle screws, turn them in till the gently seat, then back out 1 3/4 turns. That is usually a good starting spot. A vacuum gauge can help set them better.
If you don't have it, get a good timing light (I like the ones with the dial where you can set the timing advance on the gun so you can use the ZERO line on the pully rather than try to read the rusty/painted scale). Also get a vacuum gauge and a dwell tach meter. With these and a few basic tools you can get any old American car running like new.
Don
