My 67 GS 400 has some type of idle problem. Idle is fine out of gear. But when i put it in gear it wants to die. Sometime it does. Had the carb rebuilt but i'm still having the same problem. The timing seem kind of high too. I think at idle it is set a 20. It has a TA 212 cam in it. The engine is bored .040 over and the heads were shaved .006. I know it's hard to diagnois car problems online but any ideas would help.
sounds like a vaccum leak to me. i'm sure someone else smarter than me will chime in in a bit, but i'd run a vaccum test on it.
there does not seem to be a vacuum leak...the vacuum gauge the we hooked up is showing around 15 in. ONLY with the timing up near 18-20 base!!!! bring the timing down to 12 or so and the car will not idle... the mech adv. comes on @ about 1600-1700 rpm and the vacuum adv. is operating properly it is very rich..tried two different carbs and both are running the same idle is @ 950 in park and in gear it drops off to nothing???? could there be a cam timing issue?? thanks
I still think it is a vacuum leak too. With the motor warm and idling in Park, slowly close the choke. If the motor speeds up, you have a vacuum leak. Using the vacuum gauge won't help you find a vacuum leak.
Did the thing with the choke the motor never did speed up. Went all the way to close before the motor die. Did it 3 times just to make sure. I did not build this motor it also has a petronics ingnition in it. I am starting to think the the double roller timing gears or the cam where not installed with the correct degree?????
If your running vaccum advance, are you running ported or unported. If your running ported then all of your vaccum advance is in at idle and if your running unported it's not. Whichever you have change to the other and see if that helps.
We pulled the smoke machine out while we were looking for the vacuum leak.....didn't find anything.....put the smoke in the crank case and it came out the carb?????????
20 degrees is exessive with a small cam. With such a small cam I'ld set the initial to where it will fire right up at the turn of ignition weather hot or cold. If it is hard to turn over when hot back the initial up. Once the initial is set get the total advance all in by 2,500. Also the higher the initial timing is you will get more of a drop in rpm when in the trans. is put in gear. If these fail the 67's had a sheet metal plate under the carb that may be missing causing a vacuum leak or possibly you have an intake leak. They will have the same symtom. That's my opinion.........Ray
This will probably sound dumb, but the next time your fooling with the car try unhooking the vaccum advance, be sure to plug the hose and see how it acts. Had a 318 Mopar years ago that would not idle with it hooked up. o No:
Ray we saw the sheet metal spacer when we first pull the carb off and we did re-install it after the rebuild. We are going to pull the intake off and replace the valley pan gasket and the intake gasket. Dave if we don't find anything in the gaskets I'll try the vac. advance disconnect..... I am almost to the point of pull the motor and checking everything out with regards to the cam and timing.
The intake is a good thing to check. My 455 was leaking around the bottom of the ports at the intake gaskets which allowed it to suck air in from the crankcase. This caused the motor to want a lot of initial timing to run (35*). As far as the cam timing, too far retarded will make it want more initial timing as well. Do you know if you have a 9 keyway timing set? You can easily degree the cam with the motor in the car. If you want to ease your mind about this pull the timing cover while you have the intake off and check it out. As far as the idle, I don't know how these things will affect idle quaility. I had to do both of the things above and I'm still having idle problems. I just paid $275 to have my carb built. I runs like a raped ape from off idle through WFO but idles rough and erratic and drops from 900 to 750 or less when I put it in gear? Good luck and let us know what you find.
