Originally Posted by starin
Hey guys so thanks everyone helping me with my firing order issue / timing gear issue.
now my next problem is that when i have the car in park it idles at 1000 rpm but when i put it in drive it idles at 600 rpm. i sprayed some carb cleaner around the intake and carb base and no change in rpm. I'm pretty sure i have no leaks. the motor is a pontiac 350 out of a 1972 lemans. it has the original points distributor but i put a petronix in it. however im new to the whole world of wrenching and did not change the springs or the plate or the vaccuum canister and these were all original.
when i timed the car i disconnected the vac advance and plugged it as well as plugged the manifold source. i timed it at 12 degrees. when i hooked the vacumm advance line back to the manifold vac i was under the understanding the timing was supposed to go up a little. when i put the timing light to it. at idle it was still at 12 degrees.
do you guys think the distributor is the problem? i bought an A1 CARDONE reman distributor today and am going to swap my pertronix into that. but if its not the problem id rather save the money.
what do you guys think?
Thanks in advance.
If the timing isn't changing at all when you hook the vacuum advance back up, either you are using "ported" vacuum, the vacuum advance is sticking, or the diaphragm is leaking and the vacuum advance can is no good.
You can use a different vacuum port that has vacuum at idle (called "manifold" vacuum) to see if the timing and idle speed picks up. If it doesn't the can is bad or is binding.
Setting up a performance advance curve is very important- as I told you already and if you go to the link I gave you in the last thread you can bone up on it. The article is on the HEI distributor but the timing info still applies. Just remember the Pontiac distributor turns CCW, so the weights and advance cam will be "upside down" from a picture of a Chevy distributor.
You want to be sure the mechanical advance is not coming in when the engine is idling in Park. If it is, the idle speed will drop when the engine slows when you put it in gear- and that slows the idle speed even more.
If there's room for it I would be installing a HEI distributor yesterday
! The resistor wire used w/the GM points ignition needs top be replaced, otherwise it's a plug and play deal.