help!

[56 boy]

so i finally started my 56 century after four and half years rebuilding her. the engine started right up with no major problems. but now im trying to dial her in and the issues start. so i tired to follow the manual and take the steps they say but there is no way i could get the car down to 450rpms! i asked around with some of my hot rod friends and they said get her to about 700 rpms and start from there. so i did that but the car sounds like crap. i tired to check the timing and adjust it to 5 deg like the book said, but once again it sounded bad so i was playing around with the timing and got it to a spot where it sounded better, which was way off the mark. i disconnected to advance and i am pretty sure i have no air leaks. the car is 30 over and i was wondering if anyone has any suggestions or had a simialar problem when they put in a freshly built engine. let me know, anything will help. thanks

[Reatta Man]

I, too, have run into those ridiculously low RPM settings that seemed impossible to use in the REAL car world.

If it is an automatic, you may be able to get it down to 450 by setting it in drive with the emergency brake on.

As for the timing being so far off, how are the points? A change in dwell will affect the timing, so double-checking the gap (dwell) could affect the idle and timing.

Also, how is the carb? Do you think you have the idle mixture set properly? If not, adjust that and then try to idle it down.

You might also want to check the advance springs and make sure they move freely.

Also, when you say you have no vacuum leaks, does that include checking the vacuum advance to make sure it holds a vacuum. If you don't have one, go ahead and invest in a hand-held vacuum pump for testing things like that.

It looks as if you are checking the right plug, but I have to go ahead and ask; you ARE checking the plug nearest the radiator on the PASSENGER side, right? You would be surprised how many mechanics that work on other GM cars that don't know which plug is #1 on a nailhead engine.

Just a few places to start, and hope it helps. Just keep in mind that the hardest part was getting it running. You've gotten that done, so everything else should be easy.

And, don't feel bad if you do something totally wrong. You're reading the advice of a guy who once hooked up the 6V battery on a 1954 Chrysler Hemi with the negative to ground and wondered why it ran so funny. Hey, everybody knows the negative goes to ground, right? Obviously it had been quite a while since I had worked on a 6V POSITIVE ground system. DUHHH!

Joe

[56 boy]

thanks for the reply. i will try those things. yes i am checking the right #1 plug. also i rebuilt everything and im pretty sure that i did it correctly. ill check everything once more just to be sure. thanks again

[56 boy]

one more question. so i know/heard about the dwell, and i was smart enough to go buy an rpm gage that had a dwell meter on it also, but the thing i dont know how to do is check/adjust the dwell. help?

[Reatta Man]

You'll hook up the meter and set it to read the dwell according to the directions.

If your distributor cap has the small metal window on the side, you will use a small allen wrench to adjust the points while the engine is running. If not, you will set the points to the book specs with the engine not running.

If your distributor cap does have the metal window, I like to hook the allen wrench up to the points with the engine off. I've gotten shocked more than once trying to find the opening under the hood in very little light. Feeling 15,000 volts flowing through your central nervous system is an experience you really need to avoid if at all possible.

Joe

[BUICK RACER]

Go back to the Shop Manual, and read about setting the points,you need to have some feeler gauges and get the distributer on the lobe, then adjust the points to what the manual says. Hey, that's what we had to do before dwell meters were available! Hope that helps! or use your dwell meter and adjust the points accordingly, shouldn't take much to get it right!

[Gene Brink]

If you have a period correct distributor cap style you will not be able to adjust while running with an allen wrench (know what you mean about shocking oneself, Joe -- ouch!) but I've always set with a feeler feeler gauge (aiming for the largest setting so as it wears you stay in the proper range over a longer period of time) and then checking with a dwell meter. If it needs a bit of "fine tuning" I pop the cap and move just a hair and check again, etc. until it is where I want. Dwell can make a tremendous difference on how the engine will run so unless you are a tooth off on the cam to crank setting on the timing chain I'll bet it is the dwell.

Good luck.

[FireballV8]

Where did you get the engine paint from?

thx

[Guest Straight eight]

What is the vacuum with engine running at "idle"

Is the dash pot holding open the throttle? The round dish with a prong that retards the return of idle so engine doesnt stall when in gear. What is the dwell, should be 28 degrees. The timing cannot be set until the idle is slowed down to about 350 rpm. Plug off the vacuum line to the brake so you can tell if the vacuum brake cylinder is working, or leaking.

Did you overhaul the carb? Are the throttle butterflies allowing their closing?

Now lets see where things stand

[JohnD1956]

I agree on the dash pot and add : be sure the choke is opening and the fast idle cam is dropping away from the idle screw.

Since the vacuum advance is piped with a copper line, it is essential that you get the idle down before setting the timing. Mine is set for 450 RPM and runs just fine.

Jd

[NTX5467]

Many earlier cars DID have idle rpm levels that would make a newer engine (with "more" cam) stumble and be rough. The carbs were set up to tolerate that action whereas later ones are not.

With a "points" system, the dwell is set before the base ignition timing is set. MUST be done in that order!

You can set the point gap (carefully!) and let it go at that, or use the dwell tach (which can be a more accurate way of doing things). If you want to get really technical AND check the lobe-to-lobe variations, you can remove the distributor and chuck it up to use a dial indicator. If, after all of this to get the points set correctly, the dwell is not in specs, it can be either the particular meter or indications of a worn distributor cam.

It's always rewarding when you get things fine tuned and the engine runs perfectly!

Enjoy!

NTX5467

[56 boy]

thanks everyone for the reply. tomorrow before class i will play with all those and see what happens. to fill everyone in, i have rebuilt everything, from the frame off to each bolt and nut on the car, including the carb and the distributer. and the the paint question, i get most of my new production- old parts from bobs automobilia in Atascadero Ca. most of there stuff is good and i like it, not to many problems, and since i like 15 min away, and its easy to drive there, if you bring cash they give you a discount and its usually no tax about about 10-15% off there price. cool people, talk to them all the time. there phone number (which is on speed dial on my cell) is : 805-434-2963 and there web site is : www.bobsautomobilia.com. check them out...

thanks again everyone

[progoofoff]

Might consider a Pertronix Ignitor and forget about the points.