Won't idle, could this be a timing issue?

[Peter S.]

My 62 has a lot of new engine parts, and was running pretty much perfectly. I "got on it" a bit and ran it up to about 5500 rpm through the gears. It's a stone-stock 327-300.

After that little 1/4 mile, it wouldn't idle. It kept wanting to die, and I nursed it back home (gladly only a few blocks) but revving the engine up to keep it from dying and braking with my left foot.

It will start and run, running when cold and choke engaged with higher rpm (maybe 1400?) but as soon as the choke opens it wants to die unless you keep goosing the throttle.

It also wants to backfire.

I was wondering, what could have happened? Is this a timing issue?

Could the distributor have jumped a gear tooth?
Could the timing chain have done something bad?

It's kind of acting like the spark needs to be advanced, like maybe the vacuum advance is advancing the spark a little which makes it run but when going to a lower idle speed it won't run because it's too retarded?

Or am I retarded??

I can't swing the distributor any more CCW because the vacuum pod is hitting the intake manifold.

What should I try?

[William C.]

Re: Won't idle, could this be a timing issue?

OK a few basic checks should help your diagnosis. First, distributors don't "Jump" timing, however, if not properly secured using the clamp at the base, or if the distributor has excess internal drag, it can rotate and thus chabge timing, so the first step I would take is to check the base timing and advance, along with the dwell. If you need more clearance for the vacuum can, it is relatively easy to puppl the distributor up until you can feel the gear teeth disengage and rotate on tooth in the direction that you want the vacuum can to move. Start there and see where you are then...

[Larry M.]

Re: Won't idle, could this be a timing issue?

Pete:

You stated that you have a lot of new engine parts. Is it possible that you floated the valves on your 1/4 mile run and nicked a valve?? Do you know what type of valve clearance your revised engine has versus stock clearance?? Did you replace the cam and lifters?? Are they mechanical or hydraulic??

Regarding timing, as Bill said above, I would check dwell and I would also check initial timing both with the vacuum can connected and without it. See if you can get the engine to idle low enough to determine the true initial advance, but if not, post up what you find and the RPM. Again, both with and without the vacuum can connected. Also, check your timing with the vacuum can disconnected every 500 RPM up to about 4000 RPM. These numbers will give a good indication of how your distributor is working. Also note any unusual timing flutter/variations during these checks.

I would also get an engine vacuum reading at idle (or near idle) with everything connected.

I would also readjust the idle mixture screws to see if this makes a difference in idle quality. I think they typically are about 1-1/2 turns out +/- a bit.

If basic distributor checks and carb checks don't indicate anything, I would pull one spark plug wire at a time and check what happens with engine speed and idle. You may also want to pull the plugs and do a compression test if you suspect valve issues.

Larry

[William C.]

Re: Won't idle, could this be a timing issue?

Another issue I don't see is what pistons and plugs are you using? If you have a popup piston, and try to use an extended tip plug, the first high rpm runup will close the gap on one or more plug(s) Something I learned the hard way about 40 years ago...

[Duke W.]

Re: Won't idle, could this be a timing issue?

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I can't swing the distributor any more CCW because the vacuum pod is hitting the intake manifold.

What should I try?

That's the classic symptom of the dist. driven gear being indexed backwards... or it could be an improperly indexed gear on the cam. What's the mfg/pn of the camshaft?

You say the engine has a lot of new parts? What are they? Was the engine rebuilt recently? What work has been done recently?

Beyond that have you checked initial timing? Have you gone through the idle speed/mixture adjustment procedure? What is the normal idle speed and vacuum? (A 327/300 should be 18-19" @ 500 in neutral assuming it's a manual transmission.) What's the data stamped on the VAC bracket? Does the VAC work and meet spec?

Without some basic diagnostics and test data, and some idea of the engine configuration (Is is really a 327/300 as built by Flint, or does it have non-OE equivalent parts?) the list of possible problems is a mile long! You need to provide the TDB with more information or just be satisfied with guesses.

Duke

[Robert K.]

Re: Won't idle, could this be a timing issue?

Is the float stuck? Is the engine running rich? Do your eyes water while trying to keep it running? If yes then a stuck float. You might be able to un-stick it with light tapping on the carb.

[Peter S.]

Re: Won't idle, could this be a timing issue?

I appreciate everyone's advice -- I replied to the post earlier but I guess it didn't save. To answer some questions:

1) It should be stone-stock 327-300 parts. Hydraulic lifters.
2) The engine only has about 400 miles on it -- was running pretty perfect until whatever happened.
3) I checked the valves and all seem to be going up and down happily when the engine turns over -- no bent pushrods.
4) At TDC, the distributor is pointing at #6, 2 and 8 have valves open.
5) I did check the plugs to make sure they didn't get hit, they look fine.
6) I don't think the engine is running rich -- doesn't seem to be an excess of gas in the carb -- I have the air cleaner off.

I noticed the coil was hot -- should the coil be hot if the ignition is on and the distributor cap is off?

[Terry D.]

Re: Won't idle, could this be a timing issue?

No the coil should not be hot, but it doesn't sound like you checked the float level. A high or stuck float will cause your car to run at higher rpm, but not idle.

[Timothy B.]

Re: Won't idle, could this be a timing issue?

Terry,

I respectfully disagree with you about the coil.

If the ignition key is in the on position and the points are closed, current is running through the primary circuit inside the coil and it gets very hot.

There has to be a vacuum leak somewhere, can you hear anything hissing when trying to idle the car. What carburetor is on the engine.

Double check the rubber lines going to the carburetor for a split or a line that's the wrong size not sealing around a fitting.