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49 Chevy 216 won't start. It ran before, but poorly. I pulled one of the plugs and while cranking the engine shorted the plug against ground. The plugs and points are properly gaped and clean. There was a very small, almost undetectable, spark with the engine cranking. The coil and condenser were replaced a year ago as was the points, plugs, and wires. Should the spark be bigger/better? What could the problem be, and how do I check the coil, condenser, even the distributor to see if they are bad or going bad? Thanks for the help, I appreciate it.


Regards,


Dave

Hi Dave

So often electrical problems can be solved by going to the battery first. Hopefully you can check it with a hydrometer first and then charging it up. I try not to assume that all devices are still working correctly after a year. The coil can be tested at a local starter, alternator shop. I learned a trick in my mechanical apprenticeship for the condensor. Using an ohm meter you can see the needle move and then collapse right away when you touch the positive lead to the wire and the other to the case. A static test can be done to the points using a test light while turning it over. You could always get just one new spark plug if you have any doubts and compare its spark to the original. Sometimes the simplest thing can cause a problem. The timing should be checked just to eliminate any issues there. I have seen a loose distributor tightning bolt throw things out of kilter. good luck

Blanch:

Thank you, I appreciate it. The battery is new and fully charged, and the plugs were just pulled and cleaned, they are also new. The last thing we did to the engine just before this problem was time it and adjust the valves, it ran pretty good them. I will recheck all my connections but most were recently cleaned, and I used a dialectic grease on them to make sure they have good contact. I think your right, at some point I going to find an electrical problem that I did not know was there, but I sure hope it is soon it's been a long time since it last ran and I need to get this thing on the road.


God bless,


Dave

First ensure all wires to the primary circuit from the battery through the coil, points to ground are in good condition including their connections (clean the contacts of the points with a fine emmery board or emmery paper). Ensure the points are set with the correct point gap when open as per specs.
Make sure the POLARITY is correct on the primary coil connections + to battery - to the points, a coil will operate when hooked up backwards at a reduced voltage output and a reversal in secondary polarity also. (voltage to the points when they are OPEN should be 12v minimal on a 12v system,(6v on a 6v system) with ignition switch in the ON POSITION OF COURSE).
To test a condenser correctly you will need a high cost oscilloscope. Just replace the condenser, they are cheap.
A coil output test is the sure way to diagnose a failing coil. O-scope again is the best method, however, once you have ensured the primary circuit is okay. You can measure resistance of both the primary and secondary windings of the coil with an ohmmeter and compare to specs. Measure the resistance of the coil wire also to eliminate the possibility that the coil wire is defective.
A Dynamic test can be done as follows.
Remove the high tension lead from the distributor CAP and hold this lead close to a clean engine ground (1/2 inch away). With ignition switch on, and engine being cranked, you should see an intermittent "bright blue spark". An orange or yellow spark indicates low voltage.
REMEMBER the secondary circuit can ONLY work as well as the primary circuit will allow. Don't condemn the coil until you are sure that the primary circuit is functioning at the correct voltages.
If a good bright blue spark is observed, check the spark at each plug in the same manner. If the sparks differ (yellow/orange at the the plug leads) then you have either a) defective plug wires b)defective distributor cap c) defective rotor
BY THE WAY,the distributor dwell angle determines the saturation level of the coil, the condenser controls the rate at which the magnetic field collapses within the coil. The amount of voltage delivered from the coil is dependent upon secondary circuit resistance.
Therefore, distributor timing will in NO WAY affect the amount of voltage delivered by the secondary circuit. Timing means "TIME" not amount.

Will:

Thank you, I greatly appreciate your help. I will try those things today and advise as to the outcome.

God bless,


Dave

To all:

Engine started today, I put a new distributor in with new points and condenser and it ran fairly good, I think it needs to be re timed because it will not come off the choke fully. You were right Will, it was electrical, I suspect it was the condenser. Any thoughts on the choke issue please let me know. Again, I appreciate all your help.

Not sure about your choke issue. My 216 does the same thing; runs better slightly choked than wide open. If I open the carb all the way up, I get stumbling upon accell and a very low idle which leads to it dying.

Usually the need for slight choke "ON" for improving run ability is caused by improper air fuel mixture. Most commonly, a carburetor idle mixture tweek will cure this problem.
Other mixture problems can be intake manifold leaks, carburetor gasket leaks, carburetor throttle shaft leaks, leaks at the distributor vacuum advance unit and attaching tubing and let's not forget if you have a vacuum operated windshield wiper system a small leak within this unit or hoses can affect the air/fuel ratio.

PLEASE NOTE!! Don't try to adjust the idle air fuel mixture until AFTER you have ensured there are no intake air leaks and AFTER you have your electrical system adjusted which includes point gap (dwell angle) and ignition timing. To attempt air fuel mixtures before adjustment of engine electrical system settings is a waste of your time. FIRST THINGS FIRST.

After setting your ignition point gap statically with a feeler gauge to specs, check your dwell angle (duration of time in degrees that the points are closed)using a dwell meter according to specs with the engine running at or near idle rpm.

Next, adjust your timing according to specs using a timing light and the timing marks on the flywheel/pointer.

Attach a tachometer to the primary circuit and monitor the idle rpm. Adjust the idle RPM screw to obtain idle rpm's per specs (usually around 600 rpms)

Using an arousal can of carburetor cleaner with a plastic straw nozzle, spray small amounts of cleaner around any and all vacuum connections, vacuum diaphragm and carb throttle shaft, carb gasket, and intake manifold gasket. If a leak is present you will notice a drop in the RPM on your tachometer caused by the ingestion of carb cleaner into the air fuel mixture via the leak point. Repair as necessary.
With no leaks noted, ensure the choke is FULLY OFF (OPEN), and adjust the idle RPM screw to obtain spec idle rpm's.
While watching the RPM's on the tachometer, slowly turn the IDLE MIXTURE SCREW in about a 1/4 turn.....if the rpm's drop....turn the screw out and continue to back the screw out 1/4 with 1/4 turns until the rpm's climb to there utmost highest reading. When the optimum air fuel ratio is achieved the rpm's will be at the highest point and the engine will be running smooth. If you back the mixture screw out too far the rpm's will begin to drop due to an over rich condition. The key is to slowly and methodically adjust the screw either in or out and achieve a maximum rpm gain. Once mixture is set, you should readjust the RPM screw and lower the idle rpm's back to specs.
If this does not cure the "CHOKE ON" to run best problem, most likely the carburetor is in need of internal cleaning or overhaul.
Stumbling upon acceleration, and erratic idle is commonly caused by LEAN air fuel mixtures when idle/power/accelerator jets get dirty or clogged and when the accelerator pump plunger circuit begins to fail due to wear. LEAN problems within the carb are masked by choking off normal air flow with the choke valve causing an over rich condition (and excessive fuel consumption) during all ranges of engine operation.

will:

Thank you, this is the most complete explanation I have gotten yet, I appreciate it.

God bless,

Dave

Dave,

Just a word on dielectric grease. I had serious problems after using this stuff.

I found this in the tech tip section of this sight

http://www.fifthaveinternetgarage.com/index.html

Dielectric Grease Caution
DO NOT use dielectric electrical grease to keep battery posts free of corrosion, as dielectric grease is an insulator and has a low melting point. When dielectric grease melts (caused by the heat generated as the current passes thru the posts) it changes into a liquid form and runs down between the battery post and the cable clamp. All will be well until you shut off the engine and everything cools down.

When you go back to restart your car the battery will appear to be dead. In reality the current from the battery is not being allowed to pass thru to the battery cables. To correct the problem remove and clean both the cable ends and the battery posts with emery paper or a battery terminal cleaner tool and reinstall. That should restore your battery connection.

I cleaned the wretched stuff off my terminals and grounds and the truck starts like a dream.

PS they sold me this crap with my last battery.

Rich

Rich is absolutely correct.

Dielectric grease is an insulator.

What you want at a battery/ground connection is a rust-proof, highly conductive connection,

What you want to use in these locations is a highly conductive anti-oxidant (anti-corrosion) compound/grease, such as: Kopr-Kote, Kopr-Shield (no longer listed by Eastwood), or NAPA: BK 7652569.

Guys:

Thanks for the imfo on the dialectric grease, I have it on everything, including the spark plug wires to spark plugs. Should I remove and clean all the connections with the grease on it? Thanks.

Dave

I sure would, and clean well with something that removes silicone

Bill

I cleaned it off all my connections. It is difficult to get all of it off. I have re-cleaned a few times.

Bill
Thanks for the tip on the silicone remover and kopr-kote. I will try those next

Rich