Electronic ignition timing

JasonNC

I put a Petronix ignition system in my 262 and finally got it cranked about three weeks ago. The car cranks great and runs pretty well when idling, but I don't have the power that I think that I should have on the road as it just doesn't run as well as it did with the old points system when it was running right. My thoughts are that the timing is off, but for some reason when I try to time it by the mark on the flywheel, I can't get it to crank at all. (I timed it by ear and it seems to work well). Any thoughts?
Jason

[Deleted User]

After I installed my Pertronix on my 308 I discovered that it had significantly changed my timing. My symptom was knocking during uphill driving. Good Luck!

JasonNC

mjsandbe wrote:

After I installed my Pertronix on my 308 I discovered that it had significantly changed my timing. My symptom was knocking during uphill driving. Good Luck!

So what did you do? Did you finally get it to run right or do you still have a knock on uphill driving?

[Deleted User]

JasonNC wrote:

mjsandbe wrote:

After I installed my Pertronix on my 308 I discovered that it had significantly changed my timing. My symptom was knocking during uphill driving. Good Luck!

So what did you do? Did you finally get it to run right or do you still have a knock on uphill driving?

I got out my timing light and dialed in. I am no mechanic, but I think I have it pretty close. I would suggest finding top dead center, and start from there. It now starts and runs like a top.

[Deleted User]

I should also add that I checked the firing order, double checked the wires were on right for the firing sequence, checked the plugs, and pretty much everything else to do do with spark. I eliminated most causes before I hit timing.

JasonNC

I too have checked all those things. Query: Since the Petronix caused the timing to be off, did you simply find out where top dead center was located and mark the flywheel accordingly? If so, how much off the original factory mark was the new one?
Jason

[Deleted User]

Jason - earlier posts on the Forum referenced the use of a vacuum gage to adjust ignition timing; that worked pretty well for me (on a conventional points distributor). Just haven't got around to installing the Petronix gear yet; please keep us posted on your results.
J Cronk

Club Coupe

Jason: I have been using a Chrysler slant 6 electronic ignition system for close to 6 years and experienced problems like yours when it was first installed. For me the timing was not the entire problem or the total cure. I was using the original type plug wires and standard plug gap with H-8's. I switched to H-10's, gaped them at 35 and bought a set of good wires that are specifically for elcetronic ignition. Problem solved! Don't know if you have switched plugs and wires, but if not you might want to consider doing just that. My 2 cents worth anyway.

[Deleted User]

Hey, good info. Now how did you time the engine with these modifications? Thanks for the info, Bob P

[Deleted User]

JasonNC wrote:

I too have checked all those things. Query: Since the Petronix caused the timing to be off, did you simply find out where top dead center was located and mark the flywheel accordingly? If so, how much off the original factory mark was the new one?
Jason

After installing the pertronix module, the timing was so far advanced I could not see any lines on the flywheel. I retarded the timing and set via the lines on the flywheel. Nowhere in the process did I have trouble getting the engine to start.

JasonNC

I started to buy some new wires, but was told that the old wires would work. I'll try some more modern wires. As far as plugs are concerned, I bought some NKGs but they were too long and the pistons kept closing the spark gap before I figured out that I had screwed up. I went back to my original plugs.

mjsandbe what did you do to retard the spark? I tried shifting the firing order counterclockwise one plug wire spot in an attempt to line up the lines on the flywheel and couldn't get it to crank after that. I like you can't see any lines on the flywheel in the present setup.

[Deleted User]

When I installed mine in my 51 four years ago I got the matching coil and plug wire set from Pertronix. I also installed a new cap, plugs, and rotor while I was at it As stated above you need to open the plug gap. Mine it set to 36 and it works nicely.

Use standard procedure to time the engine. The Pertronix is not going to shift anything. I am assuming you pulled the distributor to install the unit. You can only reinstall the distributor 2 ways the right way and 180 degrees off. You will know you have installed in 180 degrees off pretty quickly as the engine will not start and it will backfire.

The procedure is as follows for clean install. Bring engine to TDC then remove distributor cap check first that rotor is pointing at number 1. After confirm pull distributor. Drill out rivet to remove bracket. Clean out distributor and make sure counterweights move freely and shaft is not too loose. Take time to clean and lightly grease with point lube.

Install Pertronix unit as per instructions. Reinstall distributor and start the car. When I timed the engine I used a combo of timing light and vacuum gauge to get that proper timing for my elevation. I had cleaned the flywheel through the opening so I could see the timing marks properly. I then timed as per manual and then fine tuned with vacuum gauge. I then took it for drive to make sure I was on target then fine tuned again with vacuum gauge. I have not touched the distributor or the timing in the last 4 years. Its been install and forget and has run perfectly since.

ratlee2

Jason,
One thing to note, if you are running 12 volts is that the Pertronix system needs a full 12 volt source. So if you have a ballast resistor or resistor wire installed between your coil and ignition switch then you will need to remove it. Of course if you are still running 6 volts this won't be your problem.

Rich

[Deleted User]

The best way to set the spark timing is by a vacuum gauge. The reason being that method takes into consideration the condition of your engine and your elevation/local conditions.

How to do this on a Hudson.

Attach the vacuum gauge to a source of full intake manifold vacuum. Do not attach the gauge to the vacuum advance line coming from the carburetors, as this is ported source and not full manifold vacuum. Attach the guage to the line coming from the intake that supplies the windshield wiper motor, or going TO the two-stage vacuum assist fuel pump.

Disconnect the vacuum advance line from the distributor and plug it off.

Crank the engine and watch the gauge, the needle reading should be steady. It should be reading somewhere between 18 and 28.

Loosen the 7/16" bolt that holds the distributor in the block and rotate the distributor counter-clockwise and look for a rise in your gauge reading. If it begins to miss and lower the vacuum reading, move it clockwise. Keep moving the distributor slowly in both directions until you get the highest, steady vacuum reading possible.

Once you have the highest reading your engine will achieve, move the distributor clockwise until you drop 1" Hg off the guage. For example, if your engine will make 22" Hg - lower the timing until it reads 21" Hg. The reason for this is that the 99% of the mechanical advances I've taken apart are worn at the cam plate and let the mechanicals fly out too far at max advance. This intial retard of a couple of degrees makes up for that over-advance on the high end and has no effect on the engine in the driving rpm ranges. Being a couple of degrees retard at starting makes cranking a bit easier as well.

While you have your vacuum gauge hooked up, check your Carburetor idle mixtures as well. Turn the idle mixture screws in and out one at a time while watching the vacuum gauge. Turn one idle mixture screw clockwise while watching the gauge, when you exceed the ideal lean limit of that screw - the guage reading will lower. Then turn counter-clockwise until it reaches its peak reading. Repeat this for both screws. Lower the idle speed screw and repeat the idle mixture screw process. Your goal is to lean the idle mixtures only enough to achieve maximmum vacuum at the lowest possible, smooth idle rpm. It takes a few repetitons to get it right, but eventually any slight turn of the idle mixture screws clockwise results in an immediate vacuum gauge response.

If adjusting your idle mixture gains an appreciable vacuum gauge increase, Repeat the timing proceedure, then double check your idle mixtures one more time.

Adjust your idle speed back to where you're comfortable with it.

Now hook up your timing light and just shoot at the timing marks. If the marks are jumpy at at steady idle, you have some wear in your distributor. Either the mechanical advance or the main shaft bushing. Make a note of where your timing is according to the light and check for proper mechanical advance by slowly increasing the engine speed.

Hook the vacuum advance back up properly and go Hudsoning.

dougson

All really useful information. I can't wait to get my motoer assembled and running. I am using the Petronix system, have upgraded to 12 volts, and will use only modern components. Plug and gap information very interesting. One thing I'm having done is the installation of timing marks and plate on the front of the crank. My builder is adapting a GM balancer to the crank. He's apparently done this with other older style flatheads with success.

[Deleted User]

To add to Marks excellent post on Vacuum timing is this diagram it will cover all you need to know from your gauge. There is plenty you can find out using a gauge.

Lee ODell

51hornetA wrote:

To add to Marks excellent post on Vacuum timing is this diagram it will cover all you need to know from your gauge. There is plenty you can find out using a gauge.

Thanks 51hornetA

It's nice to see a chart I don't have to use a magnafying glass to read the explanations. It is easy to read. I printed a couple of copies and will have them laminated. One for my sevice manual and one to keep in the car.

Lee O'Dell