Still can't get the car to run with the factory distributor...

[Michael L.]

Guys,

For those of you not familiar with the saga I'll briefly catch you up. I was having trouble getting my rebuilt 350/350 running on my 69 restoration despite a successful dyno run with the engine a couple of years ago. I switched out the Q-jet with a Holley spreadbore carb and that didn't work so I popped for an MSD dizzy and 6AL ignition and the car started and ran great. I figured I would work on the many other things that needed attention and that I would phase the factory components in over time.

So I've been working on the car the last couple of months and it has been running good with the aftermarket stuff. I was able to get a lot of other things squared away, like the HL and wsw doors, and troubleshoot some issues with the guages, and some other stuff. I decided to start returning to the factory components, so I switched back the Quadrajet and it still ran good. I'm not able to drive it but it started easy, idled nicely and had good throttle response. I figured it was time to re-install the factory distributor so I pulled all the MSD stuff this weekend and put the factory distributor in. I had previously put on new points but I double checked the gap prior to installation and I reset them to the factory spec .019, and I also purchased a new replacement coil in case the old coil was bad. I was very meticulous with marking the rotor position when I pulled the MSD dizzy to make sure I indexed the rotor properly on the new distributor. When I cranked it to time it prior to running it I noticed the timing light was only firing sporadically and I recalled hearing something about the repop date coded wires not having a great reputation so I opted to replace the wires with some Accel wires. The timing light then fired regularly and I was able to set the timing before I tried to run it. I also checked the dwell when I was cranking it and it was at 30. I then connected all the wires and it won't start. I checked the voltage at the coil and I'm getting between 10.5-12 when it is cranking (it fluctuates) and when the key is in the run position (but the car obviously not running) it has 5.5-5.8V.

This is a total mystery to me. I'm at a loss to figure this out. Anyone have any thoughts? Thanks for any assistance you can give.

Mike

[Patrick H.]

Re: Still can't get the car to run with the factory distributor...

Have you put it on TDC (balancer indicated) and checked the rotor position?
You may have placed it in the "same" spot when you swapped them, but I'd verify it.

What work, if any, has been done to the distributor?

[Michael L.]

Re: Still can't get the car to run with the factory distributor...

I have not double checked the position of the rotor I can certainly do that. The dizzy was restored by a guy I heard good things about named
Jerry McNeish (?sp) and it was done to factory specs. As I mentioned in the post the engine ran on the dyno with this dizzy so at least at that time it worked fine.

[Duke W.]

Re: Still can't get the car to run with the factory distributor...

The Delco single point distributor is a pretty simple electromechanical device, and because it is so reliable it is the most overlooked component on the engine. Time and miles take a toll, but performance degradation can be so slow that it's tough to recognize.

Overhauling the distributor is a fairly easy task for a DIYer as long as the shaft bushings are okay and don't need replacement, but if they do a competent machine shop should be able to replace them and hone to size for about one to two thou clearance.

Before removal, set the crank at the initial timing value, BTC #1, and verity that the wires are indexed IAW the CSM. Note the orientation of the cap window relative to engine centerline or some other reference. As you remove the distributor the rotor will rotate about 20 degrees CCW. Note the window orientation when the teeth disengage. (C2 and C3 small blocks have a different installed distributor orientation.)

Verify that the dimple in the drive gear is pointing the same direction as the rotor tip, then disassemble. The procedure is in your COM.

A common issue is the breaker plate ground wire, which is crimped/soldered to the bottom of the breaker plate. It's constantly stressed due to rotation of the breaker plate by the VAC and will eventually break, or intermittently fail. I've seen some hanging on by just a couple of strands of wire. A repair kit is available or you can fab your own. Another common problem is a shorted capacitor. This can be a hard short or intermittent. The cap and rotor should be carefully inspected for cracks or other defects. Recently I worked on a distributor where grease had been thrown around inside the camp because the centrifugal advance had grease applied. This is a sure sign or amateur work. The mechanism should not be greased... just clean and wiped with WD-40 to provide some corrosion protection. The factory DID NOT grease this mechanism.

What I'm saying is that you need to go back and start from scratch with a disassembled distributor and new or thoroughly tested and serviceable used parts. You should search for a thread started by me from about ten years ago, "L-79 Distributor Blueprint/Overhaul." It documents the process, and you can consider it a supplement to the CSM and COM information. The breaker plate ground wire broke off as I removed it. We made a temporary replacement, and then the owner bought the repair wire and installed it, which can be done without removing the distributor. That thread and a companion thread it links to discuss the breaker plate ground wire and provides the repair wire part number.

Once it's ready to install, position the rotor at the point where you felt the gears disengage upon removal and lower. If it won't seat you might have to tweak the oil pump drive shaft so the slot engages the base of the distributor shaft. A paint mixing stick is a good tool for this. Once seated rotate the base CW past where the window was when you removed it. The rotate CCW until the points just begin to open. You can eyeball it or use a meter. You know that when the points open the coil fires the spark, and since you set the crank so #1 is at the initial timing point, the engine will start and should be within a couple of degrees of the correct initial timing. With a meter and a little practice is should be dead on.

Duke

[Michael L.]

Re: Still can't get the car to run with the factory distributor...

Thanks Duke. I'm probably going to try to use a stand-in distributor first to see if I can get it running with the standard ignition, and then I can work on checking the things you mentioned on the distributor. What do you make of the fact that the timing light works, meaning the distributor is sending spark, but the car won't run? Is it possible that a defect somewhere can weaken the spark such that it can be enough to trigger the timing light but not enough to run the car? If this suggests to you that spark is good and it must be a timing issue, as Patrick suggested I can double check that the rotor is pointing to #1 at TDC but I not only triple checked the final rotor position, taking into account the rotation as the distributor drops, but I also set the timing to 12 degrees BTDC (where I had set it with the MSD dizzy) with the timing light prior to attempting to run the car. This is weird.

Mike

[Duke W.]

Re: Still can't get the car to run with the factory distributor...

There's nothing more I can add other than to say you must be certain that the distributor is assembled and installed IAW the information in the service manuals.

Duke

[Michael L.]