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From: At my Bar drinking and wrenching in Lafayette Colorado
You have an MSD "racing" distributor with no vacuum advance in your car. You cannot replace an MSD distributor cap with a stock cap - you have to use an MSD cap. Once you get it running with the correct MSD cap, I suggest you start looking for a correct, stock distributor for your car - that MSD unit is not well suited to a street driver - it is intended for drag racing, and it will not give you the performance you need on the street in terms of gas mileage and low-end throttle response. Get a stock distributor and set it up correctly - you will be surprised how well your car will run.
Lars
I installed an MSD on my big block.
Mine has the tach drive and the vacuum canister.
Check to see if you have an MSD 6AL box installed somewhere or if you have an “All in One MSD distributor?
You can properly set up an MSD for street use, but as Lars stated you really should have the vacuum advance for a street driven car.
Can you do without the vacuum advance on the street?
Yes, but it will run so much better, get better fuel economy, and you’ll notice an improvement in performance with it hooked up correctly.
Thank you everyone again. I am learning a lot of new things thanks to you. But I will still tire you with a few questions.
1) As you can see in the picture, you were right when you said that my car has an electronic ignition. I saw an MSD brand ignition and a box with it, I am sharing the pictures. My question is, should I continue on my way by taking the cover of the same distributor? Or should I get a stock distributor as a few of my friends here recommended? (non-electric)
2) A question that I have not been able to find an answer to since I bought the car is this: There are hinges on the rear window to lower the glass, but I did not want to force it because I feared the glass would be damaged. Is this an OEM conversion? What I mean is, is it a feature that was made later and is not in stock?
Whether you run the MSD or swap to a oem points type distributor is really up to you.
Without knowing your full engine setup and its components, it’s really hard to give you advice on that.
You won’t loose any performance going to an oem points distributor as long as you set it up correctly and purchase a good quality unit.
You will obtain some reliability in the ignition system with a points distributor because points rarely fail and if they do, you can replace them or reset them within a few minutes with only a screwdriver.
What ever you do, contact Lars and get a copy of his original papers on how to properly set up your timing.
Are you running the tach drive cable to your tachometer or was the tach converted to electronic?
One thing I noticed in your pictures is that you don’t have an MSD coil.
Have you checked your coil to see if it failed?
Before you start throwing money into parts, figure out why it isn’t running and start from there.
Your rear window is removable and there are numerous videos on line and forum discussions on how to remove it.
My 73 has a fixed rear window so I have no knowledge on its operation and parts.
In your pics I see accel spiral 8.8 wires. Those are very good wires and likely better insulation than stock.
So I would keep them, just test them to make sure they are good.
Same with the tower style cap. Most racers prefer it, so the least expensive thing to do would be to replace the cap. You old one wore out the contact button.
You have a MSD 6AL box. Good box. Til it fails from heat. One advantage is you can put a rev limiter chip in it to protect the engine. Because they do sometimes fail, I would check for spark, once you get a new cap, and make sure everything else is working.
Coil. I see a black ignition coil. They also fail with age & heat. Again check spark later and make sure it is good.
MSD ignitions require a full 12 Volt source to power it. The factory point setup ahs a resistor setup that only passes about 9V to make the points live. You should check the voltage at the power supply to the MSD box, with a voltmeter, and make sure it is a full 12v, while the car is running.
A question that I have not been able to find an answer to since I bought the car is this: There are hinges on the rear window to lower the glass, but I did not want to force it because I feared the glass would be damaged. Is this an OEM conversion? What I mean is, is it a feature that was made later and is not in stock?
Thank you everyone in advance.
The removable rear window is a factory installed standard feature of '68-'72 Corvette coupes. Pulling each latch toward the front of the car will release the window so it tilts inward. There are two pins in the lower track; lift the window out of the track. To stow the window for safe-keeping, there should be a hinged tray that sits under the rear deck. For '72 the tray drops down with a push button in the center.
Follow the link below to the GM Heritage site to download the specs book for '72, it'll have a bunch of info on your car.
Hello everyone, I replaced the distributor cap with a new one as I was told and thank God my car's engine started. But I am faced with a new problem. When I take my foot off the gas, the engine stalls. (It vibrates for a while and then stalls. Could the idle speed be too low?
Hello everyone, I replaced the distributor cap with a new one as I was told and thank God my car's engine started. But I am faced with a new problem. When I take my foot off the gas, the engine stalls. (It vibrates for a while and then stalls. Could the idle speed be too low?
A 4-speed should idle at ~800 rpm in neutral (according to GM specs); an automatic idles at ~600 rpm in drive.
I am glad that you fixed your starting issue. You will discover new issues routinely. That is why this forum is so great because you get answers from people that own Corvettes as well. Experience is Crucial.
