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MGB 1979 Timing problems after removing distributor - Help Please!

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zenieth

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I have owned this car for thirty years and only have 17k miles. The Lumenition electronic ignition (original) wouldn't produce spark so I installed a Petronix Ignitor and the Flamethrower 3 ohm coil . I removed the distributor to instal the Petronix unit. I marked the distributor/clamp/block precisely prior to removal. I reassembled everything the way it came off. I started the car and drove it around the block and when I turned the ignition switch off it wouldn't stop running. After about twenty seconds it stopped. I tried to restart but it wouldn't fire. I found that my third position down on the fuse box had no voltage when the ignition was in the on position. I pulled the number one plug and no fire. I replaced the ignition relay with a Moss replacement and rechecked for voltage at the fuse box and fire at plug one and it's good to go. When cranking it appears to be up against resistance. When I line up the pulley notches to TDC the rotor is at the 7:00 position. However I did not check the position of the rotor before pulling the distributor. I have no clue and I'm in need of some advice. Thank you in advance!
 
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I do no think it is the timing as it started and drove around the block. You have something wired wrong and possibly blew the electronics. Petronix has a tech line and they will advise you. With the distributor marked and it ran on start you have a hot or ground wire not in the right spot.
 
Larry, Thank you for the replay. You could still get spark and the electronics still be damaged? Install was minimal with only two wires from distributor to coil +/- and a new 12v line from the second from the bottom circuit at the fusebox. The only other wire reused on the car was the tach wires that clipped back on to the - on the replacement coil.
 
OK. Petronix worked on first go around. But, now you ha e spark and no start? Make sure rotor points to #1 (assuming MG is timed by number one). Have you turned distributor to see if it fires? But, not being there and seeing, I would turn engine to #1 TDC, reinstall dizzy with rotor one #1, see if it fires. Worst there would be 180 deg off then put engine on true #1 and reinstall. Pull plug to one, undo fuel and electrics, key off, and hand crank until pressure felt from cylinder with finger or thumb over hole. Good luck. I will check occasionally thru the day and weekend.
 
Yes, the ignitor worked first drive after install. I have spark to the number one plug which I removed and grounded to the block. I set TDC on cylinder one. The rotor was facing close to the 1:00 position. Reinstalled the cap and turned the distributor and no spark. I turned CCW a good amount and then clockwise and still no spark to the plug. I just don't understand why you would have spark cranking the engine via the key and get spark at the number one plug and then zero spark when doing it this way by hand. Thank you for your help, it's greatly appreciated!
 
I assume 1:00 is #1 plug. Check rotor button in top of cap. As a next resort maybe rotate rotor 180 deg and try. (Without moving engine). Anyone else out there, I know it is a holiday weekend.
 
Yes, one is the first plug. 1-3-4-2 firing order at distributor cap. Cap, Rotor and wires all brand new. How do I rotate the distributor with out moving the engine? Yes, holiday weekend with nice weather too!
 
Loosen distirbutor, pull out, turn rotor and put back in. With engine at your TDC. If it does not run put back.
 
Pulled the distributor and rotated the rotor to the correct position but the distributor only fits in one way. The prongs are offset in a downward position so it has to go in that way otherwise we would be good to go. What about the gear that the shaft hooks into? can that be moved in anyway without moving the crank on the engine?
 
Put back, was correct first time. Take a good wire, put on pos bat and connect to positive coil. Hit key. If it starts run for a little and stop, disconnect wire after shutting off key. Wiring problem.
 
I will try this tomorrow. I'm also going to check the three remaining plugs for fire. I tried changing the fire order at the distributor cap matching the firing order with where the closest contact was in the distributor to the rotor. The engine cranked more freely but did not start. I'll let you know how the wire from positive battery to positive coil works. Thanks again for all of your help!
 
I'll be listening, also looking up MG 1979 and check some things, see if I am missing something.
 
Tried the jump wire from battery to coil and no start. Check the remaining three cylinders and they all have fire. This is bizarre. The plugs were all getting fuel too ......... ??????
 
Doesn't make sense. Car should run on 3 cylinders. Can you do a compression test. Have you tried firing with start fluid or WD40 ( WD safer). Any MG guys out there or anyone closer than me?
 
I have had a few issues over the years but nothing like this, that couldn't be solved. I don't have a compression gauge but I can get one after the 4th holiday. I haven't tried starting fluid but could give that a whirl in the morning. I think I'll pull the valve cover tomorrow as well and remove all of the plugs. I can then turn the engine easily and see where top dead center is on cylinder one. I bet it doesn't line up anywhere near the mark on the cover. Bizarre .........
 
That's where I wanted to go, did not know how far you were in. Take cover of set TDC, look at #1 to dizzy. Might have to move wires and crank the dizzy. Hoping timing is on and cam OK. Just do not understand the run around the block and stop.
 
I had little time this evening and pulled the valve cover. TDC to plug one is right on the TDC mark of the cover. The rotor is facing between plug two and three or around the 12:30 mark. I've read that plug one should be 1:00 but it look to me that 2:00 would be more appropriate. Never the less, the next plug that the rotor will be in contact with will be plug three as it has already passed plug two. What would your thoughts be?
 
Move the wires to match. Loosen dizzy, move dizzy until 2 or 3 line up, then move wires around in firing order with 1 at rotor point.
 
Good luck.
 
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