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Discussion Starter #1
1976 Spider, stock, SPICA, Marelli points distributer and coil, is reluctant to run on four cylinders. Starts and runs, chugging on one or two. High tension leads show dead or intermitent spark on two or more cylinders at any given time using timing light. Installed new battery, points, rotor, condenser, cap and high tension leads with no improvement. Have tried two sets of spark plugs, NGK and Golden Lodge, to no effect. Points are set at .017, dwell of 60, ignition, valve, and injection timing are all correct. Wiring appears correct per wiring diagram. Substituted a test coil in place of the Marelli with no change. Ordered a Bosch Blue, not yet arrived. Spark is not as hot and blue as I would anticipate. New to Alfa's having mostly worked on British cars. Anyone have any ideas or similar experiences? I've studied the threads and found a lot of collective wisdom and experience, but didn't find a situation quite like this. Any input would be appreciated. Thanks.
 

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Spica cars are very picky on fuel pressure. Change the fuel filters. I had the tank cleaned on mine 3 times and the filter would clog in a block each time. I had to seal the tank and have not had a problem in 10 years. The other thing to look at is the Spica pump is timed to the engine. You can not just put a belt on it. Check the timing marks for that.
 

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Discussion Starter #3
Thanks Tom. The fuel system has been flushed and both filters replaced. dash fuel check light behaves normally. I tested the T.A., air gap is good, throttles are closed at idle, changed pump oil filter, checked belt and timing is right on the marks. The problem appears to be electrical. High tension spark just not making it to plugs on all four?
 

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Set the engine on TDC on #1 on the power stroke (valves closed as viewed through the spark plug hole) and note which distributor terminal the rotor is pointing to. Then recheck your firing order. 1-3-4-2. Rotor rotates clockwise, BTW. Pay NO attention to the numbers embossed on the distributor cap. They are completely irrelevant.

Check the security of the black wire from the coil that attaches to the spade terminal underneath the distributor base. If not clean and tight, a poor connection there can cause a crazy intermittent ignition.
 

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I had a problem with the distributor after I had rebuilt an engine once. The distributer needed to be reindexed. Note the lockdown bracket on the distributor is adjustable as well, so you might center the normal lock nut and adjust the distb in the sleave. Mine would run but i was starting the eng at 40 deg of timing, and it ran hot too!
 

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Also make sure the coil is wired correct; neg goes to the points, I think. I know if backwards it will only spark 50%.
 

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Discussion Starter #7
Hi John. I checked the low tension lead to distributor (black wire), tried a wire around and then replaced it, but no change.

With the engine at TDC on the #1 on the power stroke the rotor is pointing at the #1 lead. Then moving clockwise it passes in order 3-4-2. The rotor does not point directly fore and aft on the centerline of the car facing forward, as the Brookland book indicates. It points inward about 20 degrees. When you withdraw the distributor the slot on top of the oil pump that drives the dog on the bottom of the distributor is 160 degrees from the illustrated position. Does that matter as long as the rotor points at number one at TDC with the timing marks right on?
Matt
 

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The orientation of the dog doesn't matter as long as the rotor is pointing the right way compared to the cap and the ignition timing marks. You can install the whole thing wrong, and as long as you rotate the dist to account for the disassembly, it'll run fine. I put the dog slot in 180 off one time, so I installed the dist similarly 180 off and it ran fine.

Have you tested voltage at the coil, and the electrical integrity of the ignition circuit wire from the ignition switch? Make sure all the connections and wires are good.

Also, if you hook up a normal test light (12V bulb, not a timing light) to the neg side of the coil, and turn the engine over, it should blink on and off as the points open and close. It's an easy way to see if your ignition is working.

Also, have you removed a plug, laid it on the engine with the lead attached, grounded the plug, to see what kind of arc across the plug gap you get?

Andrew
 

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Hi John. I checked the low tension lead to distributor (black wire), tried a wire around and then replaced it, but no change.

With the engine at TDC on the #1 on the power stroke the rotor is pointing at the #1 lead. Then moving clockwise it passes in order 3-4-2. The rotor does not point directly fore and aft on the centerline of the car facing forward, as the Brookland book indicates. It points inward about 20 degrees. When you withdraw the distributor the slot on top of the oil pump that drives the dog on the bottom of the distributor is 160 degrees from the illustrated position. Does that matter as long as the rotor points at number one at TDC with the timing marks right on?
Matt
Sounds correct. What's the history on this? Was it running well until you did the ignition tune-up, or has the car been sitting derelict for some time? You might try installing the old condensor to see if that does anything.
 

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Discussion Starter #10
We have had the spider 2 months and it has never consistantly run on four. I don't even know what a well tuned Alfa sounds like yet. Mine chugs a bit like a VW. I ran further tests for voltage and continuity and hooked up a light in the low voltage circuit from coil to distributor- all good.
 

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Discussion Starter #11
I used a high tension harness tester from KD Tools (spark plug with ground clamp) and looked at each lead. All four had even thin blue spark. Confirmed that timing light picked up each burst. Encouraged, I then attached leads to spark plugs and started the spider.... same result confirmed with timing light cylinder 1 no spark, 2 normal, 3 almost normal, 4 intermitent. Discouraged. Switched plugs between 1 and 2, no change. Everything works great till the plugs enter the picture, then it is like they don't consistently find ground....
Ideas welcome.
 

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Based on my experiance

I had a similar problem and it turned out to be plug wires. Although they were new, the connection was not being made with the clip and the spark plug. The spark would jump the gap on occasion causing what looked like an intermittent and weak spark. Felt like a fool when I finally figured it out:eek:
 

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Pending a clean bill of health for the ignitionand Mr. Spica, have you done a compression test?
 

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Discussion Starter #15
I've inspected the distributor more than a couple of times. An elegant piece of Italian machine work, lobes don't appear excessively worn, not sloppy with side or end play. Both sets of high tension leads give the same result, one new, the other serviceable looking.
Yes, I will do a compression test, but I don't understand why low compression would affect spark. The way cylinders take turns playing dead makes me hopeful it is electrical and not worn rings, valves or holed piston. I will try all the suggestions from leads to condenser and keep trying. Thanks for the wisdom, experience and help.
 

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Lack of compression will not prevent spark from happening (especially when tested with the engine not running), but it sure will make it run rough. I had a three-cylinder Spider (0 on #1 due to burned exhaust valve) and now have a seven-cylinder Ford 360 (0 on #3 due to unknown cause thus far), and those cylinders might as well not even have a spark plug for the amount of work they do.

Andrew
 

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Discussion Starter #17
Tested compression today, on hot engine, all plugs removed, throttles wide open-#1 162,#2 163, #3 167, #4 168. I don't know if I trust the guage's numbers, but they are very even.
 

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Discussion Starter #18
A month later, closure at last. After lots of testing and weeks of reading and research, it was the simple answer. Despite using a new set of Lodge 2HL's and a new set of NGK B7ES's.....it was the plugs. I put in a third new set of Autolite 403's and she runs beautifully. Thanks to everyone who helped me with advice. Life is good again.
 

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Make sure the condensor is tight, engine is grounded properly, and the coil mounting is clean and secure.
 
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