Engine running really rough - 2 cyls?

[beebopbogo]

As some of you may know, I'm in the process of replacing the cylinder head on my '79 'B. This is the first time I've dug this deep on any car and I'm learning a ton about engines. Now that the new head is in, I finally got to test it out. I got it running with a bit of starter fluid in the air intake, but it's only running on 2 or 3 cylinders.

Compression is great: 110/110/110/110. Best I ever had.
Spark leaves something to be desired:
Plug #1 has a yellowish spark
#2 has a stronger white spark
#3 has a really strong blue spark
#4 has a very weak yellowish/red spark

So I'm thinking the problem could be due to the spark in the cylinders, but not sure. Distributer? Leads? Plugs?

I gapped the NRK plugs to 35mm, much wider than they were out of the box. That's what the Haynes manual said, though, so I'm trusting it.

Is there a solid way of knowing how the leads are performing? What about the distributer?

Also, I'm open to suggestions on what else may be causing the cylinders to not fire...

Thanks for all your help. This forum is awesome.

 

[Guest]

The only things that will make a difference between spark plug wires are the wires themselves or the distributor cap. If you have an ohm meter, you can check to see if there is a difference between wires but you may as well go ahead and put on a new set of wires and a distributor cap then you know that isn't a problem.
You must mean .035" on the spark plug gap. I am not sure on the '79 but my '72 has the old points and condensor type distributor and calls for .028 but .035 is ok for a newer solid state ignition or even wider like .040. So go by the manual on that I would say.
Also make sure your fireing order is correct on your wire placement.
Bob

 

[timbomath]

Mr. Bee, Go easy on the starter fluid- don't want to do another head gasket right away. Like Bob said check and recheck your firing order and use new wires, cap and rotor. Hopefully timing is somewhat close but it will have changed a little. That said, I had similar problems of weak and inconsistent spark on my 79 till I finally broke down and got new dizzy and coil with Pertronix to replace original CEI ignition. If yours is original I would be suspicious, none of the original electronic ignitions were reliable or long lasting. IMO
Cheers
Tim Matheis

 

[beebopbogo]

Learning things all the time: starter fluid can be hard on the head gasket? I did not know that.

Today I ohm tested the leads, which all resulted in exactly the same reading. I then tried to start the engine again, just to see if the gremlins got it working. It actually started and was running with no revving required, but still on two cylinders. I am now sure that the 1 and 4 cylinders are producing power, while 2 and 3 produce none. I checked that by removing the leads from the plugs one at a time, noting a change in engine smoothness. No change when removing 2 and 3, except for the nice shock I recieved, hehe. I then went one step further and swapped the leads around (both at the distrib cap and the plugs) but 2 and 3 were still the problems. About the spark plug gap, I did mean .35mm, which could be close to .040", not sure... But I swapped the #3 and #4 plugs to test if the plugs are the problem, but 1 and 4 continued to fire. So I think I've pretty much narrowed it down to the distributor. I have the original 45DE4 Opus distributor.

timbomath, your '79 had original CEI? My manual says only '80 had CEI... Anyway, how much money/effort would be required for the reliable Pertronix? Was it worth it? I may give that a try after going through the systematic checks recommended by my good pal Haynes.

 

[Guest]

I think I would be tempted to try the cap and rotor first. I have had other cars do some strange things and the trouble was only the cap. I had a Dodge once that suddenly backfired and quit in a bank drive-in teller. It would not restart and just missed and backfired. I walked to a parts store, after pushing the car over to the side of the parking lot, and got a distributor cap and rotor and it fired right up and had no more problem.
My MG has the older distributor and I changed to the Infra Red pickup Crane ignition and have been more than happy. I have instant starts and it runs much smoother. The Pertronix came along after I bought mine or I just didn't hear about it or I might have opted for that one. I hear nothing but good things about it.
Your compression readings are a little low for an MG but they are all the same and 110 is plenty of compression to start and run smooth. So that isn't the problem.
Bob

 

[Bugeye58]

Well, I would imagine OPUS distributor parts should be easy to get. Aren't there literally hundreds of them on shelves and in boxes out there? /ubbthreads/images/graemlins/grin.gif
Jeff

 

[timbomath]

Too much starter fluid can cause violent backfire with potential to do much damage. The fluid also washes the cylinder walls of lubrication yielding high-wear starting. It seems that the last couple of years of production saw a mix of different stock items being used up by British Motors. My 79 is actually an 80LE licensed in 79 and also came with V8 brakes. Life expectancy of the Opus elec. ign. was not very long to begin with and mounted on the engine made its life even shorter. The fender mounted CEI didn't fare much better. My experience was that after much time, money and frustration caused basically by hard-headedness, I finally ordered the Ultimate Ignition kit with Pertronix from Brit-Tek and have been extremely happy with it. De-smogged with original Zenith it runs great.
Lots of luck,
Tim Matheis

 

[Guest]

Hmmmm, I didn't know the later distributors were such bears. Might be good to follow tim's advice.
Bob

 

[beebopbogo]

Wow, those PerTronix Ignitors are not a bad deal.

And I quote:
"Cyls - Distributor Part Number - Rotation - Ignitor - Price"
"4 - 45DE4, 47DE4 (electronic, 12V neg grnd) - CCW - LU-141 - $77.45"
--https://www.vintageperformance.com/retrorockets/lucas.htm

Fortunately (unfortunately?) I have no excuse anymore to upgrade to the PerTronix because I found the problem! I'm soooo stupid. For the 10th time, I checked that the firing order was correct, but this time, instead of looking at the notes I made from last time I worked with the leads, I checked the Haynes manual. For some reason, my notes assumed a clockwise rotating distributor while the Haynes said counter-clockwise. I trust the manual more than myself, so I rearranged the leads and I'm now running on 4 cylinders. Thanks for telling me to recheck the firing order /ubbthreads/images/graemlins/smile.gif

Now none of my electric guages or cooling fans are working, so I'm scared of driving more than 5 minutes due to possible overheating. Also, the engine is idling very fast. Next up: multimeter work and carb work.

Thanks for all your input, guys and gals. I appreciate it!