Distributor Setup

78 308 GTS

Rear bank of cylinders are not firing

This is a continuation of this thread http://ferrarichat.com/forum/showthread.php?t=251671

Prior to this problem, I replaced the plug wires (accel) and extenders. Prior to doing this, I believe the rear bank was firing fine. The rear bank is now getting spark, but it visually does seem as strong as the front (but I am no expert in what a good spark should look like).

Before I tear into other things, I was hoping someone could opine if the distributors are all connected correctly, consistent with having the microswitch disabled working off a single set of points.

The front bank dizzy has nothing connected on the bottom terminal, and the rear bank dizzy has nothing connected to top terminal (there are wires, but two of them are not attached, and the other two go to the microswitch).

Thank you in advance, good friday everyone.
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another thing......after installing new plug wires and extenders, and replacing some AC jets and emulsion tubes (see referenced thread above), I set out to rebalance the carbs. I had the car running on one bank for 30 minutes or so before i realized the rear bank wasnt firing (Steve Mag pointed that out due to excessive airflow at carbs, thank you Steve). After realizing the rear bank wasnt contributing, i then noticed the coil wire for the rear bank wasnt seated all the way in the coil (stupid).

Could i have fouled the plugs during the 30 minutes the coil wire wasnt attached, to the point of them not firing now? I guess I will install new plugs and find out.

I am definately not going to quit my day job. You guys that do this for a living, or really konw what you are doing have my total respect.

 

After I installed all the new wires, i checked them. Plus, the whole bank is out..

 

good call, but no. However, one of the carbon buttons had a scar in it, but i switched that to the front bank and it worked fine. on the topic of carbon buttons, does the spring need to come into physical contact with the set screw

 

Thanks Mike. See the picture below. Can I simply remove all four of these wires, with nothing else attached to these two posts if I am running a single set of points?

I swaped coils, still weak spark to rear bank

Swaped condensors, still weak spark to rear bank
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put new plugs in, not the problem

 

Coils checked and swapped, coil wires checked and swapped. Next I will try the rotor and cap swap.

was running fine until i changed out wires. When I unplug coil wire from the bank that is firing (front) and listen the rear bank its like i have the wires on wrong or something. I have quadruple checked the wires. When i pulled the old wires off, I think I remember the white numbers on the cap not matching the routing diagram in the WSM, but of course I didnt write it down. I have it hooked up per the WSM, so unless the distributors are different or there is an alternate way to put the distributor in i am not sure how they could be connected wrong. I bet I am doing or missing something stupid..

all i monkeyed with before i lost the rear bank was the extenders and plug wires (also the routing of the small emission carb rubber hoses, hooked up per Steve Mag's diagram). Therefore i am thinking it must be the plug wires.

 

swapped rotor, then swapped caps. Still cant get the front bank to fire.

 

Thought I would summarize

78 308 GTS

Problems started with a coughing/popping carb issue that became more pronounced when I gutted my airbox. I decided to install new plug wires (Accel 4040R) and new extenders. They were pretty shot. I inspected and cleaned the caps and rotors, cleaned and regapped the plugs.

Carefully, I put everything back together, following the spark plug wire routing in the WSM. In retrospect, I remember taking off the rear bank dizzy cap and noting that the existing connections from the dizzy cap to the cylinders did not match the WSM…..but didn’t think much of it at the time (stupid in retrospect).

Put everything back together, fired up, seem to run smooth, but still the coughing, even more so with everything back together. So, I pulled the jets and found that I had a mix of emulsion tubes and AC jets (some F36’s and some F24’s, some 220’s and some 200’s), so I ordered all the right parts, going with F36, 125, 55, 200. Ah-ha problem solved I thought.

Not so fast, still lots of popping and bad behavior, so I set out to re-sync the carbs using Birdman’s excellent write up. After much fiddling around, Steve Mag pointed out that my high airflow (10) from the syncrometer meant not all cylinders were contributing. He was right, nothing was firing on the rear bank, only running on four cylinders.

Tested coils, all ok
Swapped coils, no change
Swapped rotors, no change
Tested and retested all spark and coils wires, all seated properly and correct resistance
Swapped condenser, no change
Swapped dizzy cap, no change
New plugs, no change
Swore at the car and gave it the finger, no effect

I pulled the coil wire on the front running bank (side note, amazing how these engines can run so smooth on four cylinders, i couldnt even tell it was only firing on 4), and I listened to the rear bank trying to start, sounded like a car trying to start with the wrong firing order…then I remembered taking off the old plug wires and noting they were not routed per the WSM.

AFter having read nearly every thread on fchat, I stumbled across a thread where Birdman had a car that ran fine with the cams in 180 degrees off. I began thinking that my cams might be in wrong (partly becuase of this fiasco http://ferrarichat.com/forum/showthread.php?t=225944), then I read a few other threads about this by Artvonne. I sent Artvonne a PM, and he was nice enough to coach me through the process of seeing if rear bank cams were put in wrong.

I aligned the PM14 on the flywheel with the guide arrow. The first time I did this, the dizzy rotor was aligned with the hash mark on the distributor body, but the rear bank cam marks were not aligned as viewed through the oil filler cap. Then I turned the engine over until the cam marks on the rear bank exhaust cam were aligned, observed alignment of the PM14 marks on the fly wheel (aligned), and noted that the dizzy rotor was 180 degrees off from the mark on the distributor. Conclusion: Cam are installed correctly, but the distributor is installed 180 degrees off. Ran out of time, but I suspect it will fire up if I put the plug wires in backwards!!

 

Not so fast.

Both banks are firing.

When i run the banks indepedently by pulling the coil wire, each bank runs, and when i pull each of the 4 wires one at a time the RPM's drop (when running on a single bank).

when both banks are running, the airflow is 10 kg/hr. Also, when i pull a single plug wire, there is no noticable change (when pulling any plug wire with both banks running). I have read that 10 kg/hr is way to high indicating a) a cylinder is not contibuting or b) there is an airleak.

i think all cylinders are firing, bc when i run the banks independently and pull each plug the rpm's drop

also, i disconnected and plugged all the carb emission tubes, and check the one-way vacuum valves, they appear to be in order.

Timing - i guess it could be that but it was running fine before i took off plug wires and changed jets.

One of the coils resistance was a litte out of spec, but the banks are firing..

any thoughts are appreciated.

 

Well here is where we stand, after consulting with Artvonne who has been enormously helpful.

Recall, I discovered i had a mix of emulsion tubes and idle jets in the carbs, so i set those all right.

Also recall, I discovered a highly basterdized routing of the carb emission tubes going to the electrovalves, airbox flap and charcoal cannister. The back two carbs small tubes were blocked off, while the the front two were connected, however there was a dangling/rotten tube open that was letting air into the front right carb (I think). I rerouted those per Steve Mag's diagram.

Lastly, the return spring on one of the carbs is super weak, and never fully returns - that needs to be fixed.

Prior to fixing all the above, the car ran surprisinly well, and I suspect all those issues had been masked by the carb setup.

First, I tried to back off all the idle screws. It was easy to see the left two banks were resting on the idle stops, but there are no idle stops on the right two carbs. Should there be?

Anyway, as noted above, the flow was still over 10 kg/hr on all carbs.

I backed all the screws out linking the left and right carbs until there was no engagement, that dropped the right two carbs to between 3-4 kg/hr, but the left two were still over 10. That is when i noticed the spring wasnt returning the front left rear carb. So i put a helper spring on, and that lowered 3 of the carbs to 3-4kg, with the front left carb still over 10 kg/hr. Then I monkeyed with the the front to back linkage, and that last carb settled right down.

I had to stop there, not quitting my day job , but they are all flowing at 3-4kg/hr.

So, am I missing pieces, should there be throttle stops on the right two carbs?
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Yes, I was, the carb adjustment (front to back, and side to side) was wildly off, I think i have it worked out, but need to do the final adjusting/balancing. I thought I can backed off the idle stops per birdmans's tutorial, but i think the right two were really open. That, in connection with one of the left carb return springs not fully closing the carbs was causing high idle/flow. But this is all new to me, I am not a mechanic whatsoever, but learning quickly. I wish there would have been an easier issue to cut my teeth on

 

man, that would suck, but had i not figured it out, i would have seriously considered that considering how backwards things seem have been screwed together on this car.

 

Thanks SK, I will hopefully have everything sorted out this weekend and driving to napa with my wife for our anniversary.

The great things about this car is all the things I am learning. I have never been a patient person, nor particularly skill with the wrench, but I am learning mechanics and patience - and the help from the fchat board has/is awesome.

 

Classic pinball machines too...