308 intermittently loses one bank......

1977 308 GTB.....carbs of course.....yum.

New plugs, wires, points, condensers, caps, rotors, coils........it has suddenly started losing the front bank on occasion.....it cuts in and out. We repaired a bad distributor seal on the front bank where oil had been getting thru into teh points.....but besides that, my techs have no idea why this is happening again.

Any thoughts ?

 

On my 308QV that was caused by one bank's TDC sensor. Not an expensive fix to replace it.

 

Below are the flywheel sensors and positions. I agree with Mike that you have a flywheel sensor going bad. One word of advice, while you are in there, replace all three.
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Am I missing something here? I did not think carbed 308's had TDC sensors.

Does the car have a digiplex? That is the only thing I can think of that you have not replaced.

PS: Someone let me know on the TDC question; curious.

Drew

 

No flywheel sensors on a carbed 308 (unless someone added them).

 

i was wondering if our QV brothers had lost thier minds today.......

anyway, i would check and double check the wires going to the coils, and the feed wire from the coil to the dizzy cap. next i would check the condensers on that bank and swap them out and see what happens.


is the power loss related to the temp of the engine? or is is really hit or miss.

i would suspect loose / faulty connection or broken wire first.

after all, the cars are 30 years old now!

 

kds, chech the spark plug extension for signs of burn through.

 

Ask Dr. Cosgrove about his cracked distributor and lack of carbon issue.

 

OK, now that we resolved that carbed 308's don't have TDC sensors (unless somebody added them), I cannot remember if these cars have a dinoplex. I don't think so. Can anyone comment?

Good suggestion on checking for cracked extenders.

Drew

 

Mine started this exact same thing in Atlanta at the Mitty last weekend. As long as the revs were up around 4000 it was fine. Below that the tach would die and only the front bank would fire.

I pulled the rear cap off at the track and found it was cracked badly on the bottom. I went ahead and ordered a new set yesterday. Sounds like this may not solve my problem, though.

That was one stressful drive back on Sun. 200 miles with one eye glued on the tach and the other watching for cops. I had to keep it above 85 mph all the way home - which I was able to do except through downtown Atlanta.

I'll check the TDC sensor too.

 

While I am at it, does anyone here know the Bosch coil part # or the MSD Blaster coil part # that will work in my 84 QV?

 

115013 IGNITION COIL BAE504B, 308GTB/S/MONDIAL (MARELLI # 60705406) 122462


http://www.eurospares.co.uk/partsListing.asp?M=1&Mo=662&A=1&B=38809&S=&ID4=1567380


http://www.allworldautomotive.com/vendors/sites/cosun/catalogs/COSUN_ignition_coil_catalog.pdf
RENAULT 77 01 031 135 ,33002299
12336238 U-504 ,805034, 3287677-3
CHRYSLER T031135
VOLVO 3287677-3
DUCELIER 520064 ,2526023 ,2526023A
LUCAS DLB 204
MARELLI BAE504B
VALEO 245054 ,520064A ,CD325
SAGEM 2 526 023, 2 526 048
EAGLE 88-92 JEEP 86-90
RENAULT 84-90 VOLVO 82-89
JEEP 86-90
VOLVO 82-89


There are several versions of the Blaster Coil available. All of them have the same internal specifications, but have different housings or components. Each Blaster Coil can be used with a stock ignition...

http://www.msdignition.com/coil_blaster_1_8200_8202_8223.htm

 

Thanks for that info.

Problem is the MSD link still gives me 3 choices. I'll find out this morning and post what I'm told

 

KDS, Check that the new wires have good resistance. Just because they are new does not mean that someone didn't goof putting them together. Ask me how I know! You can put a boot on and break the center conductor, making a flaky connection. Do not assume that you did not get a bad coil either. Swap them and see if the issue follows the coil.

Also, check and double check all the grounds and all wires to the points, coils, resistors, condensers. The good part about the ignition system in a carb 308 is that it's simple....this should not be too hard to find.

Birdman

 

Thanks for all the advice once again everyone !!!

We just put new coils on last week......LOL !!!

I've ordered up a Pertronix system and a CRANE one.....we're going to install one of them and double chekc all the wiring so there are no more problems.

 

Tommy -- bag it all and put in an Electromotive XDI setup! No more expensive distributor caps... or distributors either.

 

Hi KDS,
Are you still running ballast resistors on the coils? I had a similar problem with my car & it turned out to be the one bad resistor - which I only picked up when I bench tested distributors & coils. I was losing one bank at about 5000 RPM. Since then I use a Bosch blue coil which apparently does not need ballast resistor and the problem has gone away!

 

That's my point! Don't assume that just because they are new, one isn't busted! Make no assumptions.

Birdman

 

Come on you guys, its a carbed 308, It has a points ignition system. No black boxes, no dinoplex, no flywheel magnets.

Points are as simple as simple can be, not much more sophisticated than a 29 Ford or a lawn mower.

I have two 77's. I dont think they are that difficult to figure out.

I would jumper wire off the good bank hot lead to the dead banks coil, see if you have a power feed problem. You can swap the negative wires at the coils. If the problem switches banks, the coil is at fault. You can swap coil wires, if it swaps banks the coil wire is faulty. Of course if you go to the trouble to remove the caps you really should ohm all of your HT wires.

Check your dwell, check for oil on the points or water vapor inside the cap. Check the carbon brush. I had a car once that had the coil - wire to the distributor broken internally and would give intermittant running. Jumper wires can bypass that wire to test it. Condensors could be faulty, most parts stores have 400mf condensors that will fit. And as stupid as this sounds, check your ground straps. There should be two, one on either side of the gearbox to the frame. One last thing is to run a hot jumper direct from the battery to the coils to hot wire the ignition. Probably if your lucky, the points are to far open or to far closed and simple points adjustment will take care of it. Oh, wiggle all the wires and connections at the coils and pull on them some to make sure all are tight. Its funny how many times we find a loose connection.

 

I agree fully with the loose connection bit Artvonne.

Don't agree my prized 77 308 can be compared to my lawnmower though...

 

Right Ham a lawn mower has electronic ignition. Ha , I agree with Art this is a simple car and I would look back at the recent changes done and go back over them. Enjoy the ride

 

Well, I'm old. Lawnmowers used to have points too, lol

 

Yep Art I recall back in 1962 I had a gas powered reel mower that had points. Lasted 10 years before the sheet metal rusted out. After that it was electronic set up. Ha good old days.

 

Come to think of it, my lawn mower has electronic ignition, uses lead free AND has a catalyst.

I've probably got the strongest and most healthy worms and moles as well....

 

I dont really know exactly when they switched small lawnmower engines over from point fired magnetos to CDI, but I dont think it was until well into the 80's.

But stop and think for a minute how many threads come up about ignition faults where the car loses a whole bank and sets the muffler on fire. Its the dinoplex crap. Those boxes fail so often there should be a lottery, and they are expensive. WTF do you do when your out on a road trip away from home, stop at NAPA? The biggest thing you see on all the points cars is misses and the like, mostly from people who dont take the time to figure it out and get it right. This car will get sorted out, and we will find its a power feed problem, a dead coil, a shot condensor, or something equally simple. Points just dont operate intermittently very often, and virtually never fail suddenly. They slowly die off, showing up as crappy performance for the last few thousands of miles.

Or dont even try, just put some "system" on it. You can convert them over to some other electronic system for a claimed .05% gain in power with the promise you wont ever have to work on it. Yep, it will run better for a really long time, years maybe. But your still facing the same problem. Finding a part on a sunday afternoon. I have on at least two occasions on other cars, bent a set of points with a pliers to make them work. I once put points from some totally different car in and made it run. Coils from almost anything will swap over and get you running. Condensors can be found almost anywhere. Even one off of a lawnmower will work.

Years ago I was out with a friend in a 308 QV almost 300 miles from home when one of his dinoplex died, lost a bank, called a flat bed. Thats BS. For the little bit of hassle of extra maintenence, and the .05% less power, I will stick with the tried and true. If im gonna get stranded 300 miles from home in a Ferrari, I want it to be for something better than a dead ignition.

But think of this. Enzo Ferrari died in 1988. During his lifetime he won over 5000 races, won 25 world titles, 9 F1 championship titles, 8 F1 constructors titles, 9 wins at LeMans, 8 wins at Targa Florio, and 7 wins in the Mille Miglia. The points style Marelli distributors on our 308's are virtually the same units as on a P3/P4, or virtually any Ferrari all the way back to the 40's. All those Lemans, TF, and MM races, and most of the F1 titles were won with points. I would imagine well over 80% of those 5000 some victories were won with points ignition. They just arent the crap everyone is painting them out to be.