Car died while driving now won’t start

[Pescado]

Pescado, what kind of a timing light did you get? Some allow you to dial in an advance in the light so that you always just look at the TDC marks.

From what I read and your pictures, it seems that your dizzy is not advancing timing as it should.

If you remove the dizzy cap and examine the rotor, what do you find?

The rotor should turn easily by hand some 45(?) degrees. This is the mechanical advance. The two springs should then always return the rotor to the position where the counter weights are all the way in. This position should be the idle timing. As rpm increases, the counter weights swing out and advance the rotor some 27 deg (crank deg) from the idle position.

The springs may be missing or out of shape.

When working correctly, at idle, timing w/o vacuum hose is about 10BTDC. It then increases to 36-36 by somewhere 3500-4000. Never exceeding 38. The idle timing is not critical. The 36-38 max is. Less than 30 and the engine feels sluggish. Timing is set at idle assuming that the dizzy is in good working order and provides 27deg mech advance as rpm rises. The combustion event takes time to the point that at higher rpms the combustion must start 36deg before TDC in order to develop max pressure on the piston on the down stroke.

If your springs are weak, then I would set 4000rpm, max timing to like 34 so that low rpm timing is not excessive. If you feel ping/knock at low rpm, reduce timing and/or fix the springs. The springs are hard to find. A new or rebuilt dizzy would be good.

Thanks Nut...i'll have a good look at the dizzy and play with timing some more.

[Pescado]

Timing light is a Innova 3568A

[Pescado]

Ok so distributor is a suspect for sure...see video links below

got the timing dialed in pretty good at idle 10btdc w/o vacuume, but can only get it to around 25btdc at 3500rpm. To get it to 4000rpm ill need to order a new pair of pants...wow sounds like it revving so high but I guess the tach and timing light tach don't lie. maybe ill try again later with some liquid courage in me.

https://www.youtube.com/watch?v=bHrtY8K0wf8

https://www.youtube.com/watch?v=3BSAT_ZUyc8

https://www.youtube.com/watch?v=fpnivf3yaeg

[18Fiatsandcounting]

To get it to 4000rpm ill need to order a new pair of pants...

I'm not going to touch that one, so to speak...

When you say you are getting only 25 BTDC when revved, is that eyeballing it? It's hard to estimate looking at it at an angle.

Do you know if your vacuum advance works? Simple test: Take the distributor cap off. Put a hose on the vacuum fitting on the diaphragm and suck on it. You should see your magnetic pickup rotate slightly, counterclockwise around the center.

For grins, you could also advance your static timing to 15 BTDC (vacuum disconnected) and see if that buys you anything in terms of driveability.

Occasionally, I've seen timing pointers that are bent, so it wouldn't hurt to "calibrate" it. Remove the number 1 sparkplug, put a long wooden dowel or screwdriver in the hole so it contacts the top of the piston, then rotate the engine by hand until the dowel or screwdriver is at the top of its stroke. Your timing pointer should be aligned with the zero degree mark, which is the larger triangle. Safety tip: Rotate the engine by hand, not by using the starter motor. Safety tip #2: Don't drop the dowel or screwdriver completely into the plug hole.

-Bryan

[Nut124]

Pescado, so, your timing light does have the dial up advance built in. This is so you always watch the TDC marks and use the light to line them up.

Bryan makes a good point about the accuracy of timing marks. You may need to check, validate your TDC marks.

Did you look under the dizzy cover? Does the centrifugal advance mech check out?

Just a rough check, you could try advancing timing at idle to see when it starts bucking. My engine increases idle speed up to about 30-35deg advance at 1000rpm. Then, by 40 at idle it starts sounding like no more. This could vary based on static CR etc.

Make sure to disconnect vac advance tube from dizzy when working on idle advance. Once you get the mech advance set, then work on the vac advance.

[Pescado]

Pescado, so, your timing light does have the dial up advance built in. This is so you always watch the TDC marks and use the light to line them up.

Bryan makes a good point about the accuracy of timing marks. You may need to check, validate your TDC marks.

Did you look under the dizzy cover? Does the centrifugal advance mech check out?

Just a rough check, you could try advancing timing at idle to see when it starts bucking. My engine increases idle speed up to about 30-35deg advance at 1000rpm. Then, by 40 at idle it starts sounding like no more. This could vary based on static CR etc.

Make sure to disconnect vac advance tube from dizzy when working on idle advance. Once you get the mech advance set, then work on the vac advance.

Ya I'm going try the timing again using the features on the timing light...did you see the video showing the open distributor? Moves no where close to 45 degrees?

[18Fiatsandcounting]

.did you see the video showing the open distributor? Moves no where close to 45 degrees?

I did look at the videos. I think your vacuum advance is probably OK, but it does look like the centrifugal advance is sticking. Very likely just a lack of lubrication, or possibly some worn pieces of metal that are sticking.

Might be a good time to think about a distributor rebuild. Not unusual for an engine that is 40+ years old.

By the way, the centrifugal advance should not move 45 degrees. Since the specs for your centrifugal advance are 28 degrees, and the fact that the distributor moves 1/2 the crankshaft speed, means that your centrifugal advance movement should be only one-half of 28 crankshaft degrees, or 14 distributor degrees.

-Bryan

[Pescado]

Ok so today I will try and prove TDC but I have never turned an engine manually...looks like I need a 38mm socket and then just turn it clock wise...any do's or don't, provisions?

[Nut124]

With plugs out the engine should turn easy with a 1/2" ratchet. I have to remove the radiator fan to do this. Clockwise when facing the front of the engine. Turning backwards can skip belt teeth if the belt is loose at all.

If you have the $$ I would seriously consider a new distributor. The springs seem too loose to me, not returning the counterweights. I fabricated springs from HW store hobby springs for mine.

Bryan may be right about how much the rotor head should turn, 14 deg. It was either 2 x 27 or 27 divided by 2 as the cams turn half a turn for every full crank turn.

[Pescado]

With plugs out the engine should turn easy with a 1/2" ratchet. I have to remove the radiator fan to do this. Clockwise when facing the front of the engine. Turning backwards can skip belt teeth if the belt is loose at all.

If you have the $$ I would seriously consider a new distributor. The springs seem too loose to me, not returning the counterweights. I fabricated springs from HW store hobby springs for mine.

Bryan may be right about how much the rotor head should turn, 14 deg. It was either 2 x 27 or 27 divided by 2 as the cams turn half a turn for every full crank turn.

Thanks Nut…ya in the end I think I probably will just pick up a new dizzy for peace of mind but going to do some more adjusting today just to see…report back shortly.

[redcars]

I have always turned my engine over with the altinator shaft nut, even with the spark plugs in you just have to hold down on the v-belt a little. No need to remove the radiator or anything , and you just need a 3/8th inch ratchet.

[Pescado]

Ok so I did a bunch more testing and timing adjustments. Currently I have three ignition modules, one new from Fiat supplier, one from Amazon, and the OME one. Decided to test the car with all three to see if this changes the way the car runs. Here are my findings.

Supplier- adjusted timing to 0 degrees BTDC, cars sputters at 2500 rpm
5 degrees BTDC cars sputters at higher rpm but very little acceleration/power between 2000 and 3000 rpm
10 degrees and 15 degrees BTDC pretty much same results

Amazon- adjusted timing to 0 degrees BTDC, cars sputters at 2500 rpm
5 degrees BTDC cars sputters at higher rpm but very little acceleration between 2000 and 3000 rpm
10 degrees and 15 degrees BTDC pretty much same results

All testing was done with distributor vacuum disconnected and plugged.
With both the above ignition modules the timing mark would advance clockwise when increasing RPM by hand.

OME- adjusted timing to 0 degrees BTDC, no sputter at high RPM
5 degrees BTDC, no sputter at high speed, but noticed that when accelerating the timing mark would
advance/move
counter clockwise. I have seen this before when I first started troubleshooting the car with the OME ignition control
module but since I had a new one I replaced it. After replacing the OME with the Fiat supplier one the timing mark
starting moving clockwise and I made the assumption that this was correct and that the OME one was not working
properly. This time I decided to test drive the car with the OME and with the timing advancing/moving CCW and
found that the car is running great....power/acceleration has been restored and no sputtering.

Any explanation for the above findings?

[18Fiatsandcounting]

Any explanation for the above findings?

No, that is just totally weird. When your car is at idle, the timing mark on the crankshaft pulley should be somewhere between the TDC and 10 degree BTDC marks on the pointer (most people prefer towards the 10 degree mark). As you rev the engine, the timing mark should smoothly move counter-clockwise (looking from the front), until it maxes out at about 36 degrees BTDC. There are no marks for anything over 10 degrees as we discussed, but you can get close enough with an eyeball estimate.

If your other modules are moving the mark on the pulley clockwise as you rev the engine, this is retarding the spark timing and it's not surprising that the engine doesn't run well. As for why these modules appear to be operating "backwards", I have absolutely no idea...

Other than Amazon, who is the supplier for the first module?

-Bryan

[spider2081]

I really don't know much about ignition systems.
Having said that I have always thought ignition timing advance takes place in the distributor and is a physical function. The centrifugal weights and the vacuum advance are both contained in the distributor and physically change the relationship of the physical location of the distributors base plate to the distributors rotating shaft.
There are aftermarket electronic ignition systems that have programmable timing curves but I don't thing the Ignition Control Unit/Magneti Marelli has any advance other than the physical advance withing the distributor. I don't think the ICU changes the timing.

[Nut124]

Pescado, I'm glad your car is running better.

But, you sure have us confused now about those ICMs retarding timing.

To optimize your engine, try checking timing at 3500rpm and then at idle to see if the mech advance is working or not. If working properly, the mech advance should be about 27deg from idle to 3500.