I've searched but can't find an answer to this question, which is surprising.
I'm pointing my strobe light at the crank pulley, I can see two timing marks, and I think my marker on the pulley (not sure if it's a factory marker or put there by a previous owner) is some 10º before the first marker, which may explain a few things.
Should the line on the pulley line up with the first marker at idle, or is that TDC?
I'm seeing some strange things with this car so it wouldn't surprise me if the timing is way off. Has anyone seen 0.95 idle jets before on a 2400 Dino? It was running a bit rich, to say the least
TDC or 3/4 market is for the adjustment of the timing chain/camshafts towards crankshaft.
For the ignition you need to use the 10degrees marker - at idle you should have 10 degrees advance ignition. In my experience with modern petrol a bit less sometimes work better but that’s just my personal opinion/experience.
And: 0,95 idle jets is interesting… much too big. I have installed 0,55 compared to original 0,50….0,95 is „a bit“ overdone….
Thank you, Thomas. Your response is really appreciated.
OK. I think I understand. So the two markers are for adjustment of the timing chain/camshafts. Not for ignition timing.
With my timing light, I can see a marker on the pulley. It looks like a factory marker. Is this the 10º marker that you mention? And at idle, where should this marker be? Should it correspond with another marker on the crankcase that I haven't seen? Its current position at idle is roughly 10º to the left of the first of the two camshaft markers.
And can I confirm please, 10º advance BTDC at idle? (i.e. TDC would be 10º to the left of this marker as the pulley turns).
Yes, 0.95 idle jets incredibly. The previous owner passed away so not much is known but I suspect he had low-speed running problems and he, or his mechanic, tried to resolve it by fitting larger idle jets. I've returned it to 0.55 and now 0.60 and the car won't idle without having the choke at least half open. It will idle on 0.95s but as you can imagine it runs very rich. Irrespective of jet size it is lifeless below 3000rpm.
I'm satisfied that the ignition system is the cause of the problem and if I do need to repair or replace the distributor, I'll need to do the ignition timing when reinstalling. My strobe light will also confirm that it's advancing as it should, which I suspect it's not currently.
Hi,
not exactly what I meant:
the ignition advance at idle speed is 10 degrees before TDC.
The 10 degree marker is for setting this advance with the strobe light. This is the left marker on the small plate with the two marks/peaks. I hope you have this original plate with the two marks.
On the pulley you have a Marker/white line that must match with the 10 degree mark at idle speed with the strobe light, to adjust it, loosen the distributor a bit to move/turn it gently to influence the ignition advance.
On the picture the marker matches with TDC. For idle advance with the strobe light it must match the other/the left marker.
…strange: the picture looks being mirrored but when being opened correctly….
Now I understand. 1st marker on the indicator plate is 10º BTDC and the line on the pulley must coincide with that at idle, using my strobe light. Currently, that pulley line is about 10-15º to the left of that 1st marker, so I have some adjustments to do.
The second marker on the plate, marked PM, is TDC. In Spanish, we say Punto Muerto, so I suppose it's very similar in Italian.
It all makes sense now. Thank you.
I wonder why this car had its idle jets drilled out to 0,95 and ignition timing so retarded. It's a surprise that the car even ran.
Tomorrow I will adjust the timing to 10º BTDC and report back.
Does anyone know how many degrees BTDC we should see at maximum advance? 40, maybe?
PM sent. I will still come back and report here so that someone else can hopefully benefit from our experience.
If I have to be the person that fills this forum with technical "how-tos" then so be it. The lack of technical information available within the public domain is surprising to me.
I wonder if Fiat or Ferrari Dino owners generally don't like getting their hands dirty
