general tune-up

[maytag]

I am having some difficulty with the ignition timing on my car. maybe some of y'all can give me some FHE?
'76 spider with the twin points.
I've failed emissions twice. The first time, I hadn't touched a thing on the motor since buying it 2 weeks earlier. I wasn't surprised it failed. So I went home, set everything back to what the book said was factory spec, cleaned the carb up, ran a can of seafoam through the motor, etc etc.
it got worse!
see the results in this image:



I was surprised, because it seems to run so well. So I replaced the consumables that I replace just by good practice when I buy a car: points, cap, rotor, plugs, wires, fuel filter, and then I went through the carb. I've also been trying to track-down where all the emissions crap goes to, vacuum lines, etc etc, as it's quite clear the previous owner hadn't a clue on that.

All of this is leading-up to my question: tonight I'm resetting ignition timing, getting ready to go inspect it again tomorrow. I set it static at 0 degrees, as the Bradley Artigue tuning guide somebody here recommended. That puts it at about 37 degrees total, once it's all in. This same guide then gives a "by the ear" approach, which is sort of how we used to do it in the old days anyway.... basically: "just advance until it quits rampin' up....." but that puts it closer to about 20 degrees static, and WAAAY out in total advance, once it's all in.

So what's "correct"? and more than that: which state of tune is most likely to help me get past the emissions test? I mean, theoretically, more advance = more complete combustion, 'til it starts to ping. right? which should help both of those numbers?

There was another old-skool way to tune the timing: hook-up a vacuum gauge and time it to the highest reading. What do y'all think of that approach?

Help!

any knowledgeable advice is very welcome, and I appreciate it all.

Thanks!

[narfire]

I put a dob of white paint on the crank recess and a dob on the 10 deg. btdc mark on either the pointers(on my 80 fi) or now on the cam cover on my 72.
This helps seeing when matched.
Now, I have had issues when the timing belt slipped one notch on the crank when installing and the timing ended being closer to 20 deg. btdc. Car ran fine but noticed the power loss. Would that throw out the engine enough to give the readings you have?
Are you using a timing light? Beg,borrow,steal,or rent one if needed.
Others,especially Mark, might chime in and have some more sugggestions

[maytag]

call me crazy... (or color-blind): but for me, a LARGE area of white paint around the timing marks, with the marks themselves indicated with a fine line (a black permanent marker) has higher visibility when being strobed.
And yes, I've got a very, very good timing light.... (which is ALSO how I know how much total advance I've got )

I know that the mechanical / valve timing is on the money (as close as non-adjustable cam gears will let me get )

you indicate you're timing to 10 deg BTDC on both your '80 and on your '72. This would differ from what my understanding is of what Fiat intended (0 deg on pre-'78, 10 deg on '78 & up), so is there a reason you're advancing the early car too? (I can think of several.... but wondering what your impetus was)

Thanks for your suggestions Narfire.

Let's see what Mark & the others have to share too?
please?

[narfire]

A small dob of white is all I used. Found this stood out for me.
Thought you mentioned "by the ear approach" for timing then was out 20 deg.
I use 10 deg for the 80 and whether is true or not but page 41 in IAP catalogue shows up to 74- 10 deg. as well and 75-78 5 deg. btdc. I have not put the engine in the car yet but will be targeting that figure when the time comes. When putting the belt on,And sliding it over the tension bearing,I had the crank turn enough to put the marks off the 0 deg. mark. I did get it right on the second time around though.

[maytag]

Narfire:
either I'm not understanding your replies, or you;re not understanding my posts. Either way; I appreciate the effort!

What i'm saying is that there is an extreme difference in timing advance, depending on which method I use: "by the book" or "by Ear". When I say extreme, I'm talking about a full 20 degrees difference. That's a lot.

But I'm of the opinion that "by ear" is a better setting, and should probably solve the poor combustion issues I'm seeing at the Emissions station. I'm looking for further opinions or coorboration on that. (I'm only allowed one more test before I have to pay again! )

I still don't understand why Fiat would want such little advance, when the car seems to WANT so much more. ( '0' degrees is, by definition, as little advance as possible! )

Anyway; thanks again for your thoughts, Narfire.

[majicwrench]

I would certainly bring the timing advance , set with a light, up to 10deg advance. Do you have the stock emmisions sticker under the hood?? Without going out and looking, i think mine says 10deg advance. Car will run better, and have more complete combustion (less HC, less CO).
SOmeone with more emsions experiece should chime in, up here in the NW corner of MT we don't hav anym such thing, although I did have to deal with it some when i live in Washington. At any rate, you do need to get all the vacuum lines back on correctly too, I many have some old diagrams if you need them.
Good luck,
Keith

[maytag]

I would certainly bring the timing advance , set with a light, up to 10deg advance. Do you have the stock emmisions sticker under the hood?? Without going out and looking, i think mine says 10deg advance. Car will run better, and have more complete combustion (less HC, less CO).
SOmeone with more emsions experiece should chime in, up here in the NW corner of MT we don't hav anym such thing, although I did have to deal with it some when i live in Washington. At any rate, you do need to get all the vacuum lines back on correctly too, I many have some old diagrams if you need them.
Good luck,
Keith

Keith:
This was sort of my assessment of advancing it as well, so I'm glad to hear you agree. My sticker may or may not be stock... but it says '0' degrees.

And yes! If you have some diagrams and / or drawings of the vacuum lines and emissions systems, that would be very helpful.
So far, the one that's really stumping me is what looks like a temp sensor (but can't be) with two vacuum ports / tubes out the top, that is screwed-into the intake manifold, dead-center of cylinders 2 & 3. WHAT IS THAT???

[majicwrench]

Well I found a poor diagram, but it is something anyway. Now I have to figure out how to scan it, where are my kids when I need em??
That sensor with the two vacuum ports, at least according to the diagram, is the EGR thermal vacuum switch, it is to keep the EGR from operating till the enging warms up. One hose should go to a ported vacuum source, the other to the EGR. EGR is there to help lower NO's, and those numbers appear fine on the report.
Wish someone would chime in here who has to deal with this stuff on a regular basis, but my thoughts at this point is that it is simply running too rich.
Oh, and my 76 import spec book says timing is TDC. Are you checking it with the vacuum advance unplugged??
Keith

[maytag]

Well I found a poor diagram, but it is something anyway. Now I have to figure out how to scan it, where are my kids when I need em??
That sensor with the two vacuum ports, at least according to the diagram, is the EGR thermal vacuum switch, it is to keep the EGR from operating till the enging warms up. One hose should go to a ported vacuum source, the other to the EGR. EGR is there to help lower NO's, and those numbers appear fine on the report.
Wish someone would chime in here who has to deal with this stuff on a regular basis, but my thoughts at this point is that it is simply running too rich.
Oh, and my 76 import spec book says timing is TDC. Are you checking it with the vacuum advance unplugged??
Keith

Yeah, I'd really appreciate that diagram, if you can.
The P/O had the EGR plumbed direct to the base of the carb, so I'm sure it's been working all the time.,... it's nice to know how it's supposed to be plumbed.... now I'll need to figure-out how to CHECK it!

your '76 has vacuum advance? From everything I've read, that was not available on these cars until MUCH later. Mine does not have vacuum advance; only the mechanical weights, which seem to be worth about 36 degrees.

All of my books ALSO say TDC (zero degrees), as does the manufacturer's sticker under the hood, so i think we've settled on what Fiat thought they should have. I'm still uncertain why, since it seems to run so much better at 15 - 20 degrees advanced.

Thanks for the very useful input!!!
I wish too that some of the real GURUS on the forum would chime-in.... (I'm beginning to think they're either chicken, or I skeered 'em! ) but in their absence: you've been very helpful!

[majicwrench]

I'll get the diagram figured out.

Pretty easy to check EGR, if you can get your finger underneath (and not get burned) when properly plumbed, valve should not open when engine cold, when engine warm you should feel valve open as you rev motor, and should shut again as it comes back to idle. As well, with the engine idling, lift the diaphram with your finger and engine should stumble as it gets a load of exhaust gas.
Big point with EGR, it SHOULD NOT have any vacuum at valve at idle.

My 72 has a vacuum advance, interesting that yours does not. Vacuum advance is a huge player in the emisions dept.

Most engines run a bit better with the timing advanced a few degrees above spec. But with more timing, also produce more NO's, adn there is the potential for pinging, which REALLY craps the emisions and can damage the engine. SO the manufactures reach a good compromise. Methinks I would set it to 8 deg advance of so....
Keith

[mdrburchette]

Vacuum advance wasn't stock until 79 when the electronic ignition was introduced on these cars.
Retarding your timing and leaning your fuel air mixture may help you pass the emission test. You can always take it home after the test and tune it to drive. Also, driving the car on the highway for several miles just prior to the test always seems to help.

[maytag]

I'll get the diagram figured out.
Big point with EGR, it SHOULD NOT have any vacuum at valve at idle.

WELL... That certainly makes sense to me.... Majic; yer just full of useful tidbits!

My 72 has a vacuum advance, interesting that yours does not. Vacuum advance is a huge player in the emisions dept.

I researched this a bit more last night. I've copied some text from Mr. Bradley Artigues' manual, which: while perhaps not the definitive source, is certainly thorough, and it concurrs with everything else I've found. (I hope there is not an issue with me posting his text here, as he makes his manual available free online.

On Spiders manufactured after 1978 (the CS2, CS0, and all Pininfarina Spiders) the
vehicles were fitted with a Marelli electronic ignition with a pneumatically-operated
advance mechanism. It has often been misidentified as a pollution control – it certainly is
not.

Majic: I know what you meant was that total advance is a big player in the emissions dept, and I agree. I get mine mechanically, you get yours from vacuum (well, maybe a combination of both?)

Methinks I would set it to 8 deg advance of so....
Keith

I'm with ya. Sort of the same conclusion I'd come to (well, I was thinking 10 degrees, like the later cars)

last thing of note here:

In your Spider the basic ignition timing is set to either 5 degrees (1438cc), 0 degrees
(1592cc, 1608cc 1756cc) or 10 degrees (1978 1756cc and all 2000cc) behind top dead
center (BTDC).

[maytag]

Retarding your timing and leaning your fuel air mixture may help you pass the emission test.

wait! don't confuse me!

did you really mean 'retard' the timing? as in, move it to AFTER TDC, instead of the TDC it was at?

(to me, 'retard' the timing would be to delay ignition. maybe this is a question of semantics?)

[majicwrench]

Well, maybe I should look under my hood once in a while. I certainly DO NOT have a vacuum advance on my 72. Sorry to contribute to the general confusion.

But, I certainly WOULD NOT retard the timing. It is gonna increase the CO and HC even more.
Keith

[maytag]

UPDATE = MORE FRUSTRATION

So today I cranked-up the advance to 15 degrees and took it back over to reinspect. It fauield again, but was better. So sitting there in the parking-lot, I gave it 18d advance, and then leaned-out the mixture as much as possible (idle-mixture only, of course). The HC's came down enough to pass the 15mph test, but failed the 25mph, and (while much better) it is still TWICE the allowed on the CO%. (down to 7.8%)

As this got better, the NOx has been getting higher, which makes sense for improved combustion, if I understand correctly. But there's something DEFINITELY screwey here.

I'm wondering now about jetting. Looking through the "glove-box history", the car came from Las Vegas, NV, which is about 2k' in elevation. I'm at about 4k'. So it would make some certain amount of sense that it's too fat.... but I've never seen a motor be that finicky before!?!? I mean, a little off, sure. But TWICE the allowable?

Somebody help me!
Send me a good source for jets, or tell me what I'm doing wrong?