Straight into the deep end? Head Gasket?

[MMRMVA]

Thanks Bryan! You had a lot to do with this effort, it has all been so appreciated.

It sounds to me like the clearance between camshafts and tappet buckets is too large. Were these checked and/or adjusted?

We did not check them. We removed each bucket into a baggie labeled with its location and put them back to the same spot. We did not remove the camshafts themselves from the housings. So in theory everything should be as it was beforehand, right? One thing I recall when installing those, the book said how to line up the camshaft when installing, but I thought that was just to keep the buckets at their lowest across all 4 when trying to lower them to the head. Was that step more important than I gave it credit?

For other alignment, felt we lined everything to TDC, camshafts, aux, crank. Once the belt was on and had tension we turned it by hand and all seemed in order, went around pretty easily, stayed aligned.

If this is not going to hurt it running like this I will start it again in the morning and see what I can hear with closer inspection. Still have to check if the cooling system is working (fan, no air bubble, etc).

I’ll report back.

[18Fiatsandcounting]

So in theory everything should be as it was beforehand, right?

In theory, theory and practice are the same. In practice, they are not. I think Albert Einstein said that.

I'd check the camshaft / bucket clearances. Happy to offer guidance for that.

-Bryan

[MMRMVA]

Oh man, that is a daunting proposition right now. Might need some time to gear myself back up. Pun intended.

Can it drive like this (assuming everything with timing and coolant system check out)?

[Nut124]

It does sound like excessive valve clearance. However, I would run it a bit longer. After a rebuild, unless you pour oil on the cams, they will run dry for some seconds until the oil pump pushes oil into the cam boxes and floods the cams.

If the noise does not improve in a minute or so idling, then check valve clearances. It could be that the cam box gaskets you put in were thicker than what was in. Thicker gasket increases valve clearance. Running excessive clearance does result in accelerated valve/seat wear and could drop a valve over time.

After a rebuild, I always check, adjust clearances before installing the head. It is easy to with the head on a bench by removing the camboxes. With the head in the car, you will need a special tool and some skill, patience.

https://autoricambi.us/valve-adjusting-tool/

Clearance is adjusted by removing and replacing the shim disk located in a recess on top of the inverted bucket. Shims come in approx 0.001" increments.

[MMRMVA]

Hey guys, this thread is now off topic from the head gasket, but all part of the job, right? What is the protocol on this forum, should I start a different thread, or is this ok to keep going here? Again, maybe my (mis)adventures will help other new folks.

Per Nut's suggestion I checked oil and it had dropped, added some and ran it for a few minutes, rough idle, maybe a little better sounding. Then I checked timing and my mark was WAY OFF, like pointing straight up at 12 o'clock. Turned it off and let it cool down.

Rechecked my TDC. Took out the plugs (pretty black, too rich?), disconnected the battery and turned to my marks, using a rubber strap wrench which worked really well! Save that one for later.

Crank: https://photos.app.goo.gl/pEQoDkw4ScT91krW8
Exhaust cam: https://photos.app.goo.gl/2TN6g9C1c8BpbNRt5
Intake cam:https://photos.app.goo.gl/qn1DJVuwDmNTFc4x9
Distributor at the mark we made earlier (old is left, new is right): https://photos.app.goo.gl/VqDdN33FpTYCuagMA
Distributor rotor (it looks off? too far past #4?) https://photos.app.goo.gl/qT2Tepvs1UVAdyFp8

Everything else I feel is lined up well, unless I am missing something.

Question, is that circle stamped into the metal of the distributor an indicator of #4? There are triangles which appear to line up with #1 and #2 posts and then the coil post. I am thinking I can loosen the distributor, turn it so the rotor is lined up better to the #4 post. Good plan?

Any idea how this could have gotten so far off?

[Nut124]

Can you explain what timing is off and how you assessed that?

Ignition timing must always be done with a timing light. A mark on the dizzy housing is a good start but needs to be verified w a timing light. The dizzy rotor could be off by one tooth from initial.

Cams and crank timing look good.

Idle is pretty much always rich. I would not worry about plug color at this time.

[MMRMVA]

Hey Nut. Sorry. I used a timing gun (on #4 wire) and the mark on the crank was pointing up at 12 o’clock, nowhere near the timing marks on the belt cover. Ours is a 1978 with that yellow plastic cover.

I moved the distributor body to line up the rotor to that circle and fired it up. Sounds so (so!) much better! And the timing looks spot in. Going to dial in the carb.

[18Fiatsandcounting]

Any idea how this could have gotten so far off?

<< Looks like Nut was typing as I was >>

Yes, but let me take each of your questions in turn.

1. As for starting a new thread, that is pretty much up to you. Since we're talking about the same car, it's OK by me to keep it all in one thread, but some people prefer to separate out different issues into different posts. Your call.

2. If you didn't "pre-fill" your oil filter before screwing it on, it can seem like the oil pan is full as measured by the dipstick, but then when you first start up the engine, the oil filter has to fill (which doesn't drain back into the oil pan) so it can seem like you are down by a half quart or so after first starting it up. Normal.

3. Sounds like your ignition timing is off. It doesn't matter if you marked the distributor and put it back in the position, the gear at the bottom end will likely have turned and so you'll be off even if the outer marks line up. See more below.

4. Yes, black plugs are too rich, but if the engine has only run briefly after a rebuild, I wouldn't be too concerned at this point. Get everything else right, then worry about the mixture.

5. Cam timing looks good. When the #1 and #4 cylinders are at TDC and the cam marks are lined up, the engine is set to fire on cylinder #4. Here's how I initially set the ignition timing: Get the TDC/cam timing marks aligned. Loosen the base of the distributor so you can rotate it. Pull the distributor cap (not the whole distributor), and observe where the rotor contact is pointing. Hold your finger where the rotor is pointing, and mentally picture where the contact for the #4 plug wire is inside the cap, relative to where your finger is. If not, rotate the base of the distributor so your mental image of where the rotor is pointing is lined up with your mental image of where the contact for the #4 plug wire is inside the cap. Tighten the distributor base, start the engine and check with a timing light. Hope this all made sense.... There are more sophisticated ways of setting the initial timing, such as using a voltmeter to measure when the contact points open, but the above usually gets you pretty close.

6. Just for reference, turning the distributor clockwise will retard the timing, and turning it counterclockwise will advance the timing.

7. Some distributors have marks to help with #5 above, but I wouldn't trust them until you're sure what they signify.

-Bryan

[MMRMVA]

You guys are so awesome! Tomorrow, recheck levels of oil and coolant. Maybe a short road test in the neighborhood (within pushing distance).

Currently sounds better than when we started this entire process. The rough idle smoothed out. Still ticks, but I can live with that;
https://photos.app.goo.gl/M5HRTKh9WGcNE9Lh8

That smoke is off the exhaust pipe, which I hope is just Kroil burning off from the rusty bolts we fought.

Matt

[18Fiatsandcounting]

The engine sounds really good, and looks like it's running very smooth. A bit of ticking sounds, but that is the Italian version of purring. At least for Fiat engines.

And yes, every time I do a rebuild, it takes a while for the oil to burn off the exhaust manifolds. Even the oil from your hands.

Check the ignition timing, make sure temps and oil pressure are good, and button that bad boy up! Don't forget to retorque everything in a few hundred miles.

-Bryan

[MMRMVA]

We had some rain and I am back at work so it has been a few days stuck both in and out of the garage.

We tested the car at idle, the hoses all warmed up so we felt the thermostat was working, oil levels are consistent. Fan was not kicking on but then I found a loose wire, works now. Slight oil leak where our cam cover stud is not fully grabbing, but nothing like the oil leaks before we rebuilt. Added that to the list to do later.

She starts right up on the first crank and we started feeling good about trying it on the road, messed with the carb settings a little;
-with the engine totally cold, we loosened the choke screws, set it to where it just starts to move the butterfly valves
-let it warm up, choke opened the butterfly values after a few minutes
-set the mixture screw by turning it in until the engine loped, counted turns back out until it loped again, back in to half way
-checked and set idle to around the spec of 850 and is nice and smooth from the beginning

Idled well, and if I applied slow acceleration it would climb fine, but if I pushed the throttle quickly, it wanted to die and will stall if I pushed it too fast.

Went back to timing and adjusted just a bit later, dialed into TDC (our 78 calls for 0 degrees) That has seemed to clean up the issue with fast throttle.

Today, warmed it up and took a spin around the neighborhood this afternoon. Smooth sailing! She drove great. Hope we are not counting our chickens but a proud moment for my son and I.

Thank you for the advice along the way on this first adventure. Here is to more to come!

-Matt and Ryan

[18Fiatsandcounting]

Went back to timing and adjusted just a bit later, dialed into TDC (our 78 calls for 0 degrees) That has seemed to clean up the issue with fast throttle.

You can advance it a bit more than that, as Fiats like a little more advance. 0 degrees was chosen for emissions reasons, but 5 or even a few more degrees BTDC will give you quicker throttle response. Don't advance too much as you don't want to maximum advance (at rpms over 3000) to be more than about 37 BTDC.

Excellent work!

-Bryan

[Nut124]

Sounds like a nice project.

For best power, set ignition timing to about 35-36 BTDC at 3800rpm. Depending on your dizzy, condition of the advance springs, this will set your idle advance anywhere from 10 to 20 BTDC or so. Less than 34 advance at top end will rob power. Listen for ping, knock under load between 2000 and 3500 and retard if needed.

What dizzy? The 123? Or was that someone else. Factory Fiat dizzys that I have seen are designed to provide about 26-27 deg of mech advance. this is supposed to start at 1000rpm or so and be fully in by 3800 or so. But I have found that old dizzys are already deep into the mech advance at idle and then do not give you the needed 35-36 advance at top end. Therefore, better set the top end ign timing and see where the idle falls. The engine likes up to 30+ deg advance at idle, but this will cause knock under load between 1000-300o or so. So a manifold vac is used to advance timing about 15 deg at idle (high vac) for a 25 total (10+15). Then, when you step on it off idle, the vacuum drops and the vac advance is removed and the dizzy fall back to the mechanical advance curve (10 BTDC). This is supposed to prevent the ping/knock at low speed high load condition.

Are you using vac advance?

[MMRMVA]

Nut,
So much of that is beyond my knowledge but I am surprised by what I think I could follow. Our distributor does not have a vacuum advance. I assume it is stock for our ‘78. It is the one where the posts are 5 straight across, and those little metal canisters. The only thing connected to it is two wires (other then the spark plugs and coil).

I did notice that when I had the timing light on and would hit the throttle (by hand) my mark would move up (as if it was moving toward 12 o’clock on a clock). How would I measure that to your 35 recommendation. My TDC mark is 0 on the belt cover, then 5, then 10 marks. Do I just imagine increments of 5 toward 12 o’clock?

Should I not try to do that without the vacuum advance?

When our idle timing was way off the mark was almost at that 12 o’clock and it did not like it.

Sorry for really fundamental questions.

Honestly we are pretty happy that we put it back together and it works!

[Nut124]

You'll be fine w/o vac advance. It improves engine torque at idle and very low speeds, low throttle, like when driving slow in a 25mph zone. Other than that it does nothing.

The easiest way to check timing at top end is with a dial back timing light. These lights have a dial and a readout that allow you to dial in an advance. You would turn the dial until the crank mark is at TDC, then read the advance in the light display.

Without dial back, I would add a 36deg mark on the pulley w paint or file. Measure the circumference of the pulley OD where the TDC notch is. The circumference distance is 360deg. 1/10 of the distance is 36deg. This 36deg mark would be to the right of the TDC notch, looking from above. When measuring the 36 deg distance, must measure along the OD of the pulley with soft tape, not straight line.

I just use the idle speed screw to speed up the engine when I do this alone. With a helper I'd use the gas pedal. If not sure about the accuracy of your marks, err towards less advance. 32 deg runs fine, maybe lose a few HP. 40 could be trouble.

The dizzy is supposed to provide this full advance by around 3500-4000, not sooner, and then hold it 4000rpm and up. 36deg at 3000rpm would likely cause knock.