You will also need valve cover gasket(s) to check the clearances, and if the valve clearance needs to be adjusted, a special valve-adjusting tool and a selection of shims, a micrometer that you can read and understand, along with a normal selection of hand tools.

1. The engine should be cold. You can take the valve cover(s) off while it is still warm, and even remove the oil in the cam box(es) while you wait, but do not proceed until it is cold. If you need to retorque the cam boxes), do it before checking clearances!

2. Rotate the engine until the cam lobe you decided to start with is directly opposite of the valve shim. I disable the ignition system, keep the key off, put the car in 4th gear, and push it to rotate the engine.

3. Check the clearance between the base circle of the camshaft and the valve shim. If working in inches, the clearance should be within 0.001" of specifications. For example, if it calls for 0.018" of clearance and you measure 0.017" or 0.019", that clearance is OK. If however it is 0.016" or less, or 0.020" or more, you will need to adjust it.

4. Let's assume, as in the above example, that your clearance is too tight, and that you have measured the clearance at 0.016". To adjust the clearance you will need to remove the shim, measure its thickness, calculate how much thinner or thicker it needs to be to get the correct clearance, locate a new shim of the calculated clearance, install the shim, then confirm that the clearance is now within allowed specifications.
   Once you get the hang of it, it becomes second nature.

5. First write down what the clearance is supposed to be and what you measure, then calculate how much you are off.

6. To remove the shim, use one of the factory tools to depress and hold the valve bucket open. Do it in such a way that one of the two notches cut in the valve bucket are at a spot that you can access. Using either some type of small tool, pick, carefully re-sculpted small screwdriver, or even a blast of compressed air (potentially messy as the oil will be quickly disbursed) pop the shim out of its bucket. I have a magnet on a stick that assists in retrieving the oily shim.

7. Clean the oil from the shim with a clean shop rag, then carefully measure the thickness with a micrometer. I suggest writing it down.

8. In our example above, we would want a shim 0.001 to 0.003" thinner to increase our clearance to specification, so write down the allowed shim thickness you will be searching for. Then either find it in your spare shims, or order it. Confirm that the replacement shim you have chosen is clean, free of any defects, and place it into the valve bucket with the face that has the markings down (most shims are marked with their thickness on one face; do not ever put that face against the camshaft lobe)! Again I use my trusty magnet on a stick.

9. Remove the Fiat special valve tool. I use my magnet to confirm that the shim does not run away from its new home while doing this as re-depressing the bucket without a shim in place is almost impossible!

10. Once installed, rotate the shim and or bucket a revolution or two with your fingertip to confirm the shim is fully seated, then check your clearance to confirm you are within specifications.

11. All OK? Then push the car to rotate the motor, and it's on to the next one! If not, then write down what you got now and repeat until you do get an acceptable clearance.

12. When you are all done, button it up with (a) new gasket(s), reattach everything, enable the ignition system, take it out of gear and start it to confirm there are no oil leaks. Once it is warm you may wish to consider readjusting the idle mixture.

I have some serious issues about using a silicone sealer to seal an engine surface instead of (or with) a new gasket. Silicone sealers are OK for only a few very special sealing areas on Fiats, and a valve adjustment includes none of them! Silicone sealers can plug oil pump pickups, and on fuel injection cars the sealers foul oxygen sensors. Email me if you want to find out more on this subject.

Camshaft and valve wear areas you might experience while doing this job are few, but here is a quick list of things that come immediately to mind. Certainly if you locate any you should remedy the situation before continuing with the valve adjustment.

1. Fuel injected DOHC motors have a tendency to have exhaust valve stems stretch. It often seems to also happen to carbureted engines just after a valve job when the exhaust valves are cleaned and reused instead of replaced. You will find the clearance at or close to zero, you adjust if possible by shim thickness limitations to or as close as possible to specifications, then find about 3,000 miles later your "miss" at idle is back, and the clearances of the offending valve(s) is(are) back to very tight or zero.

   If this happens to you, it is time to pull the head and replace the exhaust valves! The good news is the intake valves and SOHC motors do not seem to share this problem!

2. Valve shims do wear. If one has been installed so both sides have been rubbing on the camshaft, toss it. If the surface that rubs against the cam lobe has any deformations, pits, surface imperfections you can see or feel, concentric rings worn into it, or even sanding or grinding marks, toss it. If you run your micrometer around the surface and pick up any variation in thickness that cannot be explained by paint or oil film on the back side, toss it.
   If your camshaft(s) is(are) expensive special camshaft(s), never reuse old shims, use new shims only!

3. Occasionally I have opened up a cam box on a noisy engine to find a valve shim missing or out of place. This usually destroys the camshaft, valve bucket, cam box, and depending upon where the shim ended up, many other items. And there is potentially a lot of metal floating around inside the engine. As you can imagine, this can be an expensive failure.

4. Sometimes the camshaft itself gives up and starts wearing. Usually the lobe is noticeably different from others on the stick, mashed over (like when you pound on a soft steel shaft with a hammer, the end will mushroom over), concentric wear rings are visible on the lobe, or the edge of the lobe is worn so it is sharp so it can cut you finger if rubbed against it. Of course, the shim against this lobe will also be junk. I have even opened up cam boxes to broken camshafts, but not often.

5. Cam boxes can be broken at various points, or valve covers twisted so the sealing surface is not flat. And this may not be all ... I am sure I will see something new soon!

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