The best way to take the crank front pulley nut off:
Put an impact socket of appropriate size over the nut, if you have an AC car you may have to grind the O.D. of the socket to get it to fit inside the pulley. Use a 1/2 drive breaker bar with the socket. Turn the breaker bar/engine all the way over to the driver's side and rest the breaker bar on the inner fender, put rags under the end of the bar. Disable the fuel pump (pull fuse or disconnect relay) go in the cockpit and hit the starter. This will spin that nut right off!
When lifting the engine, please note that the engine is leaning to the left. This is my Spider with the head off. The cam chain is secured by a wire and the support for the carburetors is still there. It's OK to adjust the valve clearance with the head off.
Since my Spider is a 1967 with floor-mounted pedals, the servo booster is what you see far right, green dot. You may also notice, that the liners have been removed, dots and so has the battery, blue dot. The red dot is the oil filter support. No spin-on filters 1967.
Clean the alloy head, but watch out for sharp tools. It's easily damaged when treated hard. This is the 1967 model up side down. Check the valve clearance. If incorrect, you may use any shim from an Alfa. They will fit any Alfa engine between 1965 to the 1990 I believe. Never throw away a shim, it might turn out to be useful later. I have noticed that Alfas hardly burn valves. The reason might be the fact that they are sodium cooled. The exhaust valves have natrium and sodium inside, so never ever try to brake one. This might be dangerous if the sodium is in contact with water or any other liquid or even air.
The twin overhead camshafts act directly on the valves. Thus high revs are no problem, no pushrods or rocker arms there, no, no. I have however had some trouble with oil consumption due to old engines. The engines pre 1970 approx. had no seal on the exhaust valve guides, only on the intake guides. With new guides with seals on the exhaust side too, the oil consumption goes down so check your engines. My real nightmare was my Alfa 75 who was drinking oil like hell. I overhauled the engine three times, liners rings, valve guides and all. The combustion chambers were all clean and nice every time I dismantled the engine. However, it turned out to be the head.
There was this little leak in the exhaust hole on cylinder #3. The hole expanded when hot and the oil was disappearing and my money too. A new head solved that problem.
Pistons and rings and liners!
I have made rebuilds on some pre 1972 1750 engines. This is what I always do: Step one is to certify that the pistons are the problem. Have the compression ratio checked when the engine is hot. The ratio should be the same on all four cylinders. Pour some engine oil in the spark plug hole and check the compression ratio again. If the ratio is increasing, the rings may be leaking. If the ratio is almost the same, the valves and the head need attention Remove the head and the sump.
No need to remove the engine for this kind of operation. Place a hydraulic jack and use a piece of wood under the oil sump so you do not damage the alloy fins. Loosen the engine supports. Raise the entire engine as much as possible. Normally it's enough when the gearbox hits the body, so you may place something between the engine supports and the engine bay. The dots on the photo show how I do it. The green dot shows the oil filter support.
Then raise the entire car and use supporting jacks for safety. Never ever work under the car if it's not secured by jacks. If you haven't already drained the engine oil, this is the time to do so. Otherwise you will need to wash your hair in kerosene. Undo the bolts and nuts securing the sump to the engine block. The image shows the wooden distances to raise and support the engine.
Gently draw the sump forward to get access to the crankshaft.From underneath the engine, remove the bearing caps and mark them. They are already stamped with the number of the cylinder, but just to be sure ... Start with the bearing caps on the second and third cylinders. They are at their bottom dead point if you have done the right thing. Slowly turn the crankshaft 180 degrees until the first and fourth bearing cap is at their bottom dead point and remove these too. On the Alfetta and 75/Milano overhauling is even more easy. Just raise the car and remove the sump. Note the spin-on filter, yellow dot.
Be careful so you do not damage the bearing surfaces of the crank-shaft and gently press the pistons upwards. Cover the crank-shaft bearings one by one while working. Mark the pistons so you know which is # one etc. Check if the pistons are of the offset kind. If so, there is an arrow on top of the piston. The arrow shows the direction from intake to exhaust, so be careful not to turn it the opposite way. If your engine is so old that it has the non offset pistons, I would replace them with newer ones. The Alfetta 1,8 pistons are excellent and easy to find. Both liners and pistons will fit your engine like new. The next photo shows the Milano engine with the liners removed, dots. As usual, the engine is still in the bay.
Be careful not to damage the surface when you remove and change the rings. There are several tools for this purpose, but you own hands might be OK too. The rings are marked "TOP" etc. Have a look in a workshop manual if in doubt. Remember to keep the openings of the rings away from each other, i.e. 120 degrees. To remove the liners you may try just to press and draw them upwards. There are special tools for this purpose, however some are expensive. I use an old piston with the top ring on. Put it up side down in the liner until the top ring is expanding and then use a soft hammer and a piece of wood to remove them both. Remember to use an old piston, not the new one. The next photo might give you the idea.
Liner in block
nspect the liners for scratches etc. Replace all if necessary. Use your fingertips to check them.
Clean the bottom of the liners as well as the engine block, but remember the bearings!
Replace the O-rings with new ones. Do not use more than one per liner though.
There are steel shims available for diesel engines if your liners are too short. Once, I used a set from an IVECO diesel engine. That car is still running, BTW.
The liners normally do not need any sealant, but since it is not that fun to open the engine again if it is leaking, I use a little bit of sealant. It is very important to keep the engine absolutely clean.
Check that the liners are about 0,05 mm higher than the engine block, every one of them. This is what I have learned the hard way, believe me. Have a look in the Alfa Owners Bible or any workshop manual.
I do the operation with the engine in the bay, it is not that tricky.
Finally, have the head overhauled at the same time. Valves, guides etc. may need some attention too.
Clean the pistons. Then take them to your local grocery shop and check their weight one by one.
Unless you have a weighing-machine of your own.
There should not be any difference between them. If so, see your local Alfa Service station.
While you're at it, remember to grease the propshaft at least once a year. Use the proper grease for the prp hsaft splines. The nipple is at the yellow arrow. This will make your Alfa Romeo very, very happy for many years.