If it's just the one valve, it's not a horrible rebuild. You can get new guides and as long as the seat isn't ruined, doing a decent valve job is pretty straight forward.
Time consuming- and that's why mechanics charge so much money for it. But having done one for a challenge car- not out of the relam for a DIYer.
Dude, that sucks. Hopefully the rear is fine and you can just pull the one head and be on your way! Good luck!
I wonder why the cam lobe for the failed valve is not polished up like the one next to it. If the bucket is missing, it is possible the cam was not really opening that valve and it was just sitting in place. The way it sits it look like it failed a valve spring, which would be odd since it probably was not being operated by the cam...
I suspect some very sketchy 'repair' work previously.
In reply to stafford1500: Thats exactly what I was thinking .
In reply to revseven: before you get into this any deeper you should pull the heads out and take a through examination. A proper rebuild for a pair of heads, although not cheap, will probably put you in a better a better position then going with a whole engine of unknown condition (assuming the bottom end of yours is healthy ).
I'm definitely pulling at least the front head, which should be (relatively) easy. The rear head is going to take some work. The Alfa is currently parked on a sloping part of my driveway, so I will need to flat tow it to a level part before I can safely get underneath it.
In the meantime, I've already removed the engine torque mount (black dogbone in upper left of picture) and serpentine belt. The dogbone bushings and S-belt look hosed, so a new belt and polyurethane bushings are on their way.
A bit of good news today: The borescope I bought arrived on Tuesday and I was able to scope the cylinders today. I didn't see any damage to the pistons or cylinder liners, nor did I see any foreign objects or trashed valves, so I don't think I will need to remove the heads. I do plan on removing the front exhaust manifold and having a peek at the #5 cylinder's exhaust valves to make sure the one working valve isn't toast. If it is bad then I will still need to pull the front head, but that's not as difficult as the rear.
My next step is to drag the Alfa off the sloped part of my driveway to a level part and have a look at the starter. I'm leaning towards that as the culprit.
I would think you have to pull the front head regardless? You need to fix the dropped valve, right?
A couple of folks more familiar with the 24 valve engine than I say the valve may not actually have dropped. Without the hydraulic lifter in place, the spring should be holding that valve in the closed position. I am going to do a leakdown test once the camshafts are off and I track down a compressed air source (a pal of mine lent me a leakdown tester). If the #5 cylinder checks out good then I don't think I have a dropped valve. If it does show a problem then I will pull the front head.
OK, I'm not familiar with that engine, I thought the cams were right over top of the valves, and the center of what you are calling the lifter is the top of the valve.
Despite your issues I am very tempted to pick up one of the two 164s on my local craigslist for a winter beater. I especially like the base model with plush velour seats.
The base model 164s were available only in the 12 valve versions IIRC. Somewhat easier to work on than the 24V and parts aren't quite as expensive. I almost looked at a 12V manual in July but the owner didn't reply to my text until mid-October! A few folks on the AlfaBB forums use 164s as their winter drivers and say they are great in the snow.
I'll get this problem licked. I feel much better now knowing there isn't any foreign matter rattling around in the cylinders.
I checked the timing belt and its drivetrain and found nothing jamming it up. I also removed the rear valve cover and found nothing out of the ordinary.
I can rotate the engine counter clockwise almost a full turn before it stops hard. Then when I turn it clockwise the same thing happens, in that I can turn it almost a full turn before it stops hard again. A PO drew timing marks on the cam gears, but I can't seem to get them to line up. The cam locking blocks don't match up with their respective cam lobes either.
The T-belt is off. Both serpentine idler pulleys need their bearings replaced. The T-belt tensioner bearing and one of the idler bearings also need replacing. 
Tomorrow, the camshafts and front exhaust manifold come off.
In happier news, the upper engine mount bushings (err, "bushes," in the Queen's English) from Powerflex arrived. You can see the originals are in nasty shape. I will have the big ol' bush (huh huh) pressed out by a machine shop along with the serpentine idler bearings. The shop can press in the new bearings, the Powerflex bushes look like they can be installed by hand.
Nice packaging, BTW.
So it jumped timing?
Before you get too far down the rabbit hole, can you get the timing back on and check compression to make sure you didn't bend any valves?
In reply to mazdeuce:
In this state, I would suggest more of a leak-down test. that way you can keep the cams off the car, spin the engine into position, and test it- all without needing to crank the engine via the starter.
A friend and Alfa 164 expert dropped by today to help me diagnose what's going on with my Alfa (big thanks!). For a while I was stuck because the rear intake cam sprocket was stuck fast to the camshaft. It had to be removed in order to get an upper engine mount bracket off, which in turn would allow me to get the rearmost cam off. Another Alfisti from the AlfaBB forums loaned me a cam sprocket puller. The puller + crowbar worked to remove the stuck cam sprocket, and once the upper engine mount bracket was out of the way the rear exhaust camshaft came out without removing the sprocket. We ran a leakdown test immediately after and found nothing wrong. After scoping the pistons again and using a bendy straw to feel around the cylinders, we've definitively ruled out valve damage or foreign objects in the pistons as culprits.
However, even with all of the valves up, we still could not turn the crank all of the way. It will turn about 340° either way before it stops hard. We removed an inspection panel for the flywheel, but could not see any damage to the flywheel teeth. This rules out what we thought were the next most likely culprits, a foreign object jamming up the flywheel or a bad starter
Our current theory is one of the conrod bolts may have come loose, but not all the way out, and is hitting the underside of the engine every time I turn the crank. I will drain the oil and check for metal shavings, then remove the oil pan. If anyone has any other thoughts, let me know.
A foreign object can keep the engine from turning without doing much noticeable damage to the flywheel teeth.
Thanks for the tip, Travis. There's a flywheel inspection port I scoped atop the transmission and I saw nothing there. I didn't check the inspection port underneath the car but my helper used the Mk. 1 eyeball. I'll give that another look and scope it while I'm there.
I wouldn't be shocked if you dropped the pan and found a lifter bucket down there
Then you could spend the rest of your life trying to figure out how it made it all the way down there.
That would be... well, that would be something.
BTW Thanksgiving week is my limit. If I can't fix this crankshaft problem fixed by then, then the Alfa goes to a shop. I can change the timing belt and diagnose the misfire myself but I'm running out of daylight more quickly nowadays and don't have a garage.
Since I'm in the middle of my work week (overnight shifts) I haven't been able to get back to diagnosing why my 1994 LS' crankshaft won't rotate all the way, so I've been getting some other stuff done in the meantime.
I removed the old metal bushing collars in the upper dogbone mount and upper engine bracket and installed the Powerflex bushings in their place. The timing belt tensioner bearing and one of the serpentine pulley bearings need replacement. I had the S-belt pulley bearing already so I has the old one pressed out and the new one pressed in. I had the eccentric bushing in the T-belt bearing pressed out and I'm waiting for the new one to come in. There's only one place that sells NOS T-belt tensioner bearings and they're very expensive. The separate bearing itself is also NLA but a couple places still have some in stock and they aren't quite as expensive as the whole thing. I'm holding on to the old bearing to see if I can get a new seal for it (one of the seals is broken) and relube it/have it relubed.
I also cleaned off the valve covers. The rear was pretty dirty but the front was nasty. 2 decades and 200k+ miles of dirt will do that I guess!
Eeewwww...
Cleaned and ready for paint:
I love how you're turning a cheap winter beater into a major restoration.
I thought I was the only one that did that!
FWIW I never lost money when I sold mine a summer or two down the road. Please carry on.
Haven't made much progress lately on the Alfa. I drained the oil and saw no metal shavings. Fishing the oil filter out was a major pain in the arse because the PO used a big, fat Orange Can Of Death (a.k.a. Fram) that would not come out from the wheel well or just about anywhere else I tried to squeeze it through. And yes, through the passenger side wheel well is how you normally remove an oil filter from a 24V 164. I have discovered that doing just about anything engine related is made easier by jacking the right side up and removing the wheel and fender liner. Anyway, to remove the Fram I had to move the fuel rail on the firewall out of the way and squeeze the filter out the top, through the rat's nest on the driver's side of the engine.
I've scheduled for Tuesday morning to have the car towed to a local European car specialist that has worked on 164s and other Alfas before. I don't have the space to keep disassembling the engine (like if I removed a cylinder head, I have no place to store it). I'm going to at least try to get the starter motor out as a last ditch effort to find the problem myself. I'm somewhat doubtful that's the culprit but the problems I had restarting the engine appear to have similar symptoms to a starter problem. Won't hurt anything to try at least.
That serpent on the Alfa Romeo emblem is appropriate, because I'm snakebit right now.
Took the 164 to a shop on Tuesday with Alfa experience, in the hopes they could find out why the crank isn't turning and fix it before the weather gets really nasty out here. While I'm sure some GRMers have war stories about doing engine tear-downs outside during a nor'easter with only a ratchet set, you'd either have to be a liar or a masochist to say you enjoyed it.
Even though I already told the shop the crankshaft was stopped hard due to mechanical interference and I already tried turning it loose, they still tried to turn it with a big-ass breaker bar until the crank pulley nut broke! WTF? This place has worked on Ferraris and Lambos before and gets glowing reviews from just about everywhere I look it up, and this is what happens? I wasn't charged for it, but I'm out a AAA tow and an unobtainium part thanks to this. The whole ordeal has left a bad taste in my mouth, so when the lead mechanic asked me "yank motor and tear it down, get new motor, or take it home?" you'd better believe I picked the third option.
However, there is a bit of good news. I mentioned a new friend of mine dropped by earlier this month to help out. He owns four 24V 164s and a bunch of other Alfas. He offered to lend his garage/hangar (dad's an airplane mechanic) and we can both work on it. So I ended up using another tow to bring it to his place in BFE, NH. We begin work on Sunday.
A little good news from my buddy in NH. The shop did NOT break the crank pulley nut, so we think they misspoke (maybe they meant they broke a socket?). Whatever the case we're back to square one with the crankshaft not rotating all the way. He scoped the cylinders again with a digital borescope (mine is optical) and again saw no damage or foreign objects. We're going to focus on the bottom end, so that means we're going to remove the oil pan. Stay tuned...
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