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Discussion Starter #1
This day has turned nasty.
I went out and turned over the 164 this morning, and immediately shut it off. Call it a premonition, ESP, psychosis, whatever. When the engine turned, I heard an other-worldly rattle. I opened the hood and looked around. Everything seemed to be in place.

Wait a minute. Aren’t there two ground straps on the side of the air plenum, beside the dogbone? Oh Crap!!!!!!!!!!!!

I removed the wheel, liners, serpentine belt and its’ tensioner, pulleys, crank sensor, etc. I slowly turned the crank with a large socket and ……Click. Looking around at the front (right) of the engine I saw the missing bolt. It was lodged between the oil pump cog and the left-hand side of the water pump. It was jammed! It could not be persuaded to come out by tapping it, so I unbolted the cog and the bolt dropped to the driveway.

Damage Assessment.
I have the necessary disassembly done and here is what I see:
  • The belt looks almost new. There is one tooth that is iffy-looking.
  • The oil pump, water pump, idlers, and tensioner pulley all turn freely.
  • On the top end, all cams seem to be in contact with their tappets.
  • The engine stopped almost at top-dead center. On the front bank of cylinders the timing marks on the cam wheels are lined up with each other.
  • On the rear bank, the intake cam wheel’s mark is where it is supposed to be, however I cannot see the mark on the exhaust cam wheel. I’m pretty sure it’s slipped.
Questions for the group:
  • How do I proceed?
  • How can I verify that I did not bend a valve?
PS. I have the cam locks and tensioner tools (Thanks, Jason).
 

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John hold that thought I am off to a Alfa Tech session, meeting aka pool party in a few minutes will get back to this tonight or tomorrow.
 

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Discussion Starter #3
John hold that thought I am off to a Alfa Tech session, meeting aka pool party in a few minutes will get back to this tonight or tomorrow.
Steve,
Since the cams and crank are so close to TDC, I'm going to put the camlocks on and see how far off the timing is.
I'll report tonight.
 

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Discussion Starter #4
Update

I have put the belt back on, compressed the tensioner piston, inserted a 1/8" drill bit and re-installed the tensioner. The cam locks are on and mark on the crank is aligned with the triangular pointer.

Two issues:
I am paranoid that I have the wrong cam locks on the wrong cams. The locks have different (newer, I think) numbers than those listed in TSB 01.94.07.Here's what I have in the engine now:
  • 1870896600-1 Intake cam, rear bank, cylinder #1
  • 1870896600-2 Exhaust cam, rear bank, cylinder #1
  • 1870896600-3 Exhaust cam, front bank, cylinder #4
  • 1870896600-4 Intake cam, front bank, cylinder #6
Secondly, I have managed to partially strip the threads in one of the bolt holes for a cam bearing. It is the first bearing on the exhaust cam on the rear bank (Cylinder #1).

Can I helicoil it in place?
 

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UGH! Not a good day. I would put the belt back on and run a compression test. That is about all I could imagine you can do.
 

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Discussion Starter #6
UGH! Not a good day.
True.
I looked at the probable path of the fallen fastener. On the rear bank of cylinders, right below the end of the plenum where the ground straps attach, there is an opening. The hole is between plate that the rear belt cover mounts to and the cam cover. I think the bolt came loose, found the hole (Remember the saying about the buttered bread always landing face-down), made it past the cam wheels, and lodged between the oil pump cog and the water pump.

At the very least, the rear exhaust cam slipped a couple of teeth. At most, something more expensive got brokem.
 

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On the 12V engines, I've heard that two teeth skipped is survivable. On my wife's S engine, 2 teeth on both cams dealt a death blow to the #5 rod bearing, all intake values, and two exhaust valves. Your problem may be minimal. Did you put paint marks on the cam gears when you timed it last time? Just as a verification measure in case something like this happened?

If you're fortunate, you will be able to re-time and run. Steve should be home any time now. I left the pool pa..er, tech session, while he was still there and his drive is longer than mine.

MIchael
 

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John, like my little problem I had a year ago when I dropped a 1/4" socket down between the engine and trans in a little hole. I can empathize with you. Hope for the best.
 

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Discussion Starter #9
Steve should be home any time now. I left the pool pa..er, tech session, while he was still there and his drive is longer than mine.

MIchael
A tech session devoted to examining the effects of chlorine on "Pruney Fingers".
 

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Years ago my 12 V was noisey on startup 1st thing in the morning. Fortunately my wife shut it down immediately. I love that woman! Steve recommended retiming and trying it. I was scared and took the head off. There wasn't any damage. Steve was right. I should have listened. It would have saved me a lot of time and money.
 

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On the subject of re-timing and trying.... I've suspected that Sean (elite...) of the SF Bay area had a valve drop its head into his cylinder because someone previously had damaged the valve from mistiming but retimed and ran it. I really know no way to guarantee the integrity of the valve other than opening up the head. Well, maybe one could rope-trick it and pull the spring and keepers one at a time to check for free rotation against the seat. A slightly bent valve should not turn freely. But that would be a lot of work and maybe pulling the head is best when in doubt. Just thinkin' out loud.
 

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Discussion Starter #12
Any suggestions on the stripped cam bearing cap?
 

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Helicoil holes are larger than the next size up bolt, aren't they? The cam cap is pinned, no? So you _could_ tap the hole the next size up metric thread, same pitch? If they are 6x1mm, then a 7x1mm tap should get you where you need to be You could even put a 7mmx6mm stepped stud there and use a nut on top if you didn't want to drill out the cam cap clearance hole.

Or if 7x6 stepped studs (if those are indeed the sizes) aren't available, maybe 8x6 is...
 

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Discussion Starter #14
This morning.

With the engine timed and the belt on, I began rotating the crank. After about 1/4 turn, it stopped. The crank would not turn at all. Not good.

But wait. It gets better.

I loosened the cam wheels, and attempted to re-time everything. The exhaust cams moved; the intake did not. So I loosened one of the other cam bearing halfs and pudding came out!!!!!!!!
I smelled that wonderful acrid, burnt-oil smell also

Is it terminal?
Are the head gaskets blown?

What now?
 

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I have put the belt back on, compressed the tensioner piston, inserted a 1/8" drill bit and re-installed the tensioner. The cam locks are on and mark on the crank is aligned with the triangular pointer.

Two issues:
I am paranoid that I have the wrong cam locks on the wrong cams. The locks have different (newer, I think) numbers than those listed in TSB 01.94.07.Here's what I have in the engine now:
  • 1870896600-1 Intake cam, rear bank, cylinder #1
  • 1870896600-2 Exhaust cam, rear bank, cylinder #1
  • 1870896600-3 Exhaust cam, front bank, cylinder #4
  • 1870896600-4 Intake cam, front bank, cylinder #6
Secondly, I have managed to partially strip the threads in one of the bolt holes for a cam bearing. It is the first bearing on the exhaust cam on the rear bank (Cylinder #1).

Can I helicoil it in place?
I think you mean 1/16" drill bit in tensioner body and piston rig pin hole as 1/8" will not fit. the 1/8" bit is for checking air gap between tensioner body end and tensioner pulley flat on it's arm.

As for timing dies last digit tells position so I think you had them correct. Pretty easy to tell if you also see timing lines on end of cams lined up with flat on rear of head heads when dies installed.
 

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Uh oh...this doesn't sound good at all. From the way you describe the situation, most likely a bent valve(s). Guess your heads are coming off. If you were closer I would give you a hand. Post photos when you can.

About the stripped bolt holes, I would be hesitant to do tap work with the head on the car, because of metal flakes. Yes, it can be done in the car as I probably would do just that, putting towels down all over. Since, it looks like the heads come off, the machine shop can install helicoils for you.

Any ideas where you are going to get the head work done?
 

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Discussion Starter #17
I think you mean 1/16" drill bit in tensioner body and piston rig pin hole as 1/8" will not fit. the 1/8" bit is for checking air gap between tensioner body end and tensioner pulley flat on it's arm.

As for timing dies last digit tells position so I think you had them correct. Pretty easy to tell if you also see timing lines on end of cams lined up with flat on rear of head heads when dies installed.
After doing some research on the cam locks, I believe I had them in the correct places.

But my problems with the engine are more significant now.
With goo oozing from cam bearing bolt holes, a burnt-oil smell, and the crank's refusal to be turned, I think there is serious damage inside.

I called a friend who is among one of the most clear-thinking individuals I have ever met. He drives a red, '95 LS; but his insight is not limited to things automotive. He observed that I might be in shock/denial about this whole, ugly situation.

At this point, I need to decide whether it is economically feasible to repair the car. I invite any suggestions (other that therapy) on what I should do. I am not going to rush into a decision but here is my thinking on the factors:
  1. The cost of a re-build might be more than the value of the car. The 24-valve engines have expensive parts.
  2. The time involved would be an issue. Although the daughter’s car is coming together, it still has needs, as does the ’88 spider. Oh, and I have full-time job.
  3. Could a replacement engine be found? The 24-valve engines are kinda rare.
  4. What about selling/parting out the car? Maybe looking for a good S to take it’s place? The 12-valve engines are so much less costly and plentiful.
Any thoughts?
 

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With the engine timed and the belt on, I began rotating the crank. After about 1/4 turn, it stopped. The crank would not turn at all. Not good.

But wait. It gets better.

I loosened the cam wheels, and attempted to re-time everything. The exhaust cams moved; the intake did not. So I loosened one of the other cam bearing halfs and pudding came out!!!!!!!!
I smelled that wonderful acrid, burnt-oil smell also

Is it terminal?
Are the head gaskets blown?

What now?
You can't move crankshaft either way? Do you have all four cam pulleys loose on cams with belt still tensioned on crankshaft? Hopefully you can get crank to move back towards its timing mark and then move cams and verify timing again with timing dies and marks on end of cams.

If you are real worried about valve and piston tops talking to each other loosen all cam bearing caps and release belt tension so valves will close then see if crank will move back and forth to TDC mark with valves closed. Then reinstall cams with timing marks on ends lined up and install timing dies to hold cams locked while you retension belt.

As for acrid smell with "pudding" that is pretty normal when you pop off a cam bearing cap.
 

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Secondly, I have managed to partially strip the threads in one of the bolt holes for a cam bearing. It is the first bearing on the exhaust cam on the rear bank (Cylinder #1).

Can I helicoil it in place?
Which bolt is it rear one closest to false firewall or forward one? Forgot the wrench size to remove them is it 12 or 13mm? Think 12v is 13mm hex nuts not bolts so 8 or 10 mm studs I believe.

I am away from actual car parts right now so all memory work today.
 

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Discussion Starter #20
You can't move crankshaft either way? Do you have all four cam pulleys loose on cams with belt still tensioned on crankshaft? Hopefully you can get crank to move back towards its timing mark and then move cams and verify timing again with timing dies and marks on end of cams.

If you are real worried about valve and piston tops talking to each other loosen all cam bearing caps and release belt tension so valves will close then see if crank will move back and forth to TDC mark with valves closed. Then reinstall cams with timing marks on ends lined up and install timing dies to hold cams locked while you retension belt.

As for acrid smell with "pudding" that is pretty normal when you pop off a cam bearing cap.
I could move the crank back to top-dead center. It would only move forward about 1/8 of a turn.
I'll try loosening the cam shafts completely, allowing the valves to close. If there is no "bendage" I should be able to turn the crank all the way around.

What is the pudding? It's not edible, is it?
 
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