Time for a new head gasket? - Page 2 - Alfa Romeo Bulletin Board & Forums
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post #16 of 38 (permalink) Old 09-18-2015, 07:03 AM Thread Starter
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I took the valve cover off last night and the valve clearances are all within spec (I adjusted them within the past year) and the timing marks on the cam shafts are pretty much right on. I like the idea of blowing air into the spark plug hole with both valves closed, I'll try that tonight. I also noticed that the oil in the sumps under the cams smells like gas, but that's not surprising if a cylinder is leaking compression into the crankcase somehow.

I got all the brass nuts off the exhaust manifold, but I'm having trouble getting it to break free from the head so I soaked everything with PB Blaster last night. Hopefully that will do it.

Thanks everyone!

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post #17 of 38 (permalink) Old 09-18-2015, 03:47 PM
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When pressurizing the cylinder, make sure it is exactly on TDC. Off a little and the engine will turn over.

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post #18 of 38 (permalink) Old 09-18-2015, 07:19 PM
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"I got all the brass nuts off the exhaust manifold, but I'm having trouble getting it to break free from the head so I soaked everything with PB Blaster last night. Hopefully that will do it. "

Try putting a jack under the exhaust to releve pressure and then use a a pry bar to (gently) pull ex. manifold away from the head.
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post #19 of 38 (permalink) Old 09-21-2015, 06:46 AM Thread Starter
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I got the head off yesterday (thanks for the tip dghii) and was able to get a good look at the valves. Attached is a photo of no. 1 cylinder, showing a pretty severely burned rim of the exhaust valve near the spark plug hole. From what I've read, replacing valves is a job for someone who actually knows what they're doing. What would cause a valve to burn like that? Also, what are my options here? Do I buy a rebuilt head from Centerline ($600, assuming mine is acceptable as a core), or are there other shops that can fix this one? Would this have caused any other damage in that cylinder (rings for example)?

Thanks again for all your help!
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post #20 of 38 (permalink) Old 09-21-2015, 07:38 AM
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something odd here

you say you have never had the head off? So how long have you owned the car?
That combustion chamber is just too clean......

what is the history of this car.....did it ever run perfect for you?

EDIT: got photo of the other chambers and the top of piston #1?

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post #21 of 38 (permalink) Old 09-21-2015, 07:38 AM
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Your best course of action depends upon the condition of the seats. Others may speculate on the cause of the burned valve. The combustion chamber is extremely clean, possibly an indication of a very lean mixture.

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post #22 of 38 (permalink) Old 09-21-2015, 08:21 AM
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I got the head off yesterday (thanks for the tip dghii) and was able to get a good look at the valves. Attached is a photo of no. 1 cylinder, showing a pretty severely burned rim of the exhaust valve near the spark plug hole. From what I've read, replacing valves is a job for someone who actually knows what they're doing. What would cause a valve to burn like that? Also, what are my options here? Do I buy a rebuilt head from Centerline ($600, assuming mine is acceptable as a core), or are there other shops that can fix this one? Would this have caused any other damage in that cylinder (rings for example)?

Thanks again for all your help!
that valve and valve seat don't look burned to me... it looks like a piece broke off and the valve in the next cyl over looks like shrapnel has been hammering around in there . I think that valve issue is a result of something else going on... not root cause.
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post #23 of 38 (permalink) Old 09-21-2015, 08:24 AM Thread Starter
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I've owned the car for 15+ years and my daughter owned it for a couple of years before that. I've put about 30,000 miles on it since then and it has not had the head off in that time. It ran great until this summer when it started missing, backfiring and idling poorly.

I also noticed that the No. 1 chamber was a lot cleaner than the others. Here's my theory: since it had zero compression in that cylinder (and I probably drove it 100 miles that way), the air/fuel mix was not getting compressed and therefore not igniting and the unburned fuel scoured the chamber. Does that make sense to anybody else? I can post more photos tonight.

I'm concerned that the unburned fuel may have also washed the cylinder walls and wore the rings in that cylinder. That would explain the positive pressure in the crankcase. I did pressurize the cylinder before I took it apart and the air came out the tailpipe, which the condition of the exhaust valve would explain.

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post #24 of 38 (permalink) Old 09-21-2015, 09:16 AM Thread Starter
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Steve,
I'll take a closer look tonight when I get back to it -- and take some photos. The edge of the valve looked eroded to me, not broken and the shape is very symmetrical, but I've never seen either condition before, so what do I know? If chunks of the valve did break off and bang around in the chamber, that would explain the clean aluminum. Piston 1 is at TDC and I haven't yet rotated the crank to take a look at the cylinder wall. Other than a disintegrating valve, I can't think of any way shrapnel would get into a combustion chamber. The piston heads look to be ok, as I recall.

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post #25 of 38 (permalink) Old 09-21-2015, 10:46 AM
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Steve,
I'll take a closer look tonight when I get back to it -- and take some photos. The edge of the valve looked eroded to me, not broken and the shape is very symmetrical, but I've never seen either condition before, so what do I know? If chunks of the valve did break off and bang around in the chamber, that would explain the clean aluminum. Piston 1 is at TDC and I haven't yet rotated the crank to take a look at the cylinder wall. Other than a disintegrating valve, I can't think of any way shrapnel would get into a combustion chamber. The piston heads look to be ok, as I recall.

I think this is all academic except for the sake of discussion and education. the bottom line is that at that mileage etc, it needs a freshening anyway ... I can't imagine you would put a fresh head on a 100k bottom end ... ive seen a lot of burned valves in my career and the ones ive seen look quite different and the seats always take a beating in the same area ... your stuff doesn't have those witness marks that I can see. I do agree with you relative to the cleanliness of the cc as far as the washing action... I can imagine that happening and often motors with weak rings will end up with very clean chambers as well. look... for me the path is clear. 8 new valves, cut the seats , skim the head , do the rings and bearings and that's it. if you have the money do a set of pistons and liners with a set of total seal rings and then do another 100 k on it and never look back.
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post #26 of 38 (permalink) Old 09-21-2015, 10:54 AM
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I can't recall reading if you have found the piece that broke off the exhaust valve?
The bright side to this- a fresh engine is always nice

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post #27 of 38 (permalink) Old 09-21-2015, 12:03 PM Thread Starter
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John533i, I didn't find any bits of the valve in the chamber when I pulled the head. They could have gotten broken up and blown out the exhaust, I guess. And thanks for the bright side. Since the car spent its early life in Arizona and has been stored winters up here in the frozen North, the body is in excellent shape with no rust. So it is worthy of a refreshed engine.

Steve, I'm slowly coming around to your point that I should do rings and bearings along with the head rebuild. A couple of days ago I was thinking this was a $100 head gasket job, so I'm still getting over the shock of bottom end work. Now I'm wondering if I want to tackle the work myself. I've never pulled the engine and trans, but with the head off it looks like I'm about halfway there. It would be an interesting challenge for the off season, and with a rented hoist and the excellent help of this forum I may be able to get through it.

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post #28 of 38 (permalink) Old 09-21-2015, 12:52 PM
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John533i, I didn't find any bits of the valve in the chamber when I pulled the head. They could have gotten broken up and blown out the exhaust, I guess. And thanks for the bright side. Since the car spent its early life in Arizona and has been stored winters up here in the frozen North, the body is in excellent shape with no rust. So it is worthy of a refreshed engine.

Steve, I'm slowly coming around to your point that I should do rings and bearings along with the head rebuild. A couple of days ago I was thinking this was a $100 head gasket job, so I'm still getting over the shock of bottom end work. Now I'm wondering if I want to tackle the work myself. I've never pulled the engine and trans, but with the head off it looks like I'm about halfway there. It would be an interesting challenge for the off season, and with a rented hoist and the excellent help of this forum I may be able to get through it.
well... I would think that w/the head off , the rad and water pump and ancillaries off that you could separate the engine from the box in the car and you and your buddy could lift it out w/ a chain and a pole between you pretty easy .. or you rent a lift... and the rest is pretty simple if you have ever done one before. if you have never done one before then find someone that's built any bottom end before . its not hard but its helpful if you know the difference between good parts and bad ones if you hold them in your hands and be able to id any troublesome stuff that may become evident when you have the pan off. either way , I think a full freshening is in your future. its just a matter of your skill set whether you do it or someone else does.

I never had a close look at mine but on the older ones, you could get the pan off in the car and do a freshening like this without taking the motor out at all... can you get the pan off these late cars in the car ? if so, you can be out of this job in a weekend.

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post #29 of 38 (permalink) Old 09-21-2015, 02:27 PM
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I have removed an engine and left the gearbox in the car - it was easier than pulling the engine + gearbox together, but it was a bear to re-install. I only did it once and I have gone back to pulling them together.
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post #30 of 38 (permalink) Old 09-21-2015, 02:36 PM
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I have removed an engine and left the gearbox in the car - it was easier than pulling the engine + gearbox together, but it was a bear to re-install. I only did it once and I have gone back to pulling them together.
do you know if the pan will come off w/ the motor in the car and maybe jacked up off the mounts ?
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