My 1978 3.0 L head stud replacement thread
09-27-2011, 11:00 AM
#106
RL Community Team
Rennlist Member
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Hey Brett, great job!
Unquestionably, you were very wise to take this motor all the way apart. What you photographed are all things that would likely have gotten worse and ultimately manifest themselves as deeper damage. As it is, it looks like you will be able to get a lot of this straightened out. Maybe the crank just needs a polish… Of course, we both know until all our parts are comprehensively spec’d we can’t say for sure…
Looking at the sum of all the things you found, it really does look like your extra challenges here are the result of collateral debris from a previous engine failure that was not completely eradicated during repair, and/or a less-than-pristine job by the last mechanic that took this motor apart. I think your situation is one where following the “while-you-re-in-there” instinct was the right one. It would have been a real let down to just fix that broken stud, button it all back together, and then be dropping it again next year when (perhaps) that intermediate shaft bearing goes over the cliff.
Actually Ice, I think a lot of these motors are still in pretty good shape. As mentioned, I think Brett’s discoveries are more to do with the specific history of the motor (please correct me, Brett, if you think I’m wrong) and less to do with mileage or design-related factors.
When I split the case on my 3.2, everything looked perfect except the outboard intermediate shaft bearing, which was showing copper:
The basic mystery I don’t know the answer to is how much more mileage would this intermediate shaft bearing have, before it would start to pit and break apart?
From everything I have gleaned from forum searching here and at Pelican, showing copper on the intermediate shaft bearing is very typical for a +100K motor. Yet, we know many 3.0s and 3.2s go beyond 200K without being split, which leads me to wonder if there is still a lot of life in an intermediate bearing that is showing copper (assuming it continues to see frequent oil changes etc)?
It would be nice if that one bearing could be changed without splitting case!
Unquestionably, you were very wise to take this motor all the way apart. What you photographed are all things that would likely have gotten worse and ultimately manifest themselves as deeper damage. As it is, it looks like you will be able to get a lot of this straightened out. Maybe the crank just needs a polish… Of course, we both know until all our parts are comprehensively spec’d we can’t say for sure…
Looking at the sum of all the things you found, it really does look like your extra challenges here are the result of collateral debris from a previous engine failure that was not completely eradicated during repair, and/or a less-than-pristine job by the last mechanic that took this motor apart. I think your situation is one where following the “while-you-re-in-there” instinct was the right one. It would have been a real let down to just fix that broken stud, button it all back together, and then be dropping it again next year when (perhaps) that intermediate shaft bearing goes over the cliff.
When I split the case on my 3.2, everything looked perfect except the outboard intermediate shaft bearing, which was showing copper:
The basic mystery I don’t know the answer to is how much more mileage would this intermediate shaft bearing have, before it would start to pit and break apart?
From everything I have gleaned from forum searching here and at Pelican, showing copper on the intermediate shaft bearing is very typical for a +100K motor. Yet, we know many 3.0s and 3.2s go beyond 200K without being split, which leads me to wonder if there is still a lot of life in an intermediate bearing that is showing copper (assuming it continues to see frequent oil changes etc)?
It would be nice if that one bearing could be changed without splitting case!
09-27-2011, 11:49 AM
#107
Rennlist Member
That looks to have evidence of some pretty thick coat of "adhesive". No wonder you fought it. I'd say the case was split before, possibly when the "incident" happened. They just may not have cleaned all the oil galleys out well, and some crud found it's way to that bearing.
09-30-2011, 02:45 AM
#109
Reasons #4 and 5 that I'm glad I split the case.
There's 1/3 of a tooth missing on one of the timing chain sprockets on the intermediate shaft.
And, I found more failure detritus behind the oil pump, which I removed tonight. This is a broken valve keeper.
That makes a washer, valve keeper, and valve tappet that I have found floating loose in the case. This and the tough case sealant that I encountered makes me wonder more about the history of the engine. I can't imagine that the case sealant was from the factory. So, the case must have been split at some point, but also, I can't imagine that these objects were not found and removed when the case was split. Possibly this engine has been apart twice. The first time, the case was split and resealed with the tough sealant for whatever reason. The second tear down was for the top end failure, and the unscrupulous mechanic did not split the case and clean oil passages and remove debris and fix things like the timing chain sprocket as should have been done.
I also lifted out the crankshaft and mounted it on the flywheel on the bench. The other halves of the main bearings were much like those I already posted pics of. No others with significant damage as seen earlier but just a few palpable scratches in them. Rod bearings are next.
Brett
There's 1/3 of a tooth missing on one of the timing chain sprockets on the intermediate shaft.
And, I found more failure detritus behind the oil pump, which I removed tonight. This is a broken valve keeper.
That makes a washer, valve keeper, and valve tappet that I have found floating loose in the case. This and the tough case sealant that I encountered makes me wonder more about the history of the engine. I can't imagine that the case sealant was from the factory. So, the case must have been split at some point, but also, I can't imagine that these objects were not found and removed when the case was split. Possibly this engine has been apart twice. The first time, the case was split and resealed with the tough sealant for whatever reason. The second tear down was for the top end failure, and the unscrupulous mechanic did not split the case and clean oil passages and remove debris and fix things like the timing chain sprocket as should have been done.
I also lifted out the crankshaft and mounted it on the flywheel on the bench. The other halves of the main bearings were much like those I already posted pics of. No others with significant damage as seen earlier but just a few palpable scratches in them. Rod bearings are next.
Brett
09-30-2011, 03:05 AM
#110
Rennlist Member
Reasons #4 and 5 that I'm glad I split the case.
There's 1/3 of a tooth missing on one of the timing chain sprockets on the intermediate shaft.
And, I found more failure detritus behind the oil pump, which I removed tonight. This is a broken valve keeper.
That makes a washer, valve keeper, and valve tappet that I have found floating loose in the case. This and the tough case sealant that I encountered makes me wonder more about the history of the engine. I can't imagine that the case sealant was from the factory. So, the case must have been split at some point, but also, I can't imagine that these objects were not found and removed when the case was split. Possibly this engine has been apart twice. The first time, the case was split and resealed with the tough sealant for whatever reason. The second tear down was for the top end failure, and the unscrupulous mechanic did not split the case and clean oil passages and remove debris and fix things like the timing chain sprocket as should have been done.
I also lifted out the crankshaft and mounted it on the flywheel on the bench. The other halves of the main bearings were much like those I already posted pics of. No others with significant damage as seen earlier but just a few palpable scratches in them. Rod bearings are next.
Brett
There's 1/3 of a tooth missing on one of the timing chain sprockets on the intermediate shaft.
And, I found more failure detritus behind the oil pump, which I removed tonight. This is a broken valve keeper.
That makes a washer, valve keeper, and valve tappet that I have found floating loose in the case. This and the tough case sealant that I encountered makes me wonder more about the history of the engine. I can't imagine that the case sealant was from the factory. So, the case must have been split at some point, but also, I can't imagine that these objects were not found and removed when the case was split. Possibly this engine has been apart twice. The first time, the case was split and resealed with the tough sealant for whatever reason. The second tear down was for the top end failure, and the unscrupulous mechanic did not split the case and clean oil passages and remove debris and fix things like the timing chain sprocket as should have been done.
I also lifted out the crankshaft and mounted it on the flywheel on the bench. The other halves of the main bearings were much like those I already posted pics of. No others with significant damage as seen earlier but just a few palpable scratches in them. Rod bearings are next.
Brett
The good news is: no apparent major damage, and she'll be as good as new when you're done. Done, minus a few sheckles from the family bank account.
These engines are pretty damned robust, at the end of the day. When I look at mine, and the over-rev that bent all of the exhaust valves, two of the lock nuts on the elephant feet backed off completely in my "incident". My good news is they stayed up in the cam towers, and didn't get down to the bottom end to do damage.
09-30-2011, 11:21 AM
#111
RL Community Team
Rennlist Member
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Well, at least you aren’t thinking “Ah, I shouldn’t have bothered wasting my time splitting the case." It has proven to be superb decision on your part.
It is amazing how slipshod some mechanics can be. Of course, this work could have been done by an amateur too, but certainly some “pros” are not deserving of the title.
As Ed says, everything is quite fixable and you will have the satisfaction of knowing your motor is perfect when you are done.
It is amazing how slipshod some mechanics can be. Of course, this work could have been done by an amateur too, but certainly some “pros” are not deserving of the title.
As Ed says, everything is quite fixable and you will have the satisfaction of knowing your motor is perfect when you are done.
09-30-2011, 02:24 PM
#112
09-30-2011, 02:26 PM
#113
10-07-2011, 12:17 PM
#114
I got the rods off the crank last night. It's not good news. Here are some views of the rod bearings.
And this is the rod journal corresponding to that last bearing. Seems worn through the hardened surface in a couple of spots. Not good.
The other journals seemed visually OK, but don't know about actual measurements. I don't know what this means for the crank. Possibly an undersized grind and rehardening for the rod journals, but I do know it means more money out of my pocket.
Well, that pretty much completes the tear down. Well, almost, I guess. It looks like I still need to break down the intermediate shaft to replace the timing chain sprocket, but maybe I'll leave that to the machine shop. It's been an adventure for sure. I got more than I bargained for, so to speak, and it's been incredibly educational, particularly with 500_19B breaking down an engine at the same time that was in much better shape. Comparing and contrasting has been eye opening.
Now that I'm expecting a much heftier machine shop bill, this thread may go dark for a while to allow funds to grow on some trees. I'm certain my dad has been wrong all these years. LOL
Brett
And this is the rod journal corresponding to that last bearing. Seems worn through the hardened surface in a couple of spots. Not good.
The other journals seemed visually OK, but don't know about actual measurements. I don't know what this means for the crank. Possibly an undersized grind and rehardening for the rod journals, but I do know it means more money out of my pocket.
Well, that pretty much completes the tear down. Well, almost, I guess. It looks like I still need to break down the intermediate shaft to replace the timing chain sprocket, but maybe I'll leave that to the machine shop. It's been an adventure for sure. I got more than I bargained for, so to speak, and it's been incredibly educational, particularly with 500_19B breaking down an engine at the same time that was in much better shape. Comparing and contrasting has been eye opening.
Now that I'm expecting a much heftier machine shop bill, this thread may go dark for a while to allow funds to grow on some trees. I'm certain my dad has been wrong all these years. LOL
Brett
10-07-2011, 12:58 PM
#116
RL Community Team
Rennlist Member
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When I saw your first picture in the previous post, I thought "Hey, that looks like two of mine, with radial scratches!" And, I figured that your crank throws might be fine too. But then I saw the other pictures and I get it now...
Again, it all fits in with the "story" of contamination left in the motor from some previous event/subsequent work.
I'm not sure how expensive good, used cranks are, but you may want to keep an eye out as it may be an option too.
I agree with you and have also found the teardown experience enhanced by both of us doing it at the same time. It certainly has helped me learn.
Like you, I now am facing the expensive part of the operation. Although I believe I have a good chance of having a relatively small machine shop bill, just the parts alone are a big expense, and one that I had not planned on some weeks ago.
Again, it all fits in with the "story" of contamination left in the motor from some previous event/subsequent work.
I'm not sure how expensive good, used cranks are, but you may want to keep an eye out as it may be an option too.
I agree with you and have also found the teardown experience enhanced by both of us doing it at the same time. It certainly has helped me learn.
Like you, I now am facing the expensive part of the operation. Although I believe I have a good chance of having a relatively small machine shop bill, just the parts alone are a big expense, and one that I had not planned on some weeks ago.
10-07-2011, 01:08 PM
#117
Rennlist Member
The expense is a lot of the reason my build took 9 months.....I chunked away on parts or machining each month. Once you get to assy, it goes pretty well as long as you are thinking ahead a couple of steps-this is very important-so you don't paint yourself into a corner. The dollars can add up quick.
I'd still have the crank inspected by a good shop and see what its utility (besides a lamp base) may be.
I'd still have the crank inspected by a good shop and see what its utility (besides a lamp base) may be.
When I saw your first picture in the previous post, I thought "Hey, that looks like two of mine, with radial scratches!" And, I figured that your crank throws might be fine too. But then I saw the other pictures and I get it now...
Again, it all fits in with the "story" of contamination left in the motor from some previous event/subsequent work.
I'm not sure how expensive good, used cranks are, but you may want to keep an eye out as it may be an option too.
I agree with you and have also found the teardown experience enhanced by both of us doing it at the same time. It certainly has helped me learn.
Like you, I now am facing the expensive part of the operation. Although I believe I have a good chance of having a relatively small machine shop bill, just the parts alone are a big expense, and one that I had not planned on some weeks ago.
Again, it all fits in with the "story" of contamination left in the motor from some previous event/subsequent work.
I'm not sure how expensive good, used cranks are, but you may want to keep an eye out as it may be an option too.
I agree with you and have also found the teardown experience enhanced by both of us doing it at the same time. It certainly has helped me learn.
Like you, I now am facing the expensive part of the operation. Although I believe I have a good chance of having a relatively small machine shop bill, just the parts alone are a big expense, and one that I had not planned on some weeks ago.
10-07-2011, 02:31 PM
#118
10-07-2011, 02:35 PM
#119
500_19B: Yeah, I think it is just an "unthorough" job on the last rebuild. "Just" I say... sheez, as it adds "just" a few thousand to this job.
Ed: Absolutely, the crank will be evaluated professionally. If it's not bent, I'll bet it can be fixed. It doesn't look really serious to my untrained eye. Machinists are miracle workers.
Brett
Ed: Absolutely, the crank will be evaluated professionally. If it's not bent, I'll bet it can be fixed. It doesn't look really serious to my untrained eye. Machinists are miracle workers.
Brett
10-07-2011, 11:53 PM
#120
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my condolences on the state of your bearings. i don't think i've ever seen visible metal shavings on the crank like that without catastrophic engine damage (although there was obviously serious damage before, your engine supposedly had been repaired).
your decision to open the case is looking better and better. i don't see how the engine could have kept together in its current state.
your decision to open the case is looking better and better. i don't see how the engine could have kept together in its current state.