Catastrophic Failure of the Camshaft Bearings

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340_dart_power

340_dart_power

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Took the Dart to a shop here in the area and they weren't able to determine the reason it was running so roughly at idle, so I took it to another place a friend recommended. The guy at the 2nd place had it two days before he called me and said he believed it was a camshaft issue. When he went to remove it, he and another guy had to use a pry bar to get it out of the engine. Once it was removed, he took the top components off the motor and realized the camshaft bearings had disintegrated, and of course, the bits and pieces thereof were now scattered throughout the 340.
He pulled the engine and later this week we're taking it back to the shop which rebuilt it two years and 1,900 miles ago. I called them and told them what had occurred, and they're standing behind their work. They're going to tear it down to see what happened, and go from there.
 

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Do you have pics of the cam? What kind of oil were you running? I doubt you will get the shop to eat it 2 years later. Does cam look like it wipe a lobe before bearing failure?
 
I don't think I've ever seen that in a low mileage motor. Subscribed, I'd like to know how it happened.
 
As bad as a casual look at that "looks," I'll bet there's a hell of a lot more than bad cam bearings...........
 
The cam itself hardly had any marks on it, and the lobes were intact.
To say I'm curious as to what went wrong is an understatement.
I'll keep this updated as the Titanic gets closer to the iceberg.
 
The shop should inside mic the cam bearing bores, I'll bet they are on the tight side.

Hate to read stuff like this, always a rough go, at least the shop is helping you out.
 
Had no idea what was wrong with it, and it had a bad miss but would still take off and go if you got on it. Thought perhaps it was timing or something electrical, and not (as it turned out to be) mechanical.
 
I'm gonna give this thread one of these...:happy1:.

What I've seen so far just isn't making a whole lot of sense to me at this point? I have to assume that the cam at least spun ok when the shop buttoned it up.

Cam & lobes still looks decent, plenty of oil to the top end, but multiple bearings are trashed? And the engine was just missing or running weird.

I'm not trying to make a assessment here as I'm beat and had a long day. I'd just love to know the real cause of your issue.
 
Sorry to hear about your engine,but glad they,re taking care of you.Which is usually unheard of these days.
 
OldmanRick said:
I'm gonna give this thread one of these...:happy1:.

What I've seen so far just isn't making a whole lot of sense to me at this point? I have to assume that the cam at least spun ok when the shop buttoned it up.

Cam & lobes still looks decent, plenty of oil to the top end, but multiple bearings are trashed? And the engine was just missing or running weird.

I'm not trying to make a assessment here as I'm beat and had a long day. I'd just love to know the real cause of your issue.
Click to expand...
x2 on the :happy1:
 
I had a cam bearing spin on me once on a big block. Gawd, did it make racket. Bought the engine as a private `rebuild' when I was young and naive. But it was only one bearing. I`m glad the first shop stepped up and I hope they make good.
 
Check the oil galleys that feed to that cam bearing and use a straightened wire coat hanger to make sure that the passages are not blocked.

have them measure the cam bores with a micrometer and make sure that they are the proper size.

I can think of five causes for the cam bearing to fail.

1. Improper (oversize) bore for the cam bearing.

2. Blocked oil passage feeding the bearing.

3. Dirt behind or on the bearing surface when the cam was installed.

4. They misinstalled the bearing, then removed it and reinserted it. Once you press in a cam bearing and then remove it, junk it. Do not reuse it, get a new one and install it.

On the block machining line that I worked on, once a cam bearing was installed and then removed we didn't reuse them, we replaced them with another one.

5. Bad surface finish on the bearing and/or cam journal itself.
 
Wow!
I feel for you, this shouldn't have happened obviously. I haven't seen this on engines that had 300,000 miles on them. I bet it was an oil starvation problem or possibly defective/improperly installed cam bearings.
Sorry to hear this.
I can't wait for the results of the autopsy though!
 
I would make sure you and a knowledgeable friend are there when it is tore down by "them" to diagnose the problem.

I have a feeling this is going to get interesting for you. Unless you live in a area where people are all honest. Its hard to find reputable shops. They are out there but far and few.

Best wishes keep us informed
 
krazykuda said:
Check the oil galleys that feed to that cam bearing and use a straightened wire coat hanger to make sure that the passages are not blocked.

have them measure the cam bores with a micrometer and make sure that they are the proper size.

I can think of five causes for the cam bearing to fail.

1. Improper (oversize) bore for the cam bearing.

2. Blocked oil passage feeding the bearing.

3. Dirt behind or on the bearing surface when the cam was installed.

4. They misinstalled the bearing, then removed it and reinserted it. Once you press in a cam bearing and then remove it, junk it. Do not reuse it, get a new one and install it.

On the block machining line that I worked on, once a cam bearing was installed and then removed we didn't reuse them, we replaced them with another one.

5. Bad surface finish on the bearing and/or cam journal itself.
Click to expand...

i guess they could have gouged one of the bearings real bad while inserting the camshaft also. they would really have to do a number on it, though, for the bearing to go bad after a couple thousand miles.

i'm sure a lot of us have put a scratch lol (shhhhhh )

more likely is that one of the bearings was not installed properly
 
krazykuda said:
Check the oil galleys that feed to that cam bearing and use a straightened wire coat hanger to make sure that the passages are not blocked.

have them measure the cam bores with a micrometer and make sure that they are the proper size.

I can think of five causes for the cam bearing to fail.

1. Improper (oversize) bore for the cam bearing.

2. Blocked oil passage feeding the bearing.

3. Dirt behind or on the bearing surface when the cam was installed.

4. They misinstalled the bearing, then removed it and reinserted it. Once you press in a cam bearing and then remove it, junk it. Do not reuse it, get a new one and install it.

On the block machining line that I worked on, once a cam bearing was installed and then removed we didn't reuse them, we replaced them with another one.

5. Bad surface finish on the bearing and/or cam journal itself.
Click to expand...

Several good points here-
Tight cam bearings can be a real problem, yet people still force the cam in anyway. Checking the actual clearances is something few people do, but it can save some headaches.
I will say though, I don't buy the "bad cam bearings made it idle rough" idea. Tight and/or lack of oil or debris in oil galleys from not being clean enough is likely culprit of wiped cam bearings.
If you look at the photos of your intake ports, they are rather black from oil and/or reversion, or just a bad tune-up.
Engine problems are never any fun, hope you are able to get it sorted out and back together ok.
 
wasted cam bearings and no mention of oil pressure, it had to be low.
 
CPMotorworks said:
Several good points here-
Tight cam bearings can be a real problem, yet people still force the cam in anyway. Checking the actual clearances is something few people do, but it can save some headaches.
I will say though, I don't buy the "bad cam bearings made it idle rough" idea. Tight and/or lack of oil or debris in oil galleys from not being clean enough is likely culprit of wiped cam bearings.
If you look at the photos of your intake ports, they are rather black from oil and/or reversion, or just a bad tune-up.
Engine problems are never any fun, hope you are able to get it sorted out and back together ok.
Click to expand...


I was also thinking that maybe the machine shop may not have had a bearing properly aligned and then punched it out and reinserted it. That makes it easier to push out the second time/less bearing retention force. Every time a bearing is pressed in or removed, it slightly opens up the bearing hole in the block which reduces the press fit.

You should always check the cam to see how tight it is after it is inserted. If it doesn't spin freely, there may be problems to develop later.

Some bearings, you insert and then are good to go. Others need to be machined after being pressed in. The sb mopar bearings are press in and go.

You should always make sure that the camshaft spins freely after it is inserted. Some people think a tight one will "wear in".... NOT.
 
340_dart_power said:
Had no idea what was wrong with it, and it had a bad miss but would still take off and go if you got on it. Thought perhaps it was timing or something electrical, and not (as it turned out to be) mechanical.
Click to expand...

How long did you run it with the miss???
 
Well, it died on me completely on New Years Eve day, 12/31/2012, and I had it towed to a garage here in town that same day. Turned out to be the ignition switch, which was replaced. Subsequent to that, they (the garage guys) found that the starter had come apart from the heat from the headers, presumably. Replaced the starter, and had the new one wrapped in an asbestos covering to deflect the heat from the headers. Engine would now fire up, but ran roughly and had the miss. Acting on their suggestion, I bought a new carb (a Holley) and they installed it. The miss was still present and the garage guys couldn't figure out what was causing it, and after having there for seven (7) months I finally called them in early August and told them I was coming to get the Dart. They were fine with that, as I believe they eventually realized it just wasn't something within their abilities to work upon, despite the alleged experience level of their staff. We parted company amicably, and I drove the Dart home to park it and find an alternative place to which to take it for work.
Found a new guy who came highly recommended, and dropped it off to be evaluated. In two days he called and said it was his opinion that the camshaft was the issue, and should he go ahead and pull it? I told to go ahead and do so, and that's when he discovered the bearings were toast.
The oil pressure was up in the 50 range (on the gauge installed when the rebuilt engine was re-installed) when driving the Dart prior to dropping it off at the latest place, so I had good pressure. I hardly drove it between having it at the different locations, because I knew it wasn't right and was concerned about causing more damage to it. Oil level was full, and at idle it was rough but would run down the street at speed as though nothing was wrong.
Long story, I know, but I'm just trying to give y'all a better picture of what I've been going through with this. It's a bit of a PITA, to say the least.
 
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