Catastrophic Failure of the Camshaft Bearings

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UPDATE:
Dropped the 340 off at the engine shop with a newly bought Comp cam and the guys will be tearing into it next week to see what happened.
 
Do you think the cam may have been warped?

Check the camshaft closely and inspect it for straightness. I've seen tight fitting cam bearings do this, too. Sometimes they spin by hand on install, but not easy enough. All it takes is a few thousandths.

Difficult to say if it was too tight, now that everything has gone to hell, but without knowing how it felt and measured when installed, as long as the new stuff going in feels nice and smooth spinning by hand, oil holes showing at least 50%open (I like more than that) cam bearing bores, cam journals and installed I.D. of the bearing are to spec and mic out ok, installed with good break in lube, it shouldn't happen again.
 
Just my 2 cents worth--Any engine I've had built by a reputable builder came with the blueprint sheet that lists all the measurements and bearing clearances including the cam bearings,Did u not get such a sheet when they built your engine???? It would at least show the cam bore diameters and measurements with the bearings in place.Although this would not account for the oiling holes being out of whack and not lined up ,it would at least show the measurements taken when they assembled the engine--Sad to hear about this,I enjoyed your exciting posts when you finished this car--Steve
 
Here are some photos of the camshaft which was installed in the 340 and was pulled several days ago. It appears to be straight but the photos may not be all that helpful. I'm going to drop it off today for the engine shop to evaluate, but not re-install.
I did not receive any documentation from the engine shop which built the 340 for me. This apparently is not their policy/procedure/habit to do so for customers, and I have no reason as to why they do not.
 

Attachments

Great closeup of the cam journals. NOT. It appears though, even with the long distance pictures that the center cam journal is scored. Although that's a guess at best.
 
Make sure you put in new lifters if it is a flat tappet.

As for the build sheet some builders give you all the data and others hardly any. My 540 which the builder just finished up is in the latter category. I am going to bring him a copy of the build sheet that Carlquist (Oakville, CT) sent me for the stroker I bought from Mackin here. That sheet has on it the bearing part #s and the cam bore size is described as "mid-high, OK".
 
Stopped by the engine shop yesterday and the 340 has been disassembled. However, no cause of the failure has been identified by the shop which built it. My point of contact at the shop is looking into several possible reasons but hasn't zeroed in on one in particular just yet. He was supposed to meet with another builder today and have him examine it for an opinion, so I'm waiting to hear back from him.
 

Attachments

I really wish you had gotten good, or as good as you coulda got, close ups of the cam bearings and journals. I'm sure im not the only one who is curious to see the wear on them. Its good the machine shop is eating the cost atleast.
 
i don't like that the main caps are apart from the block. hope they marked them so they know which one goes where.
 
Assuming the 340 is the only engine of it's type there - the caps are numbered during casting.
 

Still no word on the root cause of the bearing destruction.
The builder will be on vacation next week (Sep 16-21) so he won't be finishing the rebuild until the following week. I'll update this as soon as I hear something from the engine shop.
 
I just went through this myself with my engine builder. Mine wiped out crank, and all bearings. Motor had about 1000 miles on it. The oil pump checked out within specs with the exception of pieces of bearings wiping that out as well. My engine builder took care of mine as well. I had to have the valves re-done, so with them needing to dig into the heads, I had them port them and install bigger valves while they were at it! 5 weeks later, motor back in and running like a champ! I hope you have the same outcome! Good luck!
 
OK I'm going to tell on my self. I agree with several here that really question the cam bearings making the eng run ruff.

My first can swap was in a 73 cuda with a 318 in it. when i got the cam out the bearing were wasted!

when to a machine shop to see if they could replace the bearing in the car.
They said it would have to be pulled out of the car and should be disassembled to do it right.

I decide to install the new cam and lifters with out fixing the bearings.
ran just fine for another year before i pulled it out and rebuild my first 340.

You said that you had to have your ign sw replace before it would start, right?

My money is on a bad wire between the ign and the coil. probably in the fire wall connector.

Just something to think about when you get your motor back in, and it still runs bad.....or don't start at all.

Another thought would be a intake manifold leak under the manifold. did you see or keep the gasket that was taken off the eng. when they were checking out the cam/ bearings?

Just trying to get you to think out side the box a little and not be so focuses on the cam bearings. take a good look at the intake ports and spark plugs. there my be some clues for you there.
 
looking at that cam picture it looks burnt lol. like someone took a torch to it.
i've seen 100k mile cams that look better.

1900 miles? wow
 
UPDATE:
Received a call yesterday from the engine shop which is rebuilding the 340 and the suspicion is that the tolerances between the camshaft and camshaft bearings were either too great or too small, and this is why the bearings failed. My shop contact promised he will double, triple, etc., check this area during the rebuild to avoid repeating the same problem.
The shop will be done with the rebuild early next week, so hopefully we'll be able to go pick up the finished 340 Tuesday or Wednesday. I'll keep y'all posted.
 
340_dart_power said:
UPDATE:
Received a call yesterday from the engine shop which is rebuilding the 340 and the suspicion is that the tolerances between the camshaft and camshaft bearings were either too great or too small, and this is why the bearings failed. My shop contact promised he will double, triple, etc., check this area during the rebuild to avoid repeating the same problem.
The shop will be done with the rebuild early next week, so hopefully we'll be able to go pick up the finished 340 Tuesday or Wednesday. I'll keep y'all posted.
Click to expand...

We get so many bad reports of evil shops rippin people off please post the name of this one. I think they stepped up and did you right. Everybody makes mistakes. I don't care who you are. Good on them for owning up to it. Now who is it? lol
 
RustyRatRod said:
We get so many bad reports of evil shops rippin people off please post the name of this one. I think they stepped up and did you right. Everybody makes mistakes. I don't care who you are. Good on them for owning up to it. Now who is it? lol
Click to expand...
x2
 
A number of years ago a friend wanted me to help him build his 440 for his mud truck. Had a shop in Decatur, IL do all the machine work, install cam bearings, etc. Can't remember the name of the shop for the life of me though...something like P&M or so...it was two letters like that..anywho.
Well we get this thing all together and get er started up and not too long the pass side rockers were chattering really really bad.(Crane Golds) So we pull a valve cover and it was full of aluminum shavings. We figured it was a rocker arm failure..Crane ended up sending new ones.
Well after the 2nd set chewed up as well, we put a big hold on it.
Ended up there was a new guy or something at the machine shop as when a cousin of mine who's been building Mopars for 30yrs or so took it back up there and asked about it, the guy said that you install BBM cam bearings like a sbc!! My cousin was like WRONG....you have to line the holes up to feed the rockers!!
Needless to say, the shop ended up making good on it an redoing the whole thing for free...parts included.
 
Is the shop capable of maching the cam tunnel? If so have them do that and pay for it. there are a lot of stories about the Mopar cam tunnels being out of whack.
 
:-k
airwoofer said:
Is the shop capable of maching the cam tunnel? If so have them do that and pay for it. there are a lot of stories about the Mopar cam tunnels being out of whack.
Click to expand...

do 340`s have an intermidiate shaft like the big blocks? I`d take a hard look at it too-------bob :-k
 
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