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Discussion Starter #1
Hey all,

As some of you know I have my engine apart because of bearing failure. While out in my shop today I took a look at my cam just out of curiousity for some reason. I noticed something that really bothers me. It appears that my cam was just about to fail. Most of the lobes have a small polished wear in area all around the lobe, but some of the lobes are completely polished across the top of the max lift area of the lobe. Upon closer inspection, I noticed that those lobes have an almost squared off feel to them and the top of the lobe is actually wearing off. I also found one lobe were there are some wear marks like scratches in the same area and some to match on the lifter.

I just dont get it. It is my understanding and experience that a cam will generally fail quickly if not broken in properly. This cam has 5 or so run hours on it and it looks nothing like what I have seen in the past with failures. I will also say that this is the third comp cam that I have had fail. I have never had any other brand fail. I have to think that this cam is proof of a hardness issue with the cam itself.

Anybody else seen this before? My luck keeps getting worse and worse.

Chris
 

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Can you post a pic?
 

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TurboS10 said:
I will also say that this is the third comp cam that I have had fail. I have never had any other brand fail.
enough said, I really dont like comp cams anymore, all or most parts I buy are federal mogul.

Also use a riffler(metal file) to smooth out any burs or rough spots on the cam and lobes, then take a 1500, or 2000 grit sand paper and polish the lobes up with some WD-40. Just something I always do and something to try.

I'm just about done on this 231 with it's cam and intake swap, taking awhile, but I only have 1 free day a week to work. Using a federal mogul cam and timing chain. Almost time to break it in!

Also might want to run synthetic oil after a cam break-in because of todays sucky conventional oils.
 

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Chris, is it possible that the garbage in your oil caused the cam damage?

sorry to here about the run of ungood luck. You should of swapped motors with me way back when bud.:drunk:
 

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Discussion Starter #6
I really dont see how the garbage from the bearing failure could have hurt the cam, but I guess you never know. To me the fact that only a couple lobes have issues would suggest not. The one lobe that is marked up I can see having gotten trash in it, but the others I cant.

In the first pic, the left and right lobes are both starting to square off at the top and you can see the wear pattern spreads at max lift. The second is the lobe that is begining to get bad and has wear marks. It is a little hard to see in the pics.


 

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Take a look at the matching lifter face to see if it's still crowned. Depending on how the lifter bore is machined you can get some pretty odd looking wear patterns without the cam actually going bad. If the lifter is still crowned and is still rotating in its bore then the cam may still be ok.
 

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I can't see any really unusaul wear patterns there. Seems the lifters were still rotating. The pattern shows the lobes pressure agianst the bottom of the lifter spread all the way across the nose just as it should be. If the lifters are still in good shape, I see nothing really wrong other than just normal stuff.
 

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cam

This subject has been talked about so much I don’t remember how much has been shared on this forum. So here I go…

In a general statement I would say that if a cam fails during the break-in period it is something wrong with the process or the assembly. If the cam fails after the break-in, down the road some time later it is usually a problem with camshaft it self, lifter, lifter bore alignment… There are always exceptions to this rule but this has been my own personal experience.

I do not remember what block you used in you engine?????

I am sure you did the proper assembly steps for cam break–in. Including proper valve lash, correct spring installed and over the nose pressure, instant start up (no excessive cranking of the starter) zinc additive in your oil, maintained a rpm over 2200 for 20 to 30 minutes varying the rpm during this period. Made sure the lifter bores were clean and the lifters spun freely in them. Break-in lube on the cam and lifters. If the springs have more then 120 lbs seat I remove the inner spring for startup

There are some physical things that can be wrong that will also cause failures. Incorrect hardness of the cam or lifters, lifters without the proper crown on the face, lifter bores in the block that are not in the correct location, or out of perpendicular with the cam.

The amount of trash in your oil could have very easy caused this failure.

I have a hard time seeing things on the posted pictures but it looks like there are some lobes where the lifter was not tracking on the lobe correct. But it could be the result of the debris in the oil also causing the funny looking patterns. I would take a micrometer and check the lobes and see how much they are ground down..

Keith
 

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The scratches are from the debris from the bearing.

The wear on top of the lobes is indicative of either valve spring coil-binding or valve retainer-to-seal interference. Check these areas carefully.

tom
 

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Tom is correct on the binding issue. Also look at the very top of the lobe. The scratches and the tiny pits are classic cam lobe failure. DO NOT USE THIS CAM !. What is your spring pressure seated? and at max lift? Are you sure you have no bind or clearance issues?
 

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killerformula said:
I think its time for a roller cam buddy.

K
I second the roller cam :thumbup:

I know its pricey, but think of the peace of mind you will have regarding lost lobes and/or lifters.

Do any of your lifter bottoms look like this?



Note: The bottom edge was actually smooth, but there is a reflection here. You can clearly see my lifter was not rotating, even though the cam had not yet wiped (probably 3k miles on this lifter). The cam was a Crane and lifters were Speed-Pro.

Chris, IMO, as much money as you have tied up in this engine, I would put roller in it (hyd. or solid depending on the RPM redline).

Good luck , Ed www.edgesz28.com
 

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Discussion Starter #14
The block is a factory 400 block. Break in was all proper and there was no excessive cranking or anything. I did have the plugged oil passage issue to one set of lifters for a minute or so untill I killed it and fixed the problem. I would think that if the damage occured then, the cam would have failed much sooner and much worse. I am away working now so I cant look at it right now, but I dont think the lobes with odd wear are on one side or the other or all intake or exhaust. The springs are 110# and rated for .550 lift which I am just under. The guy who assembled the heads checked seat pressure and was suppose to check coil bind, but I can not guaratee it happened. Other things have certainly been missed.

The tops of the lobes are definately where the issue is so the coil bind is a possible issue. You can actually feel an edge starting to form on the crown of the lobe even though the lobe is still perfectly smooth. It is only one lobe where the scratches have started to appear. The lifter from that lobe has matching scratches in a cross patteren which would indicate that it was still spinning. All of the other lifters have a nice round wear pattern on the bottom and show no signes of problem.

I am thinking that the seal to retainer issue might be the cause of this abnormal wear. I am not sure why only a few have the problem, but I will have all of the clearances rechecked at the machine shop.

Chris
 

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johnsongrass1 said:
Those are scratches?

That looks like a good cam in a circle track engine. I've seen them a whole lot worse.
I agree, that looks like a normal cam lobe to me.
 

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Discussion Starter #16
The machine shop that did the original work is only getting the crank for turning. I am only doing that because he sends them off and does not do the work himself. I am using another shop in town (after alot of questions and explaining my situation) to reclean the block, insert cam bearings and touch up the hone.

Chris
 

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Not sure what clearances your running Turbo but I would open things up a bit, more clearance=more oil, more oil=more cooling.;)
 

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Discussion Starter #18
4 Jaw Chuck said:
Not sure what clearances your running Turbo but I would open things up a bit, more clearance=more oil, more oil=more cooling.;)
The crank was .002 on the rods and between .0025 and .003 on the mains. It is going to be ground to .002 and .003 again. Unless I was trying to make 2000HP, I would not go any looser.

Chris
 

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Chris,
I would think about coated bearings. On positive manifold pressure applications, I just think they are good insurance.

Chris
 

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