Experience a cam failure? Me too.

So Frank what model # of cam were you running?? I am curious since my stroker only has about 3k on it with a comp cams unit and I use the break in lube with every oil change this far.
 
I dont know man, most peoples cam failures can be attributed to improper install, break in, or by using the wrong springs. You sound like you did it right. Every once in a while they just fail, not often, but it happens.
 
This makes me nervous. I've got the same cam, but with stock springs. I broke in with Rotella and STP oil treatment (still running these) I've only got +- 1000 miles on the build. Anything I should look for?
 
you can pull the cover and give everything a feelski, but untill it breaks there is little you can do in the driveway for preventative measures. Make sure the springs give enough lift would be the main thing.
 
there was a discussion on this in another thread really recently, I can't remember if it was here or at colorado4x4.org, but the consensus was that stock springs with the Crane 905 do NOT produce sufficient lift... mine has the matching Crane springs with the 905 cam and is at 60k+ with no issues (knock on wood - Frank's failure makes me nervous...)
 
Since I had minimal service calls today I took advantage of the free time to pull the motor and tear it down. Based on my visit to McCabe Motorsports earlier in the day I was prepared for the worst. After getting all the preliminary work taken care of I had my son help me pull the motor and tear into it. When we finally got to the timing chain I noticed that it was fairly loose for only having 14k on it. I'm pretty sure that in the process of limping off the Hwy 191 out of Moab to I-70 on 5 cylinders I caused the chain to skip a tooth or more. No other damage indicated other than a couple of slightly bent pushrods.

We both held our breath as we wrestled the bumpstick out of the block expecting to see a shiny stick instead of a cam. We were both amazed at the condition of the lobes. Yeah the #12 lobe is worn down alot, but we really expected all of them to be in really bad shape. This was not the case.
camfailure024a.JPG


The remaining 10 lifters looked great. The cooresponding lobes for those lifters looked damn good too!

camfailure025a.JPG

camfailure028a.JPG


We then pulled the pan and once again I was expecting a thick silvery coating on the bottom. While there was evidence of metallic dust/oil it was not nearly as bad as we thought we'd see. YES!!!

camfailure030a.JPG

camfailure031a.JPG


The cylinders got a little coolant in them while we were taking stuff apart so I wiped them down with fresh oil and took a look. No scoring on any of the walls and the cross-hatch from the cylinder hone is still visible. Hopefully you can see it in the pic below.

camfailure033a.JPG


Based on everything i've read i can say with confidence that I screwed up. How? Simple...Hi-Volume Oil pump installed insted of a standard volume pump. It appears that the amount of oil in the crankcase (1/2 quart extra) has no bearing on where the oil goes....Duh! I'm fairly certain that the lifters on the ends of the block were getting less oil than than they would with a standard pump. I maybe dead wrong, but that's my position and only time and a new camshaft will tell.

I'm still going to try the Crower Cam Saver Lifters and the Crower Baja Brute Cam but I'll be replacing the HV pump with a stock flow Melling.

Rockers will stay stock for now and a new set of straight pushrods will go in as well.
Guess I might as well replace the rear main seal while I'm at it. I figure it will start leaking at the 30 mile mark...it's Jeep thing.:shrug:

A few gaskets and viola'......motor will be ready to return to work.

Anyone seen my red engine paint?
 
I dont even know if I would blame the oil pump outright, may have gotten a few bum lifters. It looks like an interesting wear pattern on the cam as well. Were all the lobes like that or just the last 3?
 
I'm not sure on the oil pump diagnosis either Frank... as you know, my engine is virtually identical to yours (except perhaps my accurate power pistons), including a Melling hi-volume pump... I'm over 60k with no signs of problems (other than above referenced leaky rear main:shhh: )... maybe I'm just lucky, although your karma ought to be better than mine.:dunno:
 
Here's a good article on cam failures:

http://www.hotrod.com/techarticles/engine/flat_tappet_cam_tech/index.html

He mentions checking the lifter bore to lifter clearance and the potential for it being too large. (?) He also talks about a tool for grooving the lifter bore to allow more oil down to the cam lobe.

You might also check the lifter pre-load. If you had metal removed from the head or block there's a potential for it to be excessive.
 
The pattern on the cam tells me you were not running enough spring pressure and the lifters were bouncing. I run a double spring setup with a dampener inbetween. At the rpms we run it should not be necessary but they were cheap at the time. I would pull the bearing caps and look at the bearing surfaces. The metal pits can embed themselves in the babbit and screw up your journals. Since you are at this point, I would most likely throw in a set of bearings if there is
ANY question.

Also, did you check the lifter preload prior to running? If you shaved the block, you can end up with too much preload.

Good luck with the rebuild. I am a bit worried about my Crane cam. It has about 20K on it and the performance is not what it used to be. I may pull the valve cover and put a mike on the valves to check how much lift each is getting.
 
Bent pushrods usually indicate coil bind or rocker bind or way excessive spring pressure...or less likely galling/sticking valvestem/guides....I have had no problems with cam or lifter in the mighty 2.5 (same architecture) turning up to over 7K at times...I have worn out a few rocker stands before I went to rollers...I use Rotella T with EOS for oil...
 
Just wondering if the machine shop checked the spring pressures at installed height and max lift. The only 'check' I didn't see was proper oil/ additives. I don't think any of this stp oil treatment or junk like that's going to work. GM Engine Oil Supplement works with any oil and definitely does the job. Or track down some Brad Penn oil, green stuff with lots of ZDDP.

As for break-in, what the manufacturers recommend is irrelevant because flat tappet pushrod motors aren't made anymore.
 
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