Why did I wipe out a cam lobe?
 

In early September we went for a ride, and did a couple of full throttle blasts about 30-45 seconds each. We were running about 5100 RPM, no big deal. Then we went crusing, at about 2800 RPM, then entered a no wake zone for about 15 minutes. We went back on plane, running about 2800 or so and the engine started sounding sour. I stoped, opened the hatch, saw nothing abnormal and went to get back on plane. It starting backfiring through the carb. Needless to say we idled back to the marina, about an hour away.

Today we finally got a chance to tear the engine down, and found a wore out cam lobe on #5E. The lifter, (flat tappet) was very much concave in the center. What a shock, I expected to see a broken valve spring! The cam has about 125 hrs on it, great oil pressure, no excessive engine tempatures, and acturally very light spring pressures. Why would this cam wipe out after this length of time? Any ideas? We are now tearing the whole engine down to clean up any debris. This is a normally asperated 461 BB. that dyno'd at 440 HP. This engine ran great!

Re: Why did I wipe out a cam lobe?
 

How many hours on the engine?
Was the cam broken in properly?
When the cam was new were new lifters used?
Fossil or synthetic oil?

Re: Why did I wipe out a cam lobe?
 

The engine was a completely rebuilt about 200 hrs ago. Yes, we broke the cam in on a dyno very carefully. I use Mobile 15-50 oil. It was broken in on 30 weight conventional oil, changed after the dyno pulls to 40 weight conventional oil and converted to Mobil One after about 25 hours. New lifters were installed with the new cam.

Re: Why did I wipe out a cam lobe?
 

Seen it many times, usually caused by a lifter bore being tight, not letting the lifter to spin in the bore. With 125 hrs on it , this would be unlikely unless a piece of debris worked its way between lifter & bore. I have seen (a while back) ,that a certain cam core supplier were having alot of problems with this,but have not seen one in a year or two. Make sure to check lifter bore for size & staightness,making sure it does not have too much clearance.....good luck

Re: Why did I wipe out a cam lobe?
 

Well, you came up with all the right answers. Kevin seems to have a handle on this. I bet he'd love to see the bottom of that lifter as much as I would!

Re: Why did I wipe out a cam lobe?
 

When we removed the lifter, that was my son's first comment, hey it still turning in the bore! Yes the lifter was perfectly concave. Maybe I can get a picture of it. I'm wondering after this long after the installation, if the camshaft may have had a "marginal" heat treat put on it. In other words close, but not perfect and this was something that would not show up immediately. Does that make any sense? Or, could there be a problem further up in the valve train causing undo stress on the lifter/cam? What would be the chances of improper lubrication at that point be also? The other lifters look good.

Re: Why did I wipe out a cam lobe?
 

Check all the spring pressures very carefully. Especially that cylinder. (check if low). Then measure the guide clearances on that cylinder too. Check the valve stems and keeper grooves for any damage. Weak spring or sticking valve making it bounce maybe?

Re: Why did I wipe out a cam lobe?
 

Every wiped lobe I have seen , had a concave lifter. Its a mystery wraped in a inigma. Because I never could find a problem with most of the lifter bores either. i would think the concave comes from drag...spin....drag....spin. But if you think about it , all it would take is a tiny flake to come off the lobe.....then not enough oil film thinkness to keep the two metal to contact each other........just a matter of time......you know the rest...

Re: Why did I wipe out a cam lobe?
 

Whiteknuckle,
There was a discussion recently about this topic and cam spalling is the most common cause for post break-in (belated) lobe/lifter failure. If you need more information shoot me an email. I will be back after PRI
Bob
http://www.offshoreonly.com/forums/s...ad.php?t=83665

Re: Why did I wipe out a cam lobe?
 

RMBuilder,
Thank you, that was a very interesting thread. My camshaft was an Ultradyne. I was very pleased with the way this camshaft performed, but obviously there may have been some quality problems. Like someone else said, they are not in business anymore. Now, I have to decide if I want to go to another flat tappet camshaft or invest in a hydrualic roller. We still do not have the camshaft out of this engine yet, it will be interesting when it is out to examine the other lobes more thoroughly.

Re: Why did I wipe out a cam lobe?
 

If possible, take some photos of the failed areas of the parts and post/send them.
Bob

Re: Why did I wipe out a cam lobe?
 

Whitekuckle,

My cousin still has an Ultradyne flat tappet hydraulic cam for a Mark-4 block that is still brand new, unused in the box that he wants to sell. Not sure what specs you had, but the one my cousin has is a 231*/239* (288*/296* advrtsd) on a 112* lobes.

Re: Why did I wipe out a cam lobe?
 

I can't find fault with anything you did and the fact that it took 125 hours is even more puzzling! I would chaulk it up to a defect in the cam or lifter surface that took a while to fail. I have used ultradyne cams in alot of flat tappet motors,even ones with superhigh opening and closing rates with no lobe problems but that doesn't mean you didn't get a bad one. Before they went out of business i called them to order a cam and they told me they were having a hard time getting cam cores,that was about 3 years or so ago,maybe they outsourced them to a different vendor and pthers will chime in with similar problems. Your doing the right thing tearing motor down completely,sooo many people tell me about cam failures and then tell how all they did was just change cam afterwards just to have more problems,Smitty

Re: Why did I wipe out a cam lobe?
 

While the initial effects of spalling can be evident as soon as the break-in is completed, unless you do an inspection you'll never see the initial signs. As evidenced here you can run a significant period of time prior to catastrophic failure.
Bob

Re: Why did I wipe out a cam lobe?
 

Gentlemen,
Again, thanks for the comments. We are only able at this point to work on this engine on the weekends. We now have the heads in the shop and will examine them completely to rule out any issues with valve guide clearance or misc upper valve train issues. Of coarse the heads (Chevy 049's) will be freshened up since they are off.

Kaama, thanks for the offer, that cam you described is very close to what I had in the motor. This camshaft that wiped out was purchased about 3 yrs ago. There seems to be a common issue with the Ultradyne products purchased around that time. I think I will pass on another Ultradyne and try something else. Like I said, I'm kicking around going to a roller.

articfriends and RMbuilder, In the next few weeks when I get these parts available for photos, I will gladly share them. Like I said before, there was a least one other lobe that we did not like the surface appearance of, but the lifter looked great. As far as tearing the engine completely down, we just can't take a chance on debris in the bottom end. This thing has got to be cleaned and checked throughly.

Re: Why did I wipe out a cam lobe?
 

I made the change from automotive to boating toys relatively recently. One of the most common serious engine problems in the boating world I've seen is folks not breaking in their cams and not doing a thorough rebuild after losing a lobe (by the way, as soon as I saw the words back fire, I said Exhaust lobe). Whiteknuckle impresses me as someone who did all the right things up front and plans to do all the right things now. Probably was a bad cam. Bob (rmbuilder) and Smitty are always on top of things. I sympathize with Whiteknuckle. It's got to be frustrating to do things right and still have problems. Lou

Re: Why did I wipe out a cam lobe?
 

Whiteknuckle
A Couple Of Things To Do On The Reassembly That We Do To Flat Tappet Cam Engines It Doest Take Much Time The First Is Check Lifter Bore Clearance We Run .0017-.0022 Max The Second Check Each Lifter For Nicks These Parts Are Production Made And Many Times Not Closely Cared For At The Factory We Check Each Lifter For Crown Height And Rockwell Hardness And The Most Important I Feel We Hone The Oil Galley Bores Internally To Eliminate Any Sharp Edges Or Burs Around The Oil Hole This Is A Pain In The Ass But We Have Never Had A Flat Tappet Cam Fail Knock On Wood I've Developed This Process Through Time With My Stock Car Engines And I Can Tell You It Works Its Probably To Late To Figure Out What Happened But This Can Help You Go Forward And Have Success If You Have Any Questions On Spring Pressures Or Anything Like That That Is Critical I Can Tell You What I Run Good Luck Going Back Together Laz Mesa 1-305-884-5368

Re: Why did I wipe out a cam lobe?
 

Ultradyne . We call it kiddydyne here in Mississippi :eek: I did not know he was still in buz

I know on his race car cam shafts they had a real steep ramps on them .I dont know how he does it now or on his Marine cams. its does sound like a bad [soft] core .

Thats a hard one :(

Good luck
Rob

Re: Why did I wipe out a cam lobe?
 

Lmarth,
Yes it is frustrating when things that are out of your control happen. I'm glad it happened as the season was ending as opposed to the start of the season. As far as doing all the right things, we try. My son is my engine builder, he is a builder for a major racing engine development company, and does the labor and heavy thinking, and we share in the selection of components. I'm just an ol'e burned out street rodder.
Mesa,
Thanks for the tips on the lifter preperation. The lifters in the engine were off the shelf Competion Cams, but in all fairness there was no sign of a lifter failure. Our lifter bores were sized appropriately, however they will be checked again at teardown.
Strip,
Ultradyne is in business with a new owner.

Re: Why did I wipe out a cam lobe?
 

Whiteknuckle-- Like a lot of us, I've been around the block a few times too. My problem is that I can't decide what I'm going to be when I grow up! My wife says I'm a perfect example of arrested development. Keep us posted on your rebuild. Lou

Re: Why did I wipe out a cam lobe?
 

Just an update:
We disassembled the short block yesterday and found a considerable amount of debris in the oil pump pick up screen. One main bearing looked like something may have gone through it and scratched the bearing. This was a journal very close to the lobe wipe out. No marks on the crank. The rest of the engine was in absolutely great condition. The oil pump is in the shop along with all the piston rod assemblies for clean up and closer examination. The block and crank will go in later. The heads are already there and were also reported to be in excellent condition, although I am going to put new springs in and they said they will "freshen the heads up". Now the guys in the engine shop are tell me to quit fooling around and put a roller cam in the thing. I'm thinking about it!