I heard yesterday (from the new owner unfortunately) that my old cam was flat! :confused: SEVEN lobes worn a tenth of an inch or more! :eek: This is something I "chose" not to see... No reason to suspect a problem, lifters all looked good, car ran fine... looked at em, did a double take, thought, "No, couldn't be" and wrapped it up and shipped it out. :clonk:

Needless to say, I shreded Mitch's check immediately. He's been extremely gracious about the whole thing, thanks Mitch.

So this morning I'll be taking some extra steps to determine the level of contamination, and make sure everything is clean. If I see spots of contamination on any of the bearings, she's gonna have to come completely apart for a thorough cleaning. :mad:

At some point this morning, the garage cam will be on. Cam link is here: http://www.camaros.net/forums/showthread.php?t=125134&highlight=garage+cam

Any clues or guesses on what caused this?

The cam, a comp 270, is not terribly radical, and not under excessive spring pressure. It was 3 years old. Initial breakin went well, no problem lighting her off or maintaining the required rpm's for the specified time.

I did switch to Mobil 1 "turbo diesel" 10-30 oil last spring.
I will be going back to a dino oil!

I run a plugged oil filter bypass, and am replacing the pan, pump, and pickup anyway. Hoping against hope that my motor's not full of metal.

Almost forgot the pictures!
http://home.comcast.net/~Jimragtop2/2008engine/flatcam1.jpg
Of the 3 lobes you can see here, the center lobe is good, the first and last are not
http://home.comcast.net/~Jimragtop2/2008engine/flatcam2.jpg
This shot is the last 4 lobes in the motor. 1 is still good, 2 are visibly worn. The one closest to the distributor gear is plain ole GONE, completely flat.


And perhaps a better timeline...

Cam & complete valvetrain was installed in the winter of 05. Odometer shows 78k. Initial startup and breakin was "by the book." As always, I had to run the valves with the motor idling after breakin.

I recall getting some "clacking" twice that summer, and determining that some of the new stock type rocker nuts were loose on the studs and backing off. I replaced those nuts.

Valve adjustment was not touched the rest of that summer, all remained quiet.

Winter of 05, motor came out again for a complete rebuild. Stroked to 383, all new rotating assy, block machining, cleaned by machinist and twice more by me before assembly. Heads were rebuilt, valvetrain went back on as it came off.

Initial startup was no problem. As usual I had to run the valves once with the motor idling.

That summer, car was used a lot, including 2 LONG trips. The following summer (last summer) she got a lot of road time, too. Engine has not been touched since I adjusted the valves that last time in may of 05. Odometer curently reads 99066, so there is 21k on this cam, very nearly all of it after the last time the valves were adjusted.

I would say those lobes became like that from the moment of break in. Anybody agree?

I would say those lobes became like that from the moment of break in. Anybody agree?
I'm leaning that way..... I wonder if the intial adjustment was too tight. I think the nuts that backed off were not backed off but the lobe worn down. I never paid too much attention to how many threads are above the nut until it was pointed out to me. I think it's about three threads on a stock cam. I guessing that it still had three threads when it was clacking.

Jeff

Jim,

How hard was it pulling the lifters out?

I ask b/c imho, if the cam and lifters were worn THAT much, I figure the lifter feet woulda had so much rolled metal b/s around their edges that it woulda been a bit-h pulling them??

pdq67

JimM Id suggest a 'depth' filter instead of paper type most commonly available. The depth filter will screen out down to less than 5 microns, the paper ones are around 25 last time I read about them. That will surely help any dirt issues.

There are several old threads discussing cam failures...even mention manfactures cant always pin piont down the cause..
I had one, when the car was stolen and reved way out, valves bouncing and even broke spings..
Another about 20 yrs ago very similar to Jim describes above..
Since the previous post have chatted to several engine builders and asked if it is usually the rear lobes that go, or are most worn...and it seems this is often the case
Also the rear drivers side valve lobes
I wonder??? anyone else noticed this???
or maybe why???

ok, I pulled the front 2 pistons. See some very light verticle marks on the cylinders, 1 or 2 on the skirts, none can be felt. Rod bearings show some wear, nothing bad, no scratches or spots.

Pulled the #2 main. Upper shell has one scratch all the way around, deep enough to catch my nail.

I've driven 21000 miles with a flat cam.

I know what I should do... What I'm gonna do is:
Pull each pair of pistons, remove rings, get them totally clean, replace bearings.
Get the inside of the motor as clean as I can get it with the crank and cam installed.
Replace the main bearings.
Put it together.

Gotta get Brian some lunch, will be out there woking in 10 minutes or so. Camera is on.

ok, rethinking a bit. Gonna pull the cam and crank so I can clean better.

Jim is that the motor I see in the Garage Cam ????

Back to yor question.. I see it is a Comp Cam but not he XE line,,,yet there is a lobe failure. All the posts over the lack of zink in most oils leads me to this result. We should have a sticky thread that contains the correct oil used in flat tappet cams.

Again I have read posts that state ( I have used this oil and I have had no problems ) when others chime in and say the same thing about other oils. The latest is using a motorcycle oil that has excessive zink.

Now if that is the block I see in yor garage cam I would strip it down to the bare block and send it out to have it tanked with the rest of the lower end. I then would put a light hone the cylinders and replace the rings. My .02

Joe

First, I'd dingle-berry hone her and leave dirty!

Then at the least I'd pull ALL the oil gallary plugs, haul her off to a car wash, soak her down w/ diesel or whatever and spray h-ll outta her using the soapy wand and then rinse a long time, then haul her back home and blow dry her fast!!

Have a clean oily rag handy to lube down the cylinders b/c they will flash rust before your eye's!! No biggie b/c they will just do it!!!

AND take a clean blanket along b/c you will need it to put on your seat when you drive back b/c you will be SOAKED!!

Been there, done this more than once!!

pdq67

Jim,

I noticed in another of your posts that your Dart heads had 135# seat pressure. I think the recommened Comp 981 are 105# at seat. Not sure if that caused the problem and it really doesn't matter now, just thought I'd throw it out there. Good luck with the clean up.

I wish it were warmer out, IK'd push her into the driveway and fire up the pressure washer. It's 3 degrees today...

Minus 3 up here, Jim. My thoughts are that the wear occured upon initial breakin and that is where the clacking came from. The lobes that are worn are quite polished again, so I think it ran that way for the duration of use without further wear. As for the lifters being mushroomed, pdq, they have a hardened pad that didn't wear near as bad as the lobe. In fact a straight edge still rocked slightly on them.
Jim, if you had the engine apart and cleaned once after original break in, I would think it's pretty well cleaned out by now. Course you don't want to find out the hard way that it isn't either.......:noway:

I know, it was 4 here early on today!

pdq67

Jim. I honestly do not recommend using a blocked oil filter bypass. If that contamination had plugged the filter, or the filter gets plugged from assembly lube and debris, then no oil will get to the bearings and , however you slice it, any oil is better than no oil.


Good luck. I'm having trouble getting the ambition to make the cold trek across the yard to the garage.

TTFN
Mat

Good luck. I'm having trouble getting the ambition to make the cold trek across the yard to the garage.

TTFN
Mat
Glad my garage is both heated and attached.

And yes, the damaged happened at breakin, 3 years and 21000 miles ago. For some reason, the lobes wore as much as they did, and then just ran like that. Other than not having as much top end power as I'd like (and who wouldn't like more regardless!) the car ran good.

All that missing metal got flushed out the bottom of the pan, or trapped by the filter, a long time ago.

I'll get her as clean as I can, then back together she goes.

when the motor was rebuilt were the lifters set back on the same lobes they came off of? dont know if this would make any difference, just thinking out loud. Dave

Look at the bright side... think of how hard that sucker will run with 16 good lobes! ;)

when the motor was rebuilt were the lifters set back on the same lobes they came off of? dont know if this would make any difference, just thinking out loud. Dave

Yes it makes a difference, and yes, always. I label 16 ziplocks before I even start pulling a valvetrain apart...1e, 1i, 3i, 3e, 5e...

Look at the bright side... think of how hard that sucker will run with 16 good lobes! ;)
Now THAT I've been thinking of.

So I got her all cleaned out. Made a lil trough out of cardboard lined with newspaper under the engine stand, filled a squirt bottle with mineral spirits, and had at it. Musta squirted a gallon of that stuff, newspaper absorbs it well. Blew a lot of air at it too. She's nice and clean now.

Cams back in, upper mainshells and seal half are in, cranks ready to drop.

Family kept me busy this evening, but I think I"ll plug that camera in and go drop the crank back in right now.

Watching the cam now... I admire your dedication working into the late hours of the night! :)

Well, that was good, man, I was "in the zone." Just over an hour to get the rotating assembly in and done.

Man...gotta make you wonder how much power you were giving up with all the worn cam lobes. Just makes the roller look that much more attractive despite the price.

Just makes the roller look that much more attractive despite the price.
The price is the tough part. I had the HR cam and new heads in my budget for this winter, but the costs were pretty steep. Near $900 for the cam and lifters, plus about 3 bills for the upgraded springs and titanium retainers added to the cost of the new heads.

Jim

Dang man. Seems like there's always something...

I remember you saying the old heads were milled. Does that make a difference if using stock length pushrods? Would the extra .040 cause increased spring pressure? Pretty weird.

Mark

You said you switched to Mobil one oil. I won't use any other oil in my other cars but mobil one but the reason I don't use it in my vert is because I read on the crane cams web site that they don't recomend sinthetic oil for any of there flat tappit cams. The reason they gave was that the oil was so slick it keeps the lifters from rotating causeing lobe failure. flat tappit cam lobes are ground at a slight angle so the lifter will rotate.
I used valvoine racing oil with GM eos in it last year. I am not sure if this is the best way to go or not I know some use shell rotella oil also.
I don't think I will buy another flat tappit cam again I will go to rollers in future builds.

Old 270H cam looks like those prototype low lift long duration cams, huh?

Well , I dont know where your are at this point, but you said you had pistons out, think it would be a good idea to go to some new 4.035 file to fit rings??? Just thinking. Going to camera room so see whats going on. Well guess not, can't get in.

First, sorry you had this problem.

Second, most cam failure metal gets imbedded into the piston skirts.

Third, I would have the block hot tanked just to be sure it's clean.

But, you cleaned it yourself, and didn't see much in the way of piston damage. Perhaps due to the fact that the wear was slow.

I think I read somewhere in the past that Comp had issues with soft cores....they don't make them themselves. At least not the lower $$$$ stuff.

Sad that oils now just don't have the zink to protect flat tappet cams. I can't believe that synthetics don't solve the problem. Too slippery? I don't get that.

My 468 had a flat tappet by Ultradyne. We broke it in on the outers, with dino oil. Replaced the inners, and ran it on the dyno. Never changed the oil. After 2 races, I switched to Mobil one.....5 seasons later, the cam looked perfect. Non rotating lifters is nonsense.

I bet your cam was soft. Wrong heat treat. Or, too much over the nose pressure. Were they the recommended Comp springs?

Were they Comp lifters as well? I also remember that the main lifter manufacturer in the US burned down some time ago (Johnson) and cheap stuff was all that was available. (Johnson, you can call me Ray, or you can call my Jay, but you don't gots to call me Johnson...... made most of the lifters sold in the US)

HR now makes sense...why chance it.

But I wonder now why the cam manufacturers haven't pulled all their flat tappet stuff......one would think given recent press that they are all bound to fail.

Maybe a guy needs to run zink addatives for life? EOS maybe?

Me, I now run a solid roler....and that is a whole other can of worms with fialures and 1000 opinions as to why.

Best of luck.

Ron

Crane said not to use syn oil for at least 5K miles. I do not see a need at all. I have a stock of 10W30 Rotella CI-4 and a 2 cases of Valvoline 10W30 VR-1. I would guess that too slippery is not the same as zinc attaching itself to the cam and being sacrificial. That probably does have a little friction to turn the lifter. If you like Rotella or Delo 400 check with a distributor to see if they still have some CI-4 oil.

Cam & complete valvetrain was installed in the winter of 05.

Before you jump all over the dino oil vs synthetic thing, keep in mind that this winter '05 time frame is consistent with that time frame when we were getting soft off shore lifters. That would be a prime suspect for cause.

If cam companires are buying these lifters don't they check the hardness? Seems stupid if they don't. Shows no quality control effort.:sad:

Just want to clarify, If you go to the Crane cams web site under " Flat Tappet cam break-in procedure" it says.
" CAUTION: We do not recomend the use of synthetic oils for "break-in" because they are to slippery. This characteristic reduces the tendency of the lifter to rotate on the camshaft lobe and mate properly."

" At this point the initial "break-in" is complete. You can drive the vehicle in your normal manner. We recomend changing the oil and filter after 500 miles. We strongly recomend mineral oils with flat tappet camshafts to help assure proper lifter rotation. You might want to put another 5000 miles on the cam before switching to synthetic oil if that is your preference."

" As stated above, we do not recommend synthetic oil on flat tappet camshafts because it is so slippery that the lifters do not rotate as well as with mineral oil, and lack of rotation is " death to the camshaft". Additionally, if a vehicle using synthetic oil is stored for a lengthy period of time, the oil falls off the camshaft and the cam is "dry" during the engine start up. We recomend only regular mineral oil for vehicles that are only started occasionally or stored for prolonged periods."

I have heard of the oil falling of of the engine parts on marine engines and this is why I don't use mobil one in my boat either. Take this for what its worth I don't know.

Since we are on the subject, help me out. I was under the impression mineral oil is synthetic. What is an examople of a mineral oil, other than baby oil.:)

Just to hit the high spots on the last couple posts....

We are talking about 3 years ago. As far as I know, prior to the reduction in zinc.
The synthetic was only in it this past season, dino oil the previous 2.

The lifters showed ZERO unusual wear. All 16 were rotating, wear pattern totally normal.

The motor was spotless inside. Bearings were good, piston skirts looked nice, no sign of any significant debris being present.

I'm thinking the cam failed within a month of install. I did have to readjust the valves three times total in that time period. For some unimaginable reason, it just pretty much stopped wearing. The motor was comepletely rebuilt the following year, and any debris got cleaned out then.

New roller cam is in.

This thread is getting pretty long so forgive me if I missed something. Are your rocker studs threaded in or pressed in. Wondering if a stud started to work it's way out. Is there any coil bind or binding between the rocker and spring retainer that might have caused things to seek new tolerances? Hopefully I'm not too far off in the weeds here.

Hopefully I'm not too far off in the weeds here.
Too far off in the weeds? dunno, let's see...
The offending cam and lifters are in a landfill in Stillwater, MN. The heads are on a truck on their way somewhere, don't recall where, "My people" handled the shipping.

Other than having to adjust the valves a couple times years ago, I never saw this coming. Even then, I blamed it on loose rocker nuts, they were so loose on the studs I could almost unscrew em with my fingers.

Lets let this one die. I really don't have a problem to solve with this anymore.