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Catastrophic cam failure... Why?

USSkoval

USSkoval

Thornbirds look cool... Yeah, I said it
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One lobe is pretty much gone, and the matching lifter has about 3/16 inch shaved off the bottom. One other lobe is not far behind, but the bottom of that lifter looks decent. A few other lobes look like they might be just a little worn. There is around 7000 miles (from what I've gathered) on this cam. Should I be looking for something else wrong, or is this likely due to a poor (or lack of) break-in procedure? I did notice that the front cam bearing has one small area that feels just a little rough, almost like a sand-blasted texture. It did not affect the surface of the cam, so I'm guessing that it is not hurting anything?
 
A lot of people are wiping lobes

Oil's have less lubricating properties now
 
I feel an oil debate coming on.....

how did you break in the cam?

look for oils with High ZDDP numbers...like over 1000ppm, which would be SG and earlier rated oils.
 
howdiy said:
A lot of people are wiping lobes

Oil's have less lubricating properties now
Click to expand...

I realize that, but this cam is just plain SHOT. I haven't had any type of cam problems with any of my flat tappet vehicles.
 
Also, the PO is the one who built and installed the motor, so I don't know what, if any, break-in procedure was used. The wal-mart near me used to carry 10/30 rotella t, but not any more. Is it OK to run the 15/40?
 
Cam lobe failures are a common thing now on a flat tappet cam since most oil companies have reduced the amount of zinc in the oil which is what is needed for cam break in. I use Valvoline VR1 racing oil on a fresh rebuild or on an engine with a new flat tappet cam for the first 500 miles.
 
Ive been running Delo 15/40 in my trucks/Blazer and Harleys in winter for some time without issues.Rotella also has a 5/40 synthetic thats not to pricy. Id imagine any CF/CD/ commercially rated oil Rotella/Delvac etc will suffice,the new breed of Al Gore blended lubricants dosent cut it for old iron. I found it interesting a couple years back talking with a guy who was in Mexico with a new jeep with the 4.0 the Oil cap said use 15/40 on it, not the usual 5/30 for north of the border vehicles .
 
Capt.D said:
Could it be the lifters were too tight....
Click to expand...

You mean in their bores? They all pulled out by hand just fine, with the exception of the mutilated one. Took a little finagling to get that little guy out of there.
 
did they not leave a note behind as to why they wanted to end their lives?? that's pretty inconsiderate of them...:mad:



:doah::p::D


anyhoo, i started using some 15/40 along time ago on a car i had, (got the oil for free) and before i could get to the next oil change time, it pretty well wiped out my cam.
I have mentioned this before, wasn't sure as to why it did that, but from what i have been learning and figureing, is that the 15/40 (multi-grade) oil has a higher detergent level or something, it cleans better. This is what i believe to have killed that motor, ran old oil for over 100k mils, then run this super clean stuff through it, breaking up all the dirt basically acting like sandpaper...

IMO, if ya wanna use 15/40, do it from the start of a new engine, or don't do it at all.
 
Oil is one of the major things, along with break in. The other is the quality of lifter used. A few years back some cheap (import) lifters hit the market, ever since then cams have been going flat for seemingly no reason (even with correct break in). The only way to know you are getting a good lifter is stick with a name brand (Comp, Delco, Crane) or use it as an excuse to go roller.

I do agree with what others have said about oil and it's zinc content (or lack of). I use Shell Rotela Diesel oil in all of my motors. With the exception of my motorcycle, that gets Amsoil.
 
Years ago like in the days of unleaded fuel still, we had a few of the Chevy 350 powered fleet trucks loose lobes on the cams for no apparent reason,these were O/E engines also. Never did figure why,they were rebuilt and sent back down the road.
 
I had a cam lobe on my harley get wiped in the early90's. Turned out there was an issue with the hardening process. Could be that simple..?

Quality issues during cam manufacturing process?
 
4X4HIGH said:
Cam lobe failures are a common thing now on a flat tappet cam since most oil companies have reduced the amount of zinc in the oil which is what is needed for cam break in. I use Valvoline VR1 racing oil on a fresh rebuild or on an engine with a new flat tappet cam for the first 500 miles.
Click to expand...
I haven't even checked around yet, but is the VR1 oil something that's available at your local speed shop, or would a PepBoys carry it?
 
NEK5 said:
I haven't even checked around yet, but is the VR1 oil something that's available at your local speed shop, or would a PepBoys carry it?
Click to expand...

X2.

The lifters I have to put back in are PBM brand, they own Erson now. The guy at Jeg's said they wouldn't be an issue, so I hope he's right. He just sold me the Comp cam, assembly lube, and the break-in oil additive.
 
GM sells EOS (engine oil supplement). Basically, the same stuff cam makers sell for break in of new cams.

Went thru this a few years back, then found an article in Car Craft magazine about taking zinc out of motor oil. Doesn't affect roller cams, but its been death on new flat tappet installs.
 
NEK5 said:
I haven't even checked around yet, but is the VR1 oil something that's available at your local speed shop, or would a PepBoys carry it?
Click to expand...

I buy it at Autozone and i'm sure Pepboys probably sells it also. Regardless any store that sells Valvoline oil can order it for you if they don't stock it.
 
That is my theory,seems cam makers do not harden the lobes correctly ,at least one lobe always goes bad on a chevy cam,on the OEM ones,the 307 and 305 engines were well known "cam eaters"..

My friend recently installed a brand new Edelbrock cam ,lifters,and valve springs on a 1969 Chevelle's original 327 ,which had the #1 cylinder push rod on the exhaust valve bend for no real reason,and another lifter was all concaved,but we forget which lobe it was on..anyway,the #1 exhaust valve was not opening much,so the exhaust escaped through the intake valve next time it opened,causing the classic "needs a cam" chevy gargle/backfire through the carb...

So the owner buys the parts,and my friend installs them,along with new valve stem seals..old ones were brittle if still there at all,so they were due--engine has 80K original miles on it,car is really nice too..was well cared for..

After he got it installed and did the break in correctly using the provided moly lube and fresh oil,the car once again ran sweet--there was debate about how many turns to tighten the rocker arms after zero lash--my friend decided to use the Motors manual specs of 1-1/2 turns,another "expert" who has installed many hi-lif cams said "I'd only go 1/2 a turn..anyway,it ran nicely,so my friend did not think it matered much..

About a week later,it came back,backfiring again!..had one bent pusrod in a different cylinder,#7 this time--and after replacing it my friend noticed that rocker arm had to be tightened a lot more than the others to get the valves adjusted,and he said "it CANT be the cam lobe worn already,can it?..I said "possibly,either that or the lifter base is wearing down (doubtfull,without taking the lobe with it!)--or the rocker arm stud is pulling out of the head maybe..(but appears not to be!)..

I'm betting they hardenen 15 out of the 16 lobes "right",and one gets a "so-so" hardening..that coupled with this new "low zinc" oil,seems to be causing a ot of grief among flat tappet engine owners..By the way,newer diesel oil is also "low zinc" to be able o be used in 2007 & up diesels,so unless your buying "old stock" somewhere,using diesel rated oil offers no real advantage I'm told,and can loosen sludge up in old hi-mileage engines and wipe cams and other parts out too..

Looks like they are going to kill off the "clunkers" one way or another..what do we have to do now,put roller lifter cams in everything??.. :(
 
Something some people do that is a no no , is running 1.6 ratio rockers without using the Louis tool to drill the pushrod slot . Bends a pushrod easily as it rubs the head .
 
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