Ok, some of you may know I've been having problems keeping the vavles adjusted properly. Well today while I was doing a head swap, I found out why. One of the BRAND NEW Comp Cams hydraulic lifters was concave on the bottom (does this mean it was stuck?) and it wore down the cam lobe and rounded the edges. I am pissed. My question is this: Do I have to tear down the bottom end now and replace all the bearings? Could the cam bearings and/or block be totally screwed? Please help me on what I should look for in a situation like this. Also I bought the cam and lifters through summit. will comp cams replace them? anybody else have problems with comps lifters?
John

 

That's what we commonly refer to as a "rolled cam lobe". It can be caused by any number of things: not enough valve spring (big cam or high-ratio rockers with small springs); incorrect break-in especially at initial start-up; new lifters on an old cam or vice-versa; incorrectly shimmed valve springs; binding valve train parts, like retainers hitting valve guides; and my personal favorite, a block with The Lifter Bore Problem, a common issue with 70s blocks where one or more of the lifter bores doesn't point straight at the cam like it's supposed to, usually one of the ones toward the rear of the block.

Comp will generally replace the cam & lifters, IF you are using the correct valve springs and other components. But, there are so many possible causes, there's no one rigt answer for your situation. Don't get PO'd, figure out what's really going on before you just slap another cam in; otherwise you might just wangle your free parts out of Comp and put them in and it will do the exact same thing again, and they won't replace it again since it clearly isn't something wrong with the cam.

Chances are, if it's only one cam lobe, your bottom end is OK. Change your oil filter every couple of hundred miles for a little while, to get as much of the metal as you can out of there.

 

unfortuanantly your cam wiped out.
When i picked up my 454,ibought it used, it was rebuilt, they ran it for about an hour but the cam wiped out. It munched out the back 8 lobes. I figured i'd just swap the cam and voila. On further inspection, there was tons of metal in the oil pan. i decided to check the bearings. They were toast. The metal debris scarred the bearings AND the crank i had to remachine the crank, new bearings, and of course the new cam. I think i used about 10+ cans of brake clean to clean tyhe block out. I even re-honed the cylinders as the cylinder wall had had some of the previous hone marks smoothed out from the crap floating around in there. Remember, all this happened with about 1 1/2 hours running time. Ideally, you'll want to rip EVERYTHING apart, hot tank the block to get out all the crap. If by some slim chance your crank is ok, get that hot tanked too.

Sorry to hear about it.

 

well I was running the cam and lifters both new out of the kit, the break in was done properly but I used synthetic oil. some people may jump on me for that. the cam is mild 268/268 .454"/.454" but with the 1.6 rockers it's .484/.484. The block is a crate motor with about 30k on it. I don't think it had a lifter bore problem but now it might The springs were the ones that came on the AFR 190 street heads and they were installed by AFR. Could a defective lifter cause everything to loosen up all the time and then when I finally got everything to stay tight, it chewed away at the cam and bottom of the lifter? That is the only thing I can think of now, because I've posted about 5 other time about my valvetrain and everyone agrees that everything sounds like a good combo of parts. I am also sure that the geometry was correct and the was no bind in the "top" of the valvetrain. ????

P.S. is there any way to test a lifter to see if it is faulty?

 

Synthetic oil during break-in is a major no-no. That's why your cam ate itself. It causes lifters not to rotate on the cam at initial start-up, which if it happens, is certain destruction. Allowing the motor to run very slowly at initial start-up is another thing to be avoided.

With flat-tappet cams, the tappets aren't actually flat, they're convex; and the cam lobes aren't parallel to the axis of the cam, they're slightly taller on the edge toward the front of the motor; and the cam isn't under the center of the lifter, it's under the front half. The way it's supposed to work is that the lifter actually only contacts the cam at one point, which should be right near the the front edge of the lobe, and near the edge of the lifter; as the cam rotates, it should force the lifter to also rotate; and the slope of the parts forces the cam rearward and thereby retains it in the block. Once the lifter begins to rotate it will usually continue to do so throughout the life of the motor; but if it doesn't rotate immediately after start-up, a groove will rapidly be worn in it that will keep it from rotating. Synthetic oil will lube the surfaces so well that the lifter fails to rotate, it develops a groove, and the lobe and lifter wipe out.

I'd bet that if you look at the bottom of all your lifters, you'll see some others with a little bar-shaped groove worn in them, instead of a circular pattern around their circumference.

Your parts would probably have worked right if you had followed the cam mfr's recommendation and used conventional oil for the first 500 to 1000 miles of the engine's life, and then switched to synthetic. NEVER put synthetic in a brand-new motor with a flat tappet cam. It's fine with a roller, but death with a flat.

 

i determined on mine that the previous owners were running new but stock replacement springs on a high lift cam. i have no clue what the did for break in, but most of the lifters looked like they had been jammed into a grinder. The grooves were so bad i couldn't even get them out of the block. i had to knock them out through the bottoms of the bores. Regardless of if it was one or all 16 lifters, if you care about the motor, i'd be pulling it out and tearing it down. It doesn't take much debris to ruin the bearings crank or even oil pump.

Btw, i forgot that the previous owners wiped out 2 cams on my motor, that is the reason i got it for a fairly cheap price.

 

well the one that is concave is a perfect concave circle like it has been rotating not just an arch. also, the other lifters have very slight (looks normal) circular wear patterns. except for one other that is starting to become concave. I wish I could post a picture of these. also I used the assembly lube that came with the cam. Ive used nothing but synthetic since the install. the two that were concave have a different color to the bottom almost looks like a different metal. maybe because there is normall some kind of coating on them. or maybe they were defective. I dont know. but this is my daily driver and I can't really afford to get a machine shop to tear down the whole motor and rebuild it. I think I caught it early enough.

 

The reason the wiped out ones are a different color is from heat. They turn yellowish brown, then as the condition gets worse, they'll actually turn blue.

Honestly, I think your malfunction was caused by using synthetic oil for break-in lube, from everything else you posted. I don't see anything else wrong with your combo. IMHO this is one you should learn from the experience and not make the same mistake again. Comp may warranty the cam & lifters anyway, I have no idea about that, you have nothing to lose by calling them up and asking them to; but next time, definitely use dinosaur juice for your initial fill fluid, and change to synthetic at the first oil change, which should be at 500 to 1000 miles. It looks to me like you did everything else right.

 

Is there any reason to use a heavier conventional oil than 10w30 during break-in?

 

good question i would like a reply as well, shorty i will be breaking mine in.. what oil weight to use? i used 10W30 the last time, it looked good when i pulled it out (the cam) but should i use a thicker stuff? hrrmm...

 

20/50 valvoline-unless its freezing where you are-dont get all freaked-chances are excellent that you did no terminal damage to the bottom end with the limited run time you did during break in. i have had customers with a flat cam driving for weeks on the thing(not reccommended) then finally show up and have me do the job-accompanied by my bottom end song and dance disclaimer-motors are still kicking. some valve spring combos on motors i built were so stiff that cam break in had to be performed with only 1 spring installed. could it be your combo is similar? after break in-and an oil change-which happened within 6 hours of run time from initial firing-gets rid of that moly break in lube on the cam lobes,moly is a filter plugger.filled er up w/oil-conventional-re-installed the springs and let er rip. BUT-chances are also excellent that in asking comp cams to bail you out of your boo-boo you would be overstepping a bit. .02 of mine

 

yeah I changed the oil/filter again about about 25 miles after break-in to get rid of the assembly lube...

BUT WTF???? I just looked at my original cam (about 30k on it) that came in this motor as I was packaging the new one back up to return and I noticed that one of the lobes of either #5 or #6 was VERY worn down on THAT cam too. I threw out the lifters a while ago so I can't look at them. This is not the same lobe that was affected on the new cam so it's probably not a bad lifter bore right?
What could this mean??? I didn't do the break in on the original cam, a dealer did it for the previous owner (along with the motor install).

as for not getting freaked cause of the limited run time....

I've been running the car off and on for about 5 months (but I was having problems getting it to run right so it was only driven about 100 miles in that time but it did do a lot of idleing)

 

ah ha- ya gotta excuse me-im a little slow on the pick up but i will get there sooner or later. i ASSUMED the problems started at break in time-sorry. gimme some history. you say that you have been having valvetrain problems with the new(latest) cam-and with old heads-meaning the ones on the motor with the cam you just noticed that is appearing worn. correct? were there any symptoms or problems when the car was set up with old cam\old heads? you changed camshafts for power and not as a required repair,correct? the new cam went in and with the old heads, you started experiencing problems?-culminating in the most recent findings of a few flat lobes that went away in about 100 miles driven over a 5 month stretch? if im getting there, post and we can proceed from that point. sounds like the original cyl.heads might have had valves hanging up-see which lobe is wiped on the old cam,an int. or exh. and the additional lift with the new cam swapped in finished it before it even started.these are only guesses now cuz i need some more particulars from you-to avoid this again.

 

heh. Ok here goes:
I bought the car in fall 98 and it had a new GM crate in it, which was installed by a reputable GM dealer around here. it was awesome but lacked power (190hp stock) so I eventually bought a lot of performance parts including AFR heads and this comp cam kit. swapped everything out (intake, heads cam lifters headers, catback, etc.) had problems with the mixture right off the bat (rebuilt the carb and must have done it wrong). Car sat for a while until I got that fixed. Also could not keep valve lash adjusted. Got adj. pushrod and found I needed longer pushrods. got them. still couldn't keep lash adjusted. broke 2 or 3 pushrods all on separate occasions with the next few months. and the last time I broke a rocker stud too. ALL of which I contributed to them coming loose and flopping around. Replaced pushrods with new ones, rocker studs with ARP strong ones. tightened studs to 60 lb-ft as instructed, and tightened the polylocks to 45 lb-ft after the allen nut was tight at a total of 3/4 turn past o lash. they stayed tight!!! until I decided that the heads were too good for my car and i needed money, so I took them out and was gonna port the original iron ones and put them back in. In the process of doing this, I took out the lifters for inspection and then noticed the flat cam lobes. pulled the cam out. looked at the original up close for the first time. It also had a flat lobe, but it was a different lobe.

Sorry its long but that is the history of this problem. What could be causing two different cams, one GM, one Comp (both quality names) to have flat lobes???? I don't know which lobe it is but it is either 5i, 5e, 6i, or 6e on the original cam. It is the sixth lobe from the back of the cam. On the new one it was some of the front ones (already sent it out to be replaced so I can't go look at it).
Thanks,
John

 

BTT
I really need help guys this is my daily driver. I find it unlikely that it was a bad install on both cams or either for that matter. Both were high quality name brand cams installed by or in the case of the comp cam with the help of professional mechanics. Also, since the lifters were spinning in their bores, as noted by the full circular wear pattern, I also doubt it was all due to using synthetic. Isn't synthetic more slippery, so therefore reducing metal-to-metal wear not increasing it? BUT I thank all who responded and respect their opinions, I just would like more people to respond please with other possible scenarios. Plus I doubt I drove the car for 30k with a flat cam lobe, this must have happened towards the end of it being in my motor.
ANYONE???

 

this is how i was instructed to break in my "new" remanufactured engine last year, drive for 500 miles with strait 50w oil, avoid idling and excessive speeds/RPMs. my favorite method is to take it doen a long deserted road and climb from 30mph to 60mph and let it back down to 30mph over and over,pulling a little stronger each time. change oil at 500mile and continue break precautions to 3000k miles,change oil...drive! they gave me similar instructions for installing a cam,use gear moly grey assembly lube on the cam lobes and run with 50w for 20 min,dump oil,change filter use regular oil and give it a 100 mile break in period....your warranty will then be voided!

 

I guess what I'm saying is that yes I will use "real" oil for the break-in next time, not synthetic and it will be a heavier weight, like I was told. I will also use the assembly lube just like last time, and bring the RPM's up right away just like last time according to the cam install instructions. But what could cause two cams to wipe out at least one lobe.
Granted I didn't own the car when the motor was put in, but I was friends with the guy who did in high school. He definitely took it to the largest and most reputable GM dealer around here ( I know cause I have the reciept). To the best of my knowledge the original cam never had synthetic oil on it. It was most likely ok for most of that 30k dont you think?
If it started to wear at the beginning, I'm sure something would have broke before 30k...... and it would have run really bad. Now I know for the last days of its life, nothing in the valvetrain was monkeyed with or over-revved. And I didnt change over to synthetic either until I replaced everything. So what else could cause this??? I'm not trying to be pig-headed about this, I just don't want the next cam to also be a victim especially since I am pulling the motor and checking all the bearings and the bottom end. Please no more repeats of the break-in recommendations, even though I know you're just trying to help. I got the point about that, and I appreciate you all sharing your knowledge on that subject.
Thanks,
John

 

if i was in your shoes, well wait a minute, what would you say is the max rpm that you have zinged your combo to? at what rpm are your shifts happening? is there any rev limit protection you have added? you have a definate geometry problem. are you sure the valves installed in the head are what you purchased? either stock or plus 100 thou. are some normal sizes. what is the installed valve height-spring seat to tip-what is the spring installed height-spring seat to underside of retainer? at what lift do the springs stack solid? have you checked for proper geometry? was it aligned properly? i know that the answer lies in the valve rocker pushrod spring mix. are the rockers you ran 1.5? roller, stamped? now i see- roller-is the inside of the rocker hitting the perimeter of the retainer?you have experienced enough problems with the first attempt to say that its gonna do it to you again unless the problem is identified. arent afr heads set-up for a roller valvetrain with some pretty stout seat pressures?BTW-last from me about synthetic oil-you want some friction during breakin and when running synthetic, you dont get enough

 

I'd say I took it up to about 5500 max on the new combo, maybe on the old combo about 5800 about 2 times (no rev limiter).

The AFR heads came with part #8020 Hydraulic 1.450 springs which I took to mean for hydraulic lifters and cams. I used the adjustable pushrod and measured that I needed .100 inch longer pushrods which I then started using. I checked the rockers for retainer clearance. I am using 1.6 pro magnum full rollers (non-self-aligning). the valvetrain was aligned with guideplates. AFR says the max lift allowed on these springs is .550", my cam had .484" with the 1.6 rockers.

But anyway, If and when I get the replacement cam I will be using it with the old iron heads, which I ported, and the springs I installed on them recently are the ones that came with the cam in the kit. I will not be using the AFR heads for other reasons (money). I may still use the 1.6 rollers, but the old heads have pressed in rocker studs and If I break one, I have to pull the head and have it machined which I really cant afford. So that's not etched in stone.

All of the rockers were moving on the afr heads when I had them on. None were stuck. the all seemed normal except they came loose all the time.

 

have you really given up on the afr's? you shouldnt. the cam you were running with them was counterproductive to getting the power out of them that they were capable of . you are going to some stock iron ones-except for springs and the cam. the cam choice is somewhat of a mystery to me why you chose it. most sbc motors with stock(ish) cylinder heads prefer a cam that favors the exhaust a bit more than the intake, a split pattern. but ok im not gonna preach, go ahead when you torque down the head-roll a couple rockers thru a open\close cycle and check the scrub across the valve tip. need to see that scrub fairly well centered across the tip. sell me them heads are they egr-ive got their application guide-what is the part # on them-what kind of cash are you lookin to get? email me