OK, now that I have figured out what was going on with my 355, (flat cam lobe during break in), I have read on the boards here and it seems to me that its pretty unanimous that most of the time when some one is breaking in a cam, and a lobe goes flat, they throw their arms up and say "now I have to rebuild the motor!"

How much of a concern is it? My Comp Cam wore a lobe off in the break in period. The motor still sounded good but I have not taken the oil pan off to check anything yet.

I just hope this doesn't turn into a horror story. If it does, I am going to the junk yard, finding a 350 out of a truck, throwing it in there and forgetting about hot-rodding it. I have too much money into this motor to only get 20 minutes out of it to only have to do it again.

I think I'll just flush the motor, throw a magnet on the oil pan, and forget it till it gives up.

 

A flat cam lobe puts alot of metal thru thru the motor. If long term durability is a concern you should pull everything apart and change the bearings. Also inspect everything. We have stabbed in a new cam and lifters when this happened to us. It worked for a short time.

 

cut the oil filter in 1/2 (use a tube cutter, not a hacksaw!) and check it for chips, I really doubt the filter got it all. Then pull of the oil pump and see what kind of crud made it through there. Ideally, you should take the motor apart, but at least you can make a better decision after looking at the parts.
Next time do this to the cam. Adjust it properly using the intake close adjust intake/intake open adjust exhaust method. (try the search button) I use Melling cam lube on the cam, some people like crane but I feel it's too abrasive. (great for the cam, hard on everything else). I then use a dab of white grease on each lifter and dip them in STP before putting them in the bore. Pre-pump the lifters. Crank the engine over by hand while using a drill to prime the oil pump. When the car starts, bring it up (about) 1500 rpm for several minutes.
Initial start up is hard on cams.

 

That just happened to me last mo.
I thought I might be lucky enough to just put a new cam/lifer set in, but after inspecting the bearings, I realized I had to tear the thing down again.
You may be more fortunate though. Mine had other chips in it from a cheapo timing set that was included with the kit that rubbed on the block, and the piston skirts were scored too.
It's too bad a rebuild with a flat tappet cam has to be such a crapshoot.
The source of the problem was lifter bore burring that prevented the lifters from turning in the bores.
I bought a lifter bore hone for $25 from Competition Products, found a Melling cam on ebay for $50, and it'll get a clean up hone with new rings and bearings. And I'll have a back up engine when all's done. I'll run that while I'm putting together a roller motor. And I'll swear off flat tappets forever.

 

that'll be when the roller comes apart and the needle bearings go through the oil pump.

 

I'd like to run a roller too.

Would be my luck too.

 

I must be the only person who's regularly gotten lucky on stuff like this. I've killed a few and always done OK by just shoving in a new cam and lifters, changing the oil and filter and crossing my fingers. Most were single lobe deaths after many hard street miles. The only one that's died on me at startup (and I've built MANY motors in the last 20 years) was this one.....

A Comp XE 282S that killed FIVE lobes on break-in. That's an AWFUL lot of metal to throw into the motor. Got a replacement set from Comp, shoved it in, changed the oil and filter and turned the key with fingers crossed. That motor is still running (almost a year later) and set it's best ever ET of 12.2 @ 110+ after this unfortunate incident.

 

I had a XE294 go flat on a breakin back in October. Lots of lobes got wiped so I pulled the motor and it is rebuild time.

 

If comp ever starts using good material again maybe we wont have this problem. I doubt the lifter bores were the problem strange things happen when a cam lobe goes south. I'm personally not buying any comp products and I think I may still take the comp cam out of the Malibu even though it survived break in and replace it with an ISKY.

 

Amazing isnt it that they are still in business? I think you are wasting your time by taking out a good cam and replacing it. Especially considering that 99.99999% of all break-in failures have nothing to do with the cam manufacturer. I can see it, if the lobe goes flat in 10K miles, but there are too many variables in break-in.

 

Funny how every speed shop or drag racer around here I have talked to have experienced or heard first hand of these cams going flat during the breakin. As well as Comp replacing them with no questions asked.

 

I have had bad luck both with a flat tappet lobe going flat (Comp Extreme Energy) and a roller cam failure due to the connecting bar failing (Comp Cams retrofit hydraulic roller). My question is who makes their parts, in house or contractor? I wonder who makes Edelbrock retrofit rollers and does their cost compare?

 

In my own case, I'm sure it was the lifter bores that were the trouble. There were scratch marks in the base of the lifters when I removed them. And the pushrods were not spinning on the lobes in question.
RB mentioned in a post a while back, "If the pushrods aren't spinning when the engine is first fired up, those lobes will go flat"
Another member posted that he had two cams go flat, and after honing the lifter bores the third cam was successful.
In some cases lifter bore honing can be the solution to the problem.

 

So doed that mean the same thing about crane and lunati? They will replace them upon request with no questions asked also. Any manufacturer will do this, because there are too many variables in break in. They cant pin point the reason, so they replace it. Its called good business.

Believe what you want. Dont buy any comp cams parts, most people still will. I would be curious to see how many people on these boards have a comp cam in thier engine. I guess those are all junk?

Bad experiences dont make bad product. Show proof that the cam was bad, and not the process. I bet you cant.

 

Please quote where I said all Comp Cams were junk.


I can't say for sure it was the cams fault or the installation processes fault. However you can say it was the installtion processes fault.

 

I will agree that in my case, I did have a lot of problems when I first fired up the motor, and I will admit that a lot of those problems were my inexperience in building and fireing an engine, since I had never done it before. I had pulled and repaired many forklift engines but pulling a 4 banger just to fix somthing (rear main seal or torque converter) is a far cry from motor rebuild and buildup.

 

Read above, I wont say that the cam wasnt at fault, but I did say that 99.99999% of cam problems are due to break-in issues. Sure some bad ones slip by comp. But to say that since the dont ask any questions when they give a replacement is a sign of bad things, doesnt make any sense. That is a sign of a company that is interested in customer satisfaction. They could just as easy blame you for it and not give anything.

Dont take what I said personally, I dont mean to imply you have a lack of ability. I dont even know you, so I dont mean to imply that.

 

I'm not going to search for your previous post(s). But, I see "882" heads, "282S cam", "1.6" rockers. That's .528" lift at the valves, which requires at least .588" clearance between each retainer and guide/seal. Was that clearance verified before you fired this puppy up?

It's common practice to break in cam/lifters of a high-lift package with reduced valve spring force - often single spring only of a dual spring setup. A lot of work, but less work than replacing a cam/lifter set or rebuilding an engine.

 

No.

I was told buy the guy at the machine shop that it was not a concern with the pistons I had because the lift wasn't going to be over .550 (which with the Comp 280H that went flat, and 1.6 to 1's, is .512), so I didn't do it. I am not saying at all that I, knowing now what I do know, would still agree with him.

I will be checking clearances when I install the 282S this weekend, or when ever I get time, and I will also be breaking in the cam with the inner springs out. I am also considering going back to a 1.5 to 1 rocker.

You can see that when I first started building this engine almost 3 years ago my lack of experience in performance engine building was evident just by looking at my sig. that has "882" and any other performance part in the same sentence. There were so many things about building a performance engine that I didn't know, and the guy at the machine shop didn't offer any advice. The one guy who I did ask a lot of questions and trusted to know how to build a performance engine, who did offer advice, turned out to be a source of bad info.

Everyone else acted like no-it-alls who chuckled at me like I was a moron for not knowing and even asking. I got sick of that and just started building the motor. Then I found TGO, but at that point all my parts had been purchaced and the engine was back from the machine shop and waiting to be put together.

Oh-well, one more thing to add to the list of thousands of lessons learned the hard way.

No biggie.

 

TGO is good to have around.
Books are good too, so are shop manuals.
Books like HP and SA design.
The guys who work at the machine shops don't have time to explain all that stuff, and the guys at the parts counter just don't know.
A lot of the SBC how to books are pretty old and they'll have you wondering whether to get a Racer Brown or Clay Smith cam to go with your torker intake and dual point dist, lol.
But there's some good stuff in there that can keep you out of trouble too.
Lately I've been realizing that any of the times I've been successful at a rebuild, there's been quite a bit of luck involved.

My point ? ?

Sheesh! . . . Idunno, I forgot

Read Up... Build cheap motors, til you're sure you know what you're doing.
Then get an LS1

 

Here are the pics of the lifter. Almost a 1/8th inch is worn off. Sorry the pics didn't come out clearer. The cam and lifters were sent back to Comp today.

 

He meant retainer to seal clearance, not valve to piston. IIRC, the 882 heads won't handle that lift (.512) without the guides cut down. I could be wrong though.

 

I meant retainer to guide clearance, yes. His machinist apparently didn't consider that and only mentioned piston to valve clearance.

Yup, that's why TGO is here...

 

I am sorry for not specifying, when I meant that the machinist said he was not concerned about the lift under .550, I had specifically asked him about valve to piston clearance. I at that point had already purchased my valve springs and it was understood in my conversation with him that he was to be installing them and they would be good for the .600 lift that the spec sheet stated, so he was to install new guides, and seals.

 

Just a side note. I got a message the other day on my answering machine that I was to call a guy in the warranty department at Comp Cams. So I finally got through yesterday and he and I discussed the break-in procedure, and came to the conclusion (under our breath) that it was my fault that the cam went flat due to excessive spring psi. because I didn't remove the inner springs on my valve springs prior to break in.

He sent me a new cam anyway. They didn't have to but were very good to me and took care of it anyway.

 

One of the problems may be related to the oil that you use for break-in. Oil USED to have a fairly high level of Zinc as an additive, and that was what helped keep the cam from wiping a lobe while everything got situated. Most of the newer oils all have very low zinc levels.

I've been told by a number of folks who know what they are taking about that the best thing you can do for your engine on initial break-in is to get a can of EOS from your local GM Dealer and add that to the oil. It's a break-in type addative and can really help. The other is that yea, it's a bit of a pain in the butt, but pulling the inner springs takes a lot of the load off the cam, and can help out a bunch. It's easy enought to pull the springs with the heads on, a line from an airtank into the sparkplug hole will be more than enough. (sort of like doing a leakdown test)

Here's some more info EOS ,

Hope this helps

Steve

 

So the machinist installed new shorter guides? Not totally clear on that. What the other guys were talking about is the distance between the valve guide and the spring retainer. It doesn't matter if the springs can handle .600 if the valves don't have enough room to open the full lift of the cam. Sorry, you probably know this already, I just want to make sure.

 

I know your pain....my engine wiped two lobes while on the dyno, and they threw a new cam and lifters in it and said it'd be fine. It wasn't....burned oil and smoked. Found out cylinders were scored and piston skirts took some abuse to. Now it's back together ready to crank back up this spring. Hope I don't wipe another lobe! At least this cam ran in the engine for awhile and is broken in already. Here's most of the saga...
https://www.thirdgen.org/techbb2/sho...hreadid=263462

 

OK... let me specify.

When I had the machinist do the heads, I brought him my new springs with the spec sheet. He totaly rebuilt the heads with new guides, umbrella seals, hard seats, studs, guide plates and valves.

When he and I talked and I brought him the springs, he and I discussed the application of the heads. He assured me that the valves and springs would open to .600, because he would machine the heads to work with the supplied springs and thier specs.

At this point I asked him if I would have problems with valve to piston clearence with the cam I chose, and he said;

"No, with the pistons you have and the rest of your combo, in my opinion, you do not have to worry about that untill your lift gets up around .550."

I at this point am going to check out the clearence anyway when I install the new cam.

I should have been more clear in my description of what the machinist said.

 

my3rdgen
Got a question for you.

When you returned your cam did you have to send a reciept?
Also, did you have to show proof that you used Comp lifters, or anything like that?
I have a comp cam with a flat lobe. It would be nice to return it and get another if possible.

Thanks

 

Nope no receipt, in fact, I had never even turned in the yellow warranty card when I bought the cam. But I did have to send the lifters, however they were Sealed Power lifters, so they didn't replace them (understandable).

I did have to talk to a tech guy before they would warrant the cam though. He just wanted to make sure I wasn't going to do anything wrong with the next break in. No sence in giving someone a new cam if they are just going to flatten another one.

They treated me well and they didn't have to.

 

Cool, Thanks
Is there anyone in particular that you'd suggest talking to?

 

Sorry for the slow reply, I am not usually around enough on weekends to mess around with the computer.

The name of the guy I talked to was "Red".