I am running a Comp Cams XE274H (.552 intake/.555 exhaust) in my 1969 Camaro SS 396/375. It has about 500 miles on it and it has begun to have symptoms like a couple of the lobes are wiped out. It has begun to backfire under acceleration and will hardly run past idle. The cam was broken in correctly and I have had no problems until now. The timing is right on, Mallory Unilite. I hear some rattling in the cam/lifter area. I pulled the valve covers and all looks normal. I guess I will rotate the engine and check each cylinder for proper lift. If the cam is wiped, is this known problem with the Comp XE cams? I was thinking of going back to a solid grind.....suggestions anyone?
If the cam was damaged, how about all that metal running thru the engine? I drained the oil and it looked ok. Maybe I can cut the filter open and look for metal.
I have installed quite a few cams and never had a problem before. Maybe I will go with a Crane product next? :confused: :mad

 

I have never heard of this before, so soon. Now you got me worried as I have the same cam...

Chris :flag

 

Bob
What oil was in the motor?

 

My XE268 wiped #7 exhaust lobe. I replaced it with the XE262. I like the 262 cam better. Seems just as strong in the middle but has better bottom end and smoother idle. I hope the 262 lasts. Cam swaps arent my idea of fun anymore.

With a high lift like the 274 has, open spring tension might be a factor in the wiped lobe. Also an old isky catalog I had stated that on some engines the lifter bores are not machined at the exact correct angle in conjunction to the cam bore. This factory defect in the block leads to premature lobe failure.

 

I installed this cam in my 427 and have not had any problems. I have around 1,700 miles on the motor since a total rebuild. Did you match the valve springs to the cam?

Dwayne

 

The XE series of camshafts run a pretty crazy ramp angle. They literally run the ragged edge of what can be done with a flat tappet lifter. As such, if you have any problematic area in the valvetrain this type of cam will bring it out quickly. You really need to make sure the lifters are rotating properly, getting adequate lubrication and that the springs match the cam.

 

Yea, I bought the entire cam kit from Comp Cams....the cam, lifters and matching springs. I broke the cam in with 10W30 and followed the break-in procedures exactly. I even placed a large fan in front of the radiator to keep the engine cooler while running during break-in. The engine has about 500-700 miles on it......I will probably not run another Comp Cams XE Hydraulic.....I am probably going to go with the Crane blueprint 396/375 hp solid lifter cam.....

 

Bob,would you please tell me what 10/30 oil you used? This is important and will explain after you reply

Also,breakin procedure calls for a straight wt 30 oil and a MOA sold by Comp is the preferred method.It is on the cam card,website and catalog

 

I ran Valvoline 10W30 and after it was broken in, I switched to Valvoline 10W40.........I used two bottlles of the lube that comp sends with the cam, springs, retainers, keepers and lifters in the kit. I don't really see how that could have caused the lobe or lobes to go. I think I will stay away from the XE cams......too hard on parts.

 

I have this cam in my 454 (on the engine stand still). Take a look at this post that I did on this cam back in January:
http://forums.corvetteforum.com/zerothread?id=224981

Mountainmotor, please chime in again!!! I plan to break it in the way you described in this posting. Which 4 cylinder treatment would you use?

Bob :cheers:

 

Bob Turner, thanks for posting that.....good reading :cheers:

 

You're welcome. Sorry to hear you had a problem with this cam. If I end up running into the same problem, I am going ROLLER with the same cam specs..... :yesnod: I will do everything to try and prevent it....

You will see by update on my BB buildup soon. I need to find a host for the pictures...

Bob :cheers:

 

If the cam was damaged, how about all that metal running thru the engine? What are the chances of the rest of the motor being OK?
I really hope I won't need to pull it with only 500-700 miles on it.....

Advice welcome :confused:

 

Ive wiped two cams in two different chevy 350 engines in the past. All I ever did was replace the cam and lifters and change the oil. Both motors, one of then after many miles still have great oil pressure and are running strong. Im not saying its good to have metal particles loose in the engine but it my case they have caused no noticable problems so far. I think most of it gets caught in the filter and magnetic drain plug. You could also stick some extra magnets on the outside of the oil pan. Of coarse you would have to leave them there untill the next time you pull the pan.

 

mountainmotor......are you there?

 

ttt

 

Quote: "This is important and will explain after you reply"

Ok explain please...

What is the story with posting that you are going to explain something and then letting it hang or having a moderator delete your post...

In my opinion this is really lame and is not of the spirit we all value on the forum...

As I have said before, I have never had a harsh word for anyone here...but this is really silly and petty.

 

I had a Comp cam go like this on a 351C Mach 1 a few years ago. The cam was well past the break in period when it started to wipe a lobe. I dropped the pan to wipe out the debris and dropped the rear main cap to see if the bearing had any traces of the cam shrapnel imbedded in it. It was clean, but the pan was full of crap. I replaced the cam with a Cobra Jet replacement from Ford and never had another problem. Around the same time a friend of mine using a Comp cam in his SB Camaro had the same problem with wiping lobes.

I've never used a Comp cam since. I'm convinced that I had a bad cam from them. I thought they'd probably overcome any quality issues they may have had because there are a lot of forum members using them successfully.

I've never heard cam lobe wiping stories about Crane or any of the other big cam manufactures (that doesn't mean that it hasn't happened, though). If you follow the manufacturer's instructions for break-in, use the right springs and new lifters, and use a quality SF, SG or better rated oil, you shouldn't have a problem. The only remaining possibility is a soft cam.

Good Luck. At least drop your oil pan to see if you've got debris in it. It's not that difficult and it may prevent even more serious problems.

 

You wipe cam lobes, you rebuild the engine.

At least you pull it, disassemble it, tank it, clean out all the oil galleys, tank it again and put it back together with new bearings and rings. You might have to get your crank polished and a fresh hone put on your cylinder walls as well.

Were you using the recommended valve springs for this cam?

 

I lost a Comp Cams Roller cam. Not only did the lobe fo, but I had a few shrapnel pieces floating around from the lifter. I put a factory Lt-1 solid lifter cam in and the motor is textbook.

Long life is possible without going through the whole motor after you loose a cam.