Whats up with Chevy 454's eating cams?

[RaysonKid]

This weekend I will be putting the third cam in this motor.
Its in my 76 dually. The motor is one I got for painting a guys car.
The first cam (not sure of make or grind) went south within 500 miles of use. Tore up the cam and one or two lifters.
Had a hotrod shop rebuild the motor and install a new cam.
Now that cam has done almost the same thing.
It was #8 exhaust valve. The lifter is toast and the cam lobe is tore up.
Have talked to a few people and seem's big Chevy's have this problem. The guy I talked to tonight at the speed shop. Guessed that I was looking for a cam for a big chev.
I cant afford to go roller. So maybe the third times the charm.
Maybe the block has issues?
I am scratching my head.
Anyone else had this problem?
I am trying to contact the guy that rebuilt it. To find out if its the same cylinder as before.
The motor only had maybe 5,000 to 6,000 miles on it since the last rebuild.
:frown:

[Hotcrusader76]

Funny thing is alot of times the #8 cylinder exhaust lifter bore is out of alignment. I would consider having your lifter bores checked out again....three cams? yikes...stop where you are in your tracks and get that block looked at.
Like I said #8 exhaust lifter probably killed your motor and it does for alot of BBC blocks.
~Ty

[Fiat48]

Use only new cam and new lifters. Old stuff doesn't mix.
Use cam prelube (moly) on all lobes and the lifter faces.
Use GM lube supplement additive.
Overfill the crankcase with oil. Lifters and cam are lubed by splash oiling.
Stock type valve spring tension if possible.
Do not idle for the first 30 minutes of operation...and keep rpm 2000 or above..reving the motor to splash oil from time to time.
And then I pray it makes the break in. Why I don't do flat tappets anymore.
PS: Small blocks did it too.

[HammerDown]

Originally posted by Hotcrusader76
Funny thing is alot of times the #8 cylinder exhaust lifter bore is out of alignment. I would consider having your lifter bores checked out again....three cams? yikes...stop where you are in your tracks and get that block looked at.
~Ty
Boy have I herd that before...And also what Fiat said about the low spring tension...On my last break in I ran it only with the outter valve springs. After some trips out, I then added the inside springs.
A little work...but I felt good about it!;)

[TIMINATOR]

We have seen BBChevys and BBFords with the lifter bores out of alignment, if that is the problem, they will eat cams for no apparent reason, sometimes 1 or more lobes, sometimes different ones with each occurence. The easy way out is to call and order a cam from Engle and tell them what the problem is, they will grind a cam with more lobe taper angle and that will solve your problem. Been there, done that many times. TIMINATOR

[Mopar426]

Sounds like a lack of propper break in. 1800-2000 rpm for 10min, then 1000-1500 for five minutes. Make sure all push rods spin during the process.

[RaysonKid]

Thanks guys.
Guess I will be pulling the motor this weekend.
So can a machine shop fix the lifter bore?
Or is the block junk?

[Hotcrusader76]

Yes a compitent....I mean someone who knows what the hell they're doing can realign them. I don't know the cost but it's something often checked on hi-po BBCs.
Good luck and keep us posted.

[RaysonKid]

Will keep you posted.
Going to call a old ,local cam grinding shop and discuss it with them.
Perhaps they can help.
Really dont want to pull the motor.
Really would rather spend this time and money on the boat.
But need the truck to reach the lake..

[Fiat48]

I think what you are talking about is incorrect lifter bore indexing. While improper boring of the lifter hole would affect valve timing by several degrees, it would have to be bored a long ways off to cause a cam failure. If that was the case, this 1976 block probably wouldn't have made the warranty period with it's original cam.
To correct lifter bores that are bored incorrectly and restore the correct relationship to the cam, the lifter bores are bronze bushed and rebored to the correct angle. This is all race stuff.
I'd check that the lifter sits in the center of the the camshaft and you might check that #8 exhaust valve (if that's the only lifter that failed) to be sure the valve or the guide isn't worn or galled which could cause the valve to hang.
It's probably all about camshaft break in.

[Moneypitt]

Have all 3 cams been used with the same valve springs? Maybe the spring rate is not compatable with the cam grind. Also what about the rockers? any problems there, galling etc. I had a simular problem with jet boat motor and it turned out to be too much lift for the springs.....Moneypitt
WANTED: 4 bolt 454 block that will clean up at .060...

[cstraub]

Everything Fiat says. . .including overfilling the crank case. Hell I posted that on another board and they thought I was crazy. This will splash oil up on the cam and help during break in.
Lifters are your problem. Quality is not what it use to be. Use a flat lifter that looks like it has a wafer on the bottom...should be a groove at the bottom on the side of the lifter about .200" from the bottom. These are the Maressa lifters made in Mexico...believe it or not they are the best.
No. 8 Exhaust is notorious for eating lifters. I foget what plant they came out of but Chevy had thousands of them at 8 degree off angle I think was the number. They love to eat cams.
Hope this helps.
Chris

[Fiat48]

cstraub69: Are those lifters actually ground flat?
Yes, the overfill the crankcase was something you said which makes perfect sense. And if I ever install a flat tappet cam (which should be over my dead body:D ) I would certainly do that.

[78Eliminator]

Yeah, and it's also a good way to tell if your oil control rings are in good working order LOL :D

[cstraub]

Fiat,
Oh. ..okay. . .someone listened. Well it has worked for years overfilling the crankcase. the lifters have about .0025" worth of crown on them.
Chris

[RaysonKid]

Wow, Information over load.
My head hurts from all I have learned about this in the last day and a half.
Heres the deal. I called a custom cam shop here in Tacoma.
"Delta Cams". They have been around for ever.
The guy I talked to knew exactly what was going on.
Same as what you guys have been writing.
They are grinding me a cam. It will have more lobe taper angle.
Like Timinator suggested. I guess this helps the lifters to rotate.
They also are selling me a better oiling lifter.
He also has some device that will help to oil the cam.
I havent seen it yet . I will pick up every thing tomorrow.
But he says I can install this item. Just drill and tap a couple holes.
I will also over fill the crankcase. for this initial start up.
Dont want to do this again.
Thanks everyone. ;)

[Fiat48]

If that cam has more lift than stock, you'll want to check for coil bind as Moneypitt was talking about.

[Blown 472]

GM makes some engine breakin shit that comes in a can and I forgot what it is. Roller cams for me from now on, splash some oil on them and start the motor.

[RaysonKid]

Thanks Fiat.
I will be checking lots of things.
And yes, Roller would be great.
But want to do all that to the boat.:D

[cstraub]

Blown,
I forgot about that, yes get the GM breakin lube stuff. Use it with any type of engine break in... gooooooodddd stuff.
Chris