Bbc Reputation For Eating Camshafts?

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11-01-2008, 12:54 AM
colesscamaro

Bbc Reputation For Eating Camshafts?

Has anybody heard the rumours that the mid to late 80's BBC are somewhat notorious for destroying cams, sometimes even during break in right after initial fire up? And is there any truth to this? I have a 87 454 block and cast crank, forged flat top pistons, static compreeion is about 10.0/1 and I am running 69 063 closed chamber heads, I had the cam custom ground, its .588/.588 lift solid flat tappet w/ 274 duration @ .050 and has 107* lobe seperation, its supposrd to be producing 560-570 hp with just shy of 500 ft./lbs, of torque. I built the motor 2yrs ago and had a clutch explosion at the dragstrip with around 1500 miles on the motor that saw the motor hit the rev limiter( thank god ) it consequently crushed the top of 2 valve guides and put it out of commision for the last couple of years. Because of the combination I had to shop around for the closed chamber heads w/ same casting numbers. The bottom end was never dissassembled, I just fired the motor last week, it ran strong and hard for the first couple of days, but I am concerned about the possibility that the cam has gone flat on me, or if the loss of power is due to ignition, ( I am running an msd 6al with pro=billet distributer) the carb has been a problem child from day one. I am hoping somebody can stere mr in the right direction, and tell me how to be certain the cam will live, k
11-01-2008, 05:35 AM
pat mccarthy

i built many bbc over the years and they can EAT cam shafts it not just the 80s blocks i seen may over the years from 70s on up if the cam is going flat you know like not holding lash .poping thru ex or intake
11-01-2008, 09:15 AM
Dave Severson

Switch to a roller cam, either hydraulic or solid, and the cam eating problem is gone......POOF!!!!!!

Not really magic, just a combination of things, lack of zinc in today's oil, people too cheap to use break in oil or a zinc additive, improper break in techniques, wrong adjustments... lots of different things....
11-01-2008, 02:03 PM
pat mccarthy

Quote:

Originally Posted by Dave Severson

Switch to a roller cam, either hydraulic or solid, and the cam eating problem is gone......POOF!!!!!!

Not really magic, just a combination of things, lack of zinc in today's oil, people too cheap to use break in oil or a zinc additive, improper break in techniques, wrong adjustments... lots of different things....

that is all true but the bbc have some lifter bore issue and yes dave you are right ... why would any one build a flat cam engine with all bad parts out there and bad oil now days ???? any one who lost a cam in a bbc and i have it not a good feeling .i just do not build the bbc with flat cams any more the last sbc and bbc soild flat cam engines i used the EDM lifters with the hole burned thru them for added oil
11-01-2008, 04:01 PM
Dave Severson

Well, with all the changes it's certainly not just the BBC's suffering from the cam going bad stuff.... Guy around here lost one in a 440 Mopar with just 300 miles on it......Lost one in a 460 about a year ago... but yeah, go roller, no problems.
11-02-2008, 12:13 AM
Rrumbler

In my experience, that legend is true, and it is not just the later model engines. I had both a '68 396, and a '70 427 that LOVED cams; in the seven years that I ran them, in drags and on the street, the 396 went through five cams, and the 427, two. I never did figure out what cause the problems, nor could Isky or Crane help. Everything seemed to be right on spec, but the danged things would lose the number seven/eight cylinder lobes; it almost looked like they were oil starved, or perhaps overheated in that region of the block. Now, I think it was because I ran too much cam and drove it on the street in commuting traffic as well as on the strip, but that is only a S-W-A-G. Today, I don't think I would build an engine without a roller - any engine, if it was possible.
11-02-2008, 04:22 AM
pat mccarthy

Quote:

Originally Posted by Rrumbler

In my experience, that legend is true, and it is not just the later model engines. I had both a '68 396, and a '70 427 that LOVED cams; in the seven years that I ran them, in drags and on the street, the 396 went through five cams, and the 427, two. I never did figure out what cause the problems, nor could Isky or Crane help. Everything seemed to be right on spec, but the danged things would lose the number seven/eight cylinder lobes; it almost looked like they were oil starved, or perhaps overheated in that region of the block. Now, I think it was because I ran too much cam and drove it on the street in commuting traffic as well as on the strip, but that is only a S-W-A-G. Today, I don't think I would build an engine without a roller - any engine, if it was possible.

i done over many many big blocks had a boat with a small cam wipe so it not just big lift and big springs at low speed have seen small cams go on other engines alot of it is when the engine was machine at GM the cam lifter bores are not were they need to be to spin the lifters and a long list of other things:( i seen a old 427 512 block eat two small soilds cam with no time on it :HMMM: