the_am_man

I have a 82' firebird with the lowly 8.6:1 LG4. Its only mods are a performer intake and edelbrock 1406 carb to replace the old holley a previous owner installed. The engine only has 49,000 miles on it, but it has alot of carbon on intake valves as I noticed when removing the intake. I wanted to up the power output some, but not wanting to spend a lot of money. I picked up a chevy 929 cam brand new for $20 since I already had pull the engine to install the shorty headers. Stocker: 179/194* @ .050 .360/.385" found on TGO 929: 195/202 @ .050" I:390" E:410" I got the stocker out of the block last night, but wanted some advice on the subject of valvesprings. The stocker did have one lobe that was excessively worn. Do I need to replace the stockers? I've heard they are worthless, but this cam isn't much of an improvement over stock. Maybe I'm being a cheapwad but I figured since the engine has such low miles and looks pretty good internally, that I could just slap this cam in her. Can I get away with this?

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1964 Honda C110 Cub 130mpg!!
1982 Pontiac Firebird Trans Am 5.0L awaiting installation of 200-4r and Ls1 brakes...
1994 Cavalier 3.1 5 spd

Damon

Not absolutely required with that cam, but 30 year old springs are always suspect, especially when you're about to work them a little harder than they were accustomed to with the "peanut cam".

A set of e-bay Z28 springs would work just fine as an upgrade or a set of Comp 981 springs. Both are drop-in replacements (yes, you can even continue to use the stock rotator/retainers). No other parts needed besides the springs themeslves.

the_am_man

Thanks for the reply, after removing the stocker I found 3 pitted lifters and some heavily worn cam lobes. I think I will use my stock springs to break in the cam, it shouldn't be too bad trying to change springs with the engine in the car should it?

Intrepid781

I've never changed springs so I'd like to know as well, although I wouldn't think it would be hard.

the_am_man

anyone? how to change springs with heads on...

Rolling Thunder

Yea its not too bad as long as you have the right tools but its not too fun either. The thing is you have to make sure you dont drop a valve so that means you have to use an air hold or nylon rope in the cylinders. Thats the only real big difference. Beyond that as long as you use a magnetic tool to keep track of the keepers when removing them and dont drop them in the motor you should be ok. Although really you probably dont need to do all that depending on what springs your useing. The real problem that causes the excessive wear are the crappy oil today and chevys high pressure bypass valve around the oil filter. Back in the day even with the good oil chevy cams generally only lasted 160-170 k as a direct result of this bypass valve. Even though people may disagree with this as theres many motors with over 160 k on them with the factory cam in place if they took it out they would see just what you found typically only 1 lobe that was excessively worn down to the point where it would need to be replaced technically. Now with the crappy oil on top of it you have to install it with something like the comp cams assembly grease, use an oil addative like GM OES or any major cam companies equivalent (not the cheap walmart crap) break it in exactly as specified and use a good quality oil with lots of anti wear agents but with a tame cam like that you shouldn't need real heavy springs and because the springs you would probably get plus the fact its not too aggressive a cam in terms of ramp rates you shouldn't need to use the old springs for the break in though i suppose it couldn't hurt. Further more i believe comp cams makes a tool to put a groove in the lifter bore to bleed some oil back to the cam to alleviate the bad oil issue with cam failure.

stroker_SS

Todays oil is not "crappy" by any means it is FAR superior to the oil that was used in the 60's 70's and 80's. The only thing that your typical Passenger car motor oil is guilty of is lacking in the Zincdithiophosphate department, which some believe is cause to accelerated cam and lifter wear.......I say believe because chevy's,and ford and chrysler, were wiping lobes since their inception in the 50's. Maybe not quite as frequently but back then cams weren;t as aggresive therefore less spring pressure was required.

If you're running a flat tappet cam I and many cam companies recommend using a Heavy Duty Engine oil, such as rotella t, just to be safe.

Those break in lubes are garbage in my opinion. sure they add plunty of ZDDP but use chlorinated base oils which are known to actually INCREASE wear over an extended period of time.