NORT

I just installed a 268H Comp cam in my 84-Z28. It is in a 355ci. SBC. I used all of the Comp.stuff on it except the rocker arm, I used the stock ones, I have adjusted the rockers down 3 times so far and I still have alot of noise like the rockers aren't adjusted far enough. I have ran them down a full turn after 0 lash, which is a half a turn more then I have ever had to before. I'am afraid to go to far with them so I thought that I had better ask some advice! I would realy appreciate some imput. As I said I used all Comp stuff on it,cam,lifters,retainers and springs and she rattles like H---. looking forward to hearing from someone.

Biochem

What kind of heads do you have... stock? Some aftermarket heads require longer pushrods... I'm not totally convinced that they are needed though. Maybe the geometry is off. I use stock length with my Edelbrock heads, but I have 1.6 rollers. They are louder then stock rockers were.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

ede

few things i thought of, did you bend a push rod? push rod length correct, shouldn't be a problem with your cam, but something to check, did you over tighten the rockers and trash a lifter?

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ICON Motorsports

1st & 3rd
MM Black Diamond 538 F&AM

NORT

Thanks for replying. I am using the L31 vortec replacement heads and the stock self-aligning rockers. Does that help? Please let me know...........NORT

Biochem

While I am NOT knowledgeable about the Vortec heads... do they require guide plates? They will be the balck plates that are held down by the rocker studs... providing you have one huge hole for both push rods instead of two small holes for each rod... You may need "self-aligning" rocker arms. I am just tossing out ideas right now...

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

NORT

They are self-aligning rockers. That is what all L31 heads require. I am confident I did not bend any push rods and I know the heads are assembled correctly. I wonder if it is possible that I got a bad set of lifters or that it does require different push rods than stocks.............NORT

SCRA rules!

I have the same cam and heads...I'm using Comp 981 springs. I also have a lot of valvetrain noise that I don't like and tried adjusting valves several times like yourself to no avail. When I later learned of the tall, huge diameter valve guide boss on the vortecs, I thought the spring damper was sitting too high on the guide boss (it doesn't fit over it) and binding, so I took out all the dampers-that didn't help the noise any.
I did notice that the little spring that goes around the valve seal was mashed on a couple of valves. I believe what is happening is that the bottom of the retainer is just contacting the top of the guide boss and seal, making the noise and harming the the top of the valve seal in some instances. The proper thing to do would be to take the heads off and have the bosses machined down to normal size so you can run any spring you want. Also would be a good time to enlarge the pushrod holes and go to screw-in studs and guideplates if it were me...I have head studs and can't take off the heads w/o removing the engine, so it's gonna wait awhile. If it's any consolation, I have over 20,000 miles on my engine, and there has never been any problems caused by this situation, aside from the noise.

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'93 2wd truck
408 sb, vortecs, 454 TBI, Comp Cam, dual exhaust

[This message has been edited by SCRA rules! (edited April 28, 2001).]

NORT

Thanks for repleying to my question, I had the valve guides cut down when I did the cam job, I had already been told about that little problem so I took care of it right then. The guy at the machine shop said that I should be good for up to a .512 lift now. Does your motor sound like it just needs the valves adjusted? Mine sounds kind of like a deisels valve train. I'am also useing the Comp. 981 springs, I wonder if they all sound that way with this setup? Are you using the stock L31 rocker arms? I am and wonder if thats not what is doing it. NORT

SCRA rules!

Damn! You just shot down my theory about the retainer hitting the boss and causing the noise... I don't know what would be causing it then. My noise does kind of have that diesel type sound that you mentioned. I am using the Comp self-aligning, roller tipped, stamped rockers (1.5). Apparently, it's not the rockers causing the noise either if you're using stock ones. Now I'm stumped again. The only other thing that I can think of would be the header gaskets at the head leaking, but I've had my engine in and out twice, with different header gaskets. The noise was the same both times and has never gotten better or worse. Maybe these cams just make this noise all the time...

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'93 2wd truck
408 sb, vortecs, 454 TBI, Comp Cam, dual exhaust

NORT

It sounds as if you are as confused as I am, I guess that I will call Comps tech line on Monday and see what they have to say.If they have anything to tell me that will put any light on this subject I will post another post on the same sight as we are on now under the heading of (Nosey valvetrain again) I am glad to hear you say that you haven't had any problems as yet with yours, you have to admit that noise will make a person nervous I sure hope Comp. has some idea!!! NORT

NORT

I'am e-mailing you about your comments on the thirdgen site. My question was about my noise valve train, it's still very loud and I have adjusted the rockers 10 times, I even broke down and did it the engine running (what a mess) and I still can't get it to quite down, it sounds like a diesel. the car seems to be running well but just noise as all H--l. What you said about trashing a lifter will that sound like the rockers are loose? I set the valves just as the Comp. instructions 0 lash and one half turn, I even went up to a full turn and it didn't change how it sounds. I have it back around a half turn now, The engine noise is louder than the exhaust and that is a far cry from quite. I would realy appreicate your imput on this matter. If I have to get another set of lifters so be it I just want to get the D--n thing right so I can go racing and see what all this money I have spent was worth it. Looking forward to hearing from you. Thanks NORT
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NORT

I have called Comp. and they weren't much help as to why our engines are so loud the valve train that is, I adjusted mine with the engine runnig today and didn't get anywhere with it. The engine seems to be runnig well but the engine is still louder than the exhaust and my exhaust isn't very quite. I'am looking into the possibilty that we may have some bad lifters. If you figure anything please let me know. Thanks NORT

SCRA rules!

I sure will-thanks for the info.

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'93 2wd truck
408 sb, vortecs, 454 TBI, Comp Cam, dual exhaust