Comp Cams 206/206 lifter noise

[BW Jones]

plugs

the 'stock AC Delco spark plugs' that originally came in your car were 44's. if you are still using these, it would be beneficial to change to the 43's (a heat range cooler). i would not advise going with the 42's however. as crazy as this seems, i've seen more than one car develope knock problems when the 43's were replaced with 42's.
bw jones

 

[wordy1]

I think they are 43's actually, I assumed these were stock.. learn something new everyday.

 

[Turbo1dr]

I think it's a "hit or miss" deal to get lifters quiet in these V6's. I've put in cams before that were quiet and then some that were noisy. I've replaced the loud lifters with different brands only to get the same thing again. I've found that if you want a quiet cam get solid lifters and adjust them. A solid lifter on a hydralic cam does not have to be noisy. It may take a couple of adjustments to get them set.

 

[wordy1]

At the advice of my mechanic we installed GM lifters today, noise is the same... Looks like its a cam issue, any chance of me getting a refund from CompCams?? Am looking for a cam now, anyone have suggestions on a better company? Also, found out today that the valve springs are stock GM 87 GN replacements, would this be a good time to replace them?

 

[WiskeyJack]

Roller Rockers

Just wondering are you running roller rockers?

 

[wordy1]

Nope, stock rockers..

 

[8UWITH6]

This is kind of new to me. My Comp Cams 206/206 has been in my GN for almost 10K miles with absolutely no problems. Only one time can I ever remember when I had a slightly louder than normal ticking noise from the valvetrain. It was after the car had sat for a while and my good friend Quick6'N'KC put it to me plain and simple......... "drive the car more!" LOL. So I changed the oil, drove the car a little more often and I have not heard anything since. I guess I will have to wait and see what happens at 15K miles huh?

 

[WiskeyJack]

Tick

I can't understand how a cam can make lifter noise unless you have a bent pushrod. Or a worn rocker Did you check pre-load on each lifter to see how far the plunger on each lifter is being pushed down. may have a loose one and that points to the cam being ground wrong or rocker worn or bent push rod.
For what it's worth my motor with the 212/212 sounds like an old LT1 solid lifter Chevy 350 but I think it's rocker noise. I'm getting use to it. BUT I don't have knock showing up either.

 

[wordy1]

I guess I'll just have to get used to it, everything else checks out fine..

 

[1 quik6]

I guess I'll just have to get used to it, everything else checks out fine..

Don't get used to that KR though. It sure sounds to me like you're running out of injector too. Good Luck!

 

[fubar2.5]

Are they "0" lash lifters?

 

[Chuck Leeper]

Just my $.02

1. Aggresive accel ramps on the cam can make for noisey lifters.
2. Using a street chip with hi boost, and race gas is not the optimal combo...Street chips usually have more timing in them.
3. If the rockers are worn, they will "rattle" on the shafts.
4. AC plugs, nor any others, will likely not perform well at 25 psi, and "stock gaps". At that cyl psi, there's too much chamber pressure to allow a stock ign to work well.
We've seen nearly 50RWHP just by pulling the plug gaps down to .028"
5. The knok sensor should be torqued to 14 #/ft.

 

[8UWITH6]

NGK UR5's Part # 2771 @ Napa here......... gapped at a tight .030" HTH!

Good Idea CHUCK LEEPER, Wordy1 pull your rockershafts and see if they rattle around on the shaft! GL!

 

[Turbo1dr]

Something else to consider, if the valve guides are worn and you don't have roller rockers it puts excessive side loads on the valve. When they close it can cause them to snap against the seat.

 

[ChrisF]

Comp Cams

I have ALWAYS had good experiences with Comp, including a few 455 Buick buildups. Ran like raped apes.

I seem to remember Kenne Bell or Poston's possibly making a statement in a catalog some years back stating that the Buick lifter diameter for the Buick V8's were slighly larger than Chevy, and to be careful to use only theirlifters. Does anyone else remember that? I wonder if it's fact and Comp gave you Chevy lifters?

That being said, I wish the Buick valvetrain was designed without the rails like a Chevy, every Buick engine I have ever owned including my GN has had a noisy valvtrain, short of a roller setup or adjustable pushrods.

Also sounds like it's leaning out causing the KR.

HTH
Just my 2 cents.

 

[87GN_70GS]

Valve noise can also come from the valves closing due to higher seating velocity.

Buick's and Chevy's have 0.842" lifters, same diameter.

 

[wordy1]

it may be helpful for you to post some scan tool readings & fuel pressure values. also, what spark plugs are you using and what's their gap set at? you could have a variety of other things causing the knock problem which are masked by the lifter noise.
just something to consider ....... :smile:
bw jones

Finally got the car out to take a reading.

93 octane, 15 psi of boost, 43 psi of fuel pressure at idle, 58 psi at full boost. Using a TT chip. Only a little KR, but not too bad... If I add some fuel to the chip, you guys think I can turn it up a little?