Can bad rocker arm adjustment cost me 100rwhp?

[Highlander]

my recent dyno after all the headaches with tuning net 387rwhp...

I have heads and cam and that same combo netted on a camaro 484rwhp on an ls1 block... cam is 226/230 113lsa

Any ideas????

afr was from 11.6 to 12.2 at the end

the dyno wb was reading 10.6 to 12.6....

still, tuning will not net 100rwhp.

[bink]

my recent dyno after all the headaches with tuning net 387rwhp...

I have heads and cam and that same combo netted on a camaro 484rwhp on an ls1 block... cam is 226/230 113lsa

Any ideas????

afr was from 11.6 to 12.2 at the end

the dyno wb was reading 10.6 to 12.6....

still, tuning will not net 100rwhp.

Not trying to be a smart aleck...but how bad is "bad" (sound like Bill Clinton?). If your preload is insufficient (hydraulic?) it will definitely be down on power.
Did you degree the cam in?

[superls1]

Several things to consider:

What kind of Dyno? I ask, but because I have seen first hand the inaccuracies of a DynoJet simply based on the position of the ambient air temperature sensor.

Can you post a graph? Bink raises a good point about whether or not the cam was installed correctly. Were there specific ICL directions for the cam? Did it make a torque curve similar to the other car you mention, or is the graph "shifted" to the left or right?

I agree with Bink, "how bad is 'bad'"? If one of your intake valves never opens, then that is a fairly costly error. If each cylinder is producing roughly 60rwhp (or should be based on your expectations), then 1 cylinder down will probably cost at least that much. It is pretty easy to take the valve covers off and check lift with a dial guage.

What lifters, rockers, and pushrods (length)?

[Highlander]

Stock rockers, stock lifters...

www.roxanette.com/awfuldyno.jpg
Pushrod length is 7.4 IIRC. This was all sent from cartek.

im down about 70rwtq of what should be expected... honestly i expected 440rwhp here on this dyno etc... still i am 60rwhp DOWN!

if only one cylinder would be off the car would have a heavy miss or imbalance.. the car feels overall w/o the power it should have..
Keep in mind that i did on that same dyno with a headers and intake on a 01 ls6 engine 340rwhp....

You are telling me that with an 04 ls6 block.. ported heads... ported intake... vararam... 226/230 cam i will only gain 47rwhp????? That doesn't sound right.[/url]

[Highlander]

One other thing.. the cam was not degreed... it was installed straight up. besides... that much horsepower on the degreeing of the cam? a degree of the cam can net you 15-20... not 75-100rwhp

[bink]

One other thing.. the cam was not degreed... it was installed straight up. besides... that much horsepower on the degreeing of the cam? a degree of the cam can net you 15-20... not 75-100rwhp

I agree if we're talking about a couple degrees (adv,ret). I'm talking about manufacturing error and/or wrong cam. The only way to know for sure is to degree it and verify lift/duration. 75 - 100 rwhp is a lot left on the bench :( .


How did it sound?? Did it sound tight and healthy?
Cheers,
joel

[bink]

if only one cylinder would be off the car would have a heavy miss or imbalance.. the car feels overall w/o the power it should have..

No, not neccessarily. A miss would be ignition. You will feel a reduction in power if the valves aren't opening/closing fully or are down on a single (or multiple) cylinder(s).
7.4 pr is stock length, right? Which heads are you using LS1 or LS6 ?? Were the heads milled? What's the base circle on the cam?
(LS1 cam has a 19.7mm base circle, 02 and up LS6 cam has a 19mm base circle.)

Cheers,
joel

[Highlander]

This is a z06... and it has an 03 engine... but it could be a mistake on the cam now that you say it.. since... they sent me the wrong studs and had to return them... hmm.. interesting...

The engine does sound tight and healthy.. we did beat a 400rwhp 350z with 2 on the vette and he was alone... and him launching first.. so... there is power there.. but... I would have expected to FLY BY!.

The cam was sent from cartek... and... there was no cam card in the box.

Suggestions?

[Highlander]

if only one cylinder would be off the car would have a heavy miss or imbalance.. the car feels overall w/o the power it should have..

No, not neccessarily. A miss would be ignition. You will feel a reduction in power if the valves aren't opening/closing fully or are down on a single (or multiple) cylinder(s).
7.4 pr is stock length, right? Which heads are you using LS1 or LS6 ?? Were the heads milled? What's the base circle on the cam?
(LS1 cam has a 19.7mm base circle, 02 and up LS6 cam has a 19mm base circle.)

Cheers,
joel

The more i think of it the more i think you are rightl. probably i have an 01 cam... and i maybe hanging the valves a bit open. In this case what is the solution? change the cam? or use a shorter pushrod?

[Brains]

Shorter pushrods, or in a pinch you can shim the rockers. Make sure you verify geometry -- you want the rocker wiping dead center on the valve stem. Easiest way to check is to pull the rocker, paint the tip of the stem with a Sharpie marker, reassemble, and crank the motor over a few times. Pull the rocker and you'll have a nice shiny stripe ;)

[bink]

Shorter pushrods, or in a pinch you can shim the rockers. Make sure you verify geometry -- you want the rocker wiping dead center on the valve stem. Easiest way to check is to pull the rocker, paint the tip of the stem with a Sharpie marker, reassemble, and crank the motor over a few times. Pull the rocker and you'll have a nice shiny stripe ;)

..............and I'd check with Cartek, verifying the goods. :)

[Highlander]

Shorter pushrods, or in a pinch you can shim the rockers. Make sure you verify geometry -- you want the rocker wiping dead center on the valve stem. Easiest way to check is to pull the rocker, paint the tip of the stem with a Sharpie marker, reassemble, and crank the motor over a few times. Pull the rocker and you'll have a nice shiny stripe ;)

I am doing that tonight.. i have my pushrod length checker here :)

[Redline Motorsports]

I do quiet a bit of business with Dave and Julio at Cartek. I know for a fact that they check every cam with a CamDoctor measuring device to ensure that all the cams they get from Comp are correct. If you got it recently that should rule that out.

Howard

[Highlander]

I am not doubting cartek... but since this is a 2001 z06 with a 04 block i can see where a lot of confussion can come in. Specially when it happened with the studs (wrong sent due to year) so it can happen with the cam too. Not bashing cartek, we are all humans and make mistakes. I just want to solve a problem.

[bink]

I am not doubting cartek... but since this is a 2001 z06 with a 04 block i can see where a lot of confussion can come in. Specially when it happened with the studs (wrong sent due to year) so it can happen with the cam too. Not bashing cartek, we are all humans and make mistakes. I just want to solve a problem.

Any news?

Cheers,
joel

[Highlander]

No, no news.. Dave says that they are all the same center circle... i will have to check... I have to measure the pushrod length and let him know...

If you have any other ideas i would love to read them.

[jfpilla]

No, no news.. Dave says that they are all the same center circle... i will have to check... I have to measure the pushrod length and let him know...

If you have any other ideas i would love to read them.

Suggest you check your preload. How many turns from 0 lash to lockdown? 1 1/2 to 2 turns is roughly 60 to 96 preload. If you are in that range or close it's not the valvetrain.