I just finished my LT1 swap a few weeks ago, and Ive got a fair bit of valvetrain clatter out of it. Ive got 1.6 rockers from the hotcam kit, how much noise will they make? The lifters have 60K on them...but it doesnt seem to be running bad...other than a knock sensor code (would this be related to the clatter?)

Also, would billet valvecovers amplify this noise?

 

Forgot to mention that it does have an LT4 Knock module in it...

I am worried that something isnt right in there and that is whats freaking out my KS.

 

My rockers are pretty noisy too, especially with the hood open. I've heard that many other people experience the same thing with the Hotcam Kit, and that this is perfectly normal. If it's a smooth, dull noise coming from all 16 rockers, then you're alright. However, if it's a sharp tappity-tap then you probably ought to look into it.

 

LT4 KM was designed due to valvetrain noise from rockers - so actually you have the rockers installed that the KM was acutally designed for. so i would doubt that is freaking out your KM. If you have headers valvtrain noise is going to be amplififed so keep that in mind. But the 1.6 rockers etc. are going to be more loud than stock period. Can you describt the noise? IS it a clack sound or clicking sound? If a clack perhaps collapsed lifter...clicking noises are usually somewhat normal if your valvtrain is adjusted right (verify lash is properly set).

EDIT: keep in mind, your knock sensor is nothing more thana microphone of sorts that is picking up noise from the engine. The knock module is what actually processes those noises (baseed on programmed criteria) and decides what is knock and what is not. The LT4 KM was programmed to ignore frequencies caused by the LT4 valve train and not report the false knock. So your knock sensor can never be "freaked out", it doesn't technically DO anything. It's a completely passive device. The KM also only reports knock to the PCM which then determines timing adjustemnts for said knock.

 

Ive got my rockers all set at a half turn past zero lash, and Ive done them twice recently because of these noises.

Ive got the normal clattery rocker sound, but its a more defined "clack" at low RPM under load (like in overdrive 1500-2000 rpm) and on deceleration when the engine idles down I seem to hear it more. I hear it a bit at any constant RPM also, unless its higher, but the exhaust overtakes it then.

It was throwing no codes before I sent the PCM off for a reprogram due to trans problems, as soon as I got it back it started throwing the code. At this time I noticed the noise (but it may have already been there). Ive had the PCM re-programmed again to try to see if it was the tune that threw the code, but it wasnt. But for the two weeks the computer was gone, the car just set in the driveway...I wouldnt know where the code would have just appeared from???

 

any other ideas? I am trying to get an idea of whether the lifters sound like a culprit, so that if I need to order new ones I can get on it soon. From the looks of what people say, I will end up going with the Comp R's.

 

I have a slight clicking sound coming from my left heads. what is this a lifter...I could name off alot of stuff what could it be?

 

Did you put a new sensor in when you swapped engines? I know I've had 2 KS's go bad on me

 

Its got a brand new Knock Module in it, and an LT4 Knock Sensor. I guess I will just pull the covers first and check to make sure everying on the heads is in order. If I take and push on the top of a rocker and its got a bad lifter, will I be able to feel it move more than the others? To determine this before I pulled the intake would be nice, just incase I dont have to go through that much extra work.

 

You mean it has a LT4 knock module and a new knock sensor

What exactly is the code you are throwing?

 

I cant remember the code number... Id have to scan it again for sure.

Tonight I am going to drain the oil and check it for metallics (worst case scenario). I also went ahead and ordered a set of Comp R's. Might as well change them broken or not...better safe than sorry. They only ran me 202.00 shipped, so thats not too bad.