jahajazz

Hi All,

Here is a video of the noise:

[autostream]http://autostream.com/camaroz28/?page_type=firebirdplayerthumbnail&framepage=2807& transactionid=1380819403-209234137135&posted_by=jahajazz_www.camaroz28.com& youtube_video_id=20nFw6aJv2s[/autostream]

This noise only occurs when the engine is HOT. When COLD, the engine is totally quiet.

Heres some valvetrain specs:

-1.65 Comp Gold Roller Rockers
-Lunati VooDoo 60121 (Duration @ .050 (Int/Exh): 221/229) .567 / .583 Lift with 1.65 Rockers
-LS7 Hydraulic Lifters 12499225
-Hardened Comp 7609-16 5/16" Pushrods

Preload set around .80", or about 1.5 turns. Less preload then this had a loud ticking noise. To the best of my understanding, the LS7 Lifter has .160" total travel, and the goal is to be in the middle of the lifer travel.

Looking at the valve covers, there are no worn marks indicating touching.

My current theory is there is some lack of pushrod-head clearance. I just pulled a pushrod last night and I found a shiny mark about halfway down the rod where some flashing from the sticks out a bit.

Thinking of something like this case:
Valve Train Noise Fixed - LS1TECH

Anyone have some other thoughts? If the head is rubbing on the say 4 of the rods, could this cause this noise? Is it only loud when hot because the head is growing and taking up all the head-pushrod clearance?

Thanks for ideas on this.

RamAir95TA

1.5 turns? That's absurd. I have found LS7s operate best at 1/4 TPZL.

jahajazz

Im glad you've found success running LS7 lifter with that little preload. With my setup, the amount of lifter clack at the that small about of preload was very intense.

The Anatomy of a Hydraulic Lifter - Corvette Forum


Crane recommends 2 full turns with their roller rockers on a LS3 (which came with the LS7 Lifter)
http://www.cranecams.com/uploads/instructions/561e_.pdf

Lastly, Comp Cams confirmed with me that 1.5 turns was reasonable for the LS7 lifter, which has a large about of travel.

I get you may run them at 1/4 turn and that works for you. when I tried that, it completely did not work. Based on GM data, Crane, and Comp, 1.5 - 2 full turns with an LS7 Lifter is most definitely not absurd.

97WS6SCharged

If it's taking 1.5 turns to hit your preload then your pushrods are likely too short which is throwing off the rocker geometry. Pull a few rocker arms and check the stems to see where the rocker tip is riding.