Is Trimalyzer for SD tunes only

[A95Y]

I just got back with a 2* change before I saw your message. What does the pattern suggest? My headers are close to knock sensors. I had to a put a 5 qt. pan back on and remove my winged pan. I nailed it a couple times on this 32 minute drive.

[steveo]

usually real knock runs along the map axis, like your WOT knock where you 'nailed it', that looks like real knock (in red)

the many tiny knock events around 2k rpm could be a rollerized valvetrain or some other harmless mechanical noise that really peaks out near that 2k rpm point screwing with your knock sensor

[A95Y]

Thanks for the reply. I have CTS-V lifters, Scorpion non-aligning aluminum rockers with guideplates. Are these inherently noisy?

[steveo]

could be but who knows
every engine is different

[LeMarky Dissod]

… CTS-V lifters, Scorpion non-aligning aluminum rockers with guideplates. Are these inherently noisy?

Oh Yes indeed.
The nonmetallic valvecovers and the hard-to-find overpriced 16214681 knock module were specifically for the LT4's noisiER valvetrain.

[A95Y]

Oh Yes indeed.
The nonmetallic valvecovers and the hard-to-find overpriced 16214681 knock module were specifically for the LT4's noisiER valvetrain.

Those components are installed.

[A95Y]

I installed a set of tall aluminum valve covers to see if there was any difference. There was not. My small alternator was not charging, so I was in a hurry and stayed in third most of the time. I still need to address the 95 kpa knock.

[steveo]

the lt4 had lighter valves too
try the original knock module to see if its better

[spfautsch]

I have CTS-V lifters, Scorpion non-aligning aluminum rockers with guideplates. Are these inherently noisy?

I've run numerous guideplate setups with two different non-aligning roller rockers (one chromoly steel and one stainless bodied) and had all sort of false knock issues ('95 Y-body LT-1).

After switching to the Scorpion shaft mount setup referenced in my signature, and Morel solid roller lifters (only needed due to very high spring load) I can finally drive an hour or two with zero knock events. Had I gone the shaft mount rocker setup from the start I would have had $500 more to spend on other fun stuff. You live and you learn.

FWIW - just speaking from experience. Not everyone has false knock problems with roller rockers. My suspicion is it's more prevalent with aluminum head engines and first-gen ODBII ecu programming (and dual knock sensors).

[A95Y]

I've run numerous guideplate setups with two different non-aligning roller rockers (one chromoly steel and one stainless bodied) and had all sort of false knock issues ('95 Y-body LT-1).

After switching to the Scorpion shaft mount setup referenced in my signature, and Morel solid roller lifters (only needed due to very high spring load) I can finally drive an hour or two with zero knock events. Had I gone the shaft mount rocker setup from the start I would have had $500 more to spend on other fun stuff. You live and you learn.

FWIW - just speaking from experience. Not everyone has false knock problems with roller rockers. My suspicion is it's more prevalent with aluminum head engines and first-gen ODBII ecu programming (and dual knock sensors).

That's interesting. I've looked at shaft rockers in the past and was dumbfounded by the cost. Why the .200 offset? What kind of valve covers do you have?
To test this on my car, I have some roller tipped stamped steel rockers in a box somewhere from days gone by. Can I leave my guide plates in for a test? I am thinking not.

[spfautsch]

That's interesting. I've looked at shaft rockers in the past and was dumbfounded by the cost. Why the .200 offset? What kind of valve covers do you have?

Thanks. Here's a crappy video showing some of the necessary mods. [link] (81mb)

I was also initially dumbfounded by the cost, until I owned two sets of very expensive stud mount roller rockers, two sets of custom length pushrods, three sets of adjustable guideplates, and all the time I wasted trying to make it all work. Hindsight is what it is.

Stock valve covers but some of the supports had to be trimmed to clear the shaft mount bases. Slightly modified 3/8" thick perimeter bolt standoff spacers were glued to the heads with rtv to give necessary clearance. Longer center studs were custom fabricated by a guy with a tig welder and lathe who needed an excuse to (use them / get away from his wife). Getting the stud height correct (the seals want about 0.040" crush) was the toughest part. The 0.200" offset corrects the difference between lifter bore centerlines and valvestem centerlines so there's no lateral deflection. Added bonus here is there was some seat of pants increase to be felt with the shaft mount setup due to eliminating all valvetrain deflection.

If I had it to do over again I would have spent more time milling the 3/8" standoffs so the valvecovers would have fit better.

To test this on my car, I have some roller tipped stamped steel rockers in a box somewhere from days gone by. Can I leave my guide plates in for a test? I am thinking not.

I doubt your roller tipped stamped rockers are self-aligning, and even if so the guideplates themselves are a possible source of noise. Without the 0.200" offset there is no way to get stud mounted rockers to align with the valve stems without having the pushrods non-parallel, which causes sideways deflection. The rocker arm tip is pushing down on the valvestem, while the spring load causes the rocker arm to want to sweep away from the cylinder bore center, loading the pushrod against the guideplate.

[A95Y]

Thanks for making that video. It's very informative and you have done a really nice job there.
When I first read the post, I read it as you getting .040 crush on the valve stem seal. I'm thinking, how in the hell am I ever going to figure that out. lol

I have a set of tall valve covers I can use while I'm trying to figure out doing it the way you did or maybe an alternative method.

Do you have to shim the mounting surface to get the proper rocker arm sweep on the valve stem? Is the preload and final adjustment done with the adjuster?

Do you just bolt them down and set your lash?

Thanks

Edit: was your knock similar to what shows in my graph?