Knock above 6300

Wilka_SS · 10-05-2019, 10:40 PM

Just installed a custom speced boost cam from tsp with tsp cnc heads decked 5 thou. Cam spec is 635/635 227/239 on a 115lsa, vvt is locked at zero. Standard ls7 lifters and ls2 trays, I do have tsp lt roller rockers increasing my ratio to 1.82 over the standard 1.8. I measured pushrod length using the comp cams 7702 tool I believe is the number and with 50 thou preload on intake and 70 thou on exhaust cam out to 7.825 push rod length. My question is with the rocker ratio change putting my lift at 641.9 am I getting piston to valve under high load or am I losing control of the spring because of the increased weight of the roller rocker? I asked texas speed and they said I should have no issues but looked at a cam from cam motion with similar lift and slightly different duration and it requires pistons with bigger valve reliefs or knotching or (flycutting) of factory piston. I've double checked my exhaust and motor mounts, haven't found anything loose. And verified knock still there with e85 and is rpm related.
Car only has 18 degrees of timing in it and me and my tuner both agree to not add anymore until the knock is sorted. I will add I removed baffles inside my valve cover because I found the roller rockers hitting the valve cover but can no longer find witness marks on the valve cover. Consulted with tuner and got my valve events from texas speed and adjusted soi and eoi tables accordingly to the cam. Any feedback is appreciated. Fixing to switch back to stock rockers and see if the roller rockers are my problem with factory length pushrods but just seeing if anyone else ran into this issue before.

Camaro_QC · 10-05-2019, 11:18 PM

Wrong sections

Wilka_SS · 10-05-2019, 11:21 PM

Thought I clicked troubleshooting/ diagnostics, sorry.

KingLT1 · 10-06-2019, 09:42 AM

It's likely false knock.. adjust the knock sensor sensitivity.

Wilka_SS · 10-06-2019, 11:35 AM

Quote:

Originally Posted by KingLT1

It's likely false knock.. adjust the knock sensor sensitivity.

I've done that as much as my tuner feels comfortable doing and its still there.

Wilka_SS · 10-06-2019, 10:46 PM

bump?

Undxrtaker · 10-07-2019, 08:23 AM

I'd report your post and try to get it moved to the right section. You would probably get a better response.

Wilka_SS · 10-07-2019, 09:00 AM

Quote:

Originally Posted by Undxrtaker

I'd report your post and try to get it moved to the right section. You would probably get a better response.

I thought everyone just clicked on new post or today's post and scroll 1 or 2 pages, at least that's what I do lol

Undxrtaker · 10-07-2019, 09:10 AM

Quote:

Originally Posted by Wilka_SS

I thought everyone just clicked on new post or today's post and scroll 1 or 2 pages, at least that's what I do lol

Not me. I click the subforums of the stuff I feel like reading about lol

10-05-2019, 10:40 PM	#1
Wilka_SS Drives: 2016 Nightfall Metallic Grey 2ss Join Date: Oct 2017 Location: New Orleans, LA Posts: 121	Knock above 6300 Just installed a custom speced boost cam from tsp with tsp cnc heads decked 5 thou. Cam spec is 635/635 227/239 on a 115lsa, vvt is locked at zero. Standard ls7 lifters and ls2 trays, I do have tsp lt roller rockers increasing my ratio to 1.82 over the standard 1.8. I measured pushrod length using the comp cams 7702 tool I believe is the number and with 50 thou preload on intake and 70 thou on exhaust cam out to 7.825 push rod length. My question is with the rocker ratio change putting my lift at 641.9 am I getting piston to valve under high load or am I losing control of the spring because of the increased weight of the roller rocker? I asked texas speed and they said I should have no issues but looked at a cam from cam motion with similar lift and slightly different duration and it requires pistons with bigger valve reliefs or knotching or (flycutting) of factory piston. I've double checked my exhaust and motor mounts, haven't found anything loose. And verified knock still there with e85 and is rpm related. Car only has 18 degrees of timing in it and me and my tuner both agree to not add anymore until the knock is sorted. I will add I removed baffles inside my valve cover because I found the roller rockers hitting the valve cover but can no longer find witness marks on the valve cover. Consulted with tuner and got my valve events from texas speed and adjusted soi and eoi tables accordingly to the cam. Any feedback is appreciated. Fixing to switch back to stock rockers and see if the roller rockers are my problem with factory length pushrods but just seeing if anyone else ran into this issue before.

10-05-2019, 11:18 PM	#2
Camaro_QC Drives: 08 Tiburon GS, 2018 Camaro 2.0T Join Date: Sep 2017 Location: Québec Posts: 1,660	Wrong sections __________________ 2018 Camaro LS \| 6 spd \| 2.0L turbo \| Nightfall Grey \| RS package \| Technology Package. --------------------- Order WDGHKX 1100 - 5/08/2018 \| 3800 - 6/18/2018 2000 - 5/09/2018 \| 4200 - 6/21/2018 3000 - 5/28/2018 \| 5000 - 6/27/2018 6000 - 6/29/2018

10-06-2019, 09:42 AM	#4
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,800	It's likely false knock.. adjust the knock sensor sensitivity. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

10-05-2019, 11:21 PM	#3
Wilka_SS Drives: 2016 Nightfall Metallic Grey 2ss Join Date: Oct 2017 Location: New Orleans, LA Posts: 121	Thought I clicked troubleshooting/ diagnostics, sorry.

10-06-2019, 10:46 PM	#6
Wilka_SS Drives: 2016 Nightfall Metallic Grey 2ss Join Date: Oct 2017 Location: New Orleans, LA Posts: 121	bump?

10-07-2019, 08:23 AM	#7
Undxrtaker Drives: 2019 2SS Camaro Join Date: Jun 2019 Location: Texas Posts: 26	I'd report your post and try to get it moved to the right section. You would probably get a better response.

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