ZL1 LT4 AFM / DOD lifter delete questions

zl1_things · 05-20-2021, 09:31 AM

So I'm new to the LT world and I know these motors have the AFM hardware but the actual activation is set to off in the factory tune.

That being said, I have been doing some reading about deleting the AFM/DOD lifters and have gotten a bit of conflicting info.

Some people say you need a different cam and some say you don't... Near as I can tell only the lifters need to be changed and if so do all the lifters need to be changed or just the intake lifters?

The plugs for the oil passages are they necessary? I have seen some kits come with them and some do not.

Also the cam phaser bolt, again some come with it and some do not... is this a TTY bolt and that is why it needs to be replaced?

KingLT1 · 05-20-2021, 10:58 AM

You have to change cam if you delete AFM/DOD. The cam lobes for the AFM lifters are not compatible with standard hydraulic lifters.

The only way I would reuse the stock Non AFM lifters is if you replacing the cam with a stock Non AFM cam such as the LT5. Other then that I would go with a better set of lifters all together with a more aggressive cam.

pavetim · 10-06-2021, 04:19 PM

Hmmm LT5 that might be too much power. I am doing an LT4 SC swqp onto my lt1 and wanna get a non dod cam. Idk maybe with the lower boost i will run it might be fine?

Flowtie1 · 10-06-2021, 04:41 PM

My understanding is the M6 ZL1 is the only model without the dod . Not just deactivated ?.

pavetim · 10-06-2021, 05:17 PM

Actually i just looked the lt5 amd lt4 camshafys are the same specs minus dod on the lt5 so i guess the lt1 cam is a supercharged cam too

Camaro1973 · 10-06-2021, 08:00 PM

Quote:

Originally Posted by pavetim

Actually i just looked the lt5 amd lt4 camshafys are the same specs minus dod on the lt5 so i guess the lt1 cam is a supercharged cam too

This is incorrect. The cam profiles are totally different.

LT4 is 189/223
LT5 is 200/207

1wraith76 · 10-06-2021, 08:22 PM

I am getting it removed and my tuner said I need a new cam. He is a certified master tech. I only found him when I took my ZLE into the dealership for some work. I trust what he says cause he works on all the high performance Chevys.

Spaceme1117 · 10-07-2021, 06:48 AM

Just reading an article talking about the LT1 engine from MotorTrend: "Speaking of cams, the LT1’s is said to be based on the LS3 and specs out at 200/207 duration at 0.050 and 0.551/0.524-inch lift on a 116.5 LSA, with lift events having been optimized based on the new higher rocker ratio and splayed valve geometry. The cam opening and closing ramps were tailored to accommodate AFM, and as with prior AFM-equipped engines, the cam lobe profiles are slightly different on cylinders that have the deactivating lifters (i.e., cylinders 1, 7, 6, and 4). According to John Rydzewski, “This is always the case with AFM because you have to accommodate some additional lash with the AFM hardware. In addition to that, on both the deactivating and non-deactivating cylinders, we did some work on opening and closing ramps for noise refinement.” He emphasized the slight difference in the cam lobes does not affect airflow cylinder to cylinder."

LT4 cam with DOD should be similar.

I would think that you could run a DOD cam with non-DOD lifters and it would be fine. You would likely need to use different length pushrods for those cylinders. But you would be putting different stresses/forces on those different cylinders which is probably not good.

Definitely better to go with a non-DOD cam. And I am sure if you wanted to stay at stock lift and duration, CamMotion or Comp could make that for you.

As for plugging the oil passages for the DOD, I would do it as it could be a way to loose a lot of oil pressure.

pavetim · 10-07-2021, 07:05 AM

Oh sorry i meant lt5 and lt1 cams are the same

05-20-2021, 09:31 AM	#1
zl1_things Drives: '17 ZL1 A10 Join Date: Jun 2020 Location: Sacramento CA Posts: 59	ZL1 LT4 AFM / DOD lifter delete questions So I'm new to the LT world and I know these motors have the AFM hardware but the actual activation is set to off in the factory tune. That being said, I have been doing some reading about deleting the AFM/DOD lifters and have gotten a bit of conflicting info. Some people say you need a different cam and some say you don't... Near as I can tell only the lifters need to be changed and if so do all the lifters need to be changed or just the intake lifters? The plugs for the oil passages are they necessary? I have seen some kits come with them and some do not. Also the cam phaser bolt, again some come with it and some do not... is this a TTY bolt and that is why it needs to be replaced?

05-20-2021, 10:58 AM	#2
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,800	You have to change cam if you delete AFM/DOD. The cam lobes for the AFM lifters are not compatible with standard hydraulic lifters. The only way I would reuse the stock Non AFM lifters is if you replacing the cam with a stock Non AFM cam such as the LT5. Other then that I would go with a better set of lifters all together with a more aggressive cam. __________________ 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

10-06-2021, 04:41 PM	#4
Flowtie1 Drives: 2017 ZL1 Join Date: Apr 2020 Location: South florida Posts: 332	My understanding is the M6 ZL1 is the only model without the dod . Not just deactivated ?. __________________ 2017 ZL1 M6 Silver Ice Metallic

10-06-2021, 04:19 PM	#3
pavetim Drives: firebird Join Date: Jan 2010 Location: valdosta, georgia Posts: 155	Hmmm LT5 that might be too much power. I am doing an LT4 SC swqp onto my lt1 and wanna get a non dod cam. Idk maybe with the lower boost i will run it might be fine?

10-06-2021, 05:17 PM	#5
pavetim Drives: firebird Join Date: Jan 2010 Location: valdosta, georgia Posts: 155	Actually i just looked the lt5 amd lt4 camshafys are the same specs minus dod on the lt5 so i guess the lt1 cam is a supercharged cam too

10-06-2021, 08:22 PM	#7
1wraith76 Drives: None Join Date: Jan 2018 Location: MN Posts: 40	I am getting it removed and my tuner said I need a new cam. He is a certified master tech. I only found him when I took my ZLE into the dealership for some work. I trust what he says cause he works on all the high performance Chevys.

10-07-2021, 06:48 AM	#8
Spaceme1117 Drives: 2017 Camaro SS, 2011 Corvette GS Join Date: Feb 2019 Location: Erlanger, Kentucky 41018 Posts: 815	Just reading an article talking about the LT1 engine from MotorTrend: "Speaking of cams, the LT1’s is said to be based on the LS3 and specs out at 200/207 duration at 0.050 and 0.551/0.524-inch lift on a 116.5 LSA, with lift events having been optimized based on the new higher rocker ratio and splayed valve geometry. The cam opening and closing ramps were tailored to accommodate AFM, and as with prior AFM-equipped engines, the cam lobe profiles are slightly different on cylinders that have the deactivating lifters (i.e., cylinders 1, 7, 6, and 4). According to John Rydzewski, “This is always the case with AFM because you have to accommodate some additional lash with the AFM hardware. In addition to that, on both the deactivating and non-deactivating cylinders, we did some work on opening and closing ramps for noise refinement.” He emphasized the slight difference in the cam lobes does not affect airflow cylinder to cylinder." LT4 cam with DOD should be similar. I would think that you could run a DOD cam with non-DOD lifters and it would be fine. You would likely need to use different length pushrods for those cylinders. But you would be putting different stresses/forces on those different cylinders which is probably not good. Definitely better to go with a non-DOD cam. And I am sure if you wanted to stay at stock lift and duration, CamMotion or Comp could make that for you. As for plugging the oil passages for the DOD, I would do it as it could be a way to loose a lot of oil pressure.

10-07-2021, 07:05 AM	#9
pavetim Drives: firebird Join Date: Jan 2010 Location: valdosta, georgia Posts: 155	Oh sorry i meant lt5 and lt1 cams are the same

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