[jclift]

Has anyone successfully swapped a cam without removing the heads on an LT4 motor?

[ZLRob]

If sticking to a DOD capable cam then yeah it's possible to do a cam swap without removing heads. If you are deleting the DOD setup then heads have to come off. The question here, is if the engine is out and opened up, why would you not remove the heads to do a DOD delete? That hardware has a known track record for premature failures.

[Mark R]

What is DOD?

[Joshinator99]

Originally Posted by Mark R

What is DOD?

Displacement On Demand. Aka Active Fuel Management “AFM”.

[Mark R]

Originally Posted by Joshinator99

Displacement On Demand. Aka Active Fuel Management “AFM”.

I didn't think the LT-4 had that, only the naturally aspirated v-8's.

[Megahurtz]

Originally Posted by Mark R

I didn't think the LT-4 had that, only the naturally aspirated v-8's.

It still has the DOD lifters even though some LT4 vehicles don't have the featured enabled.

[Joshinator99]

Originally Posted by Mark R

I didn't think the LT-4 had that, only the naturally aspirated v-8's.

Believe the AFM lifters are still in the engine though even though AFM is not active on that engine.

Edit: Megahurtz beat me to the punch.

[KingLT1]

LT OHV engines (L83,L84,L86,L87,LT1,LT2,LT4) have AFM/DOD engine internals. Only the L8T and LT5 do not. Some vehicles that are LT engine equipped with AFM/DOD hardware have the feature disabled in the ECM.

[ZLRob]

Originally Posted by Mark R

I didn't think the LT-4 had that, only the naturally aspirated v-8's.

Yeah, so the story with the LT4 is that the hardware for it is in place, lifters, VLOM integrated into the valley, and the cam as well, but anything required to activate it is disabled within the PCM parameters from the factory... I highlight the problem again though, because the hardware is in place (particularly the lifters) there is a HIGH chance of one or more of them collapsing under normal operation because of how complex and cheaply built they are. If you are going to remove DOD lifters though you need to change the cam for it as well.

[SOCAL.M6.ZLE]

Originally Posted by jclift

Has anyone successfully swapped a cam without removing the heads on an LT4 motor?

Simple answer is YES, you can... The better question might be (should I)

How many miles on the car?

[L98 Z28]

All ZL1 LT4s have AFM disabled? My manual ZL1 does not have AFM (is it just disabled?), but I thought the 10-spd automatics had AFM. My GF's (8-spd automatic) CTS-V LT4 has AFM enabled and I don't like it.

[mlee]

Originally Posted by L98 Z28

All ZL1 LT4s have AFM disabled? My manual ZL1 does not have AFM (is it just disabled?), but I thought the 10-spd automatics had AFM. My GF's (8-spd automatic) CTS-V LT4 has AFM enabled and I don't like it.

No AFM on my 2024 ZL1 auto

[RobZL1]

Originally Posted by L98 Z28

All ZL1 LT4s have AFM disabled? My manual ZL1 does not have AFM (is it just disabled?), but I thought the 10-spd automatics had AFM. My GF's (8-spd automatic) CTS-V LT4 has AFM enabled and I don't like it.

Originally Posted by mlee

No AFM on my 2024 ZL1 auto

Exactly what these guys have said. No ZL1's have it enabled, but unfortunately all the hardware is physically there in the motor. The only performance vehicles that don't have the hardware are the ZR1 and the Escalade V.

[L78toLT1]

Originally Posted by SOCAL.M6.ZLE

Simple answer is YES, you can... The better question might be (should I)

How many miles on the car?

Is the simple answer really YES? I've had my motor apart more times than I can count, and I don't see how it would be possible. I suppose if you're swapping in another DOD cam, it may be possible to remove the rockers and pushrods and raise the lifters one at a time with a magnet while working the new cam in. I don't think you can remove the lifters without removing the heads, and assuming that you can't, i cannot envision a scenario that would involve replacing a cam and retaining the oem dod lifters