Gotta do a Rebuild, Gonna Upgrade Too

[intergalactron]

So... My motor has to come out due to an AFM lifter failure. At 120K miles, I figure a total rebuild is in order. And if I have to do a rebuild, I'm gonna upgrade a bit. Nothing wild, just a little more pep. Starting to research parts. Anyone got experience with this?

1. Without a doubt, the AFM comes off. No brainer there.
2. What are the pros and cons of removing the VVT?
3. Cam, lifter, valve springs, etc., suggestions?

 

[Joseph Garcia]

Texas Speed and Summit Racing have kits available to replace AFM. Give one of them a call and see what they include in their kits.

 

[Geotrash]

So... My motor has to come out due to an AFM lifter failure. At 120K miles, I figure a total rebuild is in order. And if I have to do a rebuild, I'm gonna upgrade a bit. Nothing wild, just a little more pep. Starting to research parts. Anyone got experience with this?

1. Without a doubt, the AFM comes off. No brainer there.
2. What are the pros and cons of removing the VVT?
3. Cam, lifter, valve springs, etc., suggestions?

I don't have any direct experience with the LT motors, but on the GenIV LS 6.2 in my 2012 (L94), I went with a 3-bolt cam (no VVT) and am thrilled with it. VVT on the LS engines was only good for maybe 15hp, which is easily made up for with a bigger "truck cam". Maybe someone who's upgraded their L86 will weigh in.

 

[intergalactron]

Did more tear-down over the weekend. There was an obvious difference between the driver side and passenger side as far as tightness of rocker bolts, head bolts, etc. Leads me to believe that this motor had work done on the driver side before I got it. I purchased the truck in February 2021, with ~42000 miles.

 

[intergalactron]

No going back now.

 

[intergalactron]

Does anyone know what size the head of the rod bolts are?

 

[intergalactron]

Does anyone know what size the head of the rod bolts are?

Looks like they are a 12mm Hex head. Can anyone confirm? I was worried that they were a 12-point or something weird.

 

[Geotrash]

Does anyone know what size the head of the rod bolts are?

Should be 12mm 6-point.

 

[Marky Dissod]

What are the pros and cons of removing Variable Cam Timing?

My understandings:
GM's Variable Cam Timing retards or advances the cam relative to the crank
How GM uses it, chief benefit is MpGs in conjunction with advanced timing,
2ndary benefit is improved very low RpM torque.

Some aftermarket cams require limiting / reducing VCT's 'degrees of authority',
others require complete VCT removal; depends on the cam & valvesprings chosen.
Stiff valvesprings overcome VCT.

(Older I get, more I'd prefer a 6.0L or 6.2L, much moreso for strength UNDER 3500RpM -
I drive like I'm always running late, and even with an aftermarket pcm tune,
I STILL spend most of the time UNDER 3500RpM,
so that's where I'd want the biggest improvement - the moment I hit the pedal, not after.
I'd keep consider keeping VCT, maybe with a VCT limiter, to improve low RpM.
I'd not sacrifice ANY low RpM torque for more power at higher RpMs
because of how little time I spend over 4500RpM.)

 

[intergalactron]

Looks like they are a 12mm Hex head. Can anyone confirm? I was worried that they were a 12-point or something weird.

11mm hex head turned out to be the size.