Gen V L83 AFM Delete

[clinebarger]

This was on our own JP_Property's 2016 Silverado with IIRC 116,xxx miles, He bought a delete kit from Texas Speed & Performance. GM head gaskets are on national backorder so we decided on Mahle replacements. Uses a GM L8T 6.6L camshaft, TSP LS7 style lifters, Lifter Trays & Aluminum plugs for the AFM Towers in the block.
New Spark Plugs & a new set of Oil Cooler Lines were also installed. These have the same Exhaust Manifold Bolt problems as the Gen III & IV.....Installed chrome moly ARP bolts to eliminate breakage.

It had bent a pushrod on #7 Intake, With the Valve & Spring having no issues......Had to be the AFM lifter.

Runs great, Had to tweak the Transmission tuning to eliminate a TCC shudder.....The shudder was already present before the AFM delete. Thanks for the business JP!!!

 

[clinebarger]

 

[clinebarger]

 

[clinebarger]

 

[4WD]

Chris: How did the piston tops compare to port injected 5.3L’s with similar mileage ?

 

[MParr]

Thanks for sharing. The owner should get many happy miles from this work.

 

[jhs914]

Gotta love the simplicity of a good old pushrod engine. No labyrinth of long timing chains, tensioners, cam phasers and guides to fail. Compact heads instead of the massive double overhead cam, 4 valve heads. And the LS can still make massive power.

 

[Snagglefoot]

Pretty incredible GM couldn’t fix the broken stud issues on the exhaust manifolds on the Gen 5. They knew they had a problem with the Gen 4.

 

[wwillson]

@clinebarger thanks for another great post. I always learn something from you!

 

[4WD]

Pretty incredible GM couldn’t fix the broken stud issues on the exhaust manifolds on the Gen 5. They knew they had a problem with the Gen 4.

They are more segmented now attempting to prevent this … but I doubt anyone knows how many pop on this series compared to others … (I have owned 5 x 5.3L’s with no failures) … Have an L83 now …

Not alone ?

Seriously? 5 busted exhaust manifold studs?

Took my '15 hemi in for a clunk in the suspension. And for a proper oil change- in July they'd performed an LOF but used dino oil not synthetic, I've run synthetic since the first oil change. Service advisor tells me that they heard a tick on cold start, which I've called out in the past, but...

www.jeepgarage.org

 

[spasm3]

Makes me wonder. When I get a new truck, should I go ahead and proactively replace the exhaust manifold bolts with arp.

 

[supton]

Makes me wonder. When I get a new truck, should I go ahead and proactively replace the exhaust manifold bolts with arp.

How hard will it be worked, how long will you own for? I’m guessing those are the two variables that determine likelihood of stud breakage?

 

[nwjones18]

Pretty incredible GM couldn’t fix the broken stud issues on the exhaust manifolds on the Gen 5. They knew they had a problem with the Gen 4.

Chrysler can't get them right on Hemi's either. Pretty amazing to me that multiple major manufacturer's can't get bolts right.

 

[Astro14]

Nice work and write up, @clinebarger!

 

[Snagglefoot]

How hard will it be worked, how long will you own for? I’m guessing those are the two variables that determine likelihood of stud breakage?

Certainly my truck went up grades at 3500 rpm towing 8,000 lbs. No stories of glowing red or anything but it was burning plenty of fuel, getting only 7-8 mpg. The bolts at the outside ends of the manifolds broke on my 2008 6.0.

 

[wtd]

Nice job. Are you seeing any issues with the 6.6L gas engine. I know it doesn't have AFM but was wondering if they had any other issues.

Is that an early 70's Cutlass in the background?

 

[JP_Property]

Thanks for your hard work Clinebarger!!

 

[clinebarger]

Nice job. Are you seeing any issues with the 6.6L gas engine. I know it doesn't have AFM but was wondering if they had any other issues.

Is that an early 70's Cutlass in the background?

The L8T is too new for me to have any direct experience. I imagine DI Injectors will be an expense not seen in the HD gas segment.

'72 Cutlass with a LT1/8L90E out of a '17 Camaro SS.

 

[MacManus99]

I'm curious as to how the L83 runs with a L8T camshaft. Does the cam shift the power production to a higher rpm range at the cost of low speed torque?
GM cams tend to be pretty conservative, making me think that the L8T cam would provide a modest bump in power at almost no cost to low end torque.

Regardless, I love these threads, and all of the information they provides. Nice post, @clinebarger .

 

[wtd]

The L8T is too new for me to have any direct experience. I imagine DI Injectors will be an expense not seen in the HD gas segment.

'72 Cutlass with a LT1/8L90E out of a '17 Camaro SS.

Thanks. I'd say you are right about the DI injectors. I'm definitely not a fan of those.

That Cutlass will be sweet with that drivetrain.