AFM/DoD Delete Advice Needed

After a journey from hell, including a new longblock at 200k, an AFM delete dongle, a full software AFM block with the HP Tuner, a lifter release kit with oil passage block-off and valley gasket cutting, and then a repeat attempt at unsticking it, the #6 AFM lifter on my '07 5.3L with 330k miles has collapsed yet again.

I. Am. Done.

So, this time is the last time, and I'm tearing down the top end for a full AFM delete.

I'm taking my time this round (all previous work was attempted in 1-2 day bursts), and will be starting the teardown this weekend. I have started shopping around for the parts required, but there seems to be all kinds of questionable and contradictory info out there on what's actually required.

The part that I'm struggling to fully grasp is the cam. It seems like the "full" kits all include a cam. Obviously I'll do it if I have to, but I'd soooo rather not, LOL.

So from the experts here who have done this and have forgotten more than I'll ever know: Is the cam actually functionally different and absolutely required? Or is just contengent on whether the collapsed lifter(s) have damaged the existing cam?

Your advice is greatly appreciated!

Yes a new cam will be required. You need to decide if you want a mild cam just to get the motor running or if you looking for more power. Depending On the cam you choose then you'll need a tune to match it.

Kwing said:

After a journey from hell, including a new longblock at 200k, an AFM delete dongle, a full software AFM block with the HP Tuner, a lifter release kit with oil passage block-off and valley gasket cutting, and then a repeat attempt at unsticking it, the #6 AFM lifter on my '07 5.3L with 330k miles has collapsed yet again.

I. Am. Done.

So, this time is the last time, and I'm tearing down the top end for a full AFM delete.

I'm taking my time this round (all previous work was attempted in 1-2 day bursts), and will be starting the teardown this weekend. I have started shopping around for the parts required, but there seems to be all kinds of questionable and contradictory info out there on what's actually required.

The part that I'm struggling to fully grasp is the cam. It seems like the "full" kits all include a cam. Obviously I'll do it if I have to, but I'd soooo rather not, LOL.

So from the experts here who have done this and have forgotten more than I'll ever know: Is the cam actually functionally different and absolutely required? Or is just contengent on whether the collapsed lifter(s) have damaged the existing cam?

Your advice is greatly appreciated!

Click to expand...

I know that you referenced this weekend as a start date, but both Texas Speed and Summit Racing sell full AFM delete kits. You may want to talk to them and make your required parts acquisition easier. Yes, the cam needs to be replaced for a full AFM delete.

Regarding the cam, you have another choice. An OEM non AFM cam. For example, if you're working on the 6.2, you simply use the camshaft from an L92 version of the engine that was used prior to AFM implementation. Not only do you retain your original horsepower and torque, you retain the variable valve timing... And the only tuning necessary is to turn off the AFM. This is by far the easiest and simplest option. All of the aftermarket camshafts will require tuning, such as with HP tuners. Keep in mind that and aftermarket camshaft that will give you more top and power at 6,000 RPM, usually sacrifices torque at the bottom end.... Which will kill fuel mileage. Everything is always a trade-off. At your mileage you have to decide if it's worth investing and yet more power, making the changes to tune it, thinking about the torque converter as well as transmission lifespan.

The complete kits marketed.... You will do better sourcing your individual components. (And knowing exactly what you're buying. There's a lot of cheap components out there that simply don't last) Settle for nothing except genuine GM lifter trays. If you're going for genuine Delphi LS7 lifters, only by the ones that have the gold retaining clips in the end. Anything else is counterfeit. Michigan Motorsports is a reputable supplier of the real thing. Quality of parts is imperative for a successful delete. Getting a box full of parts at a discount price, and not knowing exactly where they came from is a disaster waiting to happen.

LH8 / LH9 / LMF cam will do your 5.3L nice & easy, any tuner with cataracts can copypaste the LMF stuff into your tune, no talent required.
Do not think a GM OE 6.0L cam (L76t/LY6/L96) or 6.2L cam (L92) would be an upgrade, even though I'd like to be wrong ...

@Kwing
I've been driving my LS powered (2008 gen4 LY5) 51 Chevy pickup for many yrs and 3,000 miles with the its AFM tuned out but all the AFM hardware intact.

Unless someone can convince me otherwise? I'm planning to leave the stock LY5 cam in place. It runs great and gets good mpg.

In the future plan to
1) change the 8 AFM lifters for 8 non-afm lifters & 4 lifter trays.
2) plug the 8 oil towers
3) install a smooth non-afm valley cover
4) I've already installed a plug where the relief valve was in the pan.

Engine today has <12,000 since new.

Thanks for all the replies!

So first and foremost, while I've always lived by the moto "if it ain't broke, don't fix it, modify it. If it is broke, fix it, then modify it", this old girl is a tool, not a toy. I'd prefer to keep the stock performance and mileage - well, truth be told, i'd prefer better mileage, but I certainly don't want worse!

My '88 Suburban is my toy, with it's hot cam and heads, stroked and bored, with long tube headers, coupled to a monster B&M filled 700r4, and a whopping... 9mpg downhill with a strong tailwind, LOL.

I just want the Tahoe to start, get where we need to go, and get home again, reliably and repeatably. So if I do have to do the cam, bone standard is preferred.

So with that out of the way... does anyone know what the actual difference is between the AFM and *stock* non-AFM cam?

donjetman said:

@Kwing
I've been driving my LS powered (2008 gen4 LY5) 51 Chevy pickup for many yrs and 3,000 miles with the its AFM tuned out but all the AFM hardware intact.

Unless someone can convince me otherwise? I'm planning to leave the stock LY5 cam in place. It runs great and gets good mpg.

In the future plan to
1) change the 8 AFM lifters for 8 non-afm lifters & 4 lifter trays.
2) plug the 8 oil towers
3) install a smooth non-afm valley cover
4) I've already installed a plug where the relief valve was in the pan.

Engine today has <12,000 since new.

Click to expand...

this will be interesting to see what you find.. I once spent some time searching before ai took over Google and killed it. I found reference to a few people that it seemed to run OK on, lots that got misfires putting non afm lifters on afm lobes. I won't pretend to know why.

there's a long thread around here somewhere someone tried it and ended up not working.

Kwing said:

anyone know what the actual difference is between the AFM and *stock* non-AFM cam?

Click to expand...

Difference between a GM OE Engine Half@$$ cam, vs a GM OE simple V8 cam ...
the part time lobes are not quite the same exact shape as the full time lobes, whereas the simple V8 cam ... you can guess the rest, yeah?

The software differences are largely dictated by the two slightly different sets of cam lobes.

Marky Dissod said:

The software differences are largely dictated by the two slightly different sets of cam lobes.

Click to expand...

So are you saying the software tweaks are a firm requirement as well?

Disabling Engine Half@$$ in an otherwise GM OE tune, is basically telling the ecm DO NOT DO THAT, EVER ...
but leaving the Half@$$-able cam & lifters in place, and leaving that cam's specs in place in the tune.

If you install a 'real V8' cam in that engine (and 'real' lifters), the VE tables, as well as a few others, need editing,
since the ecm still thinks it's using / expects a Half@$$-able cam til you inform it otherwise -
you can't just tell the ecm to 'STOP THAT', you gotta inform it of what else you've changed.

In other words, since the LH8 / LH9 / LMF cam is physically different from the LH6 / LY5 / LC9 / LMG cam,
their GM OE tunes slightly differ from each other as well.

It's not really engine tuning, it's just copypasting - replace the specs you don't want with the specs you do.
If your tuner will not offer some kind of discount, it MIGHT make some sense to 'upgrade'?

Mind, getting a 5.3L to release more power UNDER 3000RpM with a cam is harder than better axle gearing, even if it's also cheaper than better axle gearing.

donjetman said:

@Kwing
I've been driving my LS powered (2008 gen4 LY5) 51 Chevy pickup for many yrs and 3,000 miles with the its AFM tuned out but all the AFM hardware intact.

Unless someone can convince me otherwise? I'm planning to leave the stock LY5 cam in place. It runs great and gets good mpg.

In the future plan to
1) change the 8 AFM lifters for 8 non-afm lifters & 4 lifter trays.
2) plug the 8 oil towers
3) install a smooth non-afm valley cover
4) I've already installed a plug where the relief valve was in the pan.

Engine today has <12,000 since new.

Click to expand...

this was the thread. be interested in what you think

Thread 'DOD Delete Theory' https://www.tahoeyukonforum.com/threads/dod-delete-theory.147084/

j91z28d1 said:

this was the thread. be interested in what you think

Thread 'DOD Delete Theory' https://www.tahoeyukonforum.com/threads/dod-delete-theory.147084/

Click to expand...

I think my head hurts, LOL.

But that thread is the perfect example of why I posted my question in the first place. There was sooo much confidence in sooo many of those posts, but sooo many of the stated "facts" contradict others given with confidence, but no numbers given on either side to seperate fact from keyboard courage pull-it-out-of-their-@$$ "facts", LOL.

And I read every post with baited breath, because so many "this has all been hashed out and all the info is available" claims were made, but despite multiple "please share a link" requests, the "commonly available data" was never once shared. And despite my best efforts and the supposed availability of said information, I ain't found jack.

Then, just to ensure my head will throb the rest of the day, the conclusion of the thread meant to show the cam has to change, was that the engine ran great without changing the cam???

Somebody save me! ROTFL

I tell ya what though, if the information and numbers don't materialize in this thread by the time I get that far, I will simply replace the can out of safety, and while it's out I'll reverse engineer the two cams and post my findings here.

I'm'a go lay down, LOL

j91z28d1 said:

this was the thread. be interested in what you think

Thread 'DOD Delete Theory' https://www.tahoeyukonforum.com/threads/dod-delete-theory.147084/

Click to expand...

Thanks

@RET423 was successful with his DOD/AFM delete and NOT changing the cam, exactly what I may do someday. My LY5 doesn't tick, misfire, etc and the cam is like new.

One thing I forgot in my post #6 here was needing to buy 8 pushrods of the proper length (7.385" ?) to set proper preload.

donjetman said:

Thanks

@RET423 was successful with his DOD/AFM delete and NOT changing the cam, exactly what I may do someday. My LY5 doesn't tick, misfire, etc and the cam is like new.

One thing I forgot in my post #6 here was needing to buy 8 pushrods of the proper length (7.385" ?) to set proper preload.

Click to expand...

I just checked his last post, I guess I remember it incorrectly, he did have miss fires but they went away? and reminded me you can swap cam in these without pulling the heads, but not the lifters. so yeah, swap in 16 new ones. and if it doesn't end up working. Just pop the front over off and swap the cam.

worth a shot for science and for us hybrid guys that they don't make a non afm cam for it would be the best news. worth checking the push rod length for sure. stock might not be correct too

So long as the bi-mode lifters behave, you can keep your original cam / lifters / pushrods / rockers (til something goes wrong, who knows when that'll be ...)
Raise 'Enable Engine Half@$$ Coolant Temp' over 266F in the ecm, there y'go.

Kwing said:

I think my head hurts, LOL.

But that thread is the perfect example of why I posted my question in the first place. There was sooo much confidence in sooo many of those posts, but sooo many of the stated "facts" contradict others given with confidence, but no numbers given on either side to seperate fact from keyboard courage pull-it-out-of-their-@$$ "facts", LOL.

And I read every post with baited breath, because so many "this has all been hashed out and all the info is available" claims were made, but despite multiple "please share a link" requests, the "commonly available data" was never once shared. And despite my best efforts and the supposed availability of said information, I ain't found jack.

Then, just to ensure my head will throb the rest of the day, the conclusion of the thread meant to show the cam has to change, was that the engine ran great without changing the cam???

Somebody save me! ROTFL

I tell ya what though, if the information and numbers don't materialize in this thread by the time I get that far, I will simply replace the can out of safety, and while it's out I'll reverse engineer the two cams and post my findings here.

I'm'a go lay down, LOL

Click to expand...

haha, I completely forgot it worked for him lol. I wonder if a thread reply would send him an email. maybe he will come back and update 2 years later.

someone mentioned 50psi different cranking compression test. if so, that might be enough to run OK, but would he leaving some power and efficiency on the table. but who knows at this point lol.

Well this issue is well documented regarding AFM deletes.... It seems like every time somebody posts they want to do it, the whole conversation starts over. So here's the bottom line:

1. The AFM system is a ticking time bomb. That includes all the components therein. AFM lifters, AFM camshaft, VLOM, oil pressure relief valve in the oil pan.

2. Not addressing each one of those items with a replacement, or in some cases plugging it off, is only doing the job half a$$ed and won't accomplish what you're looking for.... Complete confidence and peace of mind in your engine.

3. A flat valley cover with the o-rings isn't enough by itself. O-rings shrink. Pick up the steel plugs and tap them in the oil towers for insurance.

4. What drives the price up is the list of things to do "while you are in there."
New oil pump. I personally use the Melling 10296 that comes with the +10 psi oil pressure spring pre-installed. This is a high pressure and high volume pump that is suitable if you are retaining stock configuration with variable valve timing.

5. Your timing chain and gears, with tensioner. Absurd not to do it.

6. The camshaft

7. If you're going with an oem non-afm Cam that has VVT, you're going to want to replace the VVT phaser which is a bolt on the end that retains the cams bracket to the end of the camshaft. Genuine GM only. It's a one-time use torque to yield.

8. Genuine GM lifter trays. You can go with GM performance lifters or the genuine Delphi LS7 lifters with the gold retaining clip in the end. Only buy from a reputable source.

9. I've had good luck with Fel-Pro head gaskets on multiple installs. Head bolts are one time use only, torque to yield. Replacements are not expensive. However, I prefer the arp head bolts. Not the studs, the bolts. Simply torque them down in three steps like the good old days, plus they're reusable.

10. You'll want to take your cylinder heads down to a local machine shop and have them skimmed with a proper finish on the heads for head gasket sealing. Have the head checked over, and definitely with new valve stem seals.

11. If you're north of 150,000 miles, it's worth thinking about the rocker trunnion bearings. CHE makes a decent product.

12. You want the stainless steel bolt with washer to remove and plug oil pressure relief valve in the oil pan. Readily available on Amazon, just like the steel plugs to plug the towers.

13. New genuine GM ACDelco camshaft and crankshaft position sensors. New genuine GM coolant temperature sensor.

14. New water pump since it's off. Genuine GM or AC Delco.

15. New, not rebuilt, AC Delco starter

16. If your goal is a 100,000 plus miles when you're done, and you want reliability, then it's a good time to replace the O2 sensors with genuine GM.

17. Make sure your driver side valve cover is the updated design, addressed in a TSB.

18. New plugs and new plug wires.

19. While you have that oil pan off and the differential dropped, lots of room to address the power steering hoses. (And maybe the pump itself if you're in a rust belt state and it's covered in rest)

20. All new hoses and belts, tensioner, the tee connections at the firewall, the rear heater hoses behind the right rear tire if you have rear heat. Oil cooler line replacement is super easy to do at this point. Replacing the radiator is tempting if it's also original.

The list of things to do while you're in there depends on budget and your plans for the vehicle. Some of it is a no-brainer while you have it out anyway. Some things just make sense as a form of preventative maintenance. A lot of it depends on if this is going to be a forever vehicle.

On each of the above items, you'll find in the form extensive conversations on everything from which water pumps to get, how to measure your push rods, preferences on timing chain sets, and useful information on alternatives to consider. Like the metal heater hose t fittings at the firewall. Do the research on the forum, do some reading and make some choices.

rdezs said:

Well this issue is well documented regarding AFM deletes.... It seems like every time somebody posts they want to do it, the whole conversation starts over.

Click to expand...

Because when folks A-M are saying "of course you have to replace all this stuff, you idiot" and guys M-Z are saying "you don't have to replace any of that, you moron", then the conversations don't really tell anyone anything! LOL

It keeps floating back up because, at least everything i can find, is that kind of back-and-forth with the ONLY evidence provided to support the claims on either side is "because i said so".

Conjecture is expensive. Sometimes facts are too, but at least if I'm paying for facts, I know I had to.

The alternative, of course, is to replace it all, like your list suggests, performing a concours level restoration on a 20 year old truck with 330,000 miles on it and a book value somewhere shy of $3000, LOL.

I mean I'm really not trying to be a jerk, I promise, but if I had the money to blow $10,000+ on the truck willy nilly, I wouldn't be asking about working on it at all, I'd just buy a new one, LOL.

rdezs said:

Well this issue is well documented regarding AFM deletes.... It seems like every time somebody posts they want to do it, the whole conversation starts over. So here's the bottom line:

1. The AFM system is a ticking time bomb. That includes all the components therein. AFM lifters, AFM camshaft, VLOM, oil pressure relief valve in the oil pan.

2. Not addressing each one of those items with a replacement, or in some cases plugging it off, is only doing the job half a$$ed and won't accomplish what you're looking for.... Complete confidence and peace of mind in your engine.

3. A flat valley cover with the o-rings isn't enough by itself. O-rings shrink. Pick up the steel plugs and tap them in the oil towers for insurance.

4. What drives the price up is the list of things to do "while you are in there."
New oil pump. I personally use the Melling 10296 that comes with the +10 psi oil pressure spring pre-installed. This is a high pressure and high volume pump that is suitable if you are retaining stock configuration with variable valve timing.

5. Your timing chain and gears, with tensioner. Absurd not to do it.

6. The camshaft

7. If you're going with an oem non-afm Cam that has VVT, you're going to want to replace the VVT phaser which is a bolt on the end that retains the cams bracket to the end of the camshaft. Genuine GM only. It's a one-time use torque to yield.

8. Genuine GM lifter trays. You can go with GM performance lifters or the genuine Delphi LS7 lifters with the gold retaining clip in the end. Only buy from a reputable source.

9. I've had good luck with Fel-Pro head gaskets on multiple installs. Head bolts are one time use only, torque to yield. Replacements are not expensive. However, I prefer the arp head bolts. Not the studs, the bolts. Simply torque them down in three steps like the good old days, plus they're reusable.

10. You'll want to take your cylinder heads down to a local machine shop and have them skimmed with a proper finish on the heads for head gasket sealing. Have the head checked over, and definitely with new valve stem seals.

11. If you're north of 150,000 miles, it's worth thinking about the rocker trunnion bearings. CHE makes a decent product.

12. You want the stainless steel bolt with washer to remove and plug oil pressure relief valve in the oil pan. Readily available on Amazon, just like the steel plugs to plug the towers.

13. New genuine GM ACDelco camshaft and crankshaft position sensors. New genuine GM coolant temperature sensor.

14. New water pump since it's off. Genuine GM or AC Delco.

15. New, not rebuilt, AC Delco starter

16. If your goal is a 100,000 plus miles when you're done, and you want reliability, then it's a good time to replace the O2 sensors with genuine GM.

17. Make sure your driver side valve cover is the updated design, addressed in a TSB.

18. New plugs and new plug wires.

19. While you have that oil pan off and the differential dropped, lots of room to address the power steering hoses. (And maybe the pump itself if you're in a rust belt state and it's covered in rest)

20. All new hoses and belts, tensioner, the tee connections at the firewall, the rear heater hoses behind the right rear tire if you have rear heat. Oil cooler line replacement is super easy to do at this point. Replacing the radiator is tempting if it's also original.

The list of things to do while you're in there depends on budget and your plans for the vehicle. Some of it is a no-brainer while you have it out anyway. Some things just make sense as a form of preventative maintenance. A lot of it depends on if this is going to be a forever vehicle.

On each of the above items, you'll find in the form extensive conversations on everything from which water pumps to get, how to measure your push rods, preferences on timing chain sets, and useful information on alternatives to consider. Like the metal heater hose t fittings at the firewall. Do the research on the forum, do some reading and make some choices.

Click to expand...

Seems very well-explained, with some minimum things to do, along with options if it makes sense for someone's situation.