2010 Burb Misfire

[solli5pack]

You guys think the AFM lifters are still prone to failure if they're turned off with a tune or use of a Range disabler? What's the benefit of replacing the trays? They wear out?

 

[j91z28d1]

You guys think the AFM lifters are still prone to failure if they're turned off with a tune or use of a Range disabler? What's the benefit of replacing the trays? They wear out?

yeah the trays are plastic, when they fail they let the lifter turn and it eats everything up. even the aftermarket ones seem to fail new.

I don't know about failing when turned off. but I have read on here guys saying they still do. I hope not cause i have mine turned off. but I also took the extra steps of blocking the oil supply in case the solenoids leak oil and open the pathway to "vent" any built up oil behind the lifter that might cause them to release the locks.

that's basically what happens 90% of the time. the locks release and the lifter collapses like it's supposed to, but then gets stuck and won't come back up to open the valves. by either internal wear galling up the metal, or building up sludge or varnish over time. I guess the rest of the time the lifter spins from plastic housings. if they weren't so expensive and hard to get I'd says just drop new afm lifters in and be good for another 150k.

old small block chevy had metal "dog bones" kept the lifter from spinning so they never failed from that. gm just being cheap I guess

 

[solli5pack]

yeah the trays are plastic, when they fail they let the lifter turn and it eats everything up. even the aftermarket ones seem to fail new.

I don't know about failing when turned off. but I have read on here guys saying they still do. I hope not cause i have mine turned off. but I also took the extra steps of blocking the oil supply in case the solenoids leak oil and open the pathway to "vent" any built up oil behind the lifter that might cause them to release the locks.

that's basically what happens 90% of the time. the locks release and the lifter collapses like it's supposed to, but then gets stuck and won't come back up to open the valves. by either internal wear galling up the metal, or building up sludge or varnish over time. I guess the rest of the time the lifter spins from plastic housings. if they weren't so expensive and hard to get I'd says just drop new afm lifters in and be good for another 150k.

old small block chevy had metal "dog bones" kept the lifter from spinning so they never failed from that. gm just being cheap I guess

Look like 4 afm lifters and trays are around $300....man I'm torn right now...the solid lifters are as the say.."solid"? You blocked the oil to the solenoids with the collar under the oil pressure sensor?

 

[iamdub]

Look like 4 afm lifters and trays are around $300....man I'm torn right now...the solid lifters are as the say.."solid"? You blocked the oil to the solenoids with the collar under the oil pressure sensor?

If it's any consolation, they updated the lifter and VLOM design for the 2010 model years. Yours having the updated valve cover could be an indication that you have the "latest and greatest". You could pull the VLOM to check if it's the updated one. Or maybe you can tell from the outside? Being that far in, I'd replace the VLOM gasket, at least. It's a common leak point.

I'm halfway asleep at the moment, but I'm thinking that, since you have AFM disabled, you could replace the VLOM with the non-AFM one (the "LS3" valley cover) that seals off the AFM towers and comes with a new gasket.

Disabling AFM seems to be a great preventative measure for prolonging what I'd still call the inevitable. If the solenoids in the VLOM and the lifters aren't cycling, then there's greatly reduced risk of failure. The lifters are still being pushed back and forth thousands and thousands of times per drive, so there's always some amount of chance of something happening.

 

[j91z28d1]

Look like 4 afm lifters and trays are around $300....man I'm torn right now...the solid lifters are as the say.."solid"? You blocked the oil to the solenoids with the collar under the oil pressure sensor?

I believe it's 8 afm lifters. 4cyl and 2 per cyl?

so this guy explains it in a way that made sense to me while researching this before buying the truck.

a lot of guys here have been in this much longer and they have seen more and know more than me. I just try to go with what makes sense at the time. I can always be wrong about everything lol.

but the idea. normal lifters get oil from the block to pump up the hydraulic part of the lifter that makes it a hydraulic lifter. these afm have a added oil hole that comes from the top. it releases pins that collapses the lifter inside so it "turns off" that cyl.

well that is the part that fails most of the time they stay down and don't pop back up. it starts tapping and eats itself alive trashing the whole motor. so short of replacing it all. the best you can do is have it not release those pins. to do that you need to block off the oil supply. that's what you did by turning it off in the tune. but those solenoids do fail and leak oil, which can release them even when electricity turned off. so to stop that there's a bushing you put under the oil pressure sensor. that's where the solenoids get they're oil from. that solves leaking solenoids.. the other way oil can get there is remember that bottom hole in the lifter that gets oil from the block. well as the internal lifter bores wear, oil can bypass from there and up thru the afm release hole. if the solenoid is closed, pressure can build up and release the pins. so if you see the towers under your vlom, that's the oil ports down to the lifter, and there's a gasket there. his trick is to cut a slot in that gasket, so any oil that bypasses internally of the lifter is harmlessly returned to the pan. that's also why you don't put a non afm vlom plate on a engine with the afm lifters still in it. you don't want that top part sealed off. once you put none afm lifters in, you do.

that's why I said while you have it apart, I'd pull the trays, take a look at the rollers to see any signs of damage, peek down at the cam lobe if you can. if all looks good, replace trays cause plastic and and old now. reuse your lifters, don't mix up what hole they came from and it would be cheap insurance short of a full delete.

he's got tear down videos of the lifters themselves and how to release stuck lifters if they do stick on you at some point.



the other side would be to replace the afm lifters, but yeah they seem overly expensive to me, and you should really do new vlom and solenoids at the same time. at that point youre at full delete money, but you did save pulling the cam and stuff. I'm not sure v4 helps your mph at all thou. on my hybrid one it actually is useful since it can stay in 4 mode a lot of the time with the help of electric motors but I decided to block it all off and clip the gaskets instead of pulling heads and doing the lifters and vlom replacement. I have hopes it will last a long time this way.

 

[Geotrash]

I believe it's 8 afm lifters. 4cyl and 2 per cyl?

so this guy explains it in a way that made sense to me while researching this before buying the truck.

a lot of guys here have been in this much longer and they have seen more and know more than me. I just try to go with what makes sense at the time. I can always be wrong about everything lol.

but the idea. normal lifters get oil from the block to pump up the hydraulic part of the lifter that makes it a hydraulic lifter. these afm have a added oil hole that comes from the top. it releases pins that collapses the lifter inside so it "turns off" that cyl.

well that is the part that fails most of the time they stay down and don't pop back up. it starts tapping and eats itself alive trashing the whole motor. so short of replacing it all. the best you can do is have it not release those pins. to do that you need to block off the oil supply. that's what you did by turning it off in the tune. but those solenoids do fail and leak oil, which can release them even when electricity turned off. so to stop that there's a bushing you put under the oil pressure sensor. that's where the solenoids get they're oil from. that solves leaking solenoids.. the other way oil can get there is remember that bottom hole in the lifter that gets oil from the block. well as the internal lifter bores wear, oil can bypass from there and up thru the afm release hole. if the solenoid is closed, pressure can build up and release the pins. so if you see the towers under your vlom, that's the oil ports down to the lifter, and there's a gasket there. his trick is to cut a slot in that gasket, so any oil that bypasses internally of the lifter is harmlessly returned to the pan. that's also why you don't put a non afm vlom plate on a engine with the afm lifters still in it. you don't want that top part sealed off. once you put none afm lifters in, you do.

that's why I said while you have it apart, I'd pull the trays, take a look at the rollers to see any signs of damage, peek down at the cam lobe if you can. if all looks good, replace trays cause plastic and and old now. reuse your lifters, don't mix up what hole they came from and it would be cheap insurance short of a full delete.

he's got tear down videos of the lifters themselves and how to release stuck lifters if they do stick on you at some point.



the other side would be to replace the afm lifters, but yeah they seem overly expensive to me, and you should really do new vlom and solenoids at the same time. at that point youre at full delete money, but you did save pulling the cam and stuff. I'm not sure v4 helps your mph at all thou. on my hybrid one it actually is useful since it can stay in 4 mode a lot of the time with the help of electric motors but I decided to block it all off and clip the gaskets instead of pulling heads and doing the lifters and vlom replacement. I have hopes it will last a long time this way.

Solid advice, I believe. Except that I would always put new lifters and new factory trays in if you’re in it that far. But that’s just me. Chances are the originals will outlast the rest of the truck so I really can’t argue with your advice here.

For my part, you’re so close to a full delete at that point and for the price of a few tanks of gas you can have a nice, smooth idle, cam in there like the cam motion stage 2 truck cam that gives you another 50 HP and TQ in there, and you can run all new non-afm lifters and trays, a flat valley pan with the tower seals, and a bow-tie chain tensioner. Though the latter would require dropping the oil pan to get the old tensioner out.

I went this route on my 2012 and love it, but I also do a lot of towing with it so that was the main reason.

 

[solli5pack]

Thanks for the replies and advice guys. It's much appreciated. I built this kit from Scoggin Dickey and it look like it has just about everything I need. I don't see pushrods though. Are they supposed to be replaced? Also apparently instead of replacing the Vlom they plug the ports. Unless I'm missing something it's only a few hundred more than if I piece together everything I already need to do the head gasket job with new trays included and hope that existing lifters & cam look good after inspection. I'm wondering since I'd be keeping the AFM Vlom and I have the Range disabler does the computer still need to be re flashed. Starting to lean towards the delete..lol

 

[mikez71]

With coolant in the valve area and one side being steam cleaned, I'm wondering if you have a cracked head.

I have a tough to find leak that I'm worried maybe going that way as well..

 

[solli5pack]

With coolant in the valve area and one side being steam cleaned, I'm wondering if you have a cracked head.

I have a tough to find leak that I'm worried maybe going that way as well..

I'm dropping the heads at the machine shop today so I'll know soon enough. I hope not because that would really screw up my budget! No cracks visible by eye. I still haven't found an obvious failure point as to where the coolant leaked in. The head gasket looked terrible and came apart in layers so maybe that caused the leak. All I really know is Cyl 4 is the one that had the misfire, had coolant on the plug and caused white smoke out of the tail pipe..only first thing in the morning after sitting all night. It would clear up after driving a bit but it was starting to get worse. Also it was the cleanest piston. On top of all that Cyl 4 had decent compression at around 140 but was the lowest of the others I checked which were around 150 and passed a leakdown test. Also did a pressure test on the coolant system with no results. It held 16lbs all night. My theory is it would only leak under certain conditions like when the motor was operating temp or something and then maybe the coolant leaked in when I parked. And of course had coolant loss with no visible leak..After all this I really HATE the smell of Dex-cool!! Lol

 

[mikez71]

.. maybe the coolant leaked in when I parked. And of course had coolant loss with no visible leak..After all this I really HATE the smell of Dex-cool!! Lol

I have a bad feeling I'm right behind you. Same minor symptoms, no misfire (yet?), but the smell just started and no visible leak.. Same thing, only when cold for a few seconds then clears up.

Good luck! I'll be watching your thread and thanks for the pics/documentation!