Lifters replacement

[Javie]

If you have AFM/DOD get a delete kit, and only use either GMPP 12499225 or Morel 5315 lifters.

Let me repeat that.

ONLY USE GMPP 12499225 OR MOREL 5315.

Do not get them from Ebay or Amazon! People sell knockoffs prone to failure branded as those part numbers. They are not the real thing! Unless you get the GMPP ones from a dealership that happen to still have some in stock, anyone currently advertising that part number and saying they have them in stock is selling a cheap knockoff. Also they are not the same as an oem LS7 lifter which some people try to substitute for the GMPP, I would not suggest those either.

Tick Performance and Texas Speed sell both the GMPP lifters (which are on national backorder) and the Morel lifters. They also sell a complete AFM/DOD delete kit with gmpp lifters but I'm sure they would throw in the Morels if a phone call was made when you order.

While you're inside, replace the lifter trays with brand new oem ones. They're less than $8 and you do not want to reuse the stock ones or buy ebay.

I can not stress enough the importance of buying good quality name brand lifters and oem trays.

Here are the links

https://www.tickperformance.com/tick-performance-afm-dod-delete-kit-for-ls-engines/

https://www.tickperformance.com/morel-hydraulic-roller-drop-in-lifters-for-all-lsx-engines/

https://www.tickperformance.com/gm-lifter-tray-for-all-ls-engines-1-guide/

well they're still on back order!

 

[Geotrash]

Could also be a plugged injector. Worth checking.


Sent from my iPhone using Tapatalk

 

[Chert_Detective]

well they're still on back order!

 

[Larryjb]

Because you were not sure if this was an AFM or not, are you at least aware of what kind of job it will be to change the lifters? On the LS engine you cannot replace lifters without removing the heads. It's certainly not an impossible job, but it is a lot more involved then the old Chevy blocks.

I know some decide to not do the following, but I think it is highly recommended:
1) Get a thread chaser/cleaner to clean out the head bolt holes. Then spray a solvent into each hole and dry them thoroughly.
2) Get new head bolts. OEM bolts are designed to stretch which is why they don't torque to a specified torque but rather, a specified angle of rotation. I believe the ARP bolts are not designed to stretch, so they are torqued to a specific torque spec.
3) Spend time cleaning the block and head surfaces carefully. The head surface is aluminum and can scratch easily. The head gaskets can only tolerate very small imperfections, although FelPro head gaskets are designed to cover bigger imperfections than GM head gaskets.

I don't have AFM, but from the following site I can tell that working with AFM is even more complex than non-AFM. Perhaps removing the AFM completely, if you have it, simplifies the work and makes a more reliable truck.

https://www.melling.com/wp-content/...GM-LS-Deactivation-Lifter-Issues-3.1.18-1.pdf

 

[thompsoj22]

IMO, installing lifters on a 300,000 mile engine would have to be done with your eyes shut! What about the heads, Rockers, pushrods, timing chain, tensioner, oil pump and on and on. First and foremost you have to determine absolutely that it is a lifter and than maybe attempt the youtube method of "freeing collapsed lifter on a GMC". How many more miles on this engine are you hoping to get with a set of lifters?

 

[Larryjb]

Thompsoj makes a good point. When I took off my heads, I replaced/rebuilt everything that came off. I would replace rods, rockers, springs, etc. I would probably pay someone to rebuild the heads.

The tensioner and chain could be done separately at a later date if you feel it's necessary. If your front cover is leaking, that would be a good time to do the chain.

But, I would probably only do this work if I really liked the truck, or felt that the work would make the truck last significantly longer to make it worth it.

 

[Larryjb]

Oh, and BTW, doing all that work myself having a local machine shop do both heads cost me about $2500 Canadian. I'll bet that would come to closer to $1500 USD as things are so much more expensive up here. For some one who takes an older vehicle into the shop for service, this dollar amount starts to look not so bad. Keeping things in perspective, this was the single most expensive thing I did to my truck and it added years to the life of it. Even doing my rear main oil seal myself buying the extra tools I needed added up to less than the head job I did.

There is another guy on this forum who ordered rebuilt heads online from a reputable shop. One of the replacement heads is also cracked. Hopefully the shop who supplied the head will offer an exchange for him. They better! However, this is the reason I went with a local rebuilder. It gave some local guys a paycheck and if anything did go wrong I could talk to them face to face.

Those are just a couple more thoughts on my mind.