Top End Teardown Complete

[Gangly]

I took some time off from work and decided it was a good time to go through the Z71 and have a good look at things.  I have a little under 130K miles on the truck with no issues, but I need it to go 200K.  I assumed the heads and valvetrain would need to be refreshed soon, and I would rather do it in my shop at a time of my choosing, than after breaking down on the side of the road, so I purchased the parts and tore into it.   After removing the heads and checking everything out, the valvetrain was VERY clean with no sludge buildup in the rocker arm/spring area, with valve spring constants within spec and the valve seals looking good.  The lifters were within spec, the rollers clean and clear of surface issues, and the cam lobe surfaces looked great. When visually inspecting the block, the cross hatch on the cylinder walls was exceptional, and the surfaces of the lifter rollers and cam lobes showed no excessive wear.   With the condition of the original components, I went ahead and replaced just the lifters and pushrods with GM parts since everything appeared to be in great shape.  

 

Total time from start to finish was about 30 hours, but that was me going VERY slow and triple checking everything.  Total cost for parts and materials (gaskets, bolts, cleaners, etc) was about $1500.  Doing this with the engine still in the truck was A LOT more challenging than I anticipated, with the rear head bolts being very hard to access in order to properly torque.  Also, cleaning the gasket materials from rear portions of the block took forever simply because of the poor access, and required a lot of patience and maneuvering.  Cleaning surfaces, double checking fastening torques, and running to various stores to get parts/tools took more time than what a dealer could complete the task in, but if I was to do it again I would assume I could have both heads off, cleaned, inspected, and the truck back and running in about 15 hours.  The only issue I currently have is an exhaust leak at the driver's side manifold.  I installed new GM exhaust manifold gaskets and GM exhaust manifold bolts, and torqued them to spec and sequence, but I haven't had a chance to recheck the torque on the manifold bolts since heat cycling the truck, so I assume one or two might have backed out.  I will replace them with ARP exhaust manifold bolts once they arrive.  Whenever I go with ARP bolts, it generally solves any exhaust leak issues, but I went back with all GM fasteners in hopes to avoid any issues when I should have just gone straight with the ARP bolts to begin with.  

 

For any of you who have had to scrape off old gaskets in the past with razorblades, plastic blades, gasket scrapers, etc., I would HIGHLY encourage you to get a carbide scraper.  It is by far the best scraper I have ever used, and cut my time down by AT LEAST HALF when cleaning the block and head surfaces.  It scrapes perfectly flat without gouging, and creates a fantastic surface for gaskets.  I'll leave a youtube link for anybody with questions about it, but it is by far one of my better tool acquisitions and I would highly encourage anybody who prepares mating surfaces to get one

 

Engine block still in the truck after the heads have been removed.  The lifter trays were removed from the passenger side, but not from the driver's side yet.

 

The cross hatch on the cylinders appeared to be in great shape, with minimal wear indicators.  For a little under 130K miles, I expected significantly more cylinder wear.  Sorry for the poor photo.

 

 

This is one of the cylinder heads after the gasket removal with the carbide scraper.  You can see the original machining marks by GM.  I still go over the head with CRC gasket cleaner, a rag, and elbow grease prior to installing the heads again, but the carbide tipped scraper is simply amazing.

 

OEM lifters, driver's and passenger's side that are still within operational spec

 

 

Carbide Gasket Scraper.  One of the youtube videos I found that suggested it and gave tips on its use... 

For anybody interested, I have used Castrol Edge Advanced Full Synthetic 0W-20, FRAM Ultra-Synthetic filters, and changed the oil at GM recommended intervals.  Based on my observations, I have zero complaints with the oil, filter, or OCI's at this point and will proceed with the same products and the same oil change interval.

 

 

 

 

 

Edited May 28, 2024 by Gangly

[KARNUT]

40 minutes ago, Gangly said:

I took some time off from work and decided it was a good time to go through the Z71 and have a good look at things.  I have a little under 130K miles on the truck with no issues, but I need it to go 200K and I wanted to do a valvetrain refresh.  I assumed the heads and valvetrain would need to be refreshed soon, and I would rather do it in my shop at a time of my choosing, than after breaking down on the side of the road, so I purchased the parts and tore into it.   After removing the heads and checking everything out, the valvetrain was VERY clean with no sludge buildup in the rocker arm/spring area, with valve spring constants within spec and the valve seals looking good.  The lifters were within spec, the rollers clean and clear of surface issues, and the cam lobe surfaces looked great. When visually inspecting the block, the cross hatch on the cylinder walls was exceptional, and the surfaces of the lifter rollers and cam lobes showed no excessive wear.   With the condition of the original components, I went ahead and replaced just the lifters and pushrods with GM parts since everything appeared to be in great shape.  

 

Total time from start to finish was about 30 hours, but that was me going VERY slow and triple checking everything.  Total cost for parts and materials (gaskets, bolts, cleaners, etc) was about $1500.  Doing this with the engine still in the truck was A LOT more challenging than I anticipated, with the rear head bolts being very hard to access in order to properly torque.  Also, cleaning the gasket materials from rear portions of the block took forever simply because of the poor access, and required a lot of patience and maneuvering.  Cleaning surfaces, double checking fastening torques, and running to various stores to get parts/tools took more time than what a dealer could complete the task in, but if I was to do it again I would assume I could have both heads off, cleaned, inspected, and the truck back and running in about 15 hours.  The only issue I currently have is an exhaust leak at the driver's side manifold.  I installed new GM exhaust manifold gaskets and GM exhaust manifold bolts, and torqued them to spec and sequence, but I haven't had a chance to recheck the torque on the manifold bolts since heat cycling the truck, so I assume one or two might have backed out.  I will replace them with ARP exhaust manifold bolts once they arrive.  Whenever I go with ARP bolts, it generally solves any exhaust leak issues, but I went back with all GM fasteners in hopes to avoid any issues when I should have just gone straight with the ARP bolts to begin with.  

 

For any of you who have had to scrape off old gaskets in the past with razorblades, plastic blades, gasket scrapers, etc., I would HIGHLY encourage you to get a carbide scraper.  It is by far the best scraper I have ever used, and cut my time down by AT LEAST HALF when cleaning the block and head surfaces.  It scrapes perfectly flat without gouging, and creates a fantastic surface for gaskets.  I'll leave a youtube link for anybody with questions about it, but it is by far one of my better tool acquisitions and I would highly encourage anybody who prepares mating surfaces to get one

 

Engine block still in the truck after the head have been removed.  The lifter trays were removed from the passenger side, but not from the driver's side yet.

 

The cross hatch on the cylinders appeared to be in great shape, with minimal wear indicators.  For a little under 130K miles, I expected significantly more cylinder wear.  Sorry for the poor photo.

 

 

This is one of the cylinder heads after the gasket removal with the carbide scraper.  You can see the original machining marks by GM.  I still go over the head with CRC gasket cleaner, a rag, and elbow grease prior to installing the heads again, but the carbide tipped scraper is simply amazing.

 

OEM lifters, driver's and passenger's side that are still within operational spec

 

 

 

Carbide Gasket Scraper.  One of the youtube videos I found that suggested it and gave tips on its use... 

For anybody interested, I have used Castrol Edge Advanced Full Synthetic 0W-20, FRAM Ultra-Synthetic filters, and changed the oil at GM recommended intervals.  Based on my observations, I have zero complaints with the oil, filter, or OCI's at this point and will proceed with the same products and the same oil change interval.

 

 

 

 

 

I applaud your effort. Under normal circumstances ( no bad parts) your engine is about half used up. My brother in law routinely gets 300K out of his without any work. His 06 Tahoe is currently at 290K. His wife’s 2013 is at 140K. My 02 avalanche is at 185K. 

Edited May 28, 2024 by KARNUT

[Steve-2019]

44 minutes ago, Gangly said:

I took some time off from work and decided it was a good time to go through the Z71 and have a good look at things.  I have a little under 130K miles on the truck with no issues, but I need it to go 200K and I wanted to do a valvetrain refresh.  I assumed the heads and valvetrain would need to be refreshed soon, and I would rather do it in my shop at a time of my choosing, than after breaking down on the side of the road, so I purchased the parts and tore into it.   After removing the heads and checking everything out, the valvetrain was VERY clean with no sludge buildup in the rocker arm/spring area, with valve spring constants within spec and the valve seals looking good.  The lifters were within spec, the rollers clean and clear of surface issues, and the cam lobe surfaces looked great. When visually inspecting the block, the cross hatch on the cylinder walls was exceptional, and the surfaces of the lifter rollers and cam lobes showed no excessive wear.   With the condition of the original components, I went ahead and replaced just the lifters and pushrods with GM parts since everything appeared to be in great shape.  

 

Total time from start to finish was about 30 hours, but that was me going VERY slow and triple checking everything.  Total cost for parts and materials (gaskets, bolts, cleaners, etc) was about $1500.  Doing this with the engine still in the truck was A LOT more challenging than I anticipated, with the rear head bolts being very hard to access in order to properly torque.  Also, cleaning the gasket materials from rear portions of the block took forever simply because of the poor access, and required a lot of patience and maneuvering.  Cleaning surfaces, double checking fastening torques, and running to various stores to get parts/tools took more time than what a dealer could complete the task in, but if I was to do it again I would assume I could have both heads off, cleaned, inspected, and the truck back and running in about 15 hours.  The only issue I currently have is an exhaust leak at the driver's side manifold.  I installed new GM exhaust manifold gaskets and GM exhaust manifold bolts, and torqued them to spec and sequence, but I haven't had a chance to recheck the torque on the manifold bolts since heat cycling the truck, so I assume one or two might have backed out.  I will replace them with ARP exhaust manifold bolts once they arrive.  Whenever I go with ARP bolts, it generally solves any exhaust leak issues, but I went back with all GM fasteners in hopes to avoid any issues when I should have just gone straight with the ARP bolts to begin with.  

 

For any of you who have had to scrape off old gaskets in the past with razorblades, plastic blades, gasket scrapers, etc., I would HIGHLY encourage you to get a carbide scraper.  It is by far the best scraper I have ever used, and cut my time down by AT LEAST HALF when cleaning the block and head surfaces.  It scrapes perfectly flat without gouging, and creates a fantastic surface for gaskets.  I'll leave a youtube link for anybody with questions about it, but it is by far one of my better tool acquisitions and I would highly encourage anybody who prepares mating surfaces to get one

 

Engine block still in the truck after the head have been removed.  The lifter trays were removed from the passenger side, but not from the driver's side yet.

 

The cross hatch on the cylinders appeared to be in great shape, with minimal wear indicators.  For a little under 130K miles, I expected significantly more cylinder wear.  Sorry for the poor photo.

 

 

This is one of the cylinder heads after the gasket removal with the carbide scraper.  You can see the original machining marks by GM.  I still go over the head with CRC gasket cleaner, a rag, and elbow grease prior to installing the heads again, but the carbide tipped scraper is simply amazing.

 

OEM lifters, driver's and passenger's side that are still within operational spec

 

 

 

Carbide Gasket Scraper.  One of the youtube videos I found that suggested it and gave tips on its use... 

For anybody interested, I have used Castrol Edge Advanced Full Synthetic 0W-20, FRAM Ultra-Synthetic filters, and changed the oil at GM recommended intervals.  Based on my observations, I have zero complaints with the oil, filter, or OCI's at this point and will proceed with the same products and the same oil change interval.

 

 

 

 

 

 

Great write up and info Gangly!! 

[customboss]

4 hours ago, Gangly said:

I took some time off from work and decided it was a good time to go through the Z71 and have a good look at things.  I have a little under 130K miles on the truck with no issues, but I need it to go 200K and I wanted to do a valvetrain refresh.  I assumed the heads and valvetrain would need to be refreshed soon, and I would rather do it in my shop at a time of my choosing, than after breaking down on the side of the road, so I purchased the parts and tore into it.   After removing the heads and checking everything out, the valvetrain was VERY clean with no sludge buildup in the rocker arm/spring area, with valve spring constants within spec and the valve seals looking good.  The lifters were within spec, the rollers clean and clear of surface issues, and the cam lobe surfaces looked great. When visually inspecting the block, the cross hatch on the cylinder walls was exceptional, and the surfaces of the lifter rollers and cam lobes showed no excessive wear.   With the condition of the original components, I went ahead and replaced just the lifters and pushrods with GM parts since everything appeared to be in great shape.  

 

Total time from start to finish was about 30 hours, but that was me going VERY slow and triple checking everything.  Total cost for parts and materials (gaskets, bolts, cleaners, etc) was about $1500.  Doing this with the engine still in the truck was A LOT more challenging than I anticipated, with the rear head bolts being very hard to access in order to properly torque.  Also, cleaning the gasket materials from rear portions of the block took forever simply because of the poor access, and required a lot of patience and maneuvering.  Cleaning surfaces, double checking fastening torques, and running to various stores to get parts/tools took more time than what a dealer could complete the task in, but if I was to do it again I would assume I could have both heads off, cleaned, inspected, and the truck back and running in about 15 hours.  The only issue I currently have is an exhaust leak at the driver's side manifold.  I installed new GM exhaust manifold gaskets and GM exhaust manifold bolts, and torqued them to spec and sequence, but I haven't had a chance to recheck the torque on the manifold bolts since heat cycling the truck, so I assume one or two might have backed out.  I will replace them with ARP exhaust manifold bolts once they arrive.  Whenever I go with ARP bolts, it generally solves any exhaust leak issues, but I went back with all GM fasteners in hopes to avoid any issues when I should have just gone straight with the ARP bolts to begin with.  

 

For any of you who have had to scrape off old gaskets in the past with razorblades, plastic blades, gasket scrapers, etc., I would HIGHLY encourage you to get a carbide scraper.  It is by far the best scraper I have ever used, and cut my time down by AT LEAST HALF when cleaning the block and head surfaces.  It scrapes perfectly flat without gouging, and creates a fantastic surface for gaskets.  I'll leave a youtube link for anybody with questions about it, but it is by far one of my better tool acquisitions and I would highly encourage anybody who prepares mating surfaces to get one

 

Engine block still in the truck after the head have been removed.  The lifter trays were removed from the passenger side, but not from the driver's side yet.

 

The cross hatch on the cylinders appeared to be in great shape, with minimal wear indicators.  For a little under 130K miles, I expected significantly more cylinder wear.  Sorry for the poor photo.

 

 

This is one of the cylinder heads after the gasket removal with the carbide scraper.  You can see the original machining marks by GM.  I still go over the head with CRC gasket cleaner, a rag, and elbow grease prior to installing the heads again, but the carbide tipped scraper is simply amazing.

 

OEM lifters, driver's and passenger's side that are still within operational spec

 

 

 

Carbide Gasket Scraper.  One of the youtube videos I found that suggested it and gave tips on its use... 

For anybody interested, I have used Castrol Edge Advanced Full Synthetic 0W-20, FRAM Ultra-Synthetic filters, and changed the oil at GM recommended intervals.  Based on my observations, I have zero complaints with the oil, filter, or OCI's at this point and will proceed with the same products and the same oil change interval.

 

 

 

 

 

Thanks for sharing and the effort to share so well. Whatever your doing continue on!!!

[Black02Silverado]

Great post.  Thanks for sharing!