1999 Chevy Tahoe 2 Door Refresh

Phase 3 of firewall insulation.
This final layer is DEI Floor and Tunnel shield. This material is 3/16" thick and rated for 1,700 degrees. Not only does it stop engine heat, it adds to the noise blocking too.
The edges will be sealed with a high temperature foil/fiberglass tape.
This product is rated for engine compartment and under body locations.




I am waiting for more edge tape to arrive to complete the job.
The heat shield was added to the first 5" of the transmission tunnel over the top of the sound deadener.
Heat shield will also be applied to the heat shields above the catalytic converters and muffler.

 

Next up is the engine bay wiring harness.
Every bit of convoluted tubing on the harness is crispy. Most of it just crumbles when you try to remove it.
I ordered this big box of snakes from McMaster Carr along with some Scotch Super33+ electrical tape.
Just about every size of convoluted tubing imaginable, in high strength rating, just like GM used from the factory.





This is going to be fun right???
I have been intentionally gentle with the wiring harness to not break any wires.





The old crank position sensor plug had been soaked in oil for so long that the insulation was missing from one of the wires.
A replacement pigtail was sourced and installed.





This was the lead for the former EVO power steering system. In the later 90's GM used system to make the steering light in parking lots and heavy on the freeway. It turned out to be problematic and was often bypassed.
I cant imagine that this system would have worked properly with the connection in this condition.





Slowly getting the harness stripped, cleaned, inspected and re covered.
Back when I did the conversion from automatic to manual I clicked the automatic transmission range switch to neutral, wired in the reverse light plug and wired the two purple wires together.
I have slept too many times since then to remember why I left the range switch in the vehicle and/or why I wired the two purple wires together. I am going to have to do some digging to see if I can eliminate the range switch for a cleaner install.
The ECM was re-flashed for a manual transmission back when the install was done, I am not sure that the range switch would have any effect on operation anymore.

 

Maybe the range switch in neutral is conversion result of the re-flash using same harness wires but re-flash is using same wires to bypass engaging the clutch when starting?

 

Waiting on a few small items to finish the wiring refresh and insulation install on the Tahoe.
Today the engine was harvested from the Yukon.
Once separated from the transmission it will get cleaned up and transferred to an engine stand to change the rear main seal and pan gasket.

 

Way to recycle. I love the fall harvest.

 

I'm not sure why it suddenly looks like less wiring than before, maybe its just because it no longer looks like a rats nest!
This is only the engine harness, the body harness will be refreshed as well.





With the wiring ready to go it was time to move to the new engine.
After a good washing the engine basically looked brand new.







This final iteration of 350 Chevy has a one piece rear main seal and the housing integrates into the oil pan gasket.
It is pretty impossible to replace the both of them with the engine bolted to a stand. Typically a builder would turn the engine upside down on the bench to install the seal housing and pan.
I cannot do that without damaging the intake, distributor ect...
The best option I found was to stand the engine up on its nose, strapped to a factory cart.

 

Today the oil pan and main seal housing will go in to my local engine builders hot tank.
With the exception of a little spot in the pan where not all of the oil drains out, the pan is very clean inside.

 

There is no amount of brake parts cleaner, solvent and rags that gets engine parts as clean as a parts washer.
The new rear main seal is installed in the housing.
I was hoping to reassemble the engine tonight, however my engine builder recommended replacing the oil pump with a high volume unit while I have it apart.

 

Boy, when you dive into a project…..you go DEEP.

Holy phuck!!!

well above my skill set,for sure.

 

Painfully slow progress this week.
I always have such high hopes of getting lots done... only to have "responsibilities" get in the way.

The firewall insulation was wrapped up with final edge taping using DEI's cool tape.
I ended up having to use a heat gun to get the tape to properly adhere in the low 50's temps.
The factory heat shields were reinstalled over the top of the insulation with oversize self tapping screws.
I am very happy with how this turned out.




A new starter ring gear was installed on the flywheel.





The serpentine belt brackets were cleaned up in a brand new water/abrasive blaster.
The advantage of this style blaster is it does not abrade the material surface like a standard glass bead blaster.





These parts look factory fresh, not like they were glass bead blasted!
I will give them a coat of satin clear engine enamel so they do not stain.
Note.... that random aluminum cylinder head in the background was cleaned in the same machine. You can't tell its a reman head, it looks brand new!

 

the washer box is awesome. And a ton less messy with dust, grit and more if I had to guess.

 

One step forward and 3 steps backwards.
I installed a high volume oil pump and improved oil pump drive shaft. The new oil pickup was test fitted and set into proper location with a bump of the oil pan.
Once set correctly the oil pump pickup was welded to the pump.





After the oil pump installation was complete it was time to prepare for oil pan installation.
Cleaning from the top down, engine sitting on its nose, I came to the front oil pan seal. I grabbed it with pliers and pulled it out from the round of the timing cover.
When the seal came loose on the opposite side it pulled about 3" of the timing cover seal out too.
These original GM timing covers are plastic and one time use only, they even say it on the cover. The plastic timing cover comes with a rubber rope type seal that is not glued in place, thus the reason it pulled out so easily.
After much swearing and the consumption of a beer I flipped the engine over to access the next rabbit hole.
Once the water pump and damper were removed the timing cover came off easily.
Some internet research led me to an aluminum replacement cover that cost nearly the same as a good quality plastic replacement.
New aluminum cover ordered..... might as well throw a new timing set on the engine while it is apart....
I am really starting to feel like I should just drop this engine off at my builder and have him duplicate the GM HT383E drop in replacement crate engine.

 

If your gonna do it do it right!
How big a cam and crank can you go?

 

LOL...
California emissions testing puts a damper on the HP mods pretty quick....
The factory fuel injection system is a big limiting factor and must be retained.
The GM HT383E engine is designed as a drop in replacement for the L31 350. Even with it's mild cam it still puts out 323HP and 444TQ.
It actually rivals some of the later 6.0LS engines in HP and outperforms them in the torque department.
I will be talking with my local builder this afternoon, when I pick up the new timing set from him.

 

THIS!

 

After talking with my builder I am going to run this engine as is for now.
With the updated HV oil pump and timing chain it should run another 200K miles with regular maintenance.... that of course is barring catastrophic failure.
The significant performance gains from the HT383E style build will significantly hurt fuel mileage and this rig is slated to become the go to daily driver when completed.
If we were to build another engine it would be the old engine with 400K+ miles on it.
I cannot believe how much the cost of proper 350 rebuild has gone up.... Even a stock rebuild done properly is $2500 in parts.
So we get back to the scheduled programming!

I picked up a new timing chain from my builder and installed it.





The stock timing cover on these last gen 350's is plastic and one time use only.
For nearly the same cost a a quality replacement plastic cover you can have this Holley aluminum cover!
The oil pan was reinstalled with a one piece Fel Pro gasket.
I forgot to pickup water pump gaskets when I got the timing chain....
All the little detail items have slowed progress on the project. Once the engine is back in the frame the pace should pick up significantly.

 

With the lower half of the engine resealed it was time to flip it upright.
The valve covers were removed and took a trip through the parts washer. New valve cover gaskets were installed.
Before installing the valve covers I removed the distributor and filled the engine with oil.
I had to rig up this re-circulation hose for the oil cooler lines before priming the engine.





I carefully marked the distributor before removing it. Crossing my fingers I wont have to get a hold of a scan tool to re phase the distributor.





I primed the oil system until I got a couple bubbles out of 2 push rods. My 20V drill wasn't very happy, but after a couple batteries I felt comfortable calling it done.
The fresh surfaced flywheel with new ring gear was installed as well as a roller pilot bearing.





New Luk clutch and Wilson USA rebuilt starter.





The rest of the front accessory drive system was installed.
New idler pulley and tensioner pulley/ bearings installed.
New power steering pump with EVO sensor deleted.





The rebuilt transmission was cleaned up and painted before mating it to the engine.
A new Luk hydraulic release assembly was installed on the front of the transmission.

 

I take it the throwout is an internal style?

 

Correct.
This is the 1996 and newer NV4500.

 

The last install before the engine goes to it's new home!
Engine oil cooler lines, Genuine GM units of course! These are the only lines I can find that are steel, all off brands are aluminum. In rub prone areas, the steel hold up much better.
The oil cooler lines are a PITA to install in the vehicle, on a pallet they are a breeze!






Headed for it's home for the next 200K miles.
My work bay is entered via a short steep ramp. The jib boom allows the forklift to be 10' away and on the lower elevation.






About 5 min after taking the previous pic, the engine was sitting in it's new home.
Now I have to remember where everything went.......