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Say Hello to the En Fuego Six-Oh Junkyard Engine

We attempt to rebuild the worst junkyard engine ever, so you don’t have to

Jeff Huneycutt Jul 12, 2019
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This is not the story that we planned. General Motors' 4.8/5.3-liter LS-based blocks are relatively plentiful in the junkyards, but the larger displacement 6.0-liter LQ4 and LQ9 engines are tougher to find. So when we spotted a 2005 Cadillac Escalade ESV (the Suburban-sized version) on a recon run at the local junkyard, we immediately went to take a look.

It wasn't pretty.

The engine was covered in caked-on fire extinguisher powder, and even though the plastic intake manifold wasn't melted, something had obviously been on fire. Plus, it was seized up and wouldn't turn over, even with a breaker bar on the crank bolt. Still, the eighth letter in the VIN code was "N," so we knew it was the 345-horsepower LQ9, which are tough to come by. I thought this one could be salvageable with some machine work, so I called my dad and asked if he wouldn't mind helping me pull an engine from the junkyard bright and early the next day. I told him we should be done in time for a late lunch, and the burgers were on me.

Boy, was I wrong. Practically every bolt was galled tight with rust. We worked for a day and a half to get the engine and transmission out. It rained. I collected fresh scars on my hands I will carry for the rest of my life. It was a miserable experience, and I loved every second of it.

Pretty early on we realized this LQ9 wasn't worth the effort. Because we couldn't get the engine to spin over, we couldn't reach the flexplate bolts to release the engine from the transmission. We had to pull both as one unit. Not easy in a four-wheel-drive vehicle. The engine itself didn't look too healthy either. There was water in several of the cylinders and one of the spark plugs was broken off in the cylinder head.

So, as the realization dawned on us that this particular engine was a napalm bomb of things gone wrong, instead of moving on to a better engine, we decided to see what would be required to rebuild what's possibly the worst junkyard engine ever. Yes, this is a bad idea. And maybe this engine would be better off melted down and turned into a washing machine or lockers for a middle school somewhere. But where's the fun in that?

So we're going to do our best to bring new life into what we're calling the En Fuego Six-Oh. (Because it's been on fire, get it?) Go ahead, feel free to laugh at our pain. It's all in the name of science.

General Motors produced two versions of the 6.0-liter LS-based iron block. They are designated LQ4 and LQ9. The LQ4 began production in 1999, but ignore the '99 and '00 versions because they were outfitted with iron heads, and ran until 2007. The LQ9 was first produced in 2002 and also ran until 2007. Both are mainly found in trucks, including Silverado and Sierras, as well as larger SUVs like the Escalade and Yukon Denali XL. The main difference between the two engines is the LQ9 trades in a dished piston for a flat-top to bump the compression up from 9.4:1 to a healthy 10.1:1. According to GM, that's worth about 15 horsepower and 10 lb-ft of torque.

We'll be covering the buildup of En Fuego Six-Oh in a couple of installments. This time around we're sharing the pain of discovering just how bad off this engine is and tips for determining the health of your own junkyard reclamation project. Next, we'll turn this lump of rust into something useful and strap it on the dyno to see just how much steam we can make on the cheap.

The cool thing here is that GM's 4.8-, 5.3-, and 6.0-liter engines are so similar that practically everything we're covering here will work across the board. So, while we definitely wouldn't recommend taking on a reclamation project as bad as this one, there are tons of LS-based engines in the junkyard these days. Keep looking and find a better option. Stick around while we try to dig ourselves out of this horsepower hole. CHP

2/20

No, we aren't planning to rebuild the transmission along with the LQ9 engine we pulled from the junkyard. Because the engine was seized—we couldn't spin it over to loosen the flywheel bolts—the engine and transmission had to come out as a unit. Thankfully, someone else wanted the trans so we were able to get rid of it no problem.

3/20
4/20

Here's a better look at the 6.0-liter V-8 the way we found it. That white crud all over it is apparently powder from a fire extinguisher. Shortly after this we decided to name it the En Fuego Six-Oh and were committed to this engine, no matter how bad it got.

5/20

The key to a successful engine pull at a junkyard is to spend as little time lying in the dirt as possible. To make it easier to remove the top bolt connecting the transmission to the block, pull the intake so you can reach it from above. Since the rotating assembly was seized up, it did us no good, but it did reveal the bad news that there was water sitting in every intake port.

6/20

Once the transmission was removed, the teardown could begin in earnest. First off were the coils and valve covers to reveal rocker arms and valvesprings covered in rust. The water trapped inside this engine really did severe damage. At minimum, the rocker arms would need to be sodablasted and the trunnions rebuilt, which really isn't worth the cost. Rusty valvesprings are definitely a no-go and will have to be replaced.

7/20

The knock sensors were seized in place, but a little white vinegar poured into the holes where they thread through the valley cover into the block ate away at the corrosion over a couple of days and allowed one of them to come out.

8/20

One of the valley tray's knock sensor ports was so corroded it broke off at the base. The valley was full of both rust and assorted crud.

9/20

The parade of disappointment continues. If you see this, run—don't walk—away as fast as you can. Of course, we're committed, but it was at this point we began to worry that at least a couple of cylinder bores will require sleeving. Conventional wisdom says you can bore an LQ9 0.060-over (to 4.060 inches) and sometimes more if you keep it naturally aspirated, so we'll just have to see.

10/20

One spark plug was galled in the cylinder head, and the hex for the socket had broken free from the ceramic, allowing it to spin freely. While trying to determine how to get it out, we discovered that the pad to the side of the spark plug strap in the combustion chamber was completely burned away. For comparison, you can see a "good" chamber to the left. We don't know exactly how that would have happened, but we do know the head is junk.

11/20

When we pulled the drain plug from the oil pan there was a gallon of water and practically zero lubricant. Still, the level of rust on the crankshaft and connecting rods was surprising.

12/20

Disassembling an engine with a seized rotating assembly requires a little mechanical gymnastics. Because you can't spin the crank over to better access the connecting rod bolts, you will need to use a box-end wrench to get to some of them. We didn't have any extra-long wrenches so we used the old wrench-on-wrench trick to gain enough leverage to get the rod cap bolts off. After that it was as simple as yanking the crank and using an extra-long drift (actually a cut-down axleshaft) and mallet to punch out the pistons.

13/20

Four of the pistons and rods came out easily enough, but the other four were galled to the cylinder bores and put up a fight. The collateral damage was high, but we weren't planning to reuse either the pistons or connecting rods again anyway.

14/20

Even if we hadn't absolutely destroyed four of the pistons during disassembly, we honestly didn't plan to keep them anyhow. The flat-top pistons do help bump up compression for a little extra power, but they are cast and limited in terms of how much power they can handle—especially if the engine gets into a little detonation. The powdered-metal 6.098-inch connecting rods are a little bit stronger, but they are very hard to bring back to spec. The cracked-cap design means you can't clip the caps and re-hone the big ends. Plus, the weird 0.9429-inch wristpin diameter limits your piston choices. Generally, it's just better to replace both the pistons and rods with quality aftermarket pieces any time you are rebuilding one of these engines for performance.

15/20

Here's a close-up of the damage to the crankshaft. One of the main bearings was welded to the journal, as you can see here. Besides the rust, it definitely is a victim of low oil. Before we began the teardown we were hoping to get away with turning the mains and rods down 0.010 of an inch, but that's looking unlikely now. It doesn't make sense to spend too much money rehabbing a crankshaft when Summit Racing sells reman cranks for a smidge over $300, so we may go that route.

16/20

Like the pistons, several of the roller lifters were rusted tight in their lifter bores. Because of that, we couldn't get the camshaft out of the way to knock the lifters out. If you run into this issue, there's an easy solution. The outer main cap bolts use short threaded ends on top of each bolt for securing the OEM windage tray. These are the same size as the bolts for the camshaft's timing pulley. Thread the main bolts in backward like you see here, and a large screwdriver or pry bar will give you enough leverage to spin the camshaft over and break the lifters loose.

17/20

Besides looking absolutely terrible on the outside, several of the roller lifters felt "gritty" when spinning the roller wheel with a finger. Summit Racing sells replacement lifters for $7.50 each, so it's not worth trying to rebuild them. These automatically went into the scrap pile.

18/20

The camshaft, however, might be salvageable. The rust mostly wiped right off, and the lobes all seem to be in good shape. We will check it more closely later, but for now we have our fingers crossed. With just 196/201-degrees of duration and 0.467/0.479-inch lift, a cam swap down the line will unlock a lot more power, but for now we'll try to keep it just to make a baseline.

19/20

Besides the $250 we spent to purchase the engine from the junkyard, our first real expenditure was a hundo to have the crusty block baked and blasted. No machine work has been done to it yet, but it looks respectable and allows for better inspection. Things are finally looking up.

20/20

With the cylinder bores finally clean, we can get a better look at the damage done by all that water in the block. Two cylinders had severe pitting, but we are still hoping an overbore of 0.060-inch will clean it up. We've heard that if you keep the engine naturally aspirated (forced induction puts a lot of stress on the cylinder bores) you can sometimes get away with an 0.080 overbore, but if that's necessary, we'd prefer to just install some new sleeves. We'll dive deeper into the inspection and machine work in the next installment and let you know what we find out. Keep your fingers crossed. We know we are.

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