Words by Bryan Irons @Bryanirons
In our last issue (4WDrive Volume 24, Number 1), we broke down a 2005 6.0 L Chevrolet LQ9 V8 engine we cored from a Denali pickup in a junkyard and explained what to look for when getting ready to add more trail-worthy parts for optimal performance and reliability.
Inspection of worn items and sources of leaks is always wise to do when the engine is out of the vehicle, and not on the side of a trail. Be warned, there are rabbit holes that you can get lost in and we’ll explain some to avoid and a few that we dove into - on purpose, of course!
Bryan Irons
The cylinder head gaskets on a typical LS series engine (like we have) are not known to leak and the bolts are a one-time-use only setup, which is known as ‘stretch to yield’ fasteners. Changing these for our overall goal would be a little overkill in our opinion. Plus, the process would have eaten up a large part of our budget.
Our concern of not removing the cylinder heads was that we couldn’t inspect the camshaft lifters, but this was a risk we were willing to take - famous last words. Your comfort level may differ from ours, but we drove and inspected the engine before we doled out any cash.
We have relied on Comp Cams to help us select valvetrain components for many of our previous builds and they haven’t let us down yet. We put a call into Mark Campbell, Vice President of Sales for the company, who set us straight with a setup suitable for daily driving that will also deliver some great power numbers.
A Stage 2 Thumpr Camshaft (PN 54-702-11) was chosen for its mild manners in a 6.0 L displacement engine, but it also comes with some major torque across the RPM range. Although the cam is part of Comp Cams’ NSR (No Springs Required) lineup, we chose a set of Beehive LS6+ Springs (PN 26906-16) for added stability for when we run higher RPM.
The pushrods and rocker arm assemblies connected the lifters to the valves. The ones on our LS engine were getting tired and not quite up to our standards for this build. The higher ramp profiles of the cam induced flex and strain on the pushrods, thus preventing them from achieving top performance. The Hi-Tech Pushrods (PN 7955-16) will replace the stock units with a length of 19 cm (7.4 in), like the previous ones.
The original rocker arms in the LS-based engines are built with a very nice rollerized trunnion design. Aftermarket manufacturers make them even better with trunnion bearing upgrades, which keeps all the tiny bearings from coming loose and polluting the engine while hauling heavy loads and running higher RPM (like when a camshaft and upgraded springs are added).
The problem with upgrading the engine with these components may potentially (although slight) spew their tiny metal components into the oil system as well. Comp Cams has a BSR Shaft Rocker Arm System available that doesn’t incorporate tiny bearings, which helps keep the valve train operating as it should. It also performs well and is designed much better than its stock counterpart.
Shaft-mounted rockers are typically used in high-performance engines to keep the valvetrain more stable under heavy loads and high RPM. Our part number was PN 1981-16 for the shaft rocker setup.
When we installed our new camshaft, rockers and pushrods, we ordered a cam install kit (PN 5621) and timing chain set from Comp Cams as well (PN 7102). The camshaft installation kit included all the gaskets and seals required to replace the cam as well as a new damper bolt, which is a one-time-use part. Adding a new timing chain is just a good idea when you have an engine disassembled this far and there are multiple ways to adjust it.
The double roller we ordered is way overkill but was worth it in our opinion. Spacers to keep the oil pump from contacting the much wider chain and a new oil pump drive gear were all included. With all of these fancy new parts being installed, we wanted to make sure the internals are well lubed from the first time we start the engine.
We’ve always trusted Lucas Oil for our rigs - from daily drivers to our nitrous-fed 401-equipped CJ7. We use Lucas Assembly Lube (PN 10153) like Frank's Hot Sauce - yes, we put that stuff on everything. To keep all of the lube in the pan, we ordered a Summit Racing Pro LS cast aluminum oil pan (PN 121200) that’s deep enough to handle the long stroke of the LQ9 engine and the proper shape for our engine swap. Besides, the factory pan was disgusting and way too deep. The kit came with a new pickup, gaskets, bolts and oil filter adapters.
Now that we have explained the list of parts we used for the bottom end assembly, let's get to the installation. Be sure to check out a future issue of 4WDrive for when we install the induction components and see how we’re going to control this 6.0 L trail-worthy engine.
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Bryan Irons
With our engine block still upside down to keep the lifters from getting in the way (see 4WD Volume 24, Number 1), we lubed up and installed the Thumpr Stage 2 cam. Since this is not a flat tappet cam, we only needed to use a quality assembly lube. Lucas Assembly Lube is very tacky, is a reasonable price and the bottle is easy to manipulate. Trying to install a camshaft with ‘ketchup-type packets’ of lube just sucks.
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Bryan Irons
With the cam and stock retainer plate in place, the timing-set crank gear was installed ‘straight up’ or at zero degrees. The new oil pump drive gear was pushed over to the factory keyway as well. You may need to tap this on as it is a light press fit.
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Bryan Irons
On the backside of the timing chain, the camshaft gear is a thrust roller bearing. Make sure to also apply some assembly lube here before bolting the sprocket to the camshaft.
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Bryan Irons
Included in the camshaft installation kit were three new retainer bolts (silver) and a fold-over lock plate. You can use the factory bolts (black) but just apply a little thread locking compound to keep them from getting loose. We chose the locking plate.
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Bryan Irons
You can see the included placer plates we have installed on the back of our oil pump before installation. Remember to only install and hand tighten the pump bolts at this point as you need to align the oil pump before torquing it in place.
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Bryan Irons
There are many ways to centre the oil pump gears to the crankshaft. We used 0.00381 cm ( 0.0015 in) shims around the pump gears, finger-tightened the bolts and rotated the crankshaft a few times to get it centred before final torquing. Both methods worked for us in the past. We also installed the oil pickup tube that was included with our Summit Racing oil pan. Unlike factory pickup tubes, this used both bolt holes in the oil pump to secure the tube.
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Bryan Irons
Like the oil pump, we aligned the front cover to the crankshaft and oil pan rails to prevent future leaks. We picked up this simple alignment kit for LS-based motors a while ago from Amazon. Check for proper fitment. You may need to grind away some material so the front cover will fit over the oil pump, which has now been extended out with the spacers.
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Bryan Irons
Finally, it was time to bolt on our oil pan. Summit Racing included all of the installation hardware as well as the gaskets. We used a small dab of gasket maker at the junction points. Loosely fit the bolts for now since you need to make some alignment checks.
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Bryan Irons
The transmissions in these engines bolt to the block and the oil pan so they must be perfectly aligned before torquing the oil pan bolts.
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Bryan Irons
Reinstalling our harmonic balancer/damper is the last step before turning the engine right-side-up once again. You will require a torque wrench and degree metre to get the proper bolt stretch. A degree metre can be purchased for under $10 at just about any hardware store.
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Bryan Irons
The next task we did was change the valve springs. A few specialty tools were required to get this job done since the cylinder heads were still bolted to the block. We used an air chuck (bottom) to fill the combustion chamber with compressed air to keep the valves from falling into the cylinder. We also used a valve spring compressor for this LS motor. The Lisle 16560 will work fine only if you plan on changing the valve spring once or twice. There are many better ones on the market.
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Bryan Irons
Here is the setup for replacing the springs. Our valve seals, keepers and locks were all in excellent shape. If you’re ever in doubt, valve seals can easily be replaced at this time.
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Bryan Irons
Although it’s not completely necessary, we like using new pushrods in an engine build. With a roller camshaft, the pushrods don’t rotate as they do in a flat tappet engine. They can also have some odd wear patterns. Make sure to slather these in assembly lube as well.
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Bryan Irons
Our new bushed shaft rockers are a beautiful piece of hardware that nobody but us will get to see. The shaft design maintains proper geometry and the bushing material Comp Cams developed will last many kilometres, even under extreme loads and a high lift. They also come pre-assembled!
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Bryan Irons
Again, use plenty of assembly lube and refer to Comp Cams’ installation guide for the correct torque sequence. All new hardware is included with the shaft rocker setup. Our cam measures in at 1.37 cm (.541 in) of lift, but the BSR rockers can handle up to 1.65 cm (.650 in), and still fit under the stock valve covers.
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Bryan Irons
We double-checked to make sure we had the proper preload on the lifters. Everything measured out perfectly at .127 cm (.050 in). If this is a problem, different length pushrods will be required to correct it.