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3.6L 24V VR6 Step-By-Step Engine Assembly Guide

Updated: 12 hours ago

Work-In-Progress Alert! This will be updated as the build progresses


Note: This guide was created using a BLV-coded engine (2007 Passat). Other engine codes may differ in assembly.


Step 1: Block Preparation


Before cleaning, machining, and painting the block, make sure all parts are removed from the block. Common things to miss are:

  • 6 oil squirters located in the main bearing galleys

  • cylinder head alignment dowel pins

  • oil non-return (check) valve located in an oil passage on the deck. Held in with an o-ring, just pull up with needle nose pliers to remove

If you plan on having the engine bored out, you may want to purchase a 24v VR6-specific torque plate to give to the machine shop if they do not have one.


Mounting the Engine from the Exhaust Side:

Tap out the rust on the M10 x1.5 holes on the exhaust side of the block. We will use these as an engine stand mount when we do the timing chain.


My engine stand was able to fit, but you can buy a mounting bracket pre-made if you want to. Try and mount the pivot point as close to the deck and as far over to balance it the best, especially when the cylinder head gets installed. Be careful mounting like this! The engine is more offset than the normal operation. Get a wider engine stand if it wants to tip over.



Step 2: Freeze Plugs

If you are sand blasting the block, you need to pull the one large coolant and two small oil freeze plugs and blow out those passages. The coolant passage is 34.5 mm, and the two oil passages are 15 mm freeze plugs.


The best way to install the freeze plugs is to get a socket that fits on the inside of the plug. Don't press them on the outer flange. If needed, you can apply a small amount of Indian-Head or similar shellac to help seal them.



Step 3: Install Oil Squirters


If you haven't already, first soak the oil squirters in a bath of brake cleaner. Then take each one and use a small tool to push the check ball off its seat. Spray brake cleaner down the other end of the tube as you are doing this to rinse the inside out. Oil gunk can build up easily inside these. Soak with oil and install into the main bearing galleys.



Step 4: Install Main Bearings

The main bearings with the groove and slot are for the block. The smooth ones get installed into the main caps.


Check for burrs on them! All of mine needed a little bit of de-burring with a utility knife before they could be installed.


Clean the main bearing surface of any oil from installing the oil squirters. Clean the bearings with brake cleaner and install dry (we will be checking clearances next).


Clean the main bearing caps and install the bearings dry.


Step 5: Main Bearing Clearance with Plasti-Gauge

To do our main bearing measurements, we will install the crankshaft in dry and torque to spec using the old bolts. First, make sure the crankshaft is clean and ready for installation. Blow out the oil passages in the crank that run from main bearing to connecting rod journal


Lay the crank in and place a small strip (1/4") of plasti-gauge across the crank surface. Install the main caps with their bearings. Do not try to rotate the crank. You will scuff the bearings.


Main cap orientation and numbers.


Torque: 30 N-m (22.13 ft-lbs) starting in the center and working outwards. Once complete, torque the bolts an additional 180 degrees in the same sequence. Use the old bolts as this procedure will stretch them and they will become unusable.


Remove the bolts, cap, crankshaft and check main bearing clearances.


Clearance: 0.02-0.06 mm (0.0008 - 0.0024 in) new, with a wear limit of 0.10 mm (0.0039 in)



Step 6: Install Crankshaft

We will permanently install the crankshaft with our new main bolts. Lubricate only the main bearing journals as we will individually install the connecting rods dry to check clearances on the rod bearings.


Main Bearing Cap Bolts P/N: N90 365 801


Lubricate the main bearings, block and cap side with assembly lube. Lubricate the thrust waster seats on bearing #5 on the block.


Lay the crank in.


Lubricate the two thrust washers with assembly lube and hold them in the main cap #5 as you install. They can only go in one way. This engine only has 2 thrust washers compared to the 12V VR6 which has 4.


24V Thrust Washer P/N: 022 105 635


Install the main caps, do not seat them by driving in the bolts, they must be seated beforehand.


Main cap orientation.


To get an accurate torque, lightly lubricate the threads of the main cap bolts with oil. Do not oil the end of the bolt, as this oil will not compress as you tighten the bolt and it will give you issues. Start in the center and working outwards.


Main Cap Bolt Torque: 30 N-m (22.13 ft-lbs) on all bolts first, then do an additional 180 degrees in the same sequence.


Mark the torqued bolts with paint marker.



Step 7: Crankshaft End Play


With the crank seated and the thrust washers in place, we can check end play. Stick a magnetic dial indicator on the side of the block and indicate off of the nose end of the crank.


With a screwdriver, lightly pry the crank backwards away from the indicator and set the zero position. Pry towards the indicator and take your end play readings. Rotate the crankshaft and verify the reading does not change at different positions.


End Play Clearance: 0.07 - 0.23 mm (0.0028 - 0.0090 in), maximum 0.30 mm (0.0118 in)


Step 8: Front Crankshaft Seal

Apply a light coating of rtv on to the seal. In this case I used Permatex Ultra Grey. The amount shown in the picture was almost too much.


Front Crankshaft Sealing Flange P/N: 022 103 155 D


Clean the block & crank and install. Finger tight the 6 bolts and let the RTV set for 1 hour before torque-ing.


Torque: 10 Nm (7.39 ft-lbs)



Step 9: Install Crankshaft Harmonic Balancer

Install the harmonic balance next to make it easier to turn over when installing the pistons. You may need to fabricate a lever that bolts to the flywheel end of the crankshaft to hold it in place when torquing.



Torque: 100 N-m (73.8 ft-lbs) first, then 180 degree turn


Step 10: Piston, Ring, & Bore Clearances

Flip the block over, we will now insert our new piston rings in the bores to check the ring gap clearances. As all the bores are slightly different, I recommend that you gap each ring set to a specific bore, and then install the rings in the bore used for measurement.


DNJ Piston Ring Set for 3.6L VR6


You can use the bottom piston to square up the ring in the cylinder bore. You can also use the depth gauge of a caliper to square up the ring, or machine an aluminum cylinder slightly undersized to the bore. Make sure to push the ring past any cylinder bore lip present to get an accurate reading. The ideal placement is 6 mm from the bottom of the bore, as the bottom of the bore sees less wear and the gap will measure tighter than near the deck.


Ring Gap Clearances (OEM, maker larger for forced induction)

  • Compression Ring: 0.20 - 0.40 mm (0.008 - 0.016 in), max 1.0 mm (0.0394 in)

  • Tapered Ring: 0.20 - 0.40 mm (0.008 - 0.016 in), max 1.0 mm (0.0394 in)

  • Oil Ring: 0.25 - 0.50 mm (0.010 - 0.020 in), max 1.0 mm (0.0394 in)

With the pistons cleaned up (walnut blasting works well. just make sure to tape up the skirt coating first), install the rings.


Piston Rings


With the piston grooves clean of any carbon build up, install the oil control ring. This consists of two small wiper ring sandwiching the spacer. Install the bottom one first, then the spacer, then the top one. The oil spacer ring is cut open and the ends butt up pointing towards the top of the piston as shown below. Make sure they do not overlap.


Install the bottom one wiper ring first, then the spacer, then the top one.


The first compression ring goes on. This is the darker colored one with the step in it. The step is oriented towards the bottom of the piston as shown below. If it is VAG OEM, it will have a laser-cut "TOP" mark showing orientation.


The final compression ring is lighter in color and of different thickness. Any markings, OEM or not indicate which side should be pointing towards the top of the piston.



Now, if you want to, check the groove clearances on the rings. Most likely, these clearances specified below are smaller than what your average feeler gauge set can do. If the rings installed dry can rotate freely, your probably good-to-go.


Ring To Piston Groove Clearances

  • Compression Ring: 0.04 - 0.09 mm (0.0016 - 0.0035 in), max 0.15 mm (0.0059 in)

  • Tapered Ring: 0.03 - 0.06 mm (0.0012 - 0.0024 in), max 0.15 mm (0.0059 in)

  • Oil Ring: 0.02 - 0.06 mm (0.0008 - 0.0024 in), max 0.15 mm (0.0059 in)

If you've honed you engine or have a worn bore, you may want to check the piston and bore diameters. Measure the piston about 10 mm from the bottom edge of the skirt, 90 degrees to the wrist pin axis. Note: this dimension will likely read off without the use of a torque plate. Use this diagram to measure the cylinder bores at 3 locations:

Piston Diameter: 88.945 mm (3.5018 in), maximum deviation 0.04 mm (0.0016 in)

Cylinder Bore Diameter: 89.010 mm (3.5043 in), maximum deviation 0.08 mm (0.0032 in)


Step 11: Assemble Piston & Connecting Rods

Clean up the rods, wrist pins, caps and old bolts. Un-diluted degreaser (Purple Zep) removes oil residue well.


Orient the piston and connecting rod such that the nub on the connecting rod and the laser cut arrow are both on the same side:


The two nubs on the rod and cap are oriented together, and that side of the rod faces towards the harmonic balancer


The laser cut arrow points toward the harmonic balancer. The valve reliefs will always point toward the center of the block, and the pistons with 4 valve reliefs are for even numbered cylinder (starting at #1 closest to harmonic balancer).


Install the wrist pin through the piston and connecting rod using assembly lubricant. Slide one end of the cir-clip in and progressively push it in the groove with a screwdriver.


Connecting Rod Bearings


Brake clean the rod and cap. Check for burrs and install the bearings dry.


Step 12 : Installing Pistons and Checking Connecting Rod Bearing Clearance

Piston / Rod Assembly Orientation


First, lay out the pistons and figure out which ones go into each bore. The cylinder closest to the harmonic balancer is #1, and the one closest to the flywheel is #6. Odd cylinder pistons have 2 valve reliefs, even cylinder pistons have 4.


Installing Pistons One By One


The best way to go about checking clearances is to go one piston at a time, check the clearance, then lubricate and install permanently with the new connecting rod bolts and assembly lube.


Place a piece of plasti-gauge on top of the clean crank journal in the center of where the rod cap will be.


Insert the cap & dry bearing on to the connecting rod. There will be matching marks on the sides of the rod & cap to verify orientation. Torque down with the old bolts. Use some light oil on the threads.


Connecting Rod Torque (measurement only): 30 N-m (22.13 ft-lbs) only

Connecting Rod Clearance: 0.02 - 0.07 mm (0.0008 - 0.0028 in), maximum 0.10 mm (0.0039 in)


Once you've recorded & verified the clearance, remove the old bolts, lubricate the bearing surfaces with assembly lube, and re-torque with the new bolts. Use some oil on the threads. Mark torqued bolts with paint marker.


Connecting Rod Final Torque: 30 N-m (22.13 ft-lbs), and an additional 90 degrees


Repeat for all 6 cylinders.


Step 13: Connecting Rod End Play

Using a feeler gauge set, check the gap between the connecting rod cap and the journal edge on the crankshaft.


Connecting Rod Eng Play: 0.05 - 0.31 mm (0.0020 - 0.0122 in), maximum 0.40 mm (0.0157 in)


Step 14: Relocate Engine Stand

If you haven not already, now is time to relocate the engine stand to the exhaust side of the block as shown in the first step.


Step 15: Install Oil Pickup & Coolant Crossover Tube

Install the pickup tube seal by hand with a light dab of oil:


Oil Tube Pickup Seal P/N: 03H 115 133


Install the oil pickup tube. Tighten it lightly like a valve cover, as it's plastic. No torque specified.



Lubricate & install the coolant crossover tube o-rings with a silicone or PTFE grease and install the tube with the 4 bolts. No torque specified. The part number for the two o-rings in the crossover tube is hard to find and not listed in any of VW's part diagrams, however ECS Tuning stocks it:


Crossover Tube O-Ring P/N: 021 115 444 B




Step 16: Assemble and Install Oil Pan

First step is to clean out the oil pan and to re-tap any holes if it was painted. Clean off any remaining RTV. If it was sandblasted, spend a good 20 minutes making sure the oil pan baffle holes are completely free of residual sand; blast some brake-cleaner in there and make sure they are clean. Tap size for oil pan baffle and level sensor is M6 x 1.50.



Install the oil pan baffle and its 9 bolts. No torque specified.



Install a new oil pan level sensor o-ring and install the sensor. No torque specified.


Oil Pan Level Sensor O-Ring P/N: 038 103 196



Test fit the oil pan on the block. The section of the flange that overhangs is where the timing cover will be installed later. Mark that edge with sharpie and apply RTV sealant up to the line.


Insert the 25 oil pan bolts hand tight and let the RTV set up for 1 hour before torque-ing to spec.


Oil Pan Torque: 12 N-m (8.85 ft-lbs)




Step 17: Install Oil Pump

Clean the oil pump cavity of any dirt. Since I am installing a new pump, I prefer to fill the pump with some assembly lube & spin the pump around. Lubricate the o-ring and the sealing surface on the block with oil. Install the metal gasket dry.


[insert oil pump picture]


Note: To deal with the infamous oil pump bolt failure on early versions of these engines, the oil pumps on later models (2011+) have a larger mating surface with the gear. After 2011, the 2-piece gear became a single piece, and the oil pump bolt has changed from an M10 to an M12 sized bolt. Engines produced before 2011 have I found this out trying to install my old sprockets on the new style pump.


To upgrade to the new style 2011+ oil pump and gears, you need:


Oil Pump P/N: 03H 115 105 L

Oil Pump Sprocket P/N: 03H 109 569 A (can be found used on eBay)

M12 Oil Pump Sprocket Bolt P/N: N10 203 803

Link to an ECS Tuning Kit


If you are keeping the old 2006-2011 oil pump and two-piece sprocket, replace the bolt prone to failure with the revised one below. The original bolt prone to failure was a class 8.8 bolt that would loosen up as the engine heat cycled. The replacement bolt is a class 10.9.


M10 Class 10.9 Oil Sprocket Bolt P/N: N10 613 901


Pump Housing Bolt Torque: 8 N-m (5.9 ft-lbs), light oil on threads


The oil pump sprocket will be installed later once the lower timing chain is in place.


Step 19: Install Lower Timing Components & Lower Chain:

Lower Guide Pins & Chain Guide


Install the two lower timing guide pins with some light oil.


Lower Timing Guide Pin P/N: 021 109 471


Torque: 10 N-m (7.38 ft-lbs)



Install the lower timing guide on to the pins. Mark the torqued guide pins with paint marker.


Lower Timing Guide Pin P/N: 021 109 471


Crank Alignment


First, we align the crankshaft to Top Dead Center (TDC). There is a chamfered tooth on the crank gear that gets aligned to the seam between the block and main bearing cap. Align it to the left seam (when facing timing side and engine is upright):



Oil Pump Alignment


Align the flat of the oil pump shaft upwards and perpendicular to the timing mark on the oil pump:


Lower Timing Chain & Sprocket


Lubricate the sprocket and chain with assembly lube. Start by placing the chain on the sprocket, and the sprocket placed onto the crankshaft. Then press the sprocket on the oil pump and verify the timing marks.


If you have it correct, the timing mark on the sprocket will align with the timing mark on the pump:


LEFT: Older 2-piece sprocket timing mark. RIGHT: Newer single-piece sprocket timing mark.


Lower Timing Chain P/N: 03H 109 465


Lower Timing Chain Tensioner


Lubricate the chain tensioner with assembly lube. To install, compress the tensioner by prying left on this small ratchet tab on the front of the tensioner:



Insert the tensioner and install the two bolts. Mark the bolts with a paint marker once torqued.


Lower Timing Chain Tensioner P/N: 021 109 467

Lower Timing Chain Tensioner Bolts P/N: N 909 238 01


Torque: 8 N-m (5.90 ft-lbs)



Torque Oil Pump Sprocket Bolt


With the chain in place, we can now torque the oil pump bolt by having one person hold the crank in place with a breaker bar while another person torques the bolt down.


Oil Pump Sprocket Torque: 60 N-m ( ft-lbs), + 90 degree stretch and blue thread locker (same torque for both styles of bolt)


[oil pump gear picture]



Step 18: Install Deck Components

Tap in the two cylinder head alignment dowel pins with a mallet.


[dowel pin picture]


Install the oil non-return valve with light oil on the o-ring.


[non-return valve picture]


Step 19: Clean and Lap Cylinder Head

Before Cylinder Head Disassembly


Check the state of the valve seats by spraying brake-cleaner down each intake and exhaust port. If the brake cleaner leaks past the valve while it is closed by the spring, then the valve will need to be lapped.


Cleaning


With the cylinder head fully disassembled, clean out the oil residue with a concentrated degreaser. If there is carbon buildup around the valves, walnut blast the ports and chambers. When blasting the chambers, keep the valves in to protect the valve seats. The valves are very hard material and can be cleaned with a brash brush without damaging them.


[clean & painted cylinder head]


Lap Valves


Apply sharpie or dykem-blue to the valve seats to visually see the mating surface. Lubricate the valve stem and valve guide with oil, and apply your lapping compound to the valve. Technique can be seen on YouTube videos. It is important to not get any compound in the valve guide, otherwise the valve guide will need to be replaced.


Clean Again


Clean out any abrasive compound residue completely. Its also important when taking out the valves that they go back in to their designated location.


Step 20: Install Valve Stem Seals:

With the valve grinding compound cleaned out and the head flipped over, install the valves in their locations using assembly lube. Place a piece of painters tape over the valves to retain them in their position when we flip the head over to install the valve stem seals.


Use a long socket that fits snuggly over the stem seal to push them on the valve, using the assembly lube as lubricant.


[pic]


Step 21: Install Springs and Retainers:

Place the spring over the valve, the springs ride directly on the recessed seat in the cylinder head. Place the cap on top of the valve with the chamfer pointing upwards.


[picture of spring and seat]


Compress the valve spring with a spring compressor.


With a little bit of assembly lube, install the retainers on to the valve stem. Slowly release the spring compressor.


[retainer picture]


Repeat for all valves.


Step 22: Install Lifters and Camshafts:

First, raise the cylinder head off of the table using two blocks of wood. This is because when we install the camshaft, we will be opening some of the valves


Install Lifters


Camshaft Sealing Rings


Camshaft Caps


Align Camshafts


Step 23: High Pressure Fuel Pump Lobe:



Step 23: Install Cylinder Head and Gasket

Step 24: Camshaft Adjusters


Step 25: Upper Timing Chain and Verifying Timing


Step 26: Lower Timing Cover

Tap out the old crankshaft seal and install the new one:


Rear Crankshaft Seal P/N:


Step 27: Upper Timing Cover & Camshaft Solenoids

Clean off the cover and press in two new camshaft solenoid seals:


Camshaft Solenoid Seal P/N:



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