I took apart the engine on my Infiniti G35 and would like to share with you all the teardown and how it works:


This is Nissan / Infiniti’s popular 3.5L VQ35DE V6 engine, used in many vehicles since the early 2000’s.
Here’s the engine, on the stand and the major components that surround it:


On top of the engine are the ignition coils. There are 6 total in this V6 engine, three on each bank:



With all the accessories, hoses, brackets, belts and mounts removed, here’s what the front of the engine looks like after removing the access covers on the timing cover:



The oil pan was removed next, where we have a look at the oil pump and pickup tube. There’s two bolts under here that secure the front timing cover:





Here’s the timing cover removed, with all the associated timing components. The timing system is responsible for correctly positioning the intake and exhaust valves within each cylinder during their respective position in the combustion cycle. The system is driven by the crankshaft, up through a timing chain, then across two intake camshafts. Auxiliary chains drive the exhaust camshafts.



With the valve cover removed, we have a look at the intake and exhaust camshaft. Each has a lobe on it that push down on the tappet to open the valve.



The rear timing cover is removed next:



The camshaft cap (which also houses the VVT-I solenoid and auxiliary timing tensioner) is removed next:



There’s 8 head bolts per head to remove and then the engine head (that holds the valves, spark plugs and camshafts) can be removed from the engine block revealing the pistons:



Underneath the block, with the upper oil pan removed, we have the crankshaft, held on by its main bearings through a bearing holder:



I busted my socket removing these external torx e14 main bearing bolts with an impact!



Here’s what the crankshaft looks like inside the engine block. It’s the heavy hauler in an engine, and is driven by the pistons that move in a crank-slider like mechanism. Once piece of heavy steel! Notice how the pistons are offset for each bank for this V6 engine.



Here’s the piston removed and its components:



This is the rear main seal that separates the oily part of the engine from the transmission outside:



Crankshaft removed:



The cylinders are lined with steel since the block is aluminum. You can also see the oil jet sprayer that coat the cylinder walls for lubrication.



Here’s a look under the engine head at those valves. The intake valves had quite a bit of carbon buildup.



And this is the valve removed, with its return spring:



And that’s pretty much all the components that go into an engine!



Enjoy!

 

Awesome man! Thanks for all the useful stuff that u post for us to see.

 

So badass, your desire to share all this technical information about our cars is off the charts. Thank you, thank you, thank you!!

BTW I stickied this thread, congrats!

 

You are welcome all.
Glad you enjoy my work, I really enjoy taking cars apart and seeing how they work. It brings so much appreciation to the amount of engineering, thought, manufacturing and design that went into making a single car!
Yay for the sticky!

 

Wow very technical. Thanks for sharing.
Impact Torx and Allen wrenches never seem to last!

 

I've had really good luck with the Milwaukee Shockwave stuff. Not sure if it's available for larger sizes though.

 

This is really amazing! How long did it take to tear this engine down? What was wrong with the engine? Did you put it back together?

Thanks so much... the VQ is an amazing engine! I have had the 3.0L (super smooth like a turbine) and currently have the 3.5 and 3.7 liter versions.

 

I tore this down on a hot summer day. Sure is a good motor, if you keep it well fed with oil.
I made a more recent teardown video on the benefits and weak points of the VQ here:

 

Thank you for the amazing video! Such a clear explanation... and so much knowledge!! Wow!

My 150K miles 2003 G35 barely loses any oil in between changes... but I have always changed the oil myself with Mobil 1 on a frequent basis. I did see some oil in one or 2 of the spark plug holes last time I changed plugs... but engine seems to run fine and I don't see any drips on the floor. So is that a big enough concern to change the valve cover gaskets? Thanks!!

 

Eventually those spark plug well tube seals are going to leak more and more and will reach a level where it interferes with spark. For now just check them every other month and as soon as the oil is up past the level of the metal hex part the socket grabs onto then change the valve covers.

 

I have a question, when I installed my plenum spacer I noticed that the 2 outside studs are completely missing on my upper intake manifold! I believe they are numbered 7 & 8 respectively on the diagrams of the intake manifold. I didn't notice this at first until I went to bolt the plenum back onto the upper intake manifold. The gasket I had didn't line up with these studs or in my case where they should of been. The gasket I had lined up perfectly and had the holes for the 6 center bolts. But I noticed that something didn't look right. I could tell that there should be two outside studs there. In a panic I thought maybe they broke off somehow. I looked down into the manifold and didn't see anything laying on top of the valves. I looked online and noticed that on all of the upper intake manifolds I saw had these two outside studs. So why is mine completely missing them, and why is my gasket different as well. Because If I even had these studs then that gasket wouldn't of fit. Baffled I just used a lot of RTV as a precaution. It's not really recommended from what I've read to even use RTV here. So I sealed it as best as I could and proceeded to tighten the 6 center bolts fairly well. It was also a pain in the *** to keep those 6 metal spacers that came as hardware with the plenum spacer I ordered. They kept sliding out of position and I couldn't get one to line up with the longer bolts. In this process I somehow managed to loose one of the new longer plenum bolts that came with this plenum spacer. I searched high and dry and to no avail. I think it may of fell and got caught somewhere down by the cv axle(I have a G35X). Fortunately I was able to use one of the oem bolts and it just barely was long enough to catch inside the spacer to hold it in place. I had to RTV them onto the gasket in the plenum, just to reassure they wouldn't slide out of their positions whenever I connected the two pieces of the plenum together. I bolt the 6 center bolts pretty tight. Then proceeded to tighten the remainder of the new hardware around the plenum. I had to improvise with two of these bolts though. Whenever id go to bolt them down it was pushing the spacer itself out of alignment. Creating this space that I definitely didn't want. I had to bolt it from underneath to keep the spacer itself having a tight fit. I did RTV both sides, may of went a little overboard with the RTV. But I was paranoid about having a vacuum leak. I need to go back and see if any of these bolts may of loosened on the plenum. It has been a good 3 months or so since I installed this plenum spacer. I keep getting a P0171 bank 2 lean code. It's not effecting the performance in anyways and I haven't noticed any drop in miles per gallon. The code will pop up, I'll reset the ecu and clear the code doing the little peddle dance. It'll then pop back up after maybe 150 miles of driving.
I should probably take a look at the spark plugs on bank 2? They should be in great condition, considering I changed them along with installing some new coil packs. If it's running too lean, then they'd be fouling correct? Im completely stumped in were the hell this vacuum leak is. It's either that or I may have a bad O2 sensor altogether? Im really convinced it's a vacuum leak. Could it be because of these missing studs on the upper intake manifold? It's either a vacuum leak from the CAI tubing, possibly the plenum bolts have come loose, or even a vacuum leak from my oil catch can set up? I plugged up the inlet that had the vacuum hose going from driver's side rear valve cover to the intake tube. There's definitely no leak there, I rerouted that hose behind the rear engine near the fire wall. I connected it to another hose to extend it to reach where I have my OCC. It's not even mounted, I sort of just have it sandwiched on the passenger side. In between all the hoses and wires going to the battery. I did have a pcv delete but decided last minute that I really didn't need it. Considering I don't have a FI set up, plus I was afraid it cause the oil catch can to suck up an excessive amount of oil. I just put in a new pcv valve and ran that hose to the OCC. It's a baffled can that has two inlets with both banks running into it. The center had an outlet that I have going to the lower plenum vacuum. So it's a complete closed system, it does work very well. I empty maybe an ounce or so of buildup per month. I do not think any oil vapors and blow by is managing to work its way back into the plenum. I hope this set up isn't really causing more harm than good. I don't think so as it's basically the same pcv system, it just has the OCC catching whatever blow by that comes out of the valve covers through these vacuum hoses. Well I eliminated the driver's side going back into the engine through the throttle body and going to the OCC instead. I need to go over everything I did a few months ago, to search for whatever is triggering this code.