technical BMW E46 330i Engine Rebuild OEM+

This is going to be a journey.

Was originally intending to do some basic maintenance on my 2002 E46 330i.
The original list
- Sump gasket, small oil leak (needed to drop subframe)
- Add headers, remove cats
- Water pipes: plastic parts are aging
- Engine and gearbox mounts
- Driveshaft flex disc
- Diff oil
- Gearbox oil

Attached are some basic pictures of what I started with. It should be noted that the car has been well maintained over the years. This leak started as a tiny drip and was only present for a few months before I started addressing.

Anyway, below are the basic bits ordered; little did I think at the time this was going to spiral into a full build.

The headers were ordered from UK, very hard to get well-fitting ones for RHD



The original plan was to use E46 M3 headers cut off the ends, and TIG-weld stainless flanges. This is still doable but without a proper jig and flanges to align, it would be time-consuming and require a lot of trial and error.


Some new lambda sensors with longer wires to match new locations lower down


Turner Motorsport solid rubber engine mounts: I originally thought the flex disc was worn due to a loose feeling when taking of hard; it turned out to be a broken engine mount, which I only discovered later. Worth noting the diff mounts were changed a while ago with OE ones.


Blank off the unused lambda sensor bung, as this car only had the primary; it would have coded out the secondary anyway.


The leak that started this




Worth noting SGF makes the original flex joint so this is same as OE


I used OE Diff and Transmission oils



Let's just start the journey; I removed the headers, not the easiest thing to remove.
Need to remove bolts with various socket sets and extensions 1/4" and 3/8"



Noticed this bracket, which supports the exhaust, was broken; will get to rewelding it later


Test-fitting the headers; fitment was perfect. The O2 sensors had no issues contacting the engine or body, with plenty of clearance; the steering universal joint also cleared this well.






The exhaust flange end of the headers


Intake removed to get to all the water pipes I wanted to replace.


The turning point: ever since this car was new, it has consumed a fair amount of oil. Over the years, it slowly started to increase the amount it took.

The car at this point had 240 000Kms on the clock and was consuming about 1L per 2500Kms, I knew this was most likely due to the two-piece oil ring design that BMW used and workarounds such as the pilot mod. I was going to change the spark plugs and was looking at the buildup around them, and the fact that I had removed everything around the engine to do the above-mentioned items, I said to myself, the engine could come out quite easily now , and thus I went down the rabbit hole.

Chapter One - Tools to remove the engine

Bolt-on supports for the jack stands; these help secure into the factory jack spots and safely support the car



The jacks I use: this low-profile jack helps get the front end up. The car is on H&R sports with Koni STR shocks, so normal trolley jacks don't work. I also have a higher-lift low-profile jack to lift the rear, as the racing jack runs out of lift.



A cheap engine stand did the job and made things easier



This engine stand with the balance bar made it possible to put engine and gearbox back in case as one assembly



The car support on stands

Chapter Two: The Side Quest

What really took care of the road for a week or so was a failed water pipe. I had changed the main radiator hoses to Stett Performance hoses, what I didn't expect to fail was the plastic flange that connects the hose to the thermostat. This happened one night, and I had my car flat-bedded home.

The towing service attached the safety hook to the lower control arm and forgot to remove it before trying to roll the car of. I only notice the resulting damage the next morning.

I used the TRS (cheapie) to make sure nothing else was damaged, replaces with something much better than original later.



The final replacement from Turner MS helped give better camber adjustment, with the car riding lower.



Installed, there are two types of these camber arms which Turner sells. It's worth noting that the adjustment here is on the outside, which helps because on the left side the exhaust would be in the way when doing wheel alignment on the other version



Got a set of water pipes only for the plastic flanges; I suspect the broken engine mount might have also contributed to the aging flange




Needed a car with weight on it to torque the control arms; the diff had to be unbolted and moved out of the way to get the left control arm bolt out. Other than that, it was a simple job.

Incredible write up... Please share where you got those supports for the jack stands please?

Chapter Three - Engine Removal

NBN said:

Incredible write up... Please share where you got those supports for the jack stands please?

Click to expand...

I originally bought them from eBay, but I also found them here

Chapter Three - Engine Removal

Remove Intake, Exhaust Manifolds



Remove the drive shaft bolts on the gearbox side from the flex disc


The driveshaft removed


The gear linkage removal


Gearbox removed



The flywheel is visible once the gearbox has been removed


Remove the engine harness and bell housing bolts.






Finally, the engine is removed and mounted to the stand




The empty engine bay

Chapter Four - The Engine Teardown

Vanos Removed


The dual mass flywheel wasn't in bad condition but LUK clutch and flywheel replacement was ordered


The pressure plate



Clutch after 240 000kms



Head removed condition of cylinders










Camshaft had some scoring, but apparently this is normal on M54's



Head crated up for shipment to Vanderlinder Racing for gas flow, engineering, and CAMs



Bottom end being taken apart


Rod bearings were not in bad shape for the mileage


Upper rod bearing


Main bearings could have been reused


The only real issue was the oil rings; they had a 2mm gap. The compression rings were still within tolerance, but as mentioned previously, oil rings were a known issue even when the car was new; it seems to be only the 3L M54s. I think the 2.5L used a 3-piece oil control ring



The carbonised exhaust side of the head

Brilliant write up and work so far bud!

Amazing to see some clean E46s popping up on the forum recently.

The forum delivers!

Thank you for taking the time to document the journey, as well as the pictures.

Subscribed and looking forward to future updates

gavsadler said:

The forum delivers!

Thank you for taking the time to document the journey, as well as the pictures.

Subscribed and looking forward to future updates

Click to expand...

Agree! Thank you for delivering high quality content to the forum!

Nice write up.

You might wish to reconsider porting the head unless you are changing cams as well as injectors.
The heads are typically at the upper end of performance with the standard set up.

The exhaust manifolds are certainly the trick on your build good choice.

Chapter Four - The 5th Gear Lean

This car came equipped with the five-speed manual ZF gearbox; at some point in my ownership of over 20 years, the detent must have gotten stuck. The fix involves the removal of the gearbox, so now was the best time while I wait for the headwork.


The sleeve which needs to be replaced



The tool required to drive it to the correct depth. I printed the first one out of PLA but decided this might need to take some force, so I turned it out of steel in the end. The printed one might have worked, but it wasn't tested




This tool needs to keep the shape of the bush as it is driven in; removal involves denting the edge of the old bush and using a pair of pliers to twist it out. A new cap is also required. BMW didn't have stock of these parts, so they had to be sourced online.




No more lean; this should make it easier, especially finding 3rd and 4th gear coming from 5th or 2nd.




Other gearbox items to address


Removal of the output flange needs a deep-well socket that isn't too thick to fit, and because the nut holding it is thin, it needs to bite from almost the tip of the socket; a machined impact socket did the trick




Counter-hold the output flange while loosening and tightening




Kept everything lined up; the output flange needs thread sealer on the spline and thread lock on the threads; it also needs to be heated up when installing.



The selector shaft seal is a common area for small leaks, so that was taken care of


Now is the time for some upgrades, like a short shift kit; also replaced all the bushings and the clips associated with the gear change linkage, with an original shift shift gearknob, the difference between the original and shorter level isn't much; the shorter gearknob makes things feel sportier



Changed the input seal; all parts used were OE from BMW



Next thing to service was the driveshaft; change the flex disc and the carrier bearing



OE carrier bearing; the one on the car was fine, but while I was there



Setup to drive the new carrier bearing to the correct depth


Driveshaft ready to go back although it would be a few months

Chapter Five - The Head

I see some suggestions, so I will get to it, the head was gas-flowed with CAMS, all done by Vanderlinder Developments




There is a one-way valve in the head that keeps oil from draining back when the car is turned off; the only time you can change this is when the head is of.

The specs of the CAMs used

Chapter Six - Rings, Bearings, Oil Pump etc.

Since the rings were the source of trouble since new, I was determined not to use the OE two-piece and found Hastings three-piece

The solution-hopefully






For main and big-end bearings, KS is what was chosen


Managed to get a top-end Victor Reinz Gasket kit at a good price. I used an OE head gasket and sump gasket from BMW, as well as head bolts from BMW. I did buy a set of Victor Reinz head bolts but decided not to use them, as they measured a bit smaller in diameter than OE, and since this is an aluminum block, I was nervous about the threads stripping.



The clutch, pressure plate, and dual-mass flywheel



Ordered new bolts from BMW since I wasn't sure what type of sealant or thread lock was used on them. I see LUK supplied those in the kit but used OE



New oil pump, expected OEM turned out to be overstock OE

Peter@AEW said:

Nice write up.

You might wish to reconsider porting the head unless you are changing cams as well as injectors.
The heads are typically at the upper end of performance with the standard set up.

The exhaust manifolds are certainly the trick on your build good choice.

Click to expand...

I ended up doing CAMs too, it's going to need a tune to get the benefits though

TheFlash said:

I ended up doing CAMs too, it's going to need a tune to get the benefits though

Click to expand...

Excellent choice the B30 is really an engine that can accept mods easily.
Xceede may be able to assist in a better tune for that engine.

May I equally encourage you to make contact with Beisan for their vanos repair and rattle repair kit.
Order the needle rollers as well.
A worthwhile repair.

Chapter Seven - Vanos

I looked around a bit and did end up with a seal kit from Beisan Systems, I didnt have any rattle issues so decided to only get the seal kit with new filters from BMW. Shipping ended up being same cost as part but these will last.




Vanos before



Vanos after: the gaskets for the covers holding the pistons are not sold by BMW separately; since the originals seemed fine, I reused them as I could not find a source anywhere.

Chapter Eight -The Cleanup and Cylinder Hone

Start cleaning the crankshaft and oil squirters



Once the varnish is removed, the crank shows the blue heat treatment




Vanish removed from block







Cleaned up intake, I replace the PCV a short while ago with original BMW one, also used OE pipes aftermarket seemed weaker plastic and not a job I want to repeat.





The Disa valve has an upgraded aluminum flap with a bolt, so it can't fail with the pin getting sucked into the engine; the throttle is also relatively new. I had it crashing and throwing the car into limp mode a few years ago; it turns out BMW has a software fix for that, but I had already replaced that with a mass airflow sensor and a silicone intake boot, so I don't have to worry about rubber failing


The intake boot, at least the top half; the bottom part is also silicone



Because the starter is in a difficult place to get to, I decided to replace it. The new replacement from Bosch isn't as well made as the original, but I ended up still using it. I will recondition the old one in case I need it someday.



Changed bearings on the alternator, the regulator was replaced before, so this should keep it running well for a while




Changed the fuel filter; the old one was dirtier than I expected. I need to start tracking when I change these better





Got a kit of fuel injector filters. I wasn't sure about doing this, but ended up doing it. I removed the old filter with a self-tapping screw and sprayed brake cleaner into the injector while activating to make sure they are atomising correctly. I will check if bigger injectors are required when I am tuning, but I suspect standard will be fine.


Old injector filters were brown but seemed to still be clear. I didn't have any issues with these, so I don't think there was any difference changing them


Was going to replace the crank sensor anyway, mainly due to how hard it is to get to; on close inspection, I realised the old one had a hairline crack and was letting oil in, so it was just a matter of time.




All the pipes and plastic bits will eventually fail. There is an aluminium version of one of the plastic pipes available from Turner MS, but that still leaves the other. Ended up just using OE; will see if they make both in aluminium; may change someday



The exhaust cleaned up nicely; had the secondary cats removed when the car was close to new. I like the standard look; maybe if I get an AC rear box, I will change it; for now, I will use this. I thought the flap was stuck, but I see it only works when the car is moving; plugging it only makes a slight difference to the sound at low RPM, so I left it working.



Gave some of the plates under the car a cleanup and some fresh paint


My car never came with the little trap door to access the sump nut. I thought BMW had lost it when it went for a service with them, but I remember checking while it was under Motorplan, and they said it wasn't specified for this car



Decided to fit one anyway.




Cleaned up the rear main seal cover and installed a new seal with a 3D-printed tool to set the depth.



Cleaned up and painted the damper pulley; it had no cracks. If I replace it, I will probably use a Super Damper




I noticed one of the tensioners failed. This one was replaced along with belts, pulleys, and other tensioners less than a year ago; anyway, just dropped in a new one



When going through the entire wiring harness, some of the spring sleeving was old and brittle, especially the section that goes around the oil filter housing. I was going to replace it with new unsplit sleeving but realised that even if I depin it, it would require cutting terminals and recrimping, so I decided to use split spring sleeving instead, with cloth tape, which should last better than the original.




The AC wiring has had its insulation become brittle and fall off. I glued some silicone insulation around it and made a little heat shield to stop the heat from getting to it. I suspect heat is also the reason the windscreen washer pump fails. It does have a little plastic shield; I wrapped that in foil tape to help it too.

I had replaced the water pump and the thermostat a short while ago, interestinly BMW has a core charge on their water pump. I guess they probably recondition them.



The old engine mount, which barely had any symptoms of its failure



Clean piston; the main area to get clean is the ring grooves and the holes for oil

Chapter Nine - Measuring Things

Main bearings measuring right in between tolerances








The big end measured fine as well









Double-checked block for straightness



The piston ring clearance was also checked, and all was within tolerance. Interesting to note the three-piece oil rings have wider tolerance than two piece this is probably because the upper and lower work together and don't have a straight pass-through like the two-piece.

Chapter Ten - Assembly

Clocking rings and the separator for the oil ring.




Unpack the wrapped block



Unwrap the cleaned crank



I wanted a ring squeezer that would not scratch the aluminum block surface, so this was the safest and easiest-to-use one I found, even better than the Snap-on universal one I have. Wiespeco tapered 84mm.




Bottom-end crank, pistons, baffle, oil squirters, and oil pump all installed.


Oil pump with new chain and pickup tube, and a new drilled nut for safety wire.


Head installed with OE head gasket and head bolts.





I expected these sprockets to come aligned from the engineer, but they were loose; this added a +/-6month delay, as the alignment tool was not available in SA, and the only place I found one was VAC Motorsport



The VAC Motorsport alignment tool



Its one tool for both intake and exhaust CAM, with markings on which hold to use



Bolt with threadlocker and hope you don't break the CAM due to the required procedure



Exhaust side



Guide to help with the torque angle


Safetywire the oil pump nut; I don't expect to track this car. Its intended use was fun daily, but I decided to do this in case I move the limiter. If I do, it will probably only be 7000rpm max