4.4 to 4.6 Swap

[Henn28]

I thought I'd post some highlights of a M62TUB44 to M62TUB46 swap I completed for a 2002 X53 x5 Overland project I've been working on for a while. I've got 2000 miles on the new motor. I know this is ov very limited appeal, but if any are interested I'm happy to give you a full and lengthy dump on the process and the many, many lessons learned. I think its 95% common with the 540 as well and in fact I connected with a couple guys on the forum that did this swap in their 540s and had lots of good advice. I chose to buy a new 4.6 from BMW because it was surprisingly affordable when compared to the fact that I would have had to spend a significant amount of time and money to refresh my 4.4 (that has two low compression cylinders) and not have an additional almost 70 HP. The motor was last used in 2003 I believe (Alpina maybe a little later?), but my motor was assembled in 2017 which tells me that they keep making them, probably one at a time and stick it on a shelf, until they are out of parts.

Big picture observations and lessons learned below:

-Forum help was invaluable, here and on Xoutpost.
- What is listed as a "short block" in RealOEM and the BMW parts system is in all likelihood what we consider a long block. Mine arrived from Germany as a complete motor with a water pump. It did not have valley plumbing, an intake, exhaust or accessories beyond the water pump.
- M62TUB46 will bolt right up to the ZF5HP24 and torque converter that comes with the 4.4i (and 540 I think). The 4.6 version of the 5HP24 tranny has an extra clutch and a TQ with a different stall speed, all to handle the higher torque from the 4.6. Having the transfer case bolted to the back of the gear box limits tranny options. We'll see about the long haul, but so far no problems at all with the 4.6 driving the 4.4i gearbox. I chose this route because ZF5HP24s for the 4.6 (and their torque converters) are very hard to come by and very expensive. I also wanted to limit the initial programing complexity to the DME and 4.6 motor.
- Reputable sources with first-hand experience told me that that the 4.4 DME will run the 4.6 just fine. Therefore, I was going to go this route and get a 4.6 tune at a later date, but the swap was taking so long that I elected to send my DME off to Kassle to have the 4.6 ones and zeros squirted in, along with a mild tune, and the SAP system deleted (more on this below). It all works great and the car started on the first try post-swap.
- 4.6is diffs have different ratios than 4.4i diffs. I elected to keep my 4.4 pieces as the 4.6 motor already gets terrible gas mileage. It still pulls like a monster off the line and really opens up around 4000 rpm, with a wonderful intake roar too. I now get maybe 13.5 MPG around town with the car and 17 or 18 MPG at best on the HWY, which is significantly worse than my 4.4.
- Swap started with a $40 visit to Speedee oil change to recover the refrigerant. In and out quickly and better for the environment. They recharged it when I was done.
- The swap took me twice as long as I planned, but your milage will vary due to experience level -- this was my first swap. I agonized over if I should pull it from the front, out of the top, or drop it out of the bottom on the subframe. Lift access (using a shared lift) drove me to pulling it from the top and leaving the gearbox in the car as it is a three year old remanufactured unit. I think dropping it out of the bottom would have been easier, but I couldn't hog the lift for one week, much less the three it took me to do this job. I prepped the car on the two post lift, then rolled it to a bay without a lift, put it on jackstands, pulled the front suspension and axles, then the motor came out. I'm not sure there is a right answer and there are pros and cons to each method, except if you have a two post lift then I think the "out the bottom method" gives you the most flexibility. It allows you to do the otherwise hard E53 axle and diff work out in your garage, not under the car.
- Big lesson learned is to make sure your engine hoist has enough reach to pull the motor up high enough to clear the radiator/cross member. I ran out of hoist, but fortunately the shop had a forklift. We swapped it to in mid air and finshed the job. Chalk this up to inexperience. I forklifted the new motor into place too, then swapped it back to the hoist for final alignment and differential stupidity.
- I found a good suspension shop in town to press suspension and drive bits out of the hubs/carriers, install new seals on the diff, etc. as I didn't want to buy too many single use and/or BMW tools and don't have a press of my own. I dropped the diff and the hubs with the suspension arms and axles still attached off at the shop on my way home and picked them up the next day with the old stuff out and new seals and press-in bits assembled.
- Diff had to come out to clear the power steering rack. I wanted to leave it on the old motor, then swap it to the new motor on the stand, but it wouldn't clear the rack/column connection. This was a real bummer because it is very heavy and a serious pain to get back in while working on your back. I dropped the new motor in, but then had to raise it back up and drop the subframe a few inches to get the diff back in. Textbook Bentley manual instruction that I thought I could shortcut....lesson learned.
- Front axles were a terrible pita. An X5 specific job so there are lots of lessons learned on this site and Xoutpost for doing it. Best advice I found was if an axle wouldn't seat (clip) pull it back out a bit, turn 90 degrees, try again, etc.
- Front axles will not turn smoothly with the X5 on jackstands and both joints fully extended. The inner cups hit something (subframe maybe) and make a one brain cell guy like me think he screwed the bearings up pounding the hubs onto the splines. Jack the hub a few inches and they should turn freely if you want to check your work before putting the nut on.
- getting the splines to seat fully into the hubs was a serous hassle involving a 4x4 block and a small sledge hammer. Others have no problem. There is a tool that is available on ebay for reasonable money that makes this job much easier. In hindsight I would definitely get it if I ever had to do axles again, but all four of mine are new at this point.
- Take lots and lots of pictures as you disassemble the car, and get a paint pen and witness mark every bolt and nut after final torque. Not that they would back out, but if you are ADD like me you get to wondering if you actually torqued something, then worry about it until you retorque it...etc. Marking with a paint pen after the final torque gives peace of mind.
- I did the entire job by myself with the exception of physically pulling the motor and dropping the new one in. I found some help for those steps. Pulling could have been done by me alone except for the stupidity of having to get the forklift involved, but the install of the new motor would have been tough without help.
- pulling the cowl is a must for this job as it allows access to several of the upper transmission torx bolts. the bolts at 3 and 9ish o'clock are still a PITA to reach, but doable with multiple extensions, universal joints, wobble heads and/or wrenches.
- I had a new long block 4.6 to work with, but I still used all new hoses, O-rings, mounts, bushings, etc, to assemble and install it. Basically I built as much of the motor as I could on the stand and only swapped the AC compressor and bracket, diff, and (right side) axle carrier.
- I build a "new" long runner intake from Ebay parts. I sent the ebay 540i injectors and fuel rail to InjectorRX in Houston and he did a great job of cleaning the entire mess and flow testing it to OE spec. Much cheaper than 8 new injectors and a rail, and I want to rebuild my 4.4 someday with its parts.
- I went cheap for the power steering pump (older LUK make on mine) and so far so good with the remanufactured part from Rock Auto. I will say that it makes a huge racket when you start the car for the first time after the swap so be ready to cycle the steering wheel lock to lock ASAP to move fluid into it.
- For the most part the install went very smoothly, aside from the diff stupidity. I cleaned the harness and used new OE clips if available, and lots of zip ties where they were not available. Fortunately for me, the pugs are all amateur proof and 1) are specific to the sensor they are hooking up to and 2) the specific harness wire is generally only long enough to reach the specific sensor it goes to.
- Vacuum lines were a mess so I used new lines where able or spliced in new soft rubber into hardlines where needed.
- The front diff breather tube rubber was cracked and the tranny breather was completely missing. I ran new rubber up to the cowl from the tranny before I put the motor in, and spliced new soft rubber onto the front diff hardline. These can be painful to get back on after install/work, which is probably why they go missing to begin with.
- I did a full delete on my SAP system as it hadn't worked for years and there is no emissions testing where I live. I fabricated short plugs from the OE aluminum air line/tubes going into the blocks and had the system coded out for a cleaner look under the hood.
- Finally, I bought "belt refresh kits" for the main accessory drive and the AC drive. Use these kits at your own risk as I found they were not assembled well, at all. The nut holding the pulleys to the hydraulic tensioner in particular wasn't properly torqued as it turns out and contributed to some extended main belt shedding butt-pain. A slightly deformed alternator pully that I also didn't catch was the other part of this problem.

In my final analysis this is a very doable job for the average person. Access to the right tools, a lift and lots of will power are the primary hurdles.

[mapleridge]

Thank you for taking the time to write this.

[Henn28]

My pleasure. Hope it’s helpful to the (maybe) three guys on the planet considering this swap! It was a great experience for my first swap. Easy in some ways, and a nightmare in others. I still have work to do on my X5 build, all of it cosmetic and interior restoration and upgrade related.

I did forget to mention that I added a CSF Race oil cooler in front of the lower bumper/air dam. Currently it’s got Japanese drift car look right now, but eventually I plan on fabricating a modest brush bar which will go around it. My X5 model year didn’t come with a cooler and it gets hot here in Louisiana. Fabricating the bracket was the hardest part so I eventually asked a friend with a custom shop to help…20 min later I had a nice solution.

I found a Bentley/BMW oil filter housing at a Bentley/Rolls parts business in the UK and felt fortunate that I did. I couldn’t locate a BMW piece at all. They are the same however. Pegasus Racing had all the hoses and AN plumbing I needed to install it, which was relatively simple. I ran the AN lines down to the brake cooling duct, through a small hole I drilled with a hole saw, up the duct to the AN fittings on the cooler.

it works great and I think saved my motor when it shed the main belt at a very bad time. The car got hot for a few minutes before I could cost off a bridge and down an off ramp. I was petrified I blew a head gasket, or worse. Fortunately it’s not using coolant and there was no evidence of coolant in the oil at the first oil change a few weeks ago. I’ve read the Alusil motors are not very tolerant of overheating.

[01BMWs]

Great write up and thank you for the information! I've been wanting to do this swap since I learned that the DME and engine harnesses are direct swap. BUT, I'm completely intimidated to do it myself and cannot afford to pay someone. Good to hear that there are still people out there who are brave enough to tackle this as a first time swap.

[Henn28]

Quick follow up on this swap, now that its been complete for 2 years. After working out the teeth pains due to stupid installer mistakes, the new 4.6 in my X5 has run strong for over 13k miles, including 4 road trips of over 1000 miles each, and included one overheat due to shoddy pulley installation (my fault). I was particularly worried about using my 4.4 ZF behind the 4.6 motor, which puts out significantly more torque, but so far so good. The 5HP24 that came with the 4.6 has one more clutch and a bigger torque converter than the 5HP24 version in the 4.4 X5. The 4.6 one is very hard to find though so I stuck with my recently remanufactured 4.4 gearbox.

Of note, I did have to replace the large coolant pipe due to a leak a few months ago, which I think can be chalked up to me using ebay pipes and rear manifold on my motor build. I put a new large pipe in the car, along with new plugs and coils too (I had reused the coils). I also found the small oil return line that runs under the intake from the CCV valve to the oil return hard-pipe had come off and had been leaking oil into the valley. This is a bear to get on correctly, but I think I came up with a good technique if anyone cares (PM me).

The car always needs something, and gets terrible MPG with the 4.6, but continues to be huge fun, especially now with the Quaife differential I put in the rear end.

[hakentt]

Why not 5HP30 instead?

[vipx5]

Quick follow up on this swap, now that its been complete for 2 years. After working out the teeth pains due to stupid installer mistakes, the new 4.6 in my X5 has run strong for over 13k miles, including 4 road trips of over 1000 miles each, and included one overheat due to shoddy pulley installation (my fault). I was particularly worried about using my 4.4 ZF behind the 4.6 motor, which puts out significantly more torque, but so far so good. The 5HP24 that came with the 4.6 has one more clutch and a bigger torque converter than the 5HP24 version in the 4.4 X5. The 4.6 one is very hard to find though so I stuck with my recently remanufactured 4.4 gearbox.

Of note, I did have to replace the large coolant pipe due to a leak a few months ago, which I think can be chalked up to me using ebay pipes and rear manifold on my motor build. I put a new large pipe in the car, along with new plugs and coils too (I had reused the coils). I also found the small oil return line that runs under the intake from the CCV valve to the oil return hard-pipe had come off and had been leaking oil into the valley. This is a bear to get on correctly, but I think I came up with a good technique if anyone cares (PM me).

The car always needs something, and gets terrible MPG with the 4.6, but continues to be huge fun, especially now with the Quaife differential I put in the rear end.

Thanks for your feedback.
I want to do same engine swap to my e34 540i I believe the e34 after swap will be different animal

[Henn28]

Thanks for your feedback.
I want to do same engine swap to my e34 540i I believe the e34 after swap will be different animal

There is some corporate knowledge here on that swap. A few guys have done it and I think you are right. My e53 is a much different car with 60 or 70 extra hp.

- - - Updated - - -

Why not 5HP30 instead?

Trying to keep it somewhat simple from a programming standpoint for my first swap. A few guys here had done the 4.6 into the 540 swap and said the 4.4 ECU program would run the 4.6 as is, and the 5hp24 played nicely with the 4.6 as well. My transmission had been recently rebuilt, so I opted to save a buck and not have to figure out how to get a different gearbox working with the DME.

[Iamthebull]

Sounds like it's time to put an 8HP behind it at some point.

[Henn28]

Sounds like it's time to put an 8HP behind it at some point.

I've thought about that as something down the road, when the 5HP24 inevitably wears out. I have even done a bit of research looking for a conversion kit that will allow the 8HP to bolt up to the M62. I recall being told by PMC that they don't make anything for the job, and they seemed like the obvious choice.

I also have found the bellhousing from the 5HP24 version used in the 4.6is, which has the ribs machined to allow for a larger torque converter. I'm thinking of grabbing it since the 4.6is gearboxes are few and far between. That way I can upgrade to the 4.6 torque converter at some point. Fingers crossed however, my current transmission seems to be doing great. I watch the fluid temps, which is what worries me with 50ish extra ft/lbs and they stay where they are supposed to be. If I saw them regularly getting hot, or even into the upper range for the fluid I would be more seriously considering a cooling upgrade to an E39 M5 CSF triple pass radiator and a air to fluid transmission cooler mod...also to an oversized CSF cooler.