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Subject: Finished the motor swap (very long) Author: bootysnapper : member since April, 2005 : 209 posts Posted on: 2008-04-21 21:43:06

The two M52 motors on my 1997 528i have been swapped, finally, and the new engine is running great. (knock on wood)

It took awhile to complete it, but I just wanted to be sure of the best way to tackle a cracked head.


First off if you car over heats to the point that you have coolant and oil mixed and/or coolant in one of your cylinders with the M52 I6 engine, (cast iron block/aluminum head), my advice is to write that engine off, don't even bother taking the head off (I spent a bundle in tools just to get the head off.), just go for the motor swap, its much cleaner, cheaper, and quicker with much fewer unknowns to the average DIY mechanic.

First thing to do if you suspect severe over heating is to check your coolant for contamination. (my coolant at the expansion tank was actually still unmixed, so its just one of a few checks)

Second, drain some of your oil (like a quart, easily replaced) and take a good look at it, it will look like milk chocolate (in my case of mixing synthetic motor oil and BMW coolant), if you got milk chocolate coming out, your head had a serious problem.

Third, take your spark plugs out one by one and hand crank the engine with (20mm I think) socket and rachet on the crankshaft, I had coolant squirting out about 10 feet in the air. Very bad...

Now what I did is spend a hundred or so dollars for the special tools to take the head off and began following the bentley book, but its vague in some parts and I was left unsure of the importance of each individual step, luckily my neighbor had some experience with BMW headwork and walked me through it and about 6 hours later the head was off and ready to be picked up by the machine shop.


bad head


old single VANOS

My first major clue something very bad had happened was the head gasket was intact. The crack the machinist found on the #3 exhaust port was so obvious that he didn't even charge me to diagnose the cylinder head as bad, it was that big. Automachine of Orlando is a great machine shop with honest machinists and a reputation back to the 60's. They offered to send it away to Pennsylvania to have the crack welded for $900 dollars, but being that its BMW, and aluminum, I think I was wisely advised against that by several mechanics.

So then I started looking for heads, and that resulted in finding out that assembled and ready to go head replacements are not only rare, but expensive. And it was at that moment, when I wondered if I could get one used off a salvaged motor that I realized it would be simpler to just replace the whole motor in one shot.

I had a lot to ponder as far as logistics but I asked around as much as I could and settled on LKQ Michaels Corp, which is a national salvage company with a local yard. I eventually chose a M52 motor from a 1998 328i, which is totally compatable. I ran the VIN number on the back of the engine and called the dealer to confirm that M52 used Siemens 41.1 engine management. $1,700 dollars later, and the "new" motor (160k miles) was at my garage and on an engine stand. I had already prepped the old motor by "peeling back"



as many things as possible with out interupting their connection, I was able to keep the AC compressor and the power steering pump connected to their lines. And took everything off that would get in the way of its removal.







Meanwhile I prepped the new engine by cleaning it up and replacing as many gaskets and seals as I could with the $200 dollar gasket kit I had already bought to replace the head gasket. Which included... oil pan gasket
valve cover gasket
front seal
rear main seal
injector seals



intake gasket
intake manifold gasket
exhaust gasket
exhaust manifold gasket
thermostat housing gasket
and any other gasket I could
plus
new water pump
new pulley system
new plugs
new oil filter
new starter
new flywheel bolts
and the best parts from both engines were cherry picked to make the replacement engine as "new" as I could make it.

this $200 gasket kit was very good



another night working to 4am prepping the engine

so getting the old motor out was a little tricky but I did not have to remove the transmission like the bentley said, I think it was easier to just leave it alone, I just had to make sure the torque converter did not fall out of the transmission during removal.


I did the swap in this tiny townhome garage, yes it was cramped.


With the help of my brother, we were able to get the old motor out and the new motor in.



Important note, if you have an automatic and you are putting in a motor from a manual drivetrain, there was a "nub" on the torque converter input shaft that had to be removed for the crankshaft to connect to it. Once off the rest was pretty easy.



Most of the wiring made sense, and the lengths are easy clues as to where they connect, only one or two connectors would interchange and it was their lenth that make it easy to tell them apart.




Once it was all connected and ready to test I was amazed that the motor fired right up and was soon running very smoothly with some minor adjustments.


Finished motor

I believe I could do the same swap again in much less time than it took me this time, about 2-3 weeks, mostly by myself. Overall, I would say its pretty simple, just with a lot of steps. Advanced DIY'ers could tackle this job with few problems, IMHO.

• Finished the motor swap (very long) (pic) - bootysnapper 2008-04-21 21:43:06 (3597 views)
  • Re: Finished the motor swap (very long) - dmann1 2008-09-22 12:17:32 (209 views)
  • great post! was it easy to get to the transmission bolts for removal? - ian 2008-04-24 16:03:54 (303 views)
  • Good job - way to stick with it. (nt) - Roderick 2008-04-22 18:28:44 (274 views)