Hello all! I just wanted to share my S62 engine rebuild in my 2000 E39 M5. I have been lurking around your forums for a few years and have learned a lot from it. Thank-you very much!! In return, I would like to share my experience with some pictures and details of my S62 build in the hopes I can return the favor and help some of you. I haven't had my M5 on the road very long, about a week now, but all seems to be perfect so far
I took a lot of pictures on my way to building my car and saving it from the scrap yard. I bought this car a little over a year ago for very little, because of a noise coming from the engine. The noise seemed like it was too high pitched to be anything with the bottom end of the engine, so we assumed it was something in the head. I was thinking Vanos or lifter. My brother and I drove all the way from Colorado to Arizona to pick the car up and drive it back home. When we got there, the car wasn’t like the seller described as far as him pulling parts out of it. It’s nice when someone knows you are going out of your way to get something and they pull stuff off of it.
It seems to happen to me a lot. I bought it anyway as it was a pretty amazing deal. We drove it, with the noise, from AZ to Reno Nevada, and then back to Colorado. We didn’t realize how insane this trip was to take with that noise, until I finally tore into the car back home. What I found is the noise wasn’t from the head, but from the bottom end. Here are a couple of pictures when we got to Reno:
Turns out what happened is the engine ingested water and hydro-locked two cylinders. In those two cylinders the rods bent in a way that made the piston sit crooked which destroyed the cylinder and block. On top of that, with one of them, the pressure from the water must have been so great that it blew the head gasket. After finding these things, I figured out that the noise was the rod moving back and forth on the piston pin slamming the piston as it was unable to move straight. How it survived the trip without total failure is pretty amazing. Even the rod bearings still looked perfect! The lesson here is don't do what the previous owner did and try to drive the car at WOT through large pools of water!
This created a series of problems for me. The block could be saved, but they have an Alusil coating in the cylinders from the factory which I had to have redone. In the US, no one has the equipment to do this coating, only Nickasil. After finding the issues BMW ran into over Nickasil coatings in the past, I decided to skip saving this block and find another instead.
I spent several months trying to find a block which was not outrageously overpriced, and I ran into one which was mislabeled on ebay. Due to this, the block was not going for very much money as the seller couldn’t get rid of it. The ad said it was damaged and the mounting threads for the AC compressor were broken. I thought this was great, because I am a fairly skilled welder and could easily fix this. I bought it for $1000 and found that it wasn’t as described in the ad. Not only were engine mount threads damaged, but it was on the other side of the block, and the block was also cracked all the way through. Here are some pics of the damaged area. I had cut a deep V into it as I decided to try to fix it.
Things looked pretty grim, but I decided to tackle repairing this block as the cylinders were perfect. After spending days on the block, I was pretty satisfied with the job I had done. What I did was weld the block proper, then added more aluminum and make the whole area 3x thicker than from the factory to ad strength. I can’t replicate the hardening treatment of the aluminum block at my shop, so I added strength by adding metal instead. I also made the bracket mounting area by slowly building up the aluminum. I could have made the welds smooth and more attractive, but that would have required more heat and that would risk warping the block. During the whole welding process, it was a balancing act between getting the welds hot enough, but not too hot as to damage the block. It took me days of doing this to get the added support in the area that I wanted. After careful temperature control, welding and drilling, it turned out looking a little strange, but it was solid, sealed, and good to go!
I then had the oil pan and front cover surfaces of the block milled at a machine shop (I had to weld through the sealing surfaces as the crack was there too). The person which milled it said that he took very little off as the work I did was very well done. I believe it was .006” oil pan, .004” front cover.
I then checked every surface of the block for any distortions due to the welding heat. The deck, mains, and all sealing surfaces were perfectly straight! I couldn’t believe this! Just shows how well engineered these blocks are as I have never seen a block take so much heat and not move.
Now it was finally time to put it all together. I spent a lot of time measuring parts to try to figure out what I needed to buy and what to do. I downloaded a service manual online and found the German-to-English translation made the manual very difficult to understand. It was like the translator knew nothing about mechanics, and just gave the best wording possible for the translation. For example, the manual said this for one of the Vanos procedures, "No" screws are inserted in inlet sprocket wheel yet. Inlet sprocket wheel must not slip off centering sleeve. Rotate crankshaft from 45° before TDC position in direction of rotation up to TDC firing position.
I had to do a couple of takes on this as in the lines before this they tell you which way to turn the crank by saying CW or CCW. Now they say ‘in direction of rotation’ which throws me off and has me thinking that they are not referring to crank rotation as they mention moving the crank differently in a different section. Ugh, because of this, I ended up printing a bunch of exploded views from the dealer parts section. I used the exploded views to help guide me so I was 100% sure everything was going together correctly. I also reverse engineered everything as I wanted to understand how everything worked, so this helped me understand the 'why does this have to be here' questions which the manual was worthless for. The translation made things a lot harder than it had to be. In many areas, when I figured out what they were trying to say, I would just think to myself that with half the wording it would have been a lot easier. The translator needs to also be a tech…
I ended up measuring the stretch on all of the bolts which were required to be replaced (old vs. new). I found the following:
Rod cap bolts- found no difference in stretch between old and new bolts.
Main cap bolts- found about 2MM stretch on old bolts vs. new.
Crank pulley bolts- found no difference.
Head bolts- this was interesting. The head which had the blown head gasket (due to lifting from the water) showed no stretch at all, but the head which was fine and had a perfect head gasket had bolts stretched about 1MM.
I also bought an Elring short block gasket set instead of the dealer set. This gasket set was very cheap and had all of the parts I needed! It was awesome and had quality parts! Most of them were BMW parts. What would have made it better was if it included the head gaskets, but it didn’t. I had to order those separately. Some of the things included in the kit were also parts which had nothing to do with the short block, so I felt that I scored on a lot of the extras which came with it and I didn’t have to order individually from the dealer.
The old bearings from the two engines were interesting. My original engine, with the bent rods, had main and rod bearings which looked perfect. The ebay engine had bearings which had a lot of wear. My original engine had 75k miles and the ebay engine had 100k, which is not enough mileage to make such a huge difference. From what I could see, my engine had run synthetic and the ebay engine did not. I know there is a lot of debate online about the bearing wear in the S62, and if it’s caused by the type of oil used. These two blocks would prove that to be a good theory, but I think it’s more than just the oil. After looking at the crank and rods, it looks to me like there is not one thing that will kill the bearings, but a series of things combined. I believe that oil does play a big factor and I will be using oil with high levels of zinc and phosphorous to keep things happy. I also believe that pump gas 12:1 compression engines suffer greatly from lugging due to the driver. Combined with cheap fuel, I’m sure the bearings take a beating when you are pinging and lugging the engine along on a hot day. It is easy to drive these cars at terribly low RPM, but I believe that pounds the bearings out of them, so I am going to practice keeping the RPMs up along with using race type oils with API ratings that are not SM. I also noticed this crank only has one oil galley hole per rod. Engines I see which do not have these types of bearing issues have two oil holes in the crank journal per rod to help distribute the oil better. Due to only one lubrication hole per rod bearing, it is critically important to use an oil with high levels of zinc and phosphorous.
Here are pictures of the main bearings. Original engine in 1st pic, ebay engine in 2nd: