Bemused and Confused

I decided to get my local mechanic to look at the engine. I figured that I could get them to clean the engine up and then see if they could locate the leak. However, my mechanic looked at the car and decided it was getting a lot of blow by and it was most likely the rings and maybe the valve stem seals. He wanted $3000 to do the job. There simply was not enough oil coming out of the engine to indicate that there was that much of an external leak.

I wanted to know more about what I was dealing with so I got in contact with the PO and got some further details. It was nice of him to help out. It seems the engine had been “rebuilt” prior to his buying it. He then found a problem with it. The person who did the rebuild had left a metallic clamp of some sort in the plenum and it had gotten into the #6 cylinder. The PO’s dad pulled that piston and replaced it with the rings. The piston and rings are of unknown manufacturer, but most likely are BMW. The piston had been damaged by the object. At the same time he had the head pulled off and got the valve seals done and the head machined to flatten it out and he had the cam ground. The #6 spark plug is definitely the least fouled of the bunch, but it is still getting some fouling. So, whoever did the rebuild before has screwed something up, didn’t replace parts like they should, or really didn’t know what they were doing. (The funny thing is I wrote this a while ago before I started work on the engine. It sucks that I was right)

I decided that I had to do it myself if it were to get done. I am borrowed an engine hoist and engine stand from a friend and got to work.

It is surprisingly easy to prep an engine for removal from the car especially if you are leaving the transmission attached. I disconnected the drive shaft from the back of the engine. I had to disconnect the main wiring harness from the engine computer that sits just above the glove box and then thread it out the hole into the engine bay. Then I had to disconnect a bunch of hoses and wires from here and there. I made sure I marked everything so I would know where it goes when I put things back in.

I then drained fluids out of the car, and pulled out the radiator. I unplugged a lot of stuff, but not having a power steering pump or a air conditioner installed made things easier.

I hooked up the hoist to the mount point and started lifting. Well, the engine came up, but I couldn’t get it to move very far forward. One of the problems was this little bumper thing that mounts to the transmission and provides some stabilization for the transmission by pressing up against the front sub frame. Anyway, I got it above the sub frame but the engine still wouldn’t move. I then heard a pop sound. Whoops. What did I forget?

Well, in my confident mastery of everything that is mechanical on this car, I forgot to disconnect the gear shift lever from the top of the transmission. You remember that stuff, right? The bitch clip? Well, let me tell you it is a lot easier to disconnect when the transmission is tilted at a crazy angle because the engine is partially removed. I didn’t do any damage to that stuff thankfully. Once the shifter was disconnected I continued to lift the engine. I had to do it using a very steep angle so the transmission would clear the firewall.

(Remember, you can click on these pictures to see bigger versions if you want to. Just click on the button)

It is honestly a bit scary to lift this heavy of an item out of a car like that. The hoist is a good one with plenty of capacity. This hoist could have pretty much lifted the entire car if I wanted to. But it still makes you a bit nervous.

The orange block thing with the crank handle on it that the chains are hooked to is used to balance the load. Notice that the hoist hook is mounted near the forward end of that crank thing. This allowed the engine to tilt back. You can change how much it tilts by cranking on that handle and moving the lifting point forward and backwards. It is very handy. The one thing that I learned was to have the crank on the other side. With it tilted as much as it is, I couldn’t crank the handle anymore because the arm from the hoist got in the way. The reason that box is there is because the screw inside the leveler kept shedding really fine metal dust and I didn’t want it getting on the engine.

Anyway, I got it out with no problems.

One other thing I had forgotten to do was to drain the block of coolant. I had drained the radiator and all the lines, but I forgot to do the block. So, as soon as I lifted the engine, it would start gurgling out coolant all over the floor. About the time I thought it was done, it would spew out some more. I did a lot of wiping up with towels.

After I got the engine out, I had to remove the transmission. This is pretty easy to do with the engine out of the car and took me about 10 minutes. You can see some oil in the bell housing, so some oil is definitely leaking out of the engine. It shouldn’t be the rear main seal because that was replaced when I had the clutch work done at the shop.

Now the fun stuff starts. I needed to strip all the extraneous stuff off of the engine. The clutch and flywheel had to come off first. I needed those off so that I could mount the engine on the engine stand where it would be a lot easier to work on.

Before starting that however, I decided that I needed to move the Rat outside so I could have more room to work and so I could park my other car in the garage. I don’t like leaving outside at night. So, I cleaned up a bit and prepped the Rat to move. I supported the drive shaft and shifter stuff so nothing would get dinged up. I then covered up all the hoses and pipes and stuff that was left in the engine bay to make sure nothing got in and I put the hood back on (which is a bit tricky when you are working by yourself). I then had to figure out how to roll the car outside.

I then noticed that the driver’s side window was down. Well, no big deal, right? Just roll it up. Well, duh, it is a BMW even if it is old. It has electric windows. The battery was disconnected of course while I was working on the car. So, I plugged the battery back in. Nothing. No power. I hooked up the charger to the battery; still nothing. I had of course unhooked a bunch of wires in the engine bay. One of those was the main power line that goes to the main bus and the circuit breaker panel. Ah-ha! I hooked that back up and I finally had power to raise the window. I didn’t want my poor rat sitting outside with a window down and a garbage bag taped into place. That would be demeaning. Plus, there is still a pretty good stereo in the car and I didn’t want somebody getting any ideas.

I had to get into the car and push with my foot to move it back inch by inch. Once I got over the lip of the garage and onto the driveway slope, it rolled out easily. I was going to do it from the outside, but with nobody to pull the parking brake on, it would have been difficult. The car would have ended up on the street somewhere.

I won’t bore you with the gory details of pulling all the odds and ends off the engine. I do want to point out some highlights though.

Here is the bottom side of the intake manifold. You can see the gooey oil mess inside the intake tubes. This is not horribly uncommon, these cars will sucks some oil though the intake, but this stuff was pretty thick.

Below is a shot inside of the oil pan. You can see a little nut there that definitely should not be in the pan. It is a really tiny nut and I have no idea where it goes.

This is just a nice shot of the intake side of the engine. It is pretty grimy, but not horrible for a 20 year old engine.

This is what happens when you don’t put the water pump gasket on right. I have to take responsibility for this one. It wasn’t leaking, but it sure could have. It would have been smarter to do the water pump at the same time as I did the timing belt since they are sort of hooked together (don’t ask).

This is a shot of the front cam shaft seal on the head. Yes, I should have replaced it too when I did the timing belt. It is obviously leaking a bit. Those two black half oval plugs on the end of the head are also leaking a bit. They are the plugs on the end of the rocker arm shafts in the head.

A shot of the top of the engine with the head removed. It is pretty messy with lots of baked on oil.

Here is a shot of the head. Yet again, more baked on oil. Not horrible mind you, but pretty messy. Nothing looked horribly wrong up to this point other than evidence of lots of oil being burned.

Now things got a bit ugly. This is the #5 cylinder. You can see the two big score marks in the cylinder. Those are not supposed to be there. They are pretty deep scratches too. This means that just honing the cylinders might not work. This block may be useless to me. I could get it bored out, but that would mean buying new pistons. The pistons cost $160 each, new. So that gets pretty spendy.

One of the other problems I found was some mismatched hardware on the #5 piston rod end cap. This hardware should be the same type, but isn’t. This could be enough to put things out of balance. The end caps and rods are all supposed to be oriented in the same direction too (there are markings on both that should face the same way), but they weren’t. This again could lead to some imbalances.

This is the #5 piston. It was the worst of the bunch. You can see the score marks and scratches on the side. All the pistons except the #6 (the newer one) showed signs of scratching like this. The #5 was definitely the worst though. I am not sure if this damage makes these pistons unusable or not. We’ll have to see. The rings are all fine, none are broken. I checked the gaps on one set and they were all within tolerances. 

The crank shaft looks fine and I don’t see any signs of over heating on any of the bearings or the crank shaft. There is some scoring on the bearings for sure, but no deep gouges.

So, there is no definite answer as to what happened to the engine or what caused the damage. I suspect the score marks in the cylinder causes some of the oil consumption.

My guess is that either the oil got left in the engine for way too long and got really, really dirty or some dirt got into the oil somehow, or the air filter was never replaced allowing lots of dirt into the engine, or something similar. It is hard to say.

I will try to get it over to the machine shop in the next couple of days and see what they think.

I might be on the market for a new block. I have a source for some used, standard sized pistons for cheap if I need them though.

Well, that’s the story for now. Hopefully I can get this all put back together soon and for minimal cost.