Article by: Jackcat559
Applies to: All BMW models with the M54 straight 6 engine.
I picked up a spare head off ebay for a project. One of the ideas being to eliminate down time at the machinist. The head was $200, and had signs of some sort of oil starvation. Kinda confirmed by the seller, who said the engine threw a rod.
*****Proceed at your own risk and be careful!*****
Do one cam at a time.
This procedure is pretty much the same for the all modern DOHC BMW heads. Adapt as needed with caution.
Keep the parts organized. Take pics if necessary (recommend).
If nervous, get a second person to help.
Let’s GO!
Get the bottom of the head off the table top. Wood blocks work great. This is done so the valves can move freely when rotating the cams. Also to prevent further damage to the mating surface.
Rotate the cam, either one, so the cam lobes are ONLY depressed on the cylinder 1 lifters. Use either the very rear of the cam (see pic) or there is a spot in the center of the cam where a crescent wrench will fit.
This will leave no tension on the lifters in cylinders 2-5. These 5 cylinder lifters should spin freely in their holes. If not, something is wrong.
Fully depressed:
Crack (yes I say crack, cus it sounds like a crack), Crack ALL the nuts loose on the cam carrier by 1/8th of a turn. Then loosen 2-6 cylinder bolt by about 1 turn.
They can now be taken off by hand.
Remove the carrier caps.
Part 1 of 2:
With your left hand you are going to keep the cam from ROTATING with a wrench. No need to keep it pressed into the carrier as cylinder 1 bolts are removed. If you did keep the cam depressed there could be a chance of bending the cam, IMHO.
For peace of mind , don’t depress the cam into the carrier. Let it naturally come up on it’s own. (Yep, same pic):
Part 2 of 2:
With your RIGHT hand you are going to loosen the remaining 4 bolts EVENLY by a 1/4 turn each. The entire thread of the bolt is used. As the bolts are loosened they cam may want to rotate back a forth. Don’t let it with your left hand. When you start you are committed to finish.
Be careful! There is a lot of pressure pushing the cam out of the tray, towards you!
Note: If you are sketchy on the last 4 bolts. Have one person hold the cam. While you loosen the bolts
Done!
Now take off the remaining carrier tops. Then take out the cam.
Time to test the lifters. Remember the head had signs of oil starvation. Here’s what can happen to the lifters with only 46,000 miles.
Mark the bad lifters. They will need replacement. Each one is $17-24 approx.
Free up the lower cam tray. It will be pretty well stuck in place. Then put the head on it’s side. When pulling the lower cam carrier off make sure the top (cam side) is pointed toward the floor. Essentially keeping the lifters in their comfy spots in the carrier. The lifters are dedicated to their spots in the carrier.
Don’t mix them up.
