Two weeks ago I picked up Otto’s head—the one I’d bought at the Vintage—from the machine shop. My machinist, Hal, had decreed the head was straight and crack-free. He cleaned it up, milled it, deemed the valve guides reusable, transferred over the valves and springs from the original head, lapped the valves, and installed new seals. I was about to reassemble the valve train when I discovered that the original rocker shafts were pretty obviously worn. When a set of new rockers and shafts could be had for under $150, reusing them was clearly false economy. I put in the order. The new parts arrived. 

    It was time to get my head together.

    I still had the camshaft-removal jig I’d borrowed from a CCA member (who shall remain nameless lest he be inundated with loan requests from other nefarious individuals like me). This meant that I could install the rockers and shafts and then put the cam in, using the jig to depress the valves to gain clearance for the cam. This makes the process a bit easier, because the rockers aren’t under tension.

    However, even with brand-new rocker shafts, and a head that’s been hot-tanked and is squeaky-clean, the shafts are still an interference fit in the head—which means that they have to be tapped in. Maybe they’re not supposed to be quite so tight; maybe, with a brand-new head, they’re supposed to slide right in. I don’t know; I’ve never tried it on a new head, only on a clean used one. Mind you, it’s not as bad as getting old baked-on-varnish-laden shafts out of a warped, gunked-up head, where you’re pounding the daylights out of the shafts with a drift and a small sledge. With the new shafts and the clean head, my experience has always been that many firm raps with a rubber mallet are necessary. And the further you drive the shafts into the head, the more resistance they encounter, since the shafts go through additional passageways in the head.

    Each shaft is typically slid into the head from the back, since the front end of the shaft has the notch for the lock plate that holds it in position—not that with that interference fit it’s bloody likely to move—and you don’t want to beat on the notched end and risk damaging the notch. As the shaft passes each valve, you need to thread the rocker components onto the shaft—the spring, the flat washer, the rocker arm itself (whose inner surface you’ve lubricated with assembly paste), and finally the cupped washer, with the cup facing away from the rocker arm. That’s the order for the exhaust side; on the intake side the order is reversed. 

    Oh, and the rocker arms go on with the pad side facing the middle of the head, the eccentric side facing the valve. You need to check and double-check that you’ve got it right, because you really don’t want to have to bang the shafts back out.

    I’ll drive the shafts through the head until the notches are free and clear, then test-fit the retaining plate in the notches, tap the shafts back until the plate is flush with the head, and then take the plate back out; the cam needs to be installed before bolting in the plate. 

    You also need to eyeball down the head bolt holes to be certain that the indentations in the shafts that allow the head bolts to pass by are properly aligned; test-fitting a head bolt is a good idea. If things are slightly rotationally misaligned, an Allen key can be inserted into the end of the shaft to rotate it.

    Once the rockers and shafts are in, the clips can be put back on the shafts to move the rockers into position over the valves.

    Next, you anoint the cam, lubricating it—the running surfaces and the lobes—liberally with assembly paste. Then do the same for the journals in the head. At least that’s what I do.

    Using the cam jig to install the cam is the same as using it to remove the cam. You position it on the six valve-cover studs. It presses down on the eccentrics in the rocker arms, which, in turn, push down against the valves, opening them as the jig is tightened. If one of the jig’s rocker-depressing arms doesn’t line up with a rocker, remove the rocker’s clip so the rocker can slide on the shaft. Screw the six nuts down on the six studs until the nuts are flush with the tops of the studs; then give the three nuts on the exhaust side about four full turns each, one turn at a time. Remember, it is absolutely imperative that the exhaust valves open first. If the exhaust and intake valves open at the same time, the edges of the valves will touch, and the valves will bend as they’re cranked open.

    With the exhaust valves biased to open first, crank each nut by one full turn, verifying with each iteration that the valves are not touching. When the nuts are cranked down far enough, the valves will be sufficiently depressed to allow the cam’s lobes to clear the rockers and allow the cam to be inserted into the journals. 

    When the cam is in the head, the jig can be removed, one turn on a nut at a time, allowing the exhaust valves to keep their bias and stay open longer than the intake valves. With the jig off, you can replace any clips you’d removed to slide the rockers over. Then you can bolt the retaining plate into position.

    Voilà: assembled head.

    Well, not quite. The distributor housing needs to go on the back, with a fresh gasket and that little sealing washer on the 10-mm bolt at the nine-o’clock position.

    With a beautiful, clean, assembled head sitting in front of me, the next thing to do was to have it not sit in front of me, and put it back where it belonged on the block. When re-attaching a head, the block surface must be scrupulously clean. This means scraping with a single-edged razor blade and applying brake cleaner to remove all traces of oil residue. 

    The top surface of the lower timing cover needs to be clean as well. It looked like the head had never been off this car, and the front part of the head gasket had bonded to the lower timing cover; no amount of scraping with a single-edged razor blade seemed capable of getting down to smooth bare metal. Fortunately, a mini Scotch-Brite wheel on the Dremel tool works perfectly for this application.

    Oh, and the threaded bolt holes? Getting these clean (and they should be clean to ensure that the head bolts torque down correctly) is a surprising amount of work. You typically remove a head because there has been some sort of failure of the head gasket or the head itself, and the combination of oil, coolant, compression, and time often causes a most foul mixture to roost in the bolt holes. I take a piece of a paper towel, roll it around the tip of a screwdriver with about an inch of towel at the end, fold the towel over, and twist that down the hole, repeating until it comes out clean. When it does, I spray brake cleaner down the hole and repeat the process. 

    The cylindrical dowel pins fixing the position of the head on the block were a little the worse for the wear. Initially, I thought that the recapitation might need to grind to a halt while I ordered and waited for new dowel pins, but with a little clean-up of the pins and a test-fitting, I assured myself that, once I tapped them into the block, the head would slide onto them.

    The new head-gasket sets (mine was from Reinz) are different from the originals, both in material and installation instructions. The instructions specify an initial torque, then an angle torque. Many 2002 owners report oil leaks between the lower and upper timing covers, so an old-school technique is to coat that front part of the head gasket (to be clear, this is not the part that is torqued down between the block and the head; it is the front extension that sits between the timing covers) with a high-quality gasket sealant like RTV Black or Permatex Aviation Form-A-Gasket. The instructions that come with the head gasket specifically say not to use any additional sealants, but the collective wisdom on bmw2002faq.com tilted on the side of, “That may be true for new components, but if you have old parts and you don’t want them to leak, skim-coat it between the timing covers” So I did. 

    With the gasket (and its skim-coated front portion) positioned on the dowel pins on the block, there was nothing left to do but set the head on. When I first pulled the head off, it was fully loaded with the intake and exhaust manifolds and weighed nearly 50 pounds, so I lifted it up with a PullzAll electric winch attached to the ceiling. This worked brilliantly. But the head without its manifolds is much lighter, perhaps 25 pounds, and even in my dotage I was able to simply pick it up, set it down carefully on the block, shift it slightly, and feel and hear the reassuring thock as the dowel pins slid in.

    I put the oil-distribution tube back on and torqued the head down per the instructions, to 60 Newton-meters (about 44 foot-pounds), then angle-torqued by the prescribed 33 degrees. It needs a second angle-torqueing by 25 degrees, but only after it’s been heated once to operating temperature.

    While the sealant on the front part of the head gasket was still wet, I put the cam gear on the timing chain, bolted it to the cam, and attached upper timing cover and its two thin side gaskets. 

    So not only does Otto have his head together, his body and brain have been reunited. Of course, it’s not his original head. 

    Why am I thinking of that scene in Young Frankenstein were Igor drops the brain labeled “Hans Delbruck, Scientist and Saint” on the floor and takes the brain of “Abe… somebody” (Abbie… normal)? It’s probably nothing to worry about…. 

    (Next week, LIFE! Do you hear me? Give my creation…. LIFE!!)—Rob Siegel

    Rob’s book Memoirs of a Hack Mechanic is available through Bentley Publishers, Amazon, and Bavarian Autosport—or you can get a personally inscribed copy through Rob’s website: www.robsiegel.com. His new book, The Hack Mechanic Guide to European Automotive Electrical Systems, can be pre-ordered from Bentley Publishers. Use the coupon code “BMWCCAELECTRIC” for 30% off list.