A few weeks ago, Hal the machinist called to give me the bad news about my 1974 2002tii: Otto’s head was not only warped, but cracked in two places. No problem, I thought; I have an entire spare tii engine I bought for about $400 sitting under my porch. Plan A was to steal its head—but I do not know what shape that head (or the rest of that engine) is in, and the more I thought about it, appropriating the head would reduce the value of the block to near zero, both to me or to anyone else.
So on to Plan B: As I prepared to travel to the Vintage in Asheville, North Carolina, I put out a plea on the Vintage Facebook page for an uncracked E12 2002 head.
The community being what it is, four people quickly responded. The first was Jake Barkell, who said that he could bring a bare head (valve guides only) of unknown provenance. Jake had checked the head with a straight edge, and it appeared to have only a slight high spot in the middle. I asked Jake to slide a cam in to make sure that the cam slid easily into all three journals. He did, and said the head passed the cam test.
Before I had even checked into the hotel at the Vintage, Jake and I connected in the parking lot, I handed over $120, and Otto’s greasy salvation was mine.
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I arrived home from the Vintage late on a Monday. The following Tuesday I took the head straight to the machine shop. Hal squinted at it, wiped the grime from the valve seats, threw a straight edge on it, and shrugged, “Well, I don’t see anything obviously wrong with it. It might work for you.”
I waited a few days for the phone to ring with bad news—it is a crapshoot buying a bare head whose history is completely unknown. When Hal called on Thursday, I was obviously quite pleased when he said, “That head worked out just fine. I milled it flat. Valve guides were reusable. I put in the valves and springs from your first head and milled the upper timing cover to fit. You can pick it up Friday morning.”
I swung by, paid Hal the $395 I owed him for his services, and put the head in the trunk of the Z3.
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That night, Maire Anne and I were preparing to leave for our son Kyle’s wedding in Santa Fe, but I couldn’t resist the temptation to take a few steps down the road of reassembly. I thought, well, at least I can clean the rocker shafts. I took them outside, put them in a pan, blasted them with brake cleaner, and wiped them down. I then inspected them to make sure that I could reuse them, but I regarded this as a mere formality, since Otto had not been making any alarming valve-train noises. Of course, I had also regarded Otto’s compression test a formality—and that was the act which, for better or worse, took me down the road of decapitation (worse for me; better, I guess, for the next owner).
Please bear with me while I indulge in flashbacks, strategically placed to increase tension between cleaning the rocker shafts and revealing what I found when I inspected them. This is A-level automotive writing here, folks; don’t try this at home unless you’re a trained automotive journalist.
Flashback #1: When I refreshed the engine on Kugel, the ’72 tii, a few years back, I tried to follow the guideline, “If it’s reusable, reuse it.” The problem, of course, is that nearly everything on a 100,000-mile engine is worn to some extent, and it is difficult to draw a consistent line between replacing everything and reusing everything. On Kugel, I found that one rocker arm had a chunk missing from the pad; I could’ve just replaced that one arm, but since I’m holding onto Kugel for the long term, I decided to renew all of the rockers and shafts.
Flashback #2: Before I learned that the head was cracked, I discussed the head issue with my friend Lindsey Brown. Lindsey is a pro, meticulous and thorough, and has some remarkable insights that can only be earned through wrenching professionally. Thorough, meticulous Lindsey is the one who surprised me by saying, “We have a saying in the shop: Put the goddamn part in the goddamn car!”
When I first discovered the warp/cracks in Otto’s head, Lindsey said, “I know you, Rob. You’re going to wind up installing a completely rebuilt head. And you might not need to. You don’t owe the next owner of the car anything other than a straight, uncracked head that is in a condition commensurate with the rest of the 100,000-mile motor.”
Lindsey is a smart guy.
Both my recent experience with Kugel and my conversation with Lindsey were in my mind when, after cleaning Otto’s rocker shafts, I was surprised to discover that the shafts showed obvious wear; there were broad flat spots where the rocker arms ran, as well as a few deep grooves. There’s no sense pretending that it wasn’t the motion of the rocker arms that created this wear: The bushings in the rocker arms were no doubt worn.
Now, on the one hand, seeing this kind of wear, it was clear that the rockers and shafts needed to be replaced. But on the other hand, I began thinking about Lindsey’s advice. The valve train didn’t sound loud. All the valves were easily adjustable. I’ve seen rockers and shafts so worn that the rotation of the adjusting eccentric wasn’t enough to reach the top of the valve stem, and you had to make up the gap by using the old trick of putting an Alfa valve shim on the top of the stem. This enables you to get thousands of happy miles out of a lightly-used car with worn rockers.
Yes, I thought, but have you ever re-installed an obviously worn valve train into a freshly machined head? Well, no.
This is the problem with, “If it’s reusable, reuse it.” It promotes lying to oneself about what is reusable—or at least exaggerating.
I look at these sort of things very practically in terms of cost versus benefit. The costs were already ratcheting up; between the purchase of the head, the machine work, the full head-gasket set, the plate to block off the fuel-pump rod (needed for a tii), and a few odds and ends, I already had $600 in the car (adds up quickly, huh?). I searched online and found a new-old-stock set of rocker shafts on eBay for $50 shipped, and new Febi rocker arms from RM European for $88.88 for the set, shipped. So the cost of new rockers and shafts was about $140. On top of the $600 already spent, $140 seemed an acceptable incremental cost.
I ordered the parts.
This way, when I sell the car, I can say “rebuilt head with fresh valve job and new rockers and shafts.” And if I wind up selling the car to someone I know, I won’t have to either bite my tongue about installing a clearly worn valve train or admit to having been penny-wise and pound-foolish.
(Next week, the reassembly begins. Unless something else looks “unusable.”)—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.
