At the end of last week’s column, I’d mounted the wing-cell bracket on the shark’s M30 block, and thought that a perfect photo to close the installment would be one of the Sanden 508 compressor hung off the bracket, even though I wasn’t ready to permanently install it because I still need to drain the PAG oil it came with and refill it with ester oil (which will be covered in an upcoming installment). As I hoisted the Sanden compressor toward the mounted wing-cell bracket, after all of the work I did adapting the bracket to receive the compressor, I felt like a convict climbing over the fence to escape prison—but when I tried to slide the long pivot bolt through the bracket, the metaphorical dog jumped up and grabbed my ankle and dragged me back down.

Which is to say that the pivot bolt wouldn’t go through the bracket due to a clearance issue with a mounting boss behind it on the block.

The pivot bolt can readily be slid through the front of the bracket, but not through the compressor, as the hex head of the bolt hits the compressor’s pulley. I’m virtually certain that this is an artifact of my using an M10 bolt, which is snugger in the holes in the compressor’s mounting ears than the 3/8-inch bolt most folks use, but which has a larger hex head than a 3/8-inch bolt (17 millimeters versus 9/16"). Given the choice of grinding the boss of the block, switching to a 3/8-inch bolt, or grinding one of the sides off the M10 bolt’s hex head, I did the latter. It fits fine now.

But after I did this, CCA member Barry Allen sent me an e-mail saying that an M10 bolt with an Allen head—not necessarily named after him—rather than a hex head would work without grinding, proving that I am a myopic old Hack and that there he is, smarter than I am. Thanks a lot, Barry, for making me feel inadequate.

Onto the condenser installation.

A few months back, I wrote a piece about upgrading the condenser in my E9 from the obsolete serpentine-flow condenser I’d installed as part of the from-scratch retrofit eighteen years ago to the kind of modern parallel-flow condenser that is in any new car, and is part of any a/c retrofit you’d do today. I cover similar ground here, but there enough that’s shark-specific for me to go over it again.

The condenser is the part of the a/c system that dumps the heat. You want to install as large a modern parallel-flow condenser as you can. Condensers are classified as “universal fit” or “drop-in replacements”; the universal fit models generally have brackets with dozens of equally-spaced holes on all four edges, and hose fittings that usually stick straight out one side.

In contrast, drop-in replacements are designed to replace the original condenser, and as such have brackets and hose fittings in the same places as the original. The hose fittings are often what are called “block fittings,” where rather than individual threaded input and output hose fittings, there’s a flat mounting flange for one or both fittings, to which the hoses—which also have block fittings—attach with a single bolt. Unfortunately, it’s pretty rare to find a drop-in replacement parallel-flow condenser for a car that originally had a serpentine-flow unit.

In order to install a “universal fit” parallel-flow condenser, you need to measure carefully and determine the largest unit that’ll fit into the nose of the car, mount it by hook or by crook, mount a big electric fan either on it or in front of it, and either adapt your existing hoses to fit the new condenser or fabricate new hoses. If you’re doing a from-scratch installation, you’re fabricating new hoses anyway, but if all that you want to do is replace the original obsolete serpentine-flow condenser with a modern parallel-flow unit to get the system to cool better, the bracket-and-hose adaptation is a fair amount of work.

Because of this, for a brief period, an enterprising company sold a drop-in parallel-flow condenser specifically designed to replace the E24’s original serpentine unit, with the mounting brackets and hose fittings in the same place. Unfortunately, these appear to have been like Brigadoon, emerging from the mists only to disappear from the marketplace a short time later. Folks still ask about them on web forums. Perhaps in a hundred years they’ll become available again. Until then, you just have to roll up your sleeves and adapt a universal unit.

The process I use for determining condenser size is to measure, sanity-check against web forums, decide whether to err on the conservative or aggressive side, purchase, test-fit, and return if necessary. Fortunately, the universal-fit units are inexpensive enough (often $60 or less) that even if you need to eat one before you come up with the optimal size, it’s not heavy scratch.

When measuring and ordering, the width is much more critical than the height, as the quoted width dimension of the condenser doesn’t include the brackets or the hose fittings that have to attach the side, so it’s easy to get the width wrong. In contrast, the height measurement is less squishy. You do need to understand the difference between the height of the cut-out in front of the radiator through which you need to pass the condenser to get it into the nose, and the height of the space inside the nose. Typically, if you tilt the condenser, you can get a bigger one in there than the size of the cut-out. But the height is less critical than the width; I’ve never bought a condenser and had it not fit because I’d blown the height measurement. In the shark, the cut-out height is about seventeen inches.

Here’s how the width measurement works: Accurately measure the maximum side-to-side width inside the nose, making sure to take into account any bulges in the sheet metal or other things that protrude into the space. In the shark, this side-to-side measurement is a little less than 24 inches.

Now subtract three inches from that, and that will give you the zero-clearance width for the condenser.

What do I mean by “zero-clearance width"? And why subtract three inches? The width spec of these universal-fit condensers is very misleading, as it is the measurement between the outer edges of the vertical tubes that run down the sides, and that doesn’t measurement take into account the side brackets with the mounting holes, which typically add 3/4" per side (1.5" total), or the hose fittings on one side, which typically add another 1/2". So you need to add two inches to the condenser’s stated width to get the total physical width of the condenser. Even if there is a drawing for the condenser, this is rarely shown.

But then you need to figure in the added width of the fittings on the ends of the hoses you’ll be attaching. The tightest narrowest fittings I’ve found are what are known as short-drop 90-degree fittings, and once they’re screwed onto the condenser, they add an extra inch in width. Once they’re screwed on. You need to get them on. This is why I say “subtract three inches from the width in the nose, and that’ll give you the zero-clearance width of the condenser.”

Below I show that the actual width measurement of a nineteen-inch condenser with short-drop fittings temporarily screwed into the sides is 22 inches.

Using the shark’s numbers, the width inside the nose is about 24 inches, so the zero-clearance condenser width is about 21 inches.

To be absolutely clear about this, the zero clearance width is not a number you can actually use. If you buy a condenser that size, it won’t fit. There won’t be enough clearance for you to get the hose fittings on. It’s only a reference point. You need to subtract one or two inches from the zero-clearance width to get a condenser that will actually fit.

So, which is it? Is it an extra inch, or an extra two inches? To answer that, you need to know how the condenser will actually mount. And, to know that, you need to look carefully inside the nose. If, looking through the holes where the grilles were, you see that there are flat surfaces behind and parallel to the plane of the condenser, then you can mount the condenser on stand-offs. If that’s the case, the mounting itself shouldn’t eat up much if any space, and one inch should be sufficient. But remember that you can’t center the condenser; you need to slide it all the way to the side that doesn’t have the hose fittings on it so that the hose fittings have the benefit of all of that one inch of clearance.

If, on the other hand, there aren’t mounting surfaces parallel to the plane of the condenser, and instead you need to mount it with right-angle brackets, the brackets themselves typically take up some amount of space, and it’s safer to allocate two extra inches.

Just to make sure I haven’t confused you with too much detail about zero-clearance widths as opposed to actual widths that will work:

• Measure the side-to-side width inside the nose.

• To get the aggressive condenser-width measurement, subtract four inches, which leaves one inch for hoses and brackets.

• To get the more conservative condenser width measurement, subtract five inches, which leaves two inches for hoses and brackets.

So, with the shark’s 24" nose-width measurement, if I wanted to be aggressive, I could order a 20"-wide condenser, but if I felt like I wanted to err on the safe side, I’d go for a 19"-wide unit. On the height, there was additional room in the nose, so I figured I could go up to seventeen or possibly even eighteen inches.

Once you’ve honed in on your target size, you need to see if it’s even available. I try to buy my condensers off Amazon, since, if they’re the wrong size, returns are easy, but eBay has also proven to be a good source. You can go to boutique sellers such as Vintage Air, Nostalgic Air, Old Air Products, and others, but most of what they have, they’re purchasing elsewhere and reselling.

In my case, a web search revealed that both 16"x19" and 16"x20" are readily available, but I struck out on trying to increase the height to 17" or 18"; I simply could not find anything of that height. (Actually, that’s not quite true. In spite of what I said above, Vintage Air appears to be the source of a 17"x19" condenser that even has the advantage that the hose fittings bend at 90 degrees, lessening the needed hose clearance, but its price was three times that of others, so I passed.)

I then pored over to see what size condensers folks were using, and the consensus seemed to settle on 16"x19", with a few comments saying that you might be able to get a 16"x20" unit to fit, but it would be tight.

On other projects, I’ve ordered both a conservative and an aggressive-sized condenser and returned the one I didn’t use, and I might have done here that if there was one that was not only wider but taller. But because the shark’s nose width wasn’t exactly 24 inches but a little under it, I erred on the safer side and ordered the 16"x19" unit.

The condenser arrived, and I did a quick test-fit with the short-drop fittings screwed in, which is by far the best way to judge side-to-side clearance. Even having to negotiate the right side around the bracket supporting the oil cooler, there appears to be gobs of room; with the condenser slid all the way to the right, a direct measurement appears to show that, with the short-drop fittings screwed on, there’s about 1-5/8" of space to the left of the fitting. Which means that if I went with a condenser an inch wider, I’d have 5/8" of space to get the hose on.

I nearly ponied up another $55 for a 16"x20" condenser, but I decided to wait until the brackets I’d ordered arrived and I could begin the mounting process. Sometimes what appears to be available space vanishes as you actually begin to mount the unit. [Next week: Mounting the condenser.]—Rob Siegel

Rob’s new book, Ran When Parked: How I Resurrected a Decade-Dead 1972 BMW 2002tii and Road-Tripped it a Thousand Miles Back Home, and How You Can, Too, is now available on Amazon. Or you can order personally inscribed copies through Rob’s website: