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The Hack Mechanic: Chillin' Louie (Part II: The tii-Specific a/c Crankshaft Hub)


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In last week's introduction, I talked about how a/c helps extend my enjoyment of my vintage cars through the hot summer months, how I bought a used full-up Clardy system and a tii-specific crankshaft hub with a compressor pulley on it, and how I realized that, with summer on us, there was no reason to NOT start stuffing this stuff into Louie my '72 survivor-ish tii. So in I dove.

 

In my a/c book Just Needs a Recharge: The Hack Mechanic Guide to Vintage Air Conditioning, I say that one of the nice things about a/c retrofit is that, even though it seems like a huge project, it breaks itself up nicely into the following tasks:

 

  1. Compressor and bracket
  2. Condenser and fan
  3. Evaporator assembly
  4. Receiver-drier
  5. Hose fabrication and installation
  6. Wiring
  7. Pressure-testing
  8. Evacuation and recharge
  9. Buttoning up

 

Further, for the most part, the car can remain drivable once each of these phases is completed. The radiator does need to come out to install the condenser and fan inside the nose, but after that, you can usually drop it back in, refill the cooling system, and keep driving the car.

 

On a tii, though, there's the added complication that the compressor belt runs in a groove on the crankshaft pulley behind the injection belt. This means that even to simply replace an existing compressor belt due to breakage or it being stretched past the point of adjustment, the engine has to be set to top dead center, the fan belt has to be removed, the lower pulley has to be unbolted and gently pulled off the front of the crankshaft, the upper and lower plastic timing belt covers have to be removed, and the injection belt has to be carefully slid off (and replaced if it shows signs of age). 

 

Not quite ten years ago, I'd updated the a/c in Kugel, my other '72 tii. When I bought Kugel, it still had its original York compressor and massive bracket that wrapped around the front of the water pump. As part of the update, I bought a hobiedave bracket (from Dave Donohoe here on the FAQ) and a Sanden 508 clone compressor. Any tii with dealer-installed a/c has had two slots cut into the plastic lower timing belt cover to allow the compressor belt to pass through. The Behr installation manual has a template for where to cut the slots. When I updated Kugel, I found that I not only needed to extend the slots by quite a bit, but I also needed to rout out the slots in the lower timing cover on the front of the engine itself. I'll cover these issues in the next installment. However, at least Kugel had dealer-installed air, so it already had the a/c front hub that's unique to the tii with the compressor pulley sitting behind the cogged gear for the injection belt, and slots cut for the compressor belt. Louie didn't have any of that. I'd bought the tii-specific a/c hub on eBay years back. Now I needed to install it. So, for this a/c retrofit, this was task #0 added to the above list.

 

IMG_1219.JPG The hen's-teeth-rate tii-specific a/c crankshaft hub

 

The first step was to remove the old crankshaft hub, because if I couldn't, it was game over for a/c retrofit. For that, I needed access to the hub, so the radiator had to come out and the front sway bar end links needed to be disconnected so I could tip the bar forward and out of the way.

 

I first set the engine to TDC using the marks on the front pulley and timing belt cover, then undid the four 10mm bolts holding on the front pulley and gently pulled it off. I then put a 36mm socket on a breaker bar and, with the car in gear and the handbrake on, tried to break the nut on the crank hub.

 

IMG_6218.JPG Trying to remove the crankshaft nut with a breaker bar. And failing.

 

Of course, this didn't work—it moved the car before moving the nut—but it DID succeed in moving the engine away from TDC by an amount I couldn't tell because the TDC mark was on the pulley I'd just removed. D'oh! So I temporarily put the pulley back on, lined the engine back up to TDC, made sure I could see the TDC mark through the bell housing window since the one on the front pulley was about to go away, and painted the flywheel TDC mark with Wite-Out.

 

IMG_6222.JPG Temporarily replacing the front pulley to read the TDC mark

 

I then thought to look at the index marks on the Kugelfisher pump. The one on the gear should line up with one on the pump body. To my surprise, they were off from each other by a few teeth. This was how I'd been driving the car for four years. I photographed it just in case the car ran like crap when I put it all back together with the marks lined up.

 

IMG_6221.JPG The indexing marks on the Kugelfischer injection pump and its toothed gear

 

I then did what I should've done the first time and used my impact wrench on the crankshaft nut. It spun right off.

 

IMG_6224.JPG Air tools to the rescue

 

Next, I put a puller on the crankshaft hub. Like nearly any crank and hub, there's a keyway in both and a little Woodruff key keeping them in line, so if the hub hasn't been off the car in nearly 50 years, things can sometimes be pretty stuck, but it pulled off without a lot of effort.

 

IMG_6225.JPG Extracting the old hub with a puller

 

I used a Scotch Brite pad to clean off the surface of the a/c hub that runs inside the front main seal, as it had oxidized from sitting. I later also cleaned up the grooved pulley surface as well. I then compared hubs just to make sure nothing looked amiss.

 

IMG_6232_cropped.JPG Original tii crankshaft hub (right) and tii-specific a/c hub (left)

 

Then on went the a/c hub. Unlike trying to take it off, I was able to torque it down to the required 140 ft-lbs by simply having the car in gear and the handbrake on.

 

IMG_6233.JPG And... installed

 

On a non-tii, you obviously wouldn't have to futz with the hub at all to retrofit or update a/c, and you'd go straight to installing the compressor and bracket. Or, if your tii wasn't air conditioned, you could simply put the injection belt back on and button up the car. But on an air conditioned tii, the steps are intertwined. That is, you have to:

 

  1. Install the compressor, bracket and belt, and correct any belt alignment or tension issues.
  2. Modify the slots in the plastic lower timing belt cover if they already exist, and cut them if they don't.
  3. THEN put the injection belt back on and button things up.

 

But I think I'll leave that for the next installment.

 

--Rob

 

(My a/c book Just Needs a Recharge: The Hack Mechanic Guide to Vintage Air Conditioning can be purchased here on Amazon, or personally-inscribed copies of it and my other books can be purchased directly from me here.)


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The new book The Best Of The Hack Mechanic available at https://www.amazon.com/gp/product/0998950742, inscribed copies of all books available at www.robsiegel.com

1972 tii (Louie), 1973 2002 (Hampton), 1975 ti tribute (Bertha), 1972 Bavaria, 1973 3.0CSi, 1979 Euro 635CSi, 1988 FrankenThirty 325is, 1999 M Coupe, 1999 Z3, 2003 530i sport, 1974 Lotus Europa Twin Cam Special (I know, I know...)

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