Notes from First Time Engine Drop (long)

[rsiegel]

Greetings. I've been writing the column "The Hack Mechanic" for the BMW Car Club of America Roundel Magazine for nearly 20 years. Last year I scratched a lifelong itch and bought my first 911 -- an '82 SC Targa, metallic brown, with a whale tail (which I used to think was ostentatious as hell, but now that it's mine, I think it's really cool). I absolutely love this car. This past winter it developed a pretty severe oil leak that would drip directly onto the exhaust. So I was faced with my first 911 engine drop.

I followed Wayne's excellent technical article "911 Engine Drop Made Easy" (http://www.pelicanparts.com/techarticles/911_engine_drop/911_engine_drop-1.htm) to the letter. There were a few procedural steps I'd add:

--There is a second multi-pin wiring harness connector on the shelf at the front of the engine compartment that must be unplugged.

--There are two hoses that go into the left side of the air box that must be removed.

--The wire from the electronic speedometer comes off the right side of the trani and heads through a rubber boot above the transmission mount plate. Pull the boot back and pull out the two-pronged connector.

--The speedo wire and backup switch wire are cable-tied to a bracket on the right side of the trani. If the trani is staying in, this cable tie must be cut so the wires can pull away. If the trani is coming out, it can be left in place.

Wayne's article address the removal by leaving the transmission in the car. My perspective is that your car, in fact, may dictate how this needs to be done. I thought I'd try it this way, but when I tried to remove the "hidden" 10mm allen head bolt holding the block to the trani (up above the starter), I felt it strip. Ok, I'm a pragmatist about these things. If I can't get this bolt out, then the transmission has to come out attached to the engine. So I grabbed my air tools and in about a minute per side, had the CV joints off (it's almost unfair how easy this is with an impact wrench). The point is that you may plan to do it one way, but your car may have other plans for you.

Just to be pedantic, when the transmission stays attached to the engine:

--Remove the rear sway bar.

--Support the transmission mount plate with a floor jack and undo the two 19mm bolts holding it up to the body of the car.

--DO NOT LOWER THE JACK! The shift lever is protruding forward through the body of the car, and will hang up unless the engine is first lowered and the engine and trani are pulled backward (more below).

Now for the drop itself.

1) The Basic Problem. A 911 is not like a bug or old bus, where the rear engine compartment panel simply unbolts, and you can support the engine, unbolt it, and just roll the car away from it. To get the engine out, you have to drop it down under the car and slide it out, which you have to get the back of the car higher than the top of the engine. The odds of you already owning equipment to do this are very slim. The jacks and jack stands you have won't go up high enough.

2) How Do You Get The Car Up That High? Wayne says that, to get enough height to get the CIS injection on an 'SC to clear the rear valence of the car, you need jack stands that go up at least 24.5" under the ends of the torsion tubes. I found this to be right on the money; more on that below. Because I'd already started the project (everything was already unhooked) and I wanted closure over the weekend, I went to a local auto parts store and paid more than I should've for moderate-quality "6 ton" stands that go up 24 5/16". Using a standard floor jack and a very large block of wood beneath the engine, I was able to get the car up high enough to put the stands, at their maximum height, under the ends of the torsion tubes (I also put squares of 1/2" plywood beneath the jacks to give the bottoms something to bite into). But my friends, this is a scary height for a car. You should not be able to budge a jacked-up car any visible amount, and this moved around enough to make me very uncomfortable. I would NEVER lie with my entire body beneath a car that was held up by only this method. With the floor jack continuing to support the engine, and with big wooden blocks beneath the rear wheels, I had two back-up systems in place, and would scoot in and out as I needed to (to undo the transmission mounts, for example), but even still, it gave me the creeps. Note that I had already undone nearly everything that needed undoing when the car was jacked up a more moderate amount and was far more stable.

Numerous posts on the site offer that if you remove the rear valence, you can get a few extra inches of clearance. I tried this with a phillips nut driver and a brand-spanking new bit, and the first screw started to strip. Again, I'm a pragmatist about these things. What that meant to me was that I need every bit of 24.5" of height at the torsion bar ends.

3) The Reach of the Jack to Support and Lower the Engine. With the car up this high, a standard floor jack does not have sufficient reach to get the engine all the way up and down (I got the car up that high by jacking the engine up with a huge block of wood, but I didn't want to suspend the engine and trani on that block of wood to drop it). I have access to a big, 5 ton truck jack at work that goes from 6" to 27". This was sufficient to reach and support the engine and trani.

4) Balancing the Engine and Trani. The idea of holding up 500 lbs of weight and balancing it on a little circle the size of a desert plate is enough to frighten anyone. There's a tool sold by Pelican that attaches to a standard floor jack, cradles the engine/trani by the sump, and has the balance point set just right so it'll hold up the mated engine/trani. But it ain't cheap, and I didn't have it here at the start of the weekend. I seriously looked at buying the motorcycle/ATV jack at Sears that I see talked about. Instead of having a single round jack plate, these have two rubber-covered arms, and thus seem inherently more stable. But a) a hundred bucks is a hundred bucks, and b) from what I've read, the degree of vertical motion is only about 18". I may be reading this wrong, but this kind of jack may be better suited to the "put the car at regular height, lower the engine, then pick the car up over it" paradigm than the "get the car up wicked high, then lower the engine" paradigm.

So I did what my gut told me to do -- put a piece of 3/4" plywood on the floor jack, moved it as far forward on the engine as I could, jack it up and support the engine, and put a second floor jack on the end of the transmission. Because of the angle forced by the height of the back of the car, the jack on the engine seems to want to slide backward on the piece of wood, thus it was never as far forward (near the presumed balance point) as I would've liked; it was always fairly close to the oil sump. That second jack on the end of the trani gave me a big warm and fuzzy.

One thing that is crucial is to realize that the shift lever that pokes out the front of the transmission is still protruding through the body of the car, and thus that the engine must first be lowered so that the muffler clears the valence, then both jacks must be pulled toward the rear of the car slightly so the shift lever comes out of its little tunnel before the jack on the transmission is lowered. This is another reason why having a jack on the front of the transmission makes sense.

5) The Dolly Lama. There appear to be three distinct uses of a dolly:

a) Wayne talks about having the dolly around so the engine can be transferred onto it. Nothing wrong with that. But he's not talking about dropping the engine directly onto the dolly, as many posts on this site are.

b) One set of posts has photographs that show the dolly actually between the jack and the engine as the engine is coming down. The thing that isn't obvious here is that you need a dolly and a jack paired together so that the wheels of the dolly are high enough that the dolly can roll completely over the jack. In this way, presumably you put the dolly on the jack, support the engine, let 'er down, then just roll the jack out from beneath the
dolly. For the engine to roll out from beneath the body of the car, though, this must require the car to be even that much higher, as the engine will now be sitting on a dolly with high wheels.

c) If you search the site for "u-shaped dolly," you'll see a few contraptions people have come up with. This is what I did, and it worked like a charm. I took an old low-profile furniture dolly that was made from four sections, and cut out one section so it was shaped like a U. The idea here is that, like the above option, you can drop the engine right onto the dolly and then slide the jack out from beneath it, but this way the dolly isn't between the jack and the engine as the engine is dropped; it's sitting on the ground, an upside-down U straddling the front wheels of the jack, waiting for the engine to come down on it.

Now, clearance. Wayne's article says you need 24.5" at the torsion tube ends. My jack stands said their maximum height was 24 5/16". I put pieces of 2x4 the short way on the dolly so the bottoms of the heater boxes would sit flat. I lowered the jack until the engine was on the dolly, and... I could not pull the jack out because the engine was sitting on the top of the jack, not on the dolly. I turned the 2x4s around the tall way and was able to pull the jack out. Moment of truth. I pulled the dolly backwards and scooted the engine/trani out beneath the car. Clearance: literally, zero.

If I had to buy tools, the idea of two jack-pads (using a floor jack and the stock jack points on the sides of the car), dropping the engine onto a motorcycle jack, then lifting the car over it is very appealing, but I suppose you'd need two high-lift jacks for the jack pads.

Hope this is helpful.

--Rob Siegel

[azasadny]

Rob,
Thanks for the detailed writeup, it helps alot!