Hey, I pulled it off in an hour and 45min (with the help of a lift and having any nut/bolt/washer I wanted.)
For those of you who don't know, I was going to try to fit a Volvo 240 series front air-dam onto my '84 Rabbit Convertible.
Here is what you will need, or at least what I used.
Three 6mm bolts (to bolt the spoiler to the bumper)
Six 6mm flat washers
Six 6mm Fender washers
Seven 6mm nuts
Two 5mm bolts (to bolt sides to plastic bumper ends)
Four 5mm washers
Two 5mm nuts
1 Volvo 240 front air-dam.
Tools:
Hacksaw (hehehe..)
Side Cutters (even better...)
10mm socket/driver, 10mm wrench
8mm socket
some sort of locktight (I used silicone)
First I took the spoiler and cut it in half. There are three air-scoops and one tow-hook hole, cutting it in half would be the center of the middle air-scoop. Then I took one half of the spoiler and fit it up to right half my bumper, They mount to the topside of the bottom of the bumper. I trimmed some material from the plastic bumper-end to allow the lip on the side of the spoiler up against it. Then I clamped it in place with one of those quick grip things.
I took the other half, and did the same to it, except I overlapped the two halves in the center (they fit against one-another nicely) and marked the lower bar to be cut towards the right side of the car. Then I took the right side and cut to the mark (approx 3") and put it back on to see how the cut was.
At this point the spoiler was a bit too wide for it to really fit between the bumper end-caps, and it wouldn't go any closer together because the where the upper parts of plastic where overlapped, one was too long and hitting a reinforced channel on the other, so I cut the one that was hitting the channel about an inch, and put it back on. It was still a bit too wide, and so I cut it a little more. Then the bottom bar was a little too wide, so I cut that about a quarter of an inch, and it finally was the right width.
then I took the quick grip and pinched together the split in the middle by the lower part of the bottom bar, and got the spoiler all lined up on the bumper. Now, on the 240 about 1" of the spoiler sits on the bumper and is bolted there, and it is a slightly raised section (in relation to the ground anyway) and then there is about an inch of flat-space behind that, then the spoiler starts to head towards the ground. Because of the way the Volvo bumper curved, and because I didn't think that was really enough to hold it on the way I wanted, I forgot about that lip and pushed the spoiler forwards more so that I would be bolting it onto the bumper using that second flat spot right before the spoiler goes downwards.
I got everything all lined up and clamped in place and I drilled a hole through the center of the bumper about 1/4" away from the rear edge up through the overlapped upper part of the spoiler, and put a 6mm bolt through it using the bolt head and a washer on the bottom, and a fender washer and nut on the top (fender washers are slightly larger than normal washers. I used one to hold onto the soft plastic better) Then I put two more bolts in the same way right underneath where the parking lights are in my bumper (about 1/4 way in from each side) and secured the spoiler there.
With those three bolts, it's really pretty secure. The plastic is fairly beefy. I drew a line down from the BUMPER side-cover so the rear edge of the SPOILER would be even with the rear edge of it, and cut the little leftover section off by having the hacksaw blade on upside down so I could fit the blade between the SPOILER and the body of the car and cut towards myself.
all it needed was something to keep the sides of it from tilting downwards and flexing and so fourth.. some stability. I used two 5mm bolts and bolted the SPOILER to the inside of the plastic BUMPER ends about 1/4" from the bottom. I drilled a hole so that the bolt would go through the BUMPER end on the bottom corner near where the edges were so I could fit a 6mm nut onto the bolt without it hitting the rolled sides of the BUMPER end. then I slid two 6mm nuts onto each 5mm bolt (with a 5mm washer between the BUMPER end and the bolt head) and pushed the bolts through the end caps, through the nuts and into the a hole drilled in the SPOILER'S upper (rear) corner, but low enough so that you could fit a 5mm nut onto the bolt without hitting the rolled edge of the SPOILER. Then I secured the SPOILER with a 5mm washer and a 5mm nut, using silicone to keep the nut from coming off because I couldn't really tighten it very much because the bolt head and washer was starting to squish into the plastic of the bumper end.
Now, if you really want to you can take a small piece of sheet-metal and make a rivet a backing plate to the split in the bottom bar in the middle air-scoop which is now under 1/2 the size it used to be. I'm not sure if I'm going to, it seems very strong as it is.
Be sure that your bumper ends are on the bumper well. Those upper little fasteners are going to be supporting a little more than they're used to so be sure that they're A: in place, and B: not loose and floppy.
I will try to get pictures asap.. but without my own scanner sometimes that takes a while. The spoiler is just about as low as the bottom of the front apron, definitely not a ground-scraper, but tons better than not having one.
