There are three main components in doing a headlight retrofit: the headlights, headlight buckets, and the linkages. The headlights and buckets are obviously the 4x6 units being installed, and the linkage refers to the pivot arms the headlight motor uses to raise the headlights. The main objectives here are to: 1) make the 4x6 headlights and buckets fit into the OEM 7'' round headlight mount, and 2) adjust the pivot arm linkages to lower the headlight height to that of the 4x6 headlights. Now with that in mind, let's take a look at the materials.
|These are headlights from a 1990 Eagle Talon, picked up off of eBay for just under 30$ shipped. The entire headlight housing, headlight trim, and linkage arms were included. From this setup, we will be using the 4x6 headlights, headlight bucket, headlight mounting bracket, 2 adjustable linkage arms, and the ball screws. The ball screws were salvaged (cut off with a dremel) from the headlights because do not know of a place locally where I could get these. The linkage arms are adjustable, and give a total of about 1'' expansion/contraction for some adjustability; however, later on in the construction, you'll see we need them at the maximum possible length, otherwise the ball sockets will slip off when opening/closing the headlights. Miscellaneous nuts and bolts were taken from the setup as well since they were pretty beefy and already fit the mounting bracket holes. I will also use all 4 headlight tilt adjustment screws, 2 of which will be cut in half for clearance issues.|
|We'll begin modification by fitting the bucket mounting bracket to the miata's headlight. Here we want the 4x6 headlight to be as high as possible so that we can get the lowest profile we can with a 4x6 light. I put the mounting bracket up to the miata bucket and it was far too big, so off I went with the dremel trimming away the excess. The amount I cut off was eyeballed, but it turned out to be a great fit. The two bottom-corner holes will be used to mount the bracket to the miata headlight. The two headlight tilt adjustment screw holes on the bracket will be used to adjust the 4x6s, one is on the bottom middle of the bracket, and the other is on the outside (right side of these pics).|
|To mount the bracket, two holes needed to be drilled. I basically held the bracket as high as I could against the headlight and marked the holes with a sharpie. A 3/8'' bit was used, and if you drill your hole through the T in the metal, ie where the side panel meets the front, you'll need to get creative. I just drilled a hole from the side as well.|
|In order to get the 4x6 bulb to sit as deep as possible in the headlight to prevent rubbing against the front bumper frame, the bucket needed to be trimmed and bent flush against the backside of the bulb. This lets the headlight sit approx 0.5'' deeper than it would with a full backing, and yes, they are still adjustable :)|
|Now that the headlights have a mounting area, we can move onto the second part: adjusting the pivot arms to lower the headlight height. The pivot arms are shown in the pictures to the left. They're made from 1''x1/8'' bar stock with 3/4'' legs and a 1/2'' mid-section. The salvaged ball screws are shown in on the far left, and will be JB-welded to the pivot arms because I'm not sure what metal they are comprised off (otherwise I'd weld it). A larger hole is needed on the opposite leg to mount the arm to the headlight motor. I can't remember exactly but I think it is a 3/8'' hole.|
|A comparison of the original pivot arm linkage to my linkage is shown in the middle picture to the left. As you can see my pivot arm is a little more than half the length of the original, and the arm extension is slightly shorter as well (at its max length). Fortunately, the ball sockets on the adjustable arm are the same size as the miata's, so fitting it to the backside of the headlight won't be a problem. Fitting the linkage to the headlight motor and the headlight is a bit of a challenge. It needs to be done in such a way that the headlight doesn't slam shut, because the motor is trying to pull it farther down than it can actually go, or the headlight goes up to its max point and gets pulled down again. Both situations cause the ball sockets to pop off...not good. This is where the adjustable arm linkage helps because adjusting them allows you to get the headlight lid flush with the hood. After lots of tinkering, hitting the center console button 30+ times to raise and lower the headlights, and some choice words, the headlights raise to about half of the original height.|