Hello all, I just installed a set of Sparco R100 seats into my 1973 240z. Here are the details of the installation.
The R100 seat from Sparco is their "budget" seat. They retail for about $300/ea. I chose the black vinyl ones. These are made in China. Before I purchased the set, I sat in them and really liked the fit.
There are a wide variety of "racing" seats on Ebay from unknown manufacturers for very little money. I chose the sparco seats because at least I have heard of Sparco and I think if I had any issues they would be able to take care of it.
The installation shown below covers the passenger seat. I will just repeat the process for the driver side. I did the passenger seat first in case I learned anything and had to make corrections to the install process when I got to the driver side (the important seat!).
Step 1: Remove the OEM seat:
Step 2: Remove the sliders from the OEM seat and mark the orientation of each one (FWD/Inside) Compare the seat bottoms OEM vs R100.
Step 3: Test fit the non-handle slider to the R100 seat. Line up the rear stud with the rear hole in the seat. Notice that the slider is too long for the R100 seat. You do not want to line up the front stud with the front hole of the seat . This would put the seat too far forward. Carefully mark the slider where you will need to drill the front hole
You will re-use the OEM hole for the rear bolt (after you push out the stud fastener).
Step 4: Push out all of the short (seat side) studs from the rails. The R100 seats are female threaded for M8x1.25, so you will need to find some M8x1.25 x 25mm long bolts. If you can find them in button-head allen form, that would be the best (low profile head). If you deform the steel of the rail, try to flatten it back out as much as possible.
Step 5: Drill the front hole in the rail (clearance size for M8 threaded fastener).
Step 6: Bolt the rail to the seat (assuming you drilled in the correct spot).
Step 7: Repeat the process for the side with the locking mechanism. Bolt the rail to the seat bottom. You may notice that the lock mechanism slighly interferes with the a metal bar on the underside of the seat. You can add short spacers (maybe 4mm thick) between the rails (at all four bolt points) to handle the interference, but I did not. I wanted the seat to sit as low as possible.
Step 8: Now that the rails are mounted, you will notice that they sit wider than the OEM seat by about 5/8".
Step 9: Time to slot the holes in the floor pan seat mounts.
Step 10: I slotted all four holes outward until they were wide enough to accommodate the new seat rail positions on the seat. Only about 3/8" per hole.
NOTE: when I do this for the driver side seat, I will only lot the holes by the transmission tunnel, this will move the seat inboard and allow more clearance with the B pillar.
Step 11: bolt seat in place. Use some M8 nuts with flanges and some large diameter washers (because of the slot).
The pictures below show final fitment:
This picture shows the RH reclining lever (there is one on each side) There was not enough clearance to install the plastic cover on this lever. But there was on the inner lever. So I am leaving this cover off. (you can still activate the recline pulling on the metal arm.. or use the the other lever).
As you can see in this picture there is just enough clearance for the seat belt retractor! so close! This seat belt kit is from Motorsport Auto. The OEM seat belts are non-retracting so it would not be an issue with those.
Seat fit is VERY GOOD!! Slider is fully functional and seat is positioned exactly where I would want it, although I will shift the driver seat inboard a bit more. Seat belts are still fully accessible (might add harnesses in the future). Installation was pretty easy (as you can see) which makes me like them even more.
They are comfortable and will meet my needs just fine.