So my water pump failed on my FB Racecar. For reference its a Carb'd 13B that someone else built before I bought the car, so naturally this weird little guy has its own learning curve to it. from what I knew it was a GSLSE, with S5 Rotors. Pretty standard I thought. Well my water pump failed at the track, so I ordered a replacement from atkins. "79-85 rx7 waterpump" *fits 12a and 13b* the site said. Well as I came to find out this water pump did not fit my housing, 2 of the bolts didnt line up. So I pulled out a spare N/A 13b waterpump from an 88, and it looks identical to what I removed. I also found that the top flange of the water pmp housing had three bolts instead of the 2 from the GSLSE and the S4, so now I think it has an S5 water pump housing as well. but what does this new pump even go to?? Will I encounter any other issues if I pull the trigger on another FC gen waterpump?

 

I've converted the S4 housing to fit a 12A. The S4 housing has two bolts holding the T-Stat neck. I bet you have a S5 housing and the new pump you purchased is a 12A/13B first gen one.

 

It's a bummer I had to find out this way lol. I guess now I know for the future. Thanks for confirming my suspicions