why: s4 water pump housing is aluminum, its a bunch lighter



how to tell: s4 has a 2 bolt thermostat neck, s5 is 3. s5 is usable, s4 is easier



what you need:



s4 water pump housing

s4 water pump

s4 or s5 water pump pulley

s4 or s5 alternator bracket

s4 or s5 air pump brackets, if needed

water pump housing to engine gasket (n386-15-162)

heli coil kit

silicon



what you need to fix:

the s4 lower alternator bracket bolt goes all the way thru to the engine, the 85 and earlier cars do not. it will leak if you dont do something, plus there are no threads in the water pump housing. this is what the helicoil is for. i think the stock bolt is 10x1.25 (could be wrong here), so you put a helicoil in the front and pack the rest of the bolt hole with silicon. or you could weld it and tap the weld.



the second issue is the coolant hose nipple on the rear of the water pump, if you are using the efi, or have a gsl-se just keep using it. if not this is a good place to mount a sender for an aftermarket guage. it should just tap right out.



the third is the water temp sensor, again if you're efi you need it if you're carbed, you can leave it there or buy a pipe plug.



the fb thermostat neck will bolt on the s4 water pump housing, so you can use your stock upper radiator hoses with no problems.



lower hose goes right on



you need the s4 water pump pulley, as the fb one is not deep enough



alternator, you need the s4 adjuster bracket, to put the alternator on.



the air pump is a bitch! if you gotta keep it it looks as if you need the t2 airpump bracket to get the thing to fit. the air pump physically hits the gsl-se intake manifold with the na air pump bracket

Just to add a few tidbits of into here. The bolts are 8mm x 1.25. You can tap the alt bracket hole for 10mm x 1.25 or 10mm x 1.5. These are common Mazda sizes. Personally, I'd go with 10mm x 1.5 because it is the same thread pitch as the starter to tranny bolts and front cover to front mount. Mazda chose this thread pitch for bolts going into aluminum.



My SC friend and I have done two S4 waterpumps on an R5 13B and a GSL-SE engine for Atkins SC swaps. Both had threads cut to accept bolts and they don't leak. A little drilling of the S4/S5 alt bracket and cast iron waterpump (impeller part) is required to allow the bolt to pass through and into the aluminum.



Yep, thread the aluminum and use a 10mm x 1.5 bolt of appropriate length.

Nice...since I'm the weight Nazi this is awesome! I'll have to look for S4 parts in the junkyard!

I kind of thought there were fan flange problems here largely due to the nose of the S4 pulley being larger diameter than the old ones. I made am adapter plate for mine, but the bolts are really close around it.

Does the S4 fan fit? It wouldn't on my car, but I've got other fitment issues.

I've got an entire S4 assembly (or two) kicking around for anyone who wants to do the conversion.

Bring em to rotorfest and I'll probably get one off ya. What would you want for it?

oh yea thats the other thing, the stock fb fan will not fit! the fc one looks like it should, i took out the studs though so i cant actually try it

We will finger it out when we get there.



I'll bring a few.