I recently bought an 84 GSL with a 4-port 13B and Holley 600 setup. I plan on swapping the engine, tranny, and other bits into my 12A GSL but am curious about the motor. I know it was built years ago, so relatively fresh, but nothing else. I know it's a 4-port with those holes into the water jacket that I've blocked off on the housings. It doesn't have any apparent EGR fitting on the intermediate housing, so I figure it's either a S5 block or a 70's engine. Any idea how I'd figure out what it is? I'm also curious of the compression ratio, but I imagine I'd have to know what rotors are in it. Any help?

 

pics?

 

if the water pump housing is cast iron it probably isn't a S5.

 

I'm stuck in Kansas while the car's in Atlanta. I can put up pics in 2 weeks. So without an EGR it's either S5 or 70s, and if the WP housing is plastic, it's S5? What about finding out if it's TurboII rotors (I suspect a TII block) or NA?

 

No, on the S5's the water pump housing was alluminum rather than cast iron like the 1st gen ones.

 

and the turbo II engines came without the egr valve on top of the engine

 

I was told that all S5 engines came without the EGR. If it's obvious, then I don't have it. The top of the intermediate housing is clean, but it could be a S5 NA, TII, or 70s block. Anyone know what RX-4, Cosmo, and REPU 13B blocks looked like or if they were different from S4 and S5 blocks?

 

Yeah, and yes.

 

So how would I tell an RX-4, Cosmo, or REPU engine apart from others? How are they different?

 

Well, I think you have an S4 or S5 Turbo engine.

The ports are pretty big compared to a 12A engine. The Turbo engine would also have an oil return into the front cover.

The 70's engine would have "MAZDA" on the rotor housings in a different and Large font than we are used to.

 

Like this



Here's the link. BTW, this is in the FAQ.

 

can the s5 aluminum water pump housing be swapped on to a 12a? i hate how my iron one is rusting...looks like ****.

 

I think I have TII plates too, but I'm not sure of the internals. The original owner put a full RB setup on it, from the Holley 650 to the 4-port manifold, heat shield, RB SP exhaust and stripped engine bay. With all the money he paid the builder, I wonder if it's only got TII rotors. Wish there was a way to tell. I guess good compression would mean NA rotors, low compression could be either a tired motor or TII rotors. Any idea what a warmed up engine would put out for static compression for S5 NA vs TII?

 

Might be an import japanese motor

 

not directly, the aluminium housing has an additional bolt that goes through it to the front cover that the cast iron unit does not.

so to retrofit the aluminium housing you need to plug the hole in it for the extra through bolt, which messes up the waterpump mounting, because the waterpump changed too, to reflect the difference of the changed bolt.

the iron housing has a bolt NEAR where the aluminium has the through bolt, so the waterpumps are not interchangable either.

{ I know this because I AM retrofitting an aluminium housing to take the place of my iron unit. I had to have a helicoil installed in the outer end of the bolthole, so the waterpump will still bolt on there, and am going to have the inner end welded closed, so it doesn't leak. I also removed the air pump, and am moving the alternator to the side of the engine to reduce the load on the housing, so it won't leak. }

it would be easier to paint your iron housing

 

cool thanks for the info honegod. =)

 

I guess you could cut threads in the aluminum waterpump housing and even the waterpump. Make them 10mm x 1.25 and you'll be able to use common Mazda 14mm head bolts. Simply drill the alternator bracket hole slightly larger so the bolt fits through it and you're in business. That hole is already large enough for an 8mm bolt (12mm head). All it needs is a slightly larger hole.

The alt can stay in its home. This is how it's been done succesfully around here with Atkins Camden SC installations on pre '85 engines. You need to use the '86 and later aluminum waterpump housings with the SC kit due to the idler pulley and et cetera.

 

you can put a helicoil in the fc water pump and then it bolts right on

 

I particularly like the drilling the hole in the housing out for a 10mmx1.25 bolt.

the original hole is slightly too large for a 8x1.25 helicoil, the insert has not much engagement, too little to make me happy for securing the alternator adjuster bracket.

retapping to 10mm solves that.

on the other hand, at the other end of that hole the aluminium housing loses a bit of gasket surface because of the hole.
that is a major chunk of why I want it welded, to build the seal surface back up in that spot.

plus, the hump inside the water channel for the bolt ends rather harshly, creating a spot of turbulance, I figure to grind the hump down to smooth the exit of the water from the housing into the block, a lump of weld will let me blend it all together smoothly.