This:
https://www.rx7club.com/2nd-generati...-shims-955417/

Re-installing my S5, saw the reference to shims in the FSM. I do not think shims were on the WP upon removal, and I was very careful, but there's a chance I missed them.

WP seems to fit perfectly with new gasket (Atkins kit) with no shims. Atkins kit does not come with shims.

any guidance for me? shims or no shims?

 

i wouldn't worry about it, some people think the shims are super important and that you may break an ear without them and others haven't seen any issues on engines without them.

then there are others who say the s5 never came with them, while i have seen them on every series of engine.

 

My S5 had no shims.

 

The shim is only required if you use a water pump gasket. A piece of gasket material works in a pinch.

If you use silicone, use no shim.

If you are using an RX-8 front cover gasket, don't cut any of it off, use the whole thing. The top-right corner of it acts as the shim.

 

thanks much - I'll loosen & re-torque the fittings to make sure they are not over-tight (this must be the main reaosn behind people breaking ears and shattering pumps) and call it a day.

 

i have seen engines without them but use them on my cars. better safe than sorry IMO.

 

Mazdatrix lists 74-88 Water Pump Housing Shim for $1.46. It doesn't list any for the S5. I assume they are they same, but I would call them to be sure. For that cheap, it would be silly to not use them and risk the chance of something happening.

Fan Clutches, Water Pumps, Thermostats, Belts, Pulleys

 

if you look in the parts catalog there is no shim on an S5.

if you physically look at S4 vs S5 parts, you will see that the S4 water pump housing and iron are machined flat, and "need" the shim to compensate for the water pump gasket.

the S5 parts are NOT flat, off the top i'm not sure if its the iron or the water pump housing, but they are not machined flat, so it effectively has the shim built in.

its really easy to check, its almost visible

 

i've checked numerous irons and never noticed a machining difference between S4 and S5 front irons. they all appear to be machined perfectly flat to me.

 

I have an S5 water pump housing that I can check. This is good info to know.