I recently bought some used S5 housings to rebuild my old 87 NA, I have a few questions reguarding their condition.
First, both housings have had their pitch diffusers ground out.
As seen here:


And here:


As you can see from the pictures, there is some material missing from the edge of the exaust port. As these housings are going to be street-ported, do I need to have these replaced?


Secondly, one of the housings seems to have some iron deposits encrusted in the water jacket. This stuff blows off easily with a brass brush on a dremel tool but I cannot get into everywhere with it. Should I have it ultrasonically cleaned? Phosphoric acid perhaps?

Here's a pic or the deposits:


And lastly, the same housing pictured above has a few pockmarks in the water jacket. The worst of them is pictured below.


Are any of these issues an area of concern?

 

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*tumbleweed rolls by*

 

**cougf cough

 

That happens when you get the diffusers out of the NA sleeves...the inside edge is molded a little differently than the turbo sleeves which are flat, and when you grind the old diffuser out, you're left with a little metal missing there. I would be perfectly content with that, the NA is never going to be a rocketship anyway so it is not such a big deal as if it were a 500rwhp single turbo FD or something. Just make sure not to remove too much material from the actual port right adjacent to the sleeve...you don't want to expose the front edge of the sleeve as a restriction to flow, so leave enough material on the port to let the air glide right over top and out the sleeve. You can usually take off 1-2mm right adjacent to the sleeve, and then ramp it out as necessary the further toward the inside you go.




Blow out what you can with pressure washing and then compressed air and leave the rest be. It will not harm anything. Most used housings have some form of light buildup and it never presents a problem.



As long as it doesn't protrude closer than 1mm to the coolant seal mating area it is of no concern. You can look at the housing once clean and clearly see the iner and outer coolant seal mating area on used housings. Light pitting around both of these (that helps identify where the seals actually resided) is normal and acceptable. Any heavy pitting that looks like it could encroach on a seal later on can be filled in with jb stick weld or similar. In an area such as what you pictured, it is of no concern at all.

This is what happens when coolant is neglected, or too much water is run with no corrosion protectant (coolant).

As for the very light pits on the surface of used housings, that is why I use a light coat of sealant on the rotorhousings during assembly. IT fills in any of the pits that might cause a sealing problem.