I was doing final assembly, got to the middle iron and noticed corrosion. I have no clue when or how it got there. At first I thought it was damaged when I knocked the iron over and onto some tools while putting the front rotor in.

After closer inspection and even testing a bad iron by pushing it over onto the same tools. I found that it wasn't damaged when it fell over. The only thing I can think is that I sprayed all the parts off on Sunday. After sitting for almost 2 years they had gotten dusty, spider nests, etc.

I tried cleaning the surface with some paint thinner but it won't come off. I can feel the marks with my finger. Obviously I'm concerned how they will affect compression?







My thoughts are that they must be from hosing the parts off a couple days ago. I did not coat them with anything afterwards I was expecting to do the rebuild Sunday. It has to be recent, I can't believe that I'd miss something like that.

 

I would try to scotchbright them with oil and see how they clean up

 

Not much compression goin on in that area last time I checked. Ive seen way worse go in engines and each time better results than I expected. On your budget Id rock them without a second thought.

It looks like its been there a while and your just noticing.

Just out of curiosity, what cleaner did you use?

 

What is the application--what are your goals with this engine?

 

I"m concerned that those spots will wear the side seals and in that way affect compression.

The irons and housings I simply sprayed down with water. Washed cobwebs and such out of the coolant passages. I sanded down all the gasket surfaces and that sort of thing. I also used some acetone and paint thinner to re-clean the water seal grooves on the irons.

Over the long term I put a light coat of wd-40 on everything. After re-cleaning Sunday I didn't put anything on anything. Assembly was supposed to happen
Sunday. Something came up and that didn't happen. Then I was going to do it Monday and found two of inner coolant seals were cracked.

Here's a link to the cracked seal thread
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/inner-water-jacket-seal-cracked-959887/

I quit for the day waiting to talk to Atkins about the seals. On Tues Atkins walked me through how to patch the seals and I proceeded with assembly. Then I saw the corrosion marks. I'm thinking that it was a pitted area and when I washed everything off and left it was win the pitted area got corroded.

When I knocked the middle iron over it fell on two of those bars that hold sockets. With the corrosion following a straight line pattern I thought the iron fell on the bar long ways.

Sorry I should have included that, It's a S5 13B turbo. IIRC the suspect area will be on the rear housing/rotor. My goals for the engine are mild and OEM. My build is in my signature. I'm expecting to be able to max out the OEM turbo capabilities at 12 psi. Down the road I may upgrade a spare S5 turbo to a hybrid, but don't see me goin wild with it. Probably just a BNR stage 1.

 

most of that isn't anywhere near the seal tracks, so you don't need to worry.