I just tore down my motor and upon inspection of the rotor housing, there are scuff marks on the housing that seem to be normal. But there are also deeper scuff near the last 3-4mm next to the plate. There also some chrome flaking as well(1-2mm width) Prior to the tear down, my motor had very stable vacuum reading, idle well, ran strong, until the water seal blew out.

My question are, can the rotor housing be re-finish/re-chrome? Can someone post some picture of acceptable wear on rotor housing. How much do machine shop charge for resurfacing/lapping plates? Can any machine shop lap the plate or does it have to be a rotary shop? I figure most rotary shop contract the work out anyways?


My plan are to just disassemble, clean, replace needed part; oil control rings, coolant rings, resurface the plates, clean up the ports, and put back to stock.

Thanks, Jay

 

 

Has that motor been sitting around?

 

Yes, the motor sat aroung for fout month before I got a chance to tear it out.

 

You definitely have some cleaning ahead of you

I'd recommend thoroughly cleaning the rotor housings, then take some pics and post them. We can't tell you too much with the pics you've shown us.

 

Okay, i finally had some time to do some cleaning on my rotor housings. Upon inspection of the front rotor housing, i discovered some pitting that seems close to the inner coolant seal. My motor suffered from coolant seal leak and this seem to be the only spot that my have caused it.
Please take a took at some of these photos and tell me if the hosuings are still usable. There are not deep gouges or anything, just normal wear marks, some chrome flaking, and rust build ups. The pitting mentioned earlier, are from the area near the spark plug holes, pitting on both side at the same area.

Rear hosuing







flaking

 

Front housing


wear markingPitting. After watching Bruce Turrentine video, he mentioned that pits can be repaired with epoxy? Would JB weld work?
Pitting depth from working chamber
the other side
looks like Grand Canyon

 

 

Wow, that is some REALLY bad pitting. I've only heard of repairing minor pits for better sealing, that looks like complete loss of the metal in that area. The difference being if the JB weld does not bond properly or fails, the seal could leak. On a minor repair it's not so crucial.

Have you checked around the spark plugs or exhaust ports in the coolant channels? If the pitting is that bad there, I'd imagine there may be other places that are failing. Check out this link: http://mazdatrix.com/faq/rotorhsg.htm

I've repaired used housings using JB weld with no problems and 25k and that seems to be the choice of most major builders... but that was for small irregulaities in the surface, not a lack of metal altogether.

There is also a spec for flaking width but I can't find it now.

 

Before chroming, do some major cleaning bro

 

It was a bad idea to let it sit that long with coolant o-ring failure....I wouldnt use either one of those rotor housings in an FD build. In my opinion, they're doorstops.

 

Dang, I spent 20 mins scrubbing those darn things. I was going to sand the mating surface area with 400 grit sand paper, but I should fill the pits with some JB weld first.

 

When my motor popped, I was depress and had no motivation to work on my car. Then the second wind came after I had chat with a local engine builder. He told me that the motor will rust if left untouched. The first thing that came to my mind was"Oh ****"

 

Do you really like the worry that will come with trying to repair those housings when there is better out there for sale cheap!

 

Cleaning those was time well spent because now you know what you're working with.

This is the kind of thinking you should have when inspecting internal engine parts. Not worth the risk. We know how much of a pain it is to pull a this motor in a stock engine bay, then replace all the gaskets involved, etc. Esp when you just had it apart...

If it fails again, you'll be thinking, "this was totally not worth the $500-$1200 i saved."

 

I'm just trying to explore every option that's aviable to me, I have better things to do with my money then just to spent it on my car. Don't get me wrong I love my car but the economy sucks......

As for the rotor housing surface, how does it look for a motor with 75k miles. When I was seperating the plates, I did notice a lot of sand like build ups. Is it metal/aluminum erosion? I flush my coolant every 2 years and fill it with 30/70 mix.

 

I know, but it's false economy to cut corners.

I don't have alot of experience pulling apart FD motors (mostly FC's), but it looks mediocre. Chrome flaking on the edge like that is pretty run of the mill for higher mileage housings I've seen.

The deposits and corrosion could have been from the previous owner neglecting coolant, lack of corrosion inhibitors from the thin mix, or impure water... or a combination of those things.

I always use 50/50 with distilled water. Tap or well water can have some nasty **** in it.

 

Based on your last post, I'd recommend flushing your coolant every year and switching to a 50/50 mix. This is what I do and I've never had any of that crud floating around my cooling system