Hi I went to goopy to get my rotor housings done. These are some pics I took when I got them back.
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They're almost too pretty to use. I just wanna polish them up and love on em'!

 

impressive

 

a perfect work!

 

Do you have any pictures of before? I have some rotors housing with some scouring that was pretty bad. no gouges from when the apex was ejected, but lots of grooves going around and around.

 

Goopy has some before and after photos. This coming is actually coming up in the world. It's pretty cheap to have your housing redone from them. I am very impressed with their work. I've seen some scared housings they managed to fix. I forgot the thread that showed what they did.

 

i'm mainly curious as to how long they last, as they machine the chrome layer thinner which will inevitably cause it to flake off quicker.

 

Isn't there a guy on here that resurfaces them and then puts a plasma coating on them or something to that effect?

 

I was thinking the same. Also i Recently I saw the goopy crew in a car meet and they also bore out rotors and install their own larger rotor bearings for spun rotors.

 

Honestly i dont see a problem if they'd only go 50k. Goopy is extending the life of what was more than likely a crap house set of housings.

 

The rotor housings from 86 and newer had less chrome on the surface and chipped less, now the 85 and older 13B or 12A housings have a thicker chrome layer and chrome flakes off them while the rest of the housing chrome is near perfect.

either way its an inexpensive solution that saves parts that would otherwise go to the trash..

We should all thumbs up any idea that keeps these parts on the road

 

I don't know what their chroming process is, but without the microchannels and pores that Mazda uses scratch marks or chatter marks will occur at an accelerated rate. That doesn't mean it won't get the job done. Liberal use of premix will help offset the higher amount of friction.

 

i had mine done hopefully itll be running tomorrow..

 

Judge ito, who is one of the most knowledgeable engine builders in the east coast built another engine with this process and got 140PSI of compression using this service. These #s are hard to get with new rotor housings .

he put it on the other forum rotary car club.
http://rotarycarclub.com/rotary_foru...ad.php?t=12967

 

so basically the housing is lapped in a way. That explains the flat/matte look to them. That's definitely an alternative way of doing things. It should get the job done for most applications here.

 

not really true. early 12A 6mm carbon seal engines had literally almost no chrome, it was paper thin. later 12A and early 13B truck engines had thick chrome liners for the 3mm cast iron apex seals because they would tend to chatter. 13B/BT housings were similar in thickness as the later model 12A engines. later on with the 13B-REW and S5 the chrome process was altered to harden to chrome further which helped prevent chrome flaking.

i never said it was a bad idea, nor that the housings would otherwise be garbage as i have been looking into a milling process similar to what goopy is doing but i just wanted to get more definitive results before bothering.

if we all jumped on the bandwagon of everything new, well, we have already seen the results of the cermet coated housings by JHB that generally lasted all of only a few cranks of the engine yet they still sold those as a marketable item.

 

even if it lasts 15-20k on a high powered engine (assuming the motor doesn't fail for some other reason), how many years is that? 2-4 years at least, because how many guys put 12 or 15k miles a year on a heavily modified old sports car with bad gas mileage? But I don't like marketing hype.

Don't kid yourself, this is vastly inferior to buying a new housing. Mazda published several papers which discuss the chroming and manufacturing process of the housings (PM me if interested). They have it down to a science as far as figuring out the channels and pores in the chrome and maximizing the retention of the oil film to reduce friction. But that doesn't mean the Goopy service work work; it doesn't mean you shouldn't use the service if it suits your application and budget.

 

that's my main point, which is what can/should be expected of the resurfaced housings logevity wise from a rebuilder's perspective. i generally do still aim for 100k miles from a stock rebuild and 50k from high performance builds. my current engine has about 70k miles on it with used shell motor parts that now have close to 200k miles total and still runs fine, would it have done the same with resurfaced housings? well that i'm not sure and probably will only know by trying.

the big question is how thin do they take the chrome and do they have a way of accurately measuring the thickness. the worse the housing obviously the shorter the lifespan will be after resurfacing, so deep scarring is still really salvaging the housings? well it will buy some time but still not as much as finding decent used replacements for the same cost. it will however generate more initial compression but for how long.

 

A stock car with oil drippers is vastly different than a modified premixed car in how the housings wear. On premixed cars I put a cross hatch on brand new rotor housings and get instant higher compression on rebuilds and with the sharp corner ground off arround the combustion/exhast edges of the housing the chrome is much less prone to flaking from expansion and contraction.

In my opinion (modified premixer) the mazda coating is crap. The pores get peened shut quickly and you end up with a shiny surface that cant retain anything other than your reflection while your looking at it.

 

Here is my .02 cents

Whatever the lifespan of these ground housings are I would think is relative to the apex seals used. Lifespan could be increased with a soft apex seal like als or rxparts. I'm unfamiliar with the nature of goopy seals, they may also be soft? Even if said soft seals wore out in say 20k miles, if purchasing a shorter lifespan seal meant increasing the lifespan of these ground housings than it sounds ideal to me to run the softest seals to get the maximum life out of the OEM like surface.. as opposed to running something like RA seals

 

for me personally, as long as the lapped housings last atleast 10k miles on a high hp build, its good for me. I put less then 1.5k miles a year. They say so themselves they havent had a engine with their lapped housing with thousands of miles yet.

$200/pair for lapped housing, compared to what new housing cost....seems like a good deal, as long as it last anyways.
I will ship my housings to them when I start on my rebuild.

 

it looks alright but I still see marks on it.

Will it work? I guess. its still smoother than a used housing with all the flaking/chatter marks/cracks.

but if longevity is not your main concern (and money is an issue) then its not a bad idea I guess.

Maybe I should send my housing to them and see what sup.

I bought new housings and its ported already (by Brian @ BDC) but it's always good to do a side-by-side comparison.

 

i think you are all missing the boat with honing
-bead blasted-

and they look AOK from here ,, and well worth the expense

 

These look great. I'm going to send them my housings I thought were trashed.

 

some minor grooving is still to be expected unless the housings have low mileage. taking the minor scars out completely would leave basically no chrome liner left. if there is gouging from the corner apex seal boot all the way to the steel sleeve, it will still be present after machining but not nearly as stout and deep which is what causes lower compression figures on high mileage rebuilt engines.

i've already done dozens of practice runs and know what to expect from the liners.

best i can do for a before and after comparison for now as i was mainly just trying to get the procedure perfected, a housing i previously would have classified as unusable would now be very usable except that example had a big chrome chunk missing out of picture as it was in the junk pile due to very excessive chattering(which also cleaned up):
https://www.rx7club.com/vendor-classifieds-276/rotor-housing-resurfacing-services-957625/