Howard Coleman

iTrader: (6)

O K, maybe the title is a bit over the top as, of course, some rotor housings and rotors highest and best use would be a mantle piece or boat anchor but for many FD owners there is some good news among the skyrocketing price action...

my FD turned TWENTY this month and for most FDs (the 93s) a similar celebration will be in order during the next 12 months.

consider our FDs are turbo'd, are getting elderly, and Mazda no longer makes the engine.

that's a formula for crazy pricing looking forward.

looking backward, a rotor housing in 2004 retailed for $384.

today, $864.

tomorrow?

there is some good news. a number of people are working on the re-chroming process. i am optimistic that in a while many of the trashed housings will be able to be rehabbed.

nearer term, we have the diamond honing process. both Goopy and Pettit offer the service which is around $125-150 per housing. i have used the service on many of the motors i build, including my own. you end up w a straight, repeat straight, surface that mates well w the apex seal. there are numerous housings i would not have used that have been brought back into excellent service.

here's a set...



done properly, you end up w a cross hatched pattern that mates well w the apex seal



another high cost area that often needs replacement is the rotor. rotors are now over $700 new. many rotors become unservicable just from mileage. the apex seal groove opens to the point where there is too much combustion leakage between rotor faces. in addition, this leakage is very high heat and takes the arch out of the apex seal springs which causes chatter and ruined rotor housings.

the only save is to mill the grooves out for 3 MM seals. this is costly and extremely hard to do properly. even if accomplished you end up w a very heavy seal that hammers the housing.

but help is on the way for many many rotors....

the stock apex seal is .075 in width.

the old fix, the 3 mm, is .1125 in width!

that is sort of like using a 3 pound hammer to drive a thumb tack.

the problem is typically 2 or 3 additional thousandths of groove wear.

solution:

a .079 inch apex seal! why didn't i think of that.

Goopy Performance did and currently offers such a seal.

here's the Goopy seal:



here's a stock seal:



you can do a couple of things w the mini-over-sized seal.

if your car has the original rotors and you have lots of slop from normal wear, say 5 thou, instead of either throwing the rotors away or butchering them w 3 mms and paying a bunch of money for the process, you can just slip in a set of oversized seals and you now have really good compression/sealing.

or, if you are working w newish rotors and are trying to make max power you can file fit the seals to one and a half thou.

for instance:



don't forget the corner seal groove:



we are fortunate that we have vendors that take a serious interest in our small fleet of 20 year old potential supercars.

howard

CrispyRX7

iTrader: (139)

Amen Howard. Amen.
Would you care to attest to the apex seal material used by Goopy?

FWIW I have used the rehoning process and have had multiple housings saved that were just suffering from wear but that had no chrome flaking/chipping. (Shameless plug follows) In fact I have two for sale right now.

Regards,
Crispy

thewird

iTrader: (8)

So what exactly is new in this post? Goopy has offered both of those things for years and there are other posts on the forum about it.

thewird

vrx8

iTrader: (18)

^ + 1 I learn something new.... I didn't know the housing price in 04

dguy

iTrader: (8)

I'm somewhat active, have had over a decade of experience with rotaries, and am currently looking to rebuild an FD (read: I'm checking out what the new **** is). I hadn't heard about Pettits rotor housing refinishing, or even of Goopy. It's ok to not be a kneejerk *******, really.

bumpstart

+1 .. used the goopy oversize seals to save some rare MDR 12a rotors
... have also put a few people onto them seals , the oversize bolts and the hone process
.. one of those has already survived a 28 psi overboost !!

lots of surprises in the goopy development camp ,, jack and jon have some very original ideas and exceptional machine work skills
.. oversize and also reproduction 10a rotor bearings another innovation

SA3R

I guess the oversized seals is a bit like honing a worn standard piston engine bore and then gapping and using .010 thou over rings to gain the lost compression back.

When the time comes, this is what I'll do. I dont think I'll need the housing hone though. I have extra housings tucked away.
I've been reading and learning about the role the side seals play, specifically with the diagonal slip joint. Tricky Mazda engineers. That .020 thou accounts for the side seal crush, which pushes the side seal up the diagonal cut, to meet the surface of the rotor housing, while sealing on the ends. Simple fix to a complicated problem.

JWteknix

iTrader: (2)

the stuff Goopy does is amazing. not really new, hes been doing it for years. if ur from the Tristate I'd recommend dropping by his shop he's the nicest guy And loves to talk. I currently building my 4th motor from Goopy this one will be making about 600whp and is gonna be bridged. Jonathon is porting the plates and its all done by machine, the ports look serious. Ive used most of his products including his oversized bolts and seals with no issue. my first motor build ever before the motor was even ran net 140psi compression cold with resurfaced housings, solid corners and oversized seals.
This guys magic

RX7Zamboni

JWteknix
where is goopy located

thewird

iTrader: (8)

@RX7Zamboni Contact | Goopy Performance

Yah, Jonathan is awesome. I caught a pic of him the other day...



thewird

KNONFS

iTrader: (14)

I don't remember the rotor housings being that cheap, me thinks that you are missing $300 bucks on your number

Reno_NVFD

iTrader: (2)

Im still new to the rotary world, Ive had my FD for a little over a year now, and my notor was recently rebuilt but should I be looking to buy a spare set of housing and rotors to aviod the "tomorrow" prices? What do all you engine builders see as far as the future of being able to get good parts?

indio84

iTrader: (7)

goopy FTW

jmm8904

iTrader: (19)

I think KNONFS is right I bought new housing from Mazda in 2001 and they were like $700 each if I remember right.

EjCabrera

iTrader: (4)

I bought a pair of brand new housings from pineapple racing in 2006 for $1270 so thats $635 each. $384 must be he hookup price