something about RA seals and O ring kits
 

somehow my mechanic told me that recently in my country, there are 4 rebuilds done using RA Seals and O Ring Kits...by one of our quite famous rebuilder in my country..

here's his findings...

1) the scratch mark on the Rotor housing and the side housing is very deep, it can't even be re-used again for the next rebuild. the symtom was low compression value.

2) the O ring kits failed. the main water jacket which was supplied in round cross section, after some time under pressure and heat, the jacket deformed to look like a oval shape (cross section). and the 2 corner of the oval shape tend to crack. already 3rd car in this month suffering same situation.

unlike mazda original O rings which is a square cross section o ring.



my question is

1- in the US market.... what brand of O ring kits are having the similiar design like mazda;s square cross section ?

2- does using full synt motor oil helps to reduce these kind of wear in the rotor housing?

i'm pretty sure only mazda makes the square water seals. someone correct me if im wrong.

i don't have any experience with the RA seals, but i did just install the round type viton seals that pineapple racing makes.

i have RA apex seals on my turbo II engine for 5 years and the only problem i had with the motor it self that the rear plate cracked. but still was making compression. but before the rear plate cracked, i check the compression like a week before that and it was still around 80 psi. of course i didnt used the orings,( i think they didnt offer them 5 years ago) my self i dont know about having probelm with them. i just rebuild my new 3rd gen engine with them pretty much the same setup. i say O rings, go for mazda one. i wouldnt try anybody elses apex seals well thats your decition and what tipe of used you going to put them at

well during those five years RA could have changed the alloy they used for their seals. just to keep that in mind.

80 PSI ain't that good, Ive seen no less than 5 FOB JDM motors in the 95-105PSI range

Pineapple HD coolant seals, I have used these in many builds in the last 6 months or so:

http://www.pineappleracing.com/index...PROD&ProdID=99

Idemitsu rotary-specific synthetic oil (2nd pic down):

http://www.rx7.com/store/rx7/fdengine_maintenance.html

The Idemitsu won't help the gouges in the rotor housings though......

Ive seen a couple engines torn down around 10-15k miles with the RA 3mm unbreakables and the housings werent reusable. I might still have some sitting in the garage and I will snap a couple pics if I still have them. They did hold up to a lot of abuse on a car that was trapping just shy of 100mph in the 1/8th mile but the housings did get gouged badly, got to the point where the engine would not hotstart somewhere around 12-15k miles. They didnt break though:)

yeah... indeed the seals didn't break.... the compression losses after around 3 years...when they were doing the rebuild, the housing were not usable..due to the gouges....

as for the water o rings... the outer shell of the teflon encapsulated o rings.. when that cracks.. it will fail... that's the cause of the RA 's o ring kit failure.

i was wondering the pineapple o ring.... are they round or square like mazda ? are they like RA's encapsulated with Teflon.. or it's a plain Viton large o ring ?

pineapple: viton, large, round

The RA o-rings are garbage. They don't fit well and we have seen too many failures. So far we haven't had any issues wit the Pineapple viton o-ring kits. The are round but appear to fit better than the RA. We always use Hylomar on the coolant o-rings to ensure they stay put and seal.

pineapple just recommends crisco or petroleum jelly. hylomar is pretty messy + expensive and its carcinogenic too :( health tip of the day!

The problem with those is they cause the o-rings to swell, so you have to put the motor together right away. I didn't know about the health hazards though.

great.... next if my coolant seals broke.. i'll get pineapple O ring kits...
either that or mazda coolant seals... but mazda coolant seals cost a big boom in my country... i'll take into consideration...

seems like pineapple carries mazda 2mm 2 piece apex seal...they are mazda afterall... maybe they won't cause gouges marks like the ones RA did to the housing.....

the moment i talk about this.... my O Rings are giving in ....
it's just around a year..... and it has already given in....

after a hard drive.... and i come back home pop the hood.. i hear my spare tank is bubbling... i was like F!#K

even before it cools down.. the coolant pipe already lost the pressure.. gone into the spare tank.. and i can open the filler cap witout much water in it..
i pour it in ....
after it cooled down.. i tried restarting the engine... water coming out of my exhaust....

i'm screwed....but the car is still drivable... even on idle.. i warm it up till 80 degrees.... the water doesn't get less.. but i think when i drive it hard.. it gives way to pressure...

some has RA seals for 3 years... mine only 1 yearrrrrrrrrrrrrr

I dont really understand why there is a NEED for better coolant seals than oem. Mazda has spent somewhere around 20 years and millions of dollars of R&D in arriving at the composition and design of parts they use in their rotary engine. Can we honestly sit here and think that some small budget, backyard operation is going to improve on this engineering?

Sure, there are times when the aftermarket makes improvements in power, handling, etc. because they can sell parts with no limitations, meanwhile the factory has to design parts that produce low NVH, have an acceptable cost for the manufacturer, pass emissions and safety regulations, allow the car to have ideal driveability and get decent gas mileage, etc.

And of course there are times when race-only situations demand completely redesigned parts that are superior in that respect to the oem parts that were not designed with racing in mind.

The FD engine uses the same stock coolant seals as all the other 86+ rotaries. Some of these rotaries have gone as far as 375k miles (documented by a one owner of an s5 nonturbo coupe who used it as a commuter car and maintained it himself by the maintenance book) on the original coolant seals. The seals are not the problem in these cars...the rest of the setup is.

There is too much heat generated over a period of time, and not enough places for it to transfer/escape. This is why coolant seals degrade more quickly, apex seals wear more quickly, and turbochargers are lucky to last more than 50k miles at a time. IN other less stressful applications, all of these individual parts can last 3 or 4 times as long.

Turbo II's which run less boost pressure and less CFM out of the turbo, a more conservative tune, and used a mechanical cooling fan instead of a 225* cooling fan switch, can ROUTINELY make it past 125k on the original engine/turbo. All of the internal seals and springs, except for corner seal springs, are identical to what the FD uses.

NA's which run no boost pressure at all can routinely make it past 175-200k, again on the same seals.

Does anyone see a pattern here?

I personally have no problem with oem coolant seals. We know they always fit perfectly and seal tightly if installed properly during the build. We know they were designed specifically for this engine, and not simply an o-ring for another application picked off a shelf because it is about the same size. We know that if the setup is ideal and proper heat transfer properties and tuning are applied, they can last a very long time.

i wonder if anyone has converted a FD to mechanical fans?

guess i'll be going back to OEM water seals