91 N/A vert. So my wife was driving and called saying the car ran funny and died when she took it out of gear. drove it to the shop on 1 rotor and did a compression test, front rotor lost an apex seal. Using a boroscope I tried to look as well as I could at what happened, The seal is still there but looks like it has flipped 90 degrees. I can move it with a pick so its not stuck, it looks as if it has worn down to the point that it was the same width as it is deep allowing it to rotate. I tried to check the walls with a mirror on the end of the scope but cannot see anything clearly. 2 questsions
1. Is it possible or normal for an appex seal to wear enough to beable to turn in the rotor? I have about 110k on the odometer.
2. Do you think it is worth rebuilding or do you think that it has destroyed the rotor and housing?

 

Here is a few pics.

https://www.dropbox.com/s/4wzsx6t6veofaoh/Seal1.JPG
https://www.dropbox.com/s/ubmxmcdw3zymhcv/Seal2.JPG
the bad one https://www.dropbox.com/s/r3cn021pakfjad7/Seal3.JPG

 

1. Yes, that happens from time to time, usually because seal gaps get too large. However if it was still running there's almost no chance the seal that first lost your compression is actually still in the motor.

2. That is fairly subjective, but it likely destroyed the rotor and housing. A tear down will allow you to assess that properly.

edit: just saw your pics, I think what you're looking at is the inner piece of the apex seal, meaning you've lost the outer 'half'. The original apex seals in these were 3 piece.

 

Didnt even think of that, so I for sure shot it out the exhaust. Have you ever seen an apex seal go without killing the rotor? By gaps getting too large you mean the seal clearance in the rotor correct? Once the clearance is beyond spec the only thing to do is replace the rotor right? no sleeve kits or anything to narrow the gap?

 

Normal Apex seal is 2mm wide. Some people machine them out to 3mm. Usually it's for high boost applications.
I don't see why it wouldn't work out for you though, provided that your groove is out of spec.



Stock seals are three piece:
-a tiny triangle piece that's near the corner seal
-a lower piece that's more towards the center of the apex seal
-an upper piece that rides along the rotor housing wall.

However, I believe the wear that we're concerned with is the height of the apex seal. (The distance between the edge that rubs the rotor housing wall and the edge that sits in the rotor towards apex seal springs.)

Because that upper portion rides against the rotor housing wall, it wears down. Eventually, it's not tall enough and comes out of the groove, then the lower part of the seal (What we think you're seeing) sticks out.



Best case scenario, it fell out of the exhaust port and didn't harm anything. Rebuild the engine with all new seals and drive on...

Worst case scenario, it bounced around and broke up inside the engine. The sharp iron pieces gouged up the inside of the rotor housing.


Try looking in the exhaust port by removing your header or exhaust manifold. You'll be able to see more there.

Also, remove your exhaust and try dumping it on the floor, you may find the broken piece of seal there.

 

Thanks for the tip, ill pull the exhaust manifold first when i pull the engine to get a head start on parts. can anyone give me their opinion on this housing please?

Mazda RX 7 RX7 86 88 13B Engine Rotor Housing Non Turbo NA | eBay

 

I had an apex seal Crack and it was still there and didnt do damage to the housing. You gotta take it apart to know for sure.

 

US spec S4 engines have the spark plugs in a different place, so its not a good idea in an S5.

 

so im looking into parts lists and trying to order tonight. Has anyone seen and new lists since the one in the archives? if not im going to base off of that.

 

Buy the latest stuff that works. If you do both housings you can go S6 if you want even if you stay NA. Turbo seals also, two piece apexes instead of three. That being said, if you need a new rotor housing (just one), than get one from the same series that you have. IMO, do both housings if you're popping for a kit. You might find a decent set for sale here on the forum.

Also, I think you will need a rotor too if you have thrown a seal.

 

I wouldnt order anything until you take the engine apart and actually see what you need to replace first.
I only needed apex seals, all rubber seals, and a gasket kit.
But i also had two motors to use parts from
One engine rolled a apex seal and trashed the housings and rotors
The other cracked the front iron and had a coolant seal groove failure
So between the two i barely needed anything.
just check so you dont waste money.
Its really not hard to pull an engine apart and measure

 

I plan to pull it out tomorrow and tear it down sunday, hoping to build next saturday and install sunday. Anyone familiar with Atkins shipping times?

 

I imagine whatever time they say it will take to arrive will be accurate, Atkins is very reputable. I and many others use their products, I just don't particularly remember how fast they shipped things to me.

 

I got all my parts through atkins
It was about a week in wait, im sure you could pay for faster shipping tho
then i had to wait a week more cus they sent me the wrong front cover gasket/oring
so make sure you specify if you have a large hole s5 style with teflon encapsulated oring or small hole s4 style with just a rubber oring

I'd still measure everything to make sure its usable before you order
your most likely going to need at least one rotor and maybe a housing

 

well im pulling the engine tonight, not sure if i will get to the tear down but ill post pics tomorrow.

 

K got it out and completely torn down. The pictures i took with my phone suck but the seal did score the housing, and it looks like the corner seal is welded to the rotor.... I cannot see any real damage on the front or center iron but I want to post some high res pictures and get people opinions. Heres a link to what pictures came out ok.
https://plus.google.com/photos/10047...CIKTuJCtr-qcUA

 

Irons look usable. No way to really know until you measure for step wear and warpage tho
Id say find another housing, but ive seen people reuse worse.
Definitely clean up the rotors and check to see how bad that one is. prolly gonna need another one tho

 

Alright so the cleaning is in progress, taking pics as I go and freaking out now cuz i found more damage. heres some pics of the front iron, there is a missing section of the coolant seal outer edge. Is it possible to use this still? I know the coolant seal is pretty tightly wound on the inner edge, does this still condemn the iron?
https://lh5.googleusercontent.com/-N...-42-09_576.jpg

 

https://lh3.googleusercontent.com/-y...-41-57_949.jpg
https://lh3.googleusercontent.com/-o...-42-33_885.jpg

 

that needs to be replaced, it'll use coolant for sure

 

not what i wanted to hear lol. going to have a machine shop look at it in the morning and see if they think its repairable

 

They'd have to carefully weld a new ridge in then machine it. I'm 99% sure you'll be better off buying another iron.

 

Ok well here are pics of the front rotor and housing after cleaning up a little bit, pretty sure rotor is smoked but not sure on the housing.
https://lh5.googleusercontent.com/-Q...-11-22_976.jpg
https://lh5.googleusercontent.com/-A...-11-45_972.jpg
https://lh5.googleusercontent.com/-G...-12-22_932.jpg
https://lh5.googleusercontent.com/-3...-12-47_770.jpg
and the housing.....
https://lh4.googleusercontent.com/-O...1-24-32_13.jpg
https://lh4.googleusercontent.com/-I...-24-44_498.jpg
https://lh6.googleusercontent.com/-a...-25-01_269.jpg
https://lh4.googleusercontent.com/-z...-25-25_106.jpg
https://lh5.googleusercontent.com/-g...-25-37_671.jpg
this pic was with flash so the finish looks a little funny but you can see scratch depth.
https://lh3.googleusercontent.com/-M...-26-44_259.jpg

 

If anyone is selling the front half of an s5 block please pm me or email me at mint87rx7@gmail.com
I need to get this thing running asap.

The rear looks perfect to me so i wont bother posting pics

 

Rule of thumb: if your fingernail can catch on the scratch, the housing is trashed.

That iron will have to be replaced as well. The seals are holding in combustion pressure, not just pressure from the coolant system. That amount of missing material will cause a new seal to blow out the first time that motor is started.

Rotor is gone too , obviously.

Your best bet is to go find a u-pull-it yard that has an FC. They're somewhat common. They usually charge around $150 for complete engines and chances are good you'll get good front housing parts as they tend to fail far more often on the rear.

Going rate for a S5 housing, iron and rotor will probably be $250-350 here on the forums.