Rx7Ridah

iTrader: (8)

alright so my second turbo motor in two years has cracked an apex seal and through it out i am now feed up with used and going to rebuild. my front rotor has great compression (110+) but my rear wasnt so lucky. okay here are my questions, first the rear housing has a very small scratch in it right above the exhaust port bout 2in long and probably 1mm deep, is the housing reusable? Secondly my rotor has a small chip in it right by the apex seal about 3mm long 1-2 mill deep, is that the end for that rotor (oh yeah the face has a small blemish near the compression dimple) and finally where can i get some good street port templates from i am looking for a decent sized street port as i am going to move up to a t04 60-1 p trim bb turbo in the very near future and would like to take advantage of this mishap. i am going to order a rebuild video (someone recommend a good one please) thanks to all, hopefully pics tomorrow.

RotaryResurrection

iTrader: (8)

Absolutely not.

Sounds reuseable to me. Take a small file, like an ignition file, to that apex tip. Try to keep it perfectly square when working inside the slot. Take one of your good apex seals left over and work until you get it sliding in and out smoothly like the rest of the slots. File down any burrs on the face smooth with the rest, and you should be good. Dents and scratches on the face of the rotor are of no real consequence unless it is very deep (more than 1.5mm).

Atkins, racing beat, mazdatrix, etc.

Atkins, rotaryaviation, rotaryresources...I think they're all the same thing, really.

Rx7Ridah

iTrader: (8)

thanks kevin, you wouldnt happen to have an extra turbo housing you would like to sell seperate from a complete motor would you?

RotaryResurrection

iTrader: (8)

I might have something I could sell, though I dont like to sell my stuff if I can help it.

Just to be sure, let's see a pic of your rotor and rotorhousing. The only time a groove is acceptable in a rotorhousing is when it's on the back edge, where the apex corner piece rides and causes a little flaking...that is normal. A groove or scar in the center of the housing is totaly unacceptable.

Rx7Ridah

iTrader: (8)

here are some pics i got around to taking today

Rx7Ridah

iTrader: (8)

more...

Rx7Ridah

iTrader: (8)

the more i look at it the more it hurts....

jhammons01

Your Camera focuses on the wrong thing every time. I can make out tiny grains of sand on your bedliner!!

GUITARJUNKIE28

kevin, i'm curious as to why you'd say the rotor housing would be unusable before you saw the pics? if the scratch isn't in the combustion area, what does it matter? just as long as it's not sharp. i mean it's not going to effect compression or the way the motor runs.

RotaryResurrection

iTrader: (8)

Your pics of the rotorhousing suck, but I still don't think I'd use it in one of my motors. unless it was just an emergency situation where time or money limited options.

Now that I look at the rotor, I think you could get by with filing it a bit and using it for 2mm, but if it were me, I'd mill to 3mm and be sure, all the while getting an upgrade. The one thing you want to be sure is that if any damage is on the very edge/corner of the face, that the side seal and corner seal slots havent been crushed in. You can mill an apex slot quite easily, but you can't really fix a side or corner seal slot accurately so if the seals won't fit in there properly without binding you'll want another rotor anyway.

Well, first and foremost, the odds are about 10:1 that the housing will be bad if a chunk of seal came out. Seriously, how many blown apex motors do you see with reuseable housings on the side that blew the seal?

Most of the time you'll have good size gouges around the exhaust port plus a few smaller ones where the trailing plughole is...these are the "closing points" of rotation, where the seal fragments will get pinched, as you well know. And, again, 90% of the time, the gouge usually consists of a low spot and a high spot. Any low OR high spot by the T plughole is trash; any high spot anywhere on the housing is also bad. Even though compression isnt created where most of the scarring occurs (by the exhaust port) the high spots make it VERY likely that the seal riding across will get odd wear patterns, resulting in a compression loss on the other side where the housing is smooth. Why take a chance, when used housings are floating around all day for 200 bucks or less?

As you probably well know, I'm all for reusing some parts and saving some money, but that's just too big a chance, IMO. The rotorhousing surface, along with the apex seal, is the very BASIS of compression in the engine, so the quality of housings used directly relates to how good the engine will be and how long it lasts.

RotaryEvolution

iTrader: (30)

i'd mill those rotors to 3MM also or find a good replacement, the gouge is too large for me to trust it, all of that heat would be blowtorching the apex seal in that spot and could cause a premature fracture in that area.

the pics of the housing suck but even out of focus they look trashed and unusable..

GUITARJUNKIE28

thanks for all that, but you didn't answer the question. obviously if it's scratched to hell you don't wanna use it no matter where it is, but a small nick over the exhaust port can be sanded down and used without negative consequences. again, we're not talking about the compression area--if that's not near-perfect, i don't use it, PERIOD.

RotaryEvolution

iTrader: (30)

better safe than sorry, most engine builders would not want to risk using a damaged housing and causing a premature failure. sanding down surfaces loses seal area which is what the apex seal relies on for cooling, especially after the combustion is finished. i try to only use rotor housings that have a nice even surface which reduces break in time and is less of a gamble for failures.

i would rather retrofit an n/a housing for a turbo than use a questionable turbo housing. if i have no good turbo housings available that is.


i know your question was for Kevin but for some reason i think his response is similar.

GUITARJUNKIE28

that's fine. my point was a small scratch above the exhaust port won't effect anything to the point where it would be noticable.

sure it's better to use brand new oem housings everytime, but not everyone has that kind of budget. i have to admit, i'm really a lot more bitchy about the housings i use for rebuilds than most people, but just because i WOULDN'T use something doesn't mean you COULDN'T.

point behind this is i've pulled apart some motors that maybe blew a coolant seal or whatever, but otherwise ran beautifully, and i was absolutely AMAZED at what the internals looked like.

Rx7Ridah

iTrader: (8)

okay.....anyway are the housing interchangable between n/a and turbo and s4,s5 and s6? i believe that i had read that they where but if you interchange the rotors you need to also use the approriate counterwieghts is that correct? i am thinking that i will just get a new (read used but reusable) housing and keep my eyes open for another rotor but will check into milling the ones i have out to 3mm.

RotaryResurrection

iTrader: (8)

You could use an s4 NA rotorhousing in an s4 turbo engine, as long as the NA housing is in the FRONT position on the engine...the rear housing must be a turbo, because the water feeds through the LIM and into the stock turbo. IF you're not running a stock turbo or if you're willing to pull water supply from another source, you can run an NA housing in either position or both on the turbo engine. OF course you have to modify the exhaust sleeve in the NA housings by either cutting out the diffuser or swapping the entire sleeve with your turbo housing.

You can mix and match s5 and s6 housings, but not s4 and s5/6 housings.

MARTIN

why not? whats the difference?

RotaryEvolution

iTrader: (30)

the spark plug locations are different in the S4 to the S5 housings because of the compression differences.


and you can use a n/a rotor housing in the rear if you drill out the water passage, both of my rotor housings in my car are n/a housings that i retrofitted to work and no problems whatsoever.

RotaryResurrection

iTrader: (8)

Don't question my authoritah, boy!



As mentioned above, the leading plughole is ina different location, so it wouldnt be ideal to mix and match the 2 timing/locations. I've heard of such engines going together and running fine, even in high power applications, but I still wouldn't take the chance personally.

RotaryEvolution

iTrader: (30)

well technically you could probably just change the timing to offset the plug locations but unless you're mister wizard and good at math i wouldn't want to risk detonation by advancing the timing too far.

and one other thing with n/a housings, i noticed not all turbo sleeves will fit in n/a housings, this was S4 to S4 as well. it's not tough to modify the sleeves anyways but this is just a FYI if you have never noticed it, the port flange is larger on the turbo sleeve than(some of) the n/a ones by about 3-4mm.

Rx7Ridah

iTrader: (8)

okay what about s6 housing in both, i have a friend that has a third gen that was in an engine fire and his insurance company is replacing the entire motor/harness/turbos and such?

RotaryResurrection

iTrader: (8)

s6 housings do not have any coolant passages for the turbo/lim. See above.

RotaryEvolution

iTrader: (30)

it's not tough to simply drill and auger out the port on the rear housing to feed coolant to the LIM, it would be much easier than porting out S4 and S5 housings IMO.

RotaryResurrection

iTrader: (8)

Porting out housings? you lost me on that. Why would you need to port a housing?

Drilling out the channel is no big deal, you're right. But it takes a bit more precision, something the average person couldn't do, to cut out that bevel edge for the o-ring to sit inside.

Mx6-Rx7 Addict

I swapped sleeves from both s4 and s5 TII housings into s4 NA housings. I beleive you are refering to the actual width of the sleeve? There was a spacer in the NA housing that i had to remove to make the sleeve fit in the housing.

The s4 NA sleeves are actually longer then the TII sleeves, making the turbo sleeve not flush with the housing by about 3-4 MM, unless removing this spacer.

That's what you mean right?
Sorry not enough sleep, can't really comprehend anything right now.


:edit: To the thread originator..

I'd go ahead and find some good used housings rather then chance that housing.
I'm sure it could be used, but just for the benefit of the doubt, i wouldn't risk another motor possibly failing prematurely.

I wouldn't use the rotor, unless you do mill it to 3MM.

That's just me though.

-Justin