Dom_C

Getting on the highway today I was giving it to her and everything was fine. Like 5psi in first, shifted into second and boost spiked to god knows what 15 plus psi. .this would be too big of a deal if I still had the stock turbo but I have a majestic turbos hybrid now. I have a walbro 255, rtek 1.7 with 750cc secondaries, stock intercooler. Anyhow I heard a funny noise, kind of eary thought it may have been detonation or something but the car still ran just fine so I kept driving. Pulled into a parking lot a few miles later and was leaking oil bad from up near the filter. Went home (bout 2 miles, still good oil pressure) and took it apart cleaned up all the oil and didn't see any cracks. Put it back together and had a friend start it for me and oil is leaking out from the seam between the rear iron and rear housing? What could I have broke . .the car ran fine on the way home, boosted fine and everything, idled, felt just as powerful. Could I have cracked my rear iron or did I just blow a seal or something? the oil pressure was normal, just above 60psi on the stock gauge .. Help me out please so I can know what to expect when I take it apart. Maybe just pull off the rear iron and replace soft seals and put it back together? the engine only has like 20k on a kevin landers rebuild. Thanks in advance
Dom

J-Rat

iTrader: (2)

I was under the impression that the S4s cracked in the vicinity of the oil fill tube area...

Hmm..

Carzy Driver

That thought popped into my head aswell... could be that you blew out an o-ring under the oil filter pedestal.

Dom_C

hmmm gives me a little hope. . any ideas. Is there an o-ring up there that I could have blown or somethng? I just don't understand. . if It detonated how loud would it have been? it wasn't very loud and wasn't like a bang or anything, kind of an odd kracklish noise Ithink. .I didn't pay too much attention to it because all the vitals were fine and it was still running fine.

Dom_C

nope, I popped off the oil filter pedistal .. checked everything. LIke I said the oil seaps from inbetween the rear iron and the rear housing ..comes out of the seam

Carzy Driver

I dunno, kinda got me with this one. Maybe RETed, Karack, or Kevin Landers will chime in.

Carzy Driver

Is there oil in your coolant?

Dom_C

I checked real quik and didn't see any. I'll check again in the AM but don't think so

RotaryEvolution

iTrader: (30)

nuh uh. i have an S4 rear iron which has about 4 cracks running straight out from the rear iron upper dowel pin area right below the oil filter pedestal, this is the weak point and why S5 and S6 have the rib there and a thicker casting though it is not a common failure.

as for this case you could have just blown out the o-ring but it is possible you cracked the iron but the cracks are barely visible.(in most cases the cracks are easily noticable though)

RotaryResurrection

iTrader: (8)

No, you won't have blown out the dowelpin o-ring. There's nowhere for it to go, after all...it's recessed into the rotor housing. Even if the oring hardens or cracks, you'll have a slow seep like old 12a's had, not a fast leak.

Whether or not you can see it, you've almost certainly cracked that bitch.

Here: http://www.rotaryresurrection.com/2n...ron_break.html

RotaryEvolution

iTrader: (30)

unless he rebuilt the engine and reused the o-ring, they do not like to reform to new conditions. had it happen on my own engine the second time i had it apart, live and learn, it had to come back apart anyways due to rotor housing cooling system issues.

MaczPayne

iTrader: (5)

I hope my s5 t2 block has that thicker casting....

RETed

Rear iron is done for.
I concur.

BTW, how big of a hybrid are you running?
Your fuel set-up will maybe handle 270 or 280 at the wheels.
That's not a very wide safety margin with something like a V-trim or larger!


-Ted

Dom_C

it's a majestic turbos hybrid. I'm not sure the exact specs but the site says it's good for 350hp. I bought it used so don't know much about it and the site doesn't go into any real detail about it. The crack definetly isn't external though. . the oil seeps out from between the housing and iron, so is the crack inside or something? Guess I'll never know till I pull it apart. Any more suggestions?

Dom_C

I know it's not too big of a hybrid because it still uses the stock compressor housing. it's just that the stock housing is bored out to accept a larger wheel. also has a clipped turbine wheel

Dom_C

also, how important is the knock control box. when pulling the harness I checked mine out and there is a crack in the circut board. Could this have had anything to do with it. I was under the impression that by the time that it detonates it's too late anyhow for the most part.

RETed

It's basically "useless".
The ECU totally ignores it after 4kRPM, and it is only useful for mild detonation.
If you detonate the engine hard, it will not save the motor.


-Ted

RotaryEvolution

iTrader: (30)

did they modify the wastegate on the turbo or did you have the boost controller cranked up?

Dom_C

that's the thing. I ported the wastegate. With the boost controller off of the car It would boost no higher that 7psi by redline and hold like 5 psi until 6000. The boost controller was turned almost all the way out. .thus turned down. It held 5psi through first and then spiked in second and went back down in third . .the boost controller has been acting like that ever sense I put the new turbo on. It's a dawes devices single stage MBC. That's what I contribute to the boost spike. I'm just trying to figure out where the crack is. . I can't see one. must be on the inside more . .

RotaryResurrection

iTrader: (8)

Even if by some chance there was no crack on the rear iron, the engine still has to come apart to replace the o-ring. So its a moot point in worrying about it now, is it not?

Dom_C

yea yea yea I know. . lol just postponing(sp) a bit.

mazdarick

Hey Dom,
Hate to say it, but guess what I just did to my car......Yup, cracked my rear iron too. Didn't realize it till my oil buzzer came on. Never lost oil pressure though, which is a good thing, but still think I may have lost an apex seal. Idling a little rougher. I'll know more once I get er torn down. Looks like we'll be building both our engines in my garage this winter. Sucks to be us.

Dom_C

Damn man, sorry to hear about that. Do the microtec logs tell you anything?

mazdarick

I shut off the engine too fast to even think of looking at them. Too late. Now I'm trying to decide on the ls1 or the 20b conversion. Still don't know what I want to do just yet. I don't know if it was just too much power, or a detonation or what. Oh well. We'll have a couple nice engines to work on this winter either way.

Dom_C

that's too bad about not being able to look at the logs. I poersonally think the 20b would be insane. . . but ls1 would be fun as well. we'll see.