TweakGames

iTrader: (3)

Ok so here is the story, looking for opinions on what happened to 1/4th of this lovely engine. :P

Drove out to my drift event, everything was fine. 2 days before I went from a T04S, to a PT67, had the boost set SOLID SOLID at 10 psi. (Normally I would run 11 (with boost spikes to 12 on the TO4S.) When I say solid solid, I mean my boost controller is powered by C02, and if I set it to 10 I get 10, not 10.5, not 10.3, not 9.8, 10. Also my boost gauge (prosport) has peak and hold, and after the day ended the way it did, I looked at the peak, and sure enough, 10. My ARFs were still perfect and super safe. I think 10 psi from t04s and pt67 is not much of a change.)

My day was doing great, the drifting was just starting to get warm, people were getting used to the track, was great. My car was a happy 7 drifting around the track like an angry older sister that just got news that her younger brother read her diary over the schools speaker system. That was until my 8th run.

On my 8th run, everything was still going great, I smelled a little fuel, but like the fellow rx7 owner in my passenger seat said, "Isn't that what all rx7s smell like?" lol. I took off on my 8th run, hit the first banked right corner, boost hit late, but it hit, then suddenly NO power. lol. I put the clutch in (mid drift) and watch the tach drop down and hold at 1k, knew it wasn't blown, and finished the run still drifting hehe.

I get back to the pits, and I see that my 4 layer flex coupler exploded.
(I cut off the other side, to use for the quick temp fix so I could get home, but you can see what happened.)


When I dynoed the car a couple months ago I had a different coupler blow in a different part of the system also. (I have t-bolt clamps, so they never blow off, they just blow up lol.)


I let the car cool down for a good 15-20 minutes, as I just let the car idle while I loaded up all my tires and all the crap in my mobile rx7 repair center lol. Don't lie, you have one too. :P Also I just switched from a water cooled, to oil only, so I am over cautious. Everything was fine, car idled fine, great response (unable to get into boost for obvious reasons.)

Got back into the car, and limped it home (30 mins highway) where I got in my g/fs volvo and went out to home depot in search of a temp fix to get me home. Got the temp PVC pipe, installed it, and went for a test drive. Everything seemed well, boost was coming on, a little buck or miss at .7 psi (where my transision to secondaries is) but all in all fine. Right before I got back to the g/fs house, one last pull to make sure everything was fine, the temp pvc pipes couplers slipped off. (Had to use regular clamps for the temp) I tightened them down and started on my trip home. (2 hours highway)

Driving home, I noticed that there was a miss or something going on at the transition problem, but I stayed out of boost most the time. I noticed actually that the transition skip was getting less and less as I drove. Maybe I was getting used to it, but I think by the time I got home I didn't notice it.

Got home, put on a real replacement 90* coupler, and went for a test drive. Car wasn't the most happy it has ever been, but it wasn't bad. No shaking engine or anything, just the same transition problem, and a slightly weird idle. I thought maybe the spark plugs needed changed or something (and I was late for class that morning) so I started my 3 hour highway drive to college lol.

As I went, this time the transition was getting worse and worse, and my ARFs were getting richer and richer. As they got richer (About 2 hours into the drive) I started to notice it because the car was missing randomly just cruising. Normally I am 14 afr cruising, instead I was 13.5, then 13, then 12.5, then high 11, and the car was getting REALLY hard to keep accelerating. The 13.5-11 was over a good hour of driving. I limped it the last few minutes into town and shut her down. Still hoping it was just really bad spark plugs I took it to schucks and changed em. At this point, the car was very hard to start (but I have a lot of experience starting blown engine lol), it idled at 500 rpm, and shook like veteran meth addict that just went cold turkey. I pulled the spark plugs, cranked it over and listened. I actually had some pretty even pulses, no puff puff .... puff ... puff puff. I did compression test and got 10 10 60 front rotor (compression tester was horrid lol)

Anyways, had my car towed home by an awesome friend. Took the engine apart this morning and saw this. (2 blown side seals, and 2 cracked corner seals.)

You can see where the side seals are gone and the exhaust got in.








Top corner seal cracked:


Left corner seal cracked:


Here is a pretty high quality video of the above. In the picture above its hard to see, but the left, and top corners seals were both cracked. You can see that in the video.

http://files.filefront.com/crackedco.../fileinfo.html

There is NO MARKS, ANYWHERE, on the engine. ALL my plates, all my housings, all my rotors, are perfectly clean. Where did the side seals go? How did they get out? I DID notice when taking the engine apart, one of the needle bearings at one point got semi squished, but somehow worked it way out and was fine. All the bearings were fine, and working fine, just at one point it got tightened down with the bearing out of place. I never had any metal in my oil plug. (magnet)

I also noticed that I had some (enough to pinch it and squish all the oil out of it) paper/cardboard (I am going to guess from my oil filter) stuck to the bottom of my oil pickup. No more paper oil filters for me. :/ The oil pickup was definitely not blocked bad at all though. Could easily pick it up on the sides, the paper was only stuck to the filter in the direct center.

Let me know what you think.
A. The rotary gods hate me.
B. Something flew in my engine while I drove home NA from the drift.
C. The semi crushed but working needle bearing caused something.
D. I set the clearance for the side seals incorrectly.
E. The corner seals broke leaving extra much space for the side seal to move and let pressure pass slowly breaking it off.
F. The side seals broke first breaking the corner seal somehow.
G. Just unlucky or something else caused it. (please explain)


Thanks
~Tweak

mono4lamar

iTrader: (32)

Did Brian build the motor? Possibly the side seal clearance wasn't correct. If Brian did then I won't question it at all. I just think it's strange that the corner seal cracked like that and how the side seal is following it...

TweakGames

iTrader: (3)

BDC did NOT build this motor. I built it all myself (from the looks at it, incorrectly lol) I have built 3 other engines in the past, each running strong and great. But I just daily drive them. He just did the porting. Yes I think it was really weird also. Weird that it does it 6 months after running fine. lol.

Here is an idea. What if I didn't clearance the side seals enough? This is by FAR the hardest I have drove the car, and definitely the hottest I have got the engine. If the side seals were in there too tight, would they expand and put pressure on the corner seals cracking them? Then once they crack, there is too much space slowly breaking away the side seal. :/

I really doubt that the exploded, or blown off coupler would have caused this. I would think a apex would blow much sooner than a side seal if it was caused by improper combustion. Also, when a coupler blows off, doesn't it just go super rich for that engine cycle while it realizes the massive boost lose? Wouldn't that be like just snapping the throttle closed quickly?

BDC

I still think it's foreign object damage related to the broken coupler. That's my guess. It's all in one corner, if I'm understanding this correctly, of one rotor. Is that right?

TweakGames

iTrader: (3)

It's actually 2 sides as far away from each other as you can in a triangle at least. Here I will circle where the side seals are missing.

BDC

Yep I'm still thinking FOD.

B

TweakGames

iTrader: (3)

Yeeeeeuppp, looks like you nailed it.

I found some scraches on the inside of the rotors, AND some nicks out of the top of the primary port on the front rotor's side. :/ Dang it. I wish I could learn a single lesson an easy way instead of a hard way.

The video showing the scratches on the rotor, but not the primary port. If someone wants to see that let me know, I can go back and out and take a video easily.
http://files.filefront.com/rebuild2r.../fileinfo.html

Thanks.

Monkman33

iTrader: (28)

Think when the coupler blew, that the turbo over spun, and then a piece of the compressor wheel may have broken off and subsequently gotten ingested?

TweakGames

iTrader: (3)

Going to go check the turbo.

Here is a video of the primary port on the blown side seal side. You can see where something got stuck between the port and the rotor or something like that. :/

http://files.filefront.com/portnotch.../fileinfo.html

(Update : Checked compressor wheel, everything is good. Thanks for the tip.)

BluRR

iTrader: (1)

I guess maybe its something you ingested after the coupler blew and were driving to th gf's house without the coupler. Some kind of road debris or something.

mono4lamar

iTrader: (32)

I'm skeptical about it being debris. If it were an NA car with a broken coupler I could see it. With a rip in intercooler piping it's realistically only going to relieve pressure when boosting "boost leak." Someone will probably argue that the engine will suck debris through that rip, but just like everything else in the world, everything follows the path of least resistance. The engine will still ingest its necessary amount of air via the compressor inlet of the turbo.

I'm not going to say its normal but every motor I've taken apart usually has some sort of marking on the rotors. Whether it be the side seal corner area in the combustion chamber or the area nearing the apex seal.

Check out your turbine wheel, if there was ANY foreign debris it will make it's mark right there...

TweakGames

iTrader: (3)

Hehe, I think you might have missed the first picture, the one with a 6 inch huge gash in the coupler that opened up wider than that girl Candy will for $50. Let me just say the rip was so bad that I couldn't even make a .5 psi of boost after it blew (or on the drive home) even if I tried.

This was a coupler that was connected to the throttle body elbow, AFTER the intercooler, not before it. Why would you think it's different on an NA engine, than a turbo engine that has basically been turned into an NA without a filter? Yes it will still suck in all the air it needs, but having the turbo and intercooler, and air filter would cause more resistance on that side, there would be less resistance pulling it out of the gash in the flexible coupler. I don't understand the logic behind that at all. Please explain.

After looking at the rotor more closely, the busted corner seals (I have never even heard of them ever breaking), the marks on the top of the ports that match that side of the rotor, it all adds up, something got stuck between the primary ports, and the rotor on its way up. All my apex seals are perfectly fine nothing wrong anywhere else. There are 0 marks on the rear rotor. If you still don't think so, please look at the high quality videos. They really speak for themselves.

BUT, if you don't think something got sucked in (small road rock, some metal shavings flying around my engine bay, anything), what do you think happened? What could take out two side seals and 2 corner seals on one side but leave the apex seals, and the whole other side of the rotor / engine happy?

Thank you for your opinion, I want to make it clear that I am open to hear any theory, obviously there is no way to know for sure, but could you please explain your theory more clearly? I don't quite understand what you mean on most of it.

~Tweak

dpf22

I have seen side seal grooves become deformed. It is also possible that if this motor is ported that for some reason or another the side seal was vibrating along the edges of the intake port as it dropped in and then receded. This could cause the side seal to break off and fall into the intake port, then get sucked in and ingested, then digested through the turbo or wastegate tube thusly poof, you have your disappeared side seal.
Just a hypothesis though. I have no idea what port you have so I'm just throwing this out there. I know those side seals don't like to bend sideways much without breaking.

What was your side seal clearance?

RacerXtreme7

iTrader: (2)

I'm going to go with over ported intakes. Every side seal that is broken is the leading edge. If the ports were over ported (the area where the open side and closing side meet specifically), even with a smooth ramp up, the side seals still goes through a fluttering motion and will work harden the seals causeing fratures like you have. As dpf22 pointed out, the fractured peices could have gotten into the intake port, then got sucked/blown into the combustion chamber then out the engine it went leaving some scoring marks in the housings / on the rotor and missing side seals pieces. I realy dont see how FOD could cause side seal damage like that, more often then not it crunches apex seals/rotor housings/rotor faces.

Over ported intakes/and or not clearanced properly side seals or both.

EDIT: I just realised BDC did the porting, so it's not as likely that they are over ported, but its still possible.

~Mike...........

mono4lamar

iTrader: (32)

I'm not sure how much more in depth I can go. Your theory about the compressor cover and filter being more restrictive can be dispelled in two ways...

One being that people have dynoed with and without an air filter on their compressor cover and shown no difference in power.

Two the turbine wheel is driven by exhaust, likewise the turbine wheel will promote airflow through the intercooler piping air will more than likely follow it's path through the filter than through the hole in your coupler. Furthermore, it's more likely to push air out of that hole than to pull it in (the whole NA to turbo "theory" I have).

Now, we can do one of two things. I can ask you if you remember what your side seal clearance was and if you recorded them (blueprinting). Or you can pull off your turbine housing and check out the turbine wheel for the "foreign" debris. If you want to hold any water with your theory of something going into the engine and causing the damage you will only be able to prove it with that. There's no way something went through the engine without going out and hitting those blades.

I will also ask you to make sure you have every corner plug counted and every side seal piece counted to make sure they did not leave through the exhaust port. Honestly pull that turbine cover so we can get something concrete and stop building of all of our theories

BDC

^^^ I agree even though I still think it's foreign object damage.

B

AnthonyNYC

iTrader: (3)

I've seen nicks on the top of the port when the port is too big. When you see that, it's usually the side seal passing over the open port and then transitioning back to metal. The nicks should look like almost a very shallow grove and diagonal going upwards to a 45deg angle. The nick is usually just 1/8-1/4 of an inch.

Take a pic of the nicks you are talking about on the port. There are a few simple ways to check to see if it is the port itself, PM me and I'll explain it if you think you need to.

I highly doubt BDC would make a porting mistake. Did you touch the ports at all after it was ported?

Anthony

crispeed

Were you on the rev limiter for any extended time?

silverfdturbo6port

iTrader: (26)

damn dude thats shitty be sure to keep us posted, get that turbo apart and see if it tore the turbine up. it is possible porting had something to do with this but very very unlikely.

AlexG13B

iTrader: (7)

wow thats sucks man

TweakGames

iTrader: (3)

I have a video posted above of the nicks.
No, I would never ruin a port job by touching it after BDC did his work.

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No, I never have hit the rev limiter (7,500 rpm) even at the dyno. (Only went to 6,800 when I thought I was at 7000.) My friend rob took the engine the highest it has ever been, ~7200 because he didn't know I was not going to take this engine that high.

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Here are some pictures of the primary ports before and after BDC. I know BDC didn't port them too big, he only took the tiny RE primary ports and opened them up to stock S5 turbo size.

BEFORE:







AFTER:





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If it was the port size being too big, would it have happened 5000+ miles later on the build? Wouldn't it have happened on my 3 dyno pulls or all the times I have passed people WOT? The dyno was the hardest on my car by far.

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Yes, it is darn near making me want to sell it all and go LS1. SOOOO close.

AnthonyNYC

iTrader: (3)

It's hard to say but I don't think it's the ports looking at the pics. I don't see the nics that I had when it happened to me. A while long time ago I was naive and bought a set of irons that were ported already. The port was slightly overported in a very small area, about 1/2 inch. It took a while to break but it did and when it did, it had the same symptoms as yours. I did not break any corner seals though. I don't see any of the markings that I saw on mine so I would think it's something else and not the porting.

TweakGames

iTrader: (3)

Those pictures AFTER, are showing the before and after of the BDC port job. The video I posted above are the only documentation I have (I am back in college) of the damage to the rotor and nicks on the plates. So again, the pictures above do not show the nicks, that was just to show that the port job was not crazy or anything.

arghx

iTrader: (3)

J-rat, a veteran 25+ psi guy here, once told me to stay away from all angled couplers, and I have religiously done so.

AnthonyNYC

iTrader: (3)

OK I understand now. I just saw that video.

I took a few screen captures from the video to get a better idea of what happened. From my experience, it looks to me the side seal is making contact with the port but I would get other opinions...