Is it torn down? Pick-chars?

 

not yet, i got everything ready to pull the motor last night, a couple fellow rotorheads are coming to help me lift it out of the engine bay tonight, i will probably just let the shop tear it down and decide what happened. I'll see if u can be there and get some pics

 

I think it would be quite handy to have someone at the teardown and get some pics. Good to know 1st hand what happened to your motor. Beats getting handed a dented rotor and the claim it was just plain ole' detonation.

 

The likelyhood that the builder will find any wrong doing on his/her part is slim to none. Here's how it will go. The builder will show you some damaged parts and say "see detonation caused this" You can't prove him wrong (a fact not lost on the builder) he'll use some big words, little razzle dazzle and before you know it you'll be paying for them to build you a new one. And before the next driving season is out this senario will play out again. I would take boost creeps advice and take your motor to your builder with a camera, document the whole disassembly make sure you got what you paid for inside the motor. There is a whole host of poor craftsmanship issues that could "look" like detonation (again don't think the builder is unaware of this).

 

Earlier you mentioned that a side seal let go. I assumed that you had already taken the engine apart. How do you know a side seal is at fault?

 

Does it matter what happend to the engine? A blown motor by any other name is still a blown motor. A bee could have flown in the intake. I've seen crazier things happen.

I dont think who built it is important. I think a builder standing by his work is more important.

Some builders build better engines. Some stand by their work.

 

Huh? What does that mean?

It's not important to understand what caused the failure? Uh OK

Nobody has asked who built the motor, and to my knowledge knowbody has said this is specifically a failure due to the engine build quality. Just talking about what the potential causes of the failure could be so they can be avoided in the future, this includes but is not limited to the quality of the engine build.

I don't know maybe it's just me but when I blew my motor those many years ago I wanted to know exactly why it went so that mistake couldnt be made again. I generally like to learn from my mistakes. Sounds like Alak would like us all to repeat them? Weird.

 

It doesn't matter to me what happened to the engine nor did I ever inquire as to who built the engine - it could have been built by a monkey with incorrectly clearanced parts or mismatched rotors for all that I care. It's not my engine. However, Smitter diagnosed the problem as a blown side seal without opening the engine up and I was wondering how he came to that conclusion. Personally I think the untuned map he was using is the cause of his engine failure and as others here have suggested the result should be a blown apex seal. Obviously after all this discussion a number of guys are curious as to what the final diagnosis is.

As for the last comment, I got rid of my old RX7 because even though the builder was standing behind his work it was all that time it spent going back again and again to get the same shitty results that frustrated me. I would have gladly taken a correctly built engine with no need to go back again. However that's ancient history now and not relevant to Smitters case unless he is having similar issues.

P.S. You'll have to send me the link to the "Killer Bee" blown engine. To the best of my knowledge bee parts wouldn't make it much further than the front of the air filter.

 

The bee was a joke lol. You guys take everything so serious around here.

You guys are right though, Its important to find out how the engine blew so the results wont be repeated. I know that from personal experience in my shoddy wiring.

But heres the thing. He states where he got it tuned. You guys jump all over the tuner and his way of things. Car worked fine for a year or however long.

You might find out who built it and then jump all over his way of things. Even if it worked fine for a year or however long.

Could have been anything that attributed to the blown engine. As far as Im concerned, after a year or however long, Its nobody's fault. And yet, I think its funny everyone comes out of the woodworks when theres a possible blame to be placed on someones way of buisiness.

I dont blame you, I'd have it out against someone if they screwed me around.

Problem is, people know where not to go, but they dont know where to go.

 

Im sure by now you've read my post, you'll twist my words in some way and etc. showing your absolute zealous rightousness over whatever it was we were talking about. What were we talking about? The title said something about tony looking for someone to tune his Power FC.

If this keeps going on, we'll all be doomed!

http://www.youtube.com/watch?v=fqcn_TPu4qQ

 

I still get the impression that you still believe altitude played a part when it is not possible using the Speed Density Method and a MAP sensor. Is it because you don't know the relationship between pressure and density? Lets start with a few basics:

Denser air has more o2 than less dense air.
Pressurized air is denser than unpressurized air.

You with me so far?

Now at sea level the air is at 14.7 psi of pressure and the air is at maximum density

At 18,000 feet the air pressure is approx 7.3 psi and the air is less dense

The reason there is more O2 at sea level is because the air is under more pressure (14.7 psi vs. 7.3 psi)

If you went up to 18,000 ft and then pressurized the air to 14.7 psi the 02 content would be exactly the same as the 02 content at sea level.

Still with me?

Now let's say your turbo is set to make 10 psi of boost at sea level which is 24.7 psi absolute pressure (pressure of the air at sea level plus the extra 10 psi the turbo adds) Your boost gauge will read 10 psi but your map sensor will read 24.7 psi.

Now go up to 18,000 feet. Since your boost gauge is referenced to sea level it will need 7.4 psi of boost from the turbo just to get the gauge to register 0 psi. To get the boost gauge to read 10 psi you need 24.7 psi absolute pressure in the intake manifold as we showed earlier. So the boost controller will keep the turbo going until it pushes enough air in to reach this limit. In this case the turbo has to add 17.4 psi (24.7 minus 7.3 psi air pressure). Obviously the turbo is working much harder now to keep up but at least the intake manifold pressure will actually be exactly the same as when you had 10 psi at sea level. Thus the 02 level will be exactly the same.

Now if your EMS was adding fuel based on your boost gauge it would be seeing readings all over the map and would only be correct at sea level. Fortunately though our cars use the handy MAP sensor. It's only reading the actual pressure in the manifold regardless of altitude and since it's referenced to absolute 0 you have no worries. The right amount of fuel is injected and everything is happy.

The other variable that can affect air density is temperature but fortunately our cars also have air temp sensors that compensate for that as well.

Does this clear things up for you?

 

He never stated where he got the car tuned. In fact he said that he didn't have the car tuned at all. All he said was that he was given a map from a car that had similar modifications. That is not tuning by any stretch of the imagination.

 

You mean where he got "a map from a similar car"

About a year or so......but how many KM's? I put just over 25,000kms on my car this year in the first part of the season and went through two engines. In my experience whether build quality is a concern or whether its a tuning or engine control issue it doesn't mean the thing will pop the first time out. Something needs to be severly wrong for an engine to blow the first time out (like say, with 300km's on it when it pops in vaccum while cruising.......cuz yeah - I've done that )

I'm just curious as to the real failure here. I don't care about who did it and pointing fingers because that does nothing to solving the issue in the future. I had presumed he'd torn the engine down since it seemed as though that was case. Being that he indicated its a side seal.

I'm sure I'm not as curious as Smitter in this case, but nonetheless, that doesn't mean that we can't discuss the failure and possible causes whether they be from an engine build standpoint or otherwise. Its just discussion.

 

See this is the type of thinking in the rotary world that chaps my ***

A properly built, tuned, and supported motor should have NO issue runing for longer than a year, regardless of whether you drive to a town thats lower in altitude. What a sad day it is for us rotary owners when we throw a party for anyone who can get more than a year of use out of their motor.

Again I don't know who built the motor, don't care. I never read who tuned it, don't really care. I what smitter and others to understand why this motor had such a typical rotary life for our area so it can be avoided in the future.

 

Obviously there's a lot of history here and although it tends to bring out strong opinions on either side, I don't think we should be afraid of it. In my mind on a open forum people should be able to express their opinions reasonably. Personally, I saved a lot of money years ago because a few people warned me. I am so gratefull! Instead of a blown engine after 20k (as what happened to friend), I have the same rebuilt engine from 02' still putting 10-15k a year. Regardless of loyalties or who built what, it doesn't matter because I have the proof for myself in my drive-way. Frankly I was shocked a few years ago when the old owner of this forum got involved and threatened people who had legit complaints.... but anyways. Some people like to ice skate up hill, some people don't, just let people decide for themselves.

Anyway...


The moral of the story is: there is no one. Browsing the engine management forum, the prevailing opinion is repeated weekly: get the stand-alone that your tuner recommends and can tune. Now too late, either make sure that Kahn tuning session happens, learn yourself, or go outside of Calgary.

 

Sounds to me your still running around the can and not being straight up even after you made the remark.

And thanks soloracer, i didnt know that at the same PSI (absolute pressure) you have the exact same amount of 02 in the air. I still dont know if this is true, sounds difficult to achieve. But who knows, ill do some more of my own research too.

 

Ben I have been trying to decifer what happened here, please send me a PM with the information.

FWIW Flash you are absolutely right.

 

Although the point of this thread isn't about this, I'm glad I found this. This is actually not true. I spent 6 hours on his car. The first 5 were a complete waste bcause the base timing was actually retarted 15*. He was told however that I'd advanced it when in fact I didn't. I fixed it and zero'd it out properly. I showed two people (one was Carl Byck) how to zero timing on a Haltech and noticed it was off exactly 15* which then explained the way it was running low on power on the dyno and sluggishly around town. While still on the dyno, immediately thereafter, his first boost run went from 330rwhp to 374rwhp with nothing changed. The engine broke shortly after getting off the dyno. I should've known better back then not to keep running it hard due to the random and hard misfires. The cause of the blow-up I much later figured out was too hot of a plug for the load even though at the time I had no idea what it was.

 

There could have been a thousand possible causes of the engine going. Im sure everyone will take a look and all come to a common solution, which is fine. We'll learn from the infraction and move on. In a week, we'll forget this ever happend.

And your right TD07. I agree that a properly built and tuned engine should last a lifetime. I wish mine had, and Im sure alot of other folks had.

But I've seen properly dyno tuned and built engine's last mere weeks. And I've seen properly built, improperly tuned engines last 6 years and probably 100,000Miles of fierce, ungodly abuse. Its just the way the world of fortune works I guess.


So where were we?

So hes driving his car along and the engine blows. He takes a guess as to why, and hes wrong. You've stated why you think hes wrong, which is good that you've supported that thought. I tend to somewhat agree with the elevation theory being incorrect. He takes a guess that a side seal went, which is an educated guess. Depending on who built it, and with what parts, the builder probably said its unlikely an apex seal went. Considering the fact theres some really strong apex seals out there, its a possibility.

Or maybe he did a compression check and theres only one lost face of compression. *Shrug* Best guess at this point.

My Theory is bad gas. He had to fill somewhere between here and there. Sometimes you have no choice where to fill up and you just get that batch of bad gas.

 

...

 

....

...I'll be nice....

 

Sorry for the late response guys,
the reason i have concluded it is a side seal is from performing the poor mans compression test with a piston compression tester. 3 strong pulses on the front rotor, 2 pulses and a pause on the rear rotor. The motor had aproximately 8000kms on it since it was built for the 3rd time in 3yrs last year. I have gone through an engine every year since i bought my fd in 2005, car was completly stock then and i took out the stock engine the following May because of my own newbism and stupidity. The second engine i had built was with 3mm seals and was at the time when i was introduced to this forum and my internet buddies soloracer & TD07 who have always had an objective opinion, which believe it or not i do appreciate.
The 3mm motor was a straight up pos. shitty cranking compression, hard starting and had a shortened life due to a side seal aswell. i am trying to find my documentation to see if it was in fact a rear seal aswell. I rebuilt the engine once again (at no monetary cost) going back to 2mm seals and it had been great , most fun i have had with my fd to date by far. i added the single turbo to it at this time aswell.

it is no secret who built the engines, to any of the local guys posting in this thread. i dont hold the builder accountable in anyway, he has always treated me well on a business and friendly level. I would chalk most of my hardships up to my lack of knowledge and bad luck. Although never being able to achieve a proper tune is probably my biggest issue.

we pulled the motor lastnight so its sitting on my garage floor waiting to be stripped to its short block state before taking it in for repair. What would u guys, Soloracer, TD07, Alak. Boost Creep & Rx72heaven(and whoever else would like to attend) think about coming by to pop the rear iron off to have a look for yourselves? then u can see first hand and voice your opinions??
I just ask if that is the case u try to keep an non biased opinion.

 

I'd be curious to see it myself. I'd like to see not only the damage but also the secondary intake porting as well. Side seals don't typically just blow up; there's a reason why that would've happened.

As far as an engine just happening to "let go", there's really no such thing. If the quality of the tune (the target air/fuel ratio and the lead and trail-split spark advance at whatever boost/rpm) is tip-top, then if an engine just happens to blow up, excluding any other possibility of foreign object damage, it will be because of the quality of the fuel. Everything has to do with cylinder pressure and chamber temps -- the type of fuel being used for the load has to be able to not only meet that load but also exceed it for the sake of having some fault tolerance. I was just explaining this to a customer yesterday -- in this community we're plagued with this practice of trying to make race car power on street car gas. The gas we use is inferior to how hard we're aspiring to push these engines. Ever wonder why ya hardly ever see anything blow up on race gas even though those cars make loads more power than most of us do?

B

 

Ben??? I dont know who Ben is Alex,

here is a link to the thread which i posted in the 3rd gen section that may give u guys a little more background on what happened. This was when i thought the problem was due to oil pressure & temps.

https://www.rx7club.com/showthread.p...rning+disaster

 

I would love to have your expertise there when the engine comes apart. Are u saing that the porting on the secondary intake could have something to due with a side seal failure?
I would like to blame the failure on bad fuel aswell, i did in fact have to fill up @ a shell in Swift Current, Saskatchewan.