MR2 broken

[custardavenger]

So it's 2 + 3 then. Looks the same as what I did mate with a bad map except you did it with two. My opinion is get the injectors tested and the rest of the fuel components. If it's not that then it has to be the map. Like I  said it would only take one cruise cell to be lean and you to have kept it there in the map for a nice long time to overheat the cylinder.

I guess you have to do what you have to to put the bottom end back together and get the engine running again. But I wouldn't run it till you can identify the cause.

What speed and gear were you cruising in? If you can remember you can get it on the dyno once built again and prove the map to a point.

[philster_d]

Motorway so 5th or 6th pushing along in light traffic (7:30am saturday m25)

[muffdan]

What's the head and valves like?

[custardavenger]

Ooh scratch that. looks like damage in 1,2+3.

You'd need to know the exactly which gear and what speed you were doing Phil.

I'm assuming the head and valves will be ok. They will need a clean to remove the molten Alu and the seats done again.

[markiii]

anyone spoken to Thor or MWR yet?

[Wabbitkilla]

Makes me wonder if the 700cc injectors are too big and the fuel is losing atomization as it goes through the inlet valves into the chamber. You could get hot spots caused by that in the same way a mapping problem can cause it.
Troubling problem and a huge shame considering the low number of miles it's done.

Can Rogue replace the pistons?
How are the bores, will they clean up?
What's the head & valves like?

[philster_d]

My baby!!!!! No!!!!!!!

Based on the first description I was thinking maybe you got a coolant bubble at the water pump which stopped coolant flow and caused the engine to overheat quickly. This is very common with recently assembled ZZ engines even if they appear to be operating normally. Always watch those coolant needles closely.


Looking at those pistons though it must have been running very lean and/or detonating. Damage usually happens on the exhaust side forst as seen in the pics. It's almost impossible to hurt a Wiseco piston without a huge detonation problem.
 

I've only heard of a couple people ever trying to run a ZZ with a Link so I can't be too much help. If you have a timing map you can post I can give it a look.

[ChrisGB]

Erosion like that can occur at really low power levels if combustion is too hot / too advanced. How do the plugs look?

A thought or two:

Injectors may be OK, but is the ECU firing them at the right time? What can happen is that if the ECU has the wrong injector sequence (or if the injectors are wired up in the wrong order), the fuel can be fired early then pools on the back of the valve. Atomisation is lost, you get "lumpy" mixture that is effectively lean due to the bigger droplets being too large to burn with the main charge.

As others have said, a dodgy cell in the timing or mixture map could do it.

Post MAF air leak or dodgy air metering calibration.

A pic of the head / plugs would be interesting.

Cooling circuit failure is possible too. If the middle two cylinders get hotter than the end two, that could cause the head to overheat. I am surprised that level of detonation was not audible in the car though.

Chris

[custardavenger]

Chris. Wouldn't the injector firing order be the same as the spark firing order (in normal single shot injection)?

[philster_d]

I had the top down so its noisy from the wind. I didnt hear something particular or different to usual.

[Wabbitkilla]

Trouble is it's a new engine with different from normal parts - only done a few miles so hard to say what's a normal noise and what's not!

[markiii]

Chris. Wouldn't the injector firing order be the same as the spark firing order (in normal single shot injection)?

it would if its was wired up correctly and teh ECU was setup correctly, one of these out could change that

I did notice when I first sore Phils car that it was running way way hotter than I would have expected but put that down to teh higher boost

2 Questions Phil

1. Did you ever get the leaky intercooler fixed?
2. What boost (Not power) levels were you running

[philster_d]

Yep fixed IC as part of the build. The mapping was done (and the boost control set) from .7 min to 1.4 bar max.

I was variing between the minimum .7 (general driving around) and about the half way mark or slightly over (booting it). Keeping it down because I was letting it all bed in.

Thor said they didnt go above 1.4 bar because it was getting too hot.

What about the link safety features? I thought that would kick in when it saw any trouble.

Phil

[markiii]

what are the link safety features?

[custardavenger]

Good point Mark.

Link safety features? Have they definitely been set up?

[philster_d]

Dont know. It was set up by Thor and they were directed by Rogue.

Matt at MWR says "It's almost 100% got to be the tune. "

[Curt]

Do you have any updated information? I passed on the links to this thread (as well as the one you posted on Spyderchat) to a couple of very experienced engine people to sollicit their thoughts. You might want to also post onto NewCelica.org where there are some other talented engine builders as well.
Inquiring minds want to know!

[philster_d]

Still waiting on Rogue. They were continuing to take it apart and then going on to price up the repairs.

Phil

[Curt]

Here are a couple of interesting threads on the Subaru Forum where ring end gap may have been the culprit:
http://forums.nasioc.com/forums/showthread.php?t=1790262
http://forums.nasioc.com/forums/showthread.php?t=1774841
I've also done a little searching over on that Forum, and there seems to be some conjecture or confusion about what the appropriate ring end gap measurement ought to be. Some say that Subaru recommends 0.004" (and I don't recall if that was a "factor" per inch of piston diameter, or interpreted by some as a total amount), where a more common factor figure is in the 0.005" to 0.006" per inch of diameter (and tending to be even a little more for serious FI).
A very knowledgeable automotive engineer suggested to me in regard to this issue that in these situations a good deal can be learned by studying the ends of the rings (even if the rings have broken into pieces). The objective of setting the proper ring end gap is so that when the piston and ring achieve their maximum operating temperature, as a result of the thermal expansion the ends of the ring ought to be not quite touching each other. If they have been in contact with each other, they will exhibit some shininess or polishing from having rubbed together.

[philster_d]

they rechecked these again Curt after your tip off, and the ring gaps werent the problem.

[custardavenger]

Must be the map then Map then. Have the injectors been sent off yet?

[philster_d]

yes off to be checked now.

[philster_d]

Injectors are all checked and fine. Working well and within 1c of each other.

Wow nearly a year now since I began this doomed engine build plan. Slowest ever progress of any work I have ever had done, its been painful.

[custardavenger]

I know the feeling. But you'll get there mate. Baby steps.

[ChrisGB]

Chris. Wouldn't the injector firing order be the same as the spark firing order (in normal single shot injection)?

Sorry, missed this. Injector timing could be off if wiring from the ecu is somehow crossed. Loom would need to be checked.

Chris