Mitsubishi Eclipse 3G Club banner
1 - 20 of 45 Posts

·
Premium Member
Joined
·
1,107 Posts
Discussion Starter · #1 ·
I recently had an engine failure and started checking everything out. I got it dyno tuned properly across the board and had no lean conditions. I was running around 11 psi. When I broke down the engine, I found that 3 of the six pistons were chipped, melted. They were all on the front back 2,4,6. The furthest (2) from the throttle body was all the way through loosing total compression. The middle of the front bank (4) was chipped moderately, the closest (6) was chipped slightly. I think that the plenum's uneven distribution of the air caused the problems. So I'm looking for another plenum now :( . If you have a better reason this may have happened, let me know.
 

·
Registered
Joined
·
1,463 Posts
doubt its the plenum, talk to some other people that had blown engines. could also be the cam differences from front to rear
 

·
Registered
Joined
·
1,203 Posts
perna00 said:
I recently had an engine failure... I was running around 11 psi... I think that the plenum's uneven distribution of the air caused the problems... If you have a better reason this may have happened, let me know.
it wasnt because of the plenums alleged 'uneven distribution of air'.. it was because you were running 11 psi :naughty:

stock pistons?
 
G

·
Yup. It must have been the 11 PSI and/or the tune. Unless you were spraying fuel into the intake and it wasn't atomized properly or it condensated, there should have been equal distribution of air @ 11 PSI. In fact, if your tune was "good across the board" "with no lean conditions", then all 6 cylinders should have got an equal amount of fuel unless you are controlling individual injector pulse. The order of cylinder/piston damage (2,4,6) is just a characteristic of the engine when things go wrong. Every engine will have damage occur in certain areas before others due to the position of the engine, heat energy dissipation through the block/head, etc.
 

·
Registered
Joined
·
107 Posts
Once I also chipped pistons in 2 and 4. When it was tuned the leanest AFR was 13.7. I wish I have AFR graph, but no. Hows yours?

I ran 9 psi that time.
 

·
Premium Member
Joined
·
1,107 Posts
Discussion Starter · #9 ·
I got it tuned a month ago. It wasn't running lean at all. It was running slightly on the hot side. I thought that maybe since they were all on the front bank it was cause of the plenum. I'm still going to get a new plenum, especially since I can up the boost slightly with forged pistons.
 

·
OMFG
Joined
·
6,632 Posts
perna00 said:
I got it tuned a month ago. It wasn't running lean at all. It was running slightly on the hot side. I thought that maybe since they were all on the front bank it was cause of the plenum. I'm still going to get a new plenum, especially since I can up the boost slightly with forged pistons.
So Im assuming that you were data logging with a wideband, since you are sure that it wasnt the tune?
 

·
Premium Member
Joined
·
1,107 Posts
Discussion Starter · #14 ·
Some of the damage could have occured before the retune. I went from stage 1 to stage 2 and drove it for a while before I got it retuned; probably around 5 months. I noticed that it would cut out under high rpms cause of the leaning out so i never really pushed it. After I moved I took it to a greddy dyno shop which tuned it properly for the different pulley setup. I drove it for about 2 months after the new tune with no problems until it finally blew.

So where's the cheapest place to find all the bearings and gaskets at for my engine rebuild. I guess tearstone is the cheapest I can find but I'm worried that .011 over might not be enough to smooth out the scrapes on my cylinder walls. Any one know of any around .020 - .030 over?
 

·
Registered
Joined
·
1,654 Posts
perna00 said:
So where's the cheapest place to find all the bearings and gaskets at for my engine rebuild. I guess tearstone is the cheapest I can find but I'm worried that .011 over might not be enough to smooth out the scrapes on my cylinder walls. Any one know of any around .020 - .030 over?

http://www.importperformanceparts.net/imports/pek-mitsubishi.html

Scroll down to #9. Pistons, rings, bearings, etc. for $1199 :dunno: Not sure how that price stacks up.
 

·
Registered
Joined
·
118 Posts
perna00 said:
So where's the cheapest place to find all the bearings and gaskets at for my engine rebuild. I guess tearstone is the cheapest I can find but I'm worried that .011 over might not be enough to smooth out the scrapes on my cylinder walls. Any one know of any around .020 - .030 over?
You better make sure you engine is rebuildable 1st before you start buying parts.....and
Originally Posted by NAPALM
So Im assuming that you were data logging with a wideband, since you are sure that it wasnt the tune?
 

·
Premium Member
Joined
·
1,107 Posts
Discussion Starter · #18 ·
I wasn't dada logging. I got it tuned at a dyno shop which printed me out the air/fuel ratio 2 separate times after they tuned it.

I wish I would have had that link for the parts. I ended up paying $1215 for ross pistons .030 over and all the nessesary gaskets/parts for the rebuild.
 

·
Premium Member
Joined
·
1,107 Posts
Discussion Starter · #20 ·
So how can i be sure I get a good tune? I get all the printouts and fuel/air graphs. Is there something else I should ask for?
 
1 - 20 of 45 Posts
Top