I think you found your problem once you took her apart. All the possible issues have been pointed out. Good luck with the repairs sir!

 

Can you take a pic UNDER the piston?

 

More detailed description is engine was run lean. Detonation cracked the rings. That ring overheated from no longer having good contact with cylinder wall.. The tip of rings where gaps are, is where ring would get hottest first. causing the piston to melt in those areas.

Seeing this I dont know why people remove oil squirters during a build. Oil cooling from underneath is half the piston cooling. The other half is rings transfer heat to cylinder wall.

In the end a lean A/F causes this. detonation was the killer.

 

So how much money do you have for a build? If you search and shop around your likely able to find a SB 4g63 built for pretty cheap. You can also buy one new from mitsu for about 3800 built to spec, but then your getting close to built budget.

 

Finally an excuse to build the motor, lucky

 

wow ur bearings are shot. ive seen bearings that come out of cars with 100k miles on them that looked better! might i ask, what oil were you running?

 

but his pocket is not.

GL with your new build, take your time and read whats best.

 

I'll take one tonight and post it.

94AWDcoupe, thanks for the descriptions. And yes, oil squirters will be left in for the build.

I may look in to these options, but I'm a little leery of taking over somebody's old engine. As for a new mitsu build one, I don;t like the idea of going through this to end up with what I had before. I find these things much easier to swallow if I can at least end up with something better than I started with.

I do have 120K+ on the engine, so perhaps they aren't that bad? I did notice last night that the bearing closest to the pulley was worn down right to what looks to be a copper (??) layer, though. I was running Mobil 1 synth.

Thanks Mr. Evo. Been doing a ton of reading over the last few weeks so I think I've got a good idea what direction I want to go. Will be posting my planned build sometime soon.

 

Ouch i have a headache now. My motor has over 108k now and I can imagine thats
going to happen to my motor.. F***

 

I think this motor went south because of a combination of things. From what the OP is saying, lack of maintenance seems to be one of them.

We drive cars with a good amount of power stock. Most of us on here are close to or are double the factory power. You have to stay on top of it and go through the under hood stuff every once in awhile.

I wouldn't worry about mileage as long as the car has been taken care of. There are guys closing in on 200k and still rocking 25psi everyday.

 

Tweak the tune and get used to working on things yourself and with that WBO2 you will be fine.

We all make mistakes, and eventually have to pay for them in the end. So, relax and take your time on the build. You will find plenty of parts/motors here on EvoM. Last time I saw 94AWDCoupe had one posted up, too.

You have shown us the carnage of your old motor, don't forget to show us the shiny new one next thread!

Good luck with it all

 

What condition is the head in? spun bearings and almost detonated pistons..problems usually come in 3's

 

I wouldn't worry, 4g63Moon. Like nightwalker said, there were a few things that contributed to this, most or all of which could have probably been prevented if I'd stayed on top of things. Time has been scarce the last while so the Evo hasn't gotten the attention it's needed.

On the plus side, by the time this is done I'm going to know every inch of that engine and engine bay like the back of my hand.

So, almost time to put this behind me and get on with the fun stuff! I'll be meeting with the machinist today or tomorrow to get his take. Been reading for a couple of months now on parts, etc. (even before I pulled it apart I figured I'd be doing a full build, so I've got a head start), so once I get the $$$ together and get some opinions on my planned set-up, the ordering can start (solicitation is welcome ).

And thanks again for all of the help and comments. I've been lurking here for quite some time and it's nice to finally get in to some real interaction on here. Awesome site and a great bunch of people. I will most definitely be sharing my build with the community here.

And I will post pics of the head and underside of the piston tonight if anyone's still interested.

 

The bearings look really good to me. Especially for the mileage.

 

Wow. I can't believe it's been 2 months since this thread. I've been out of town and life's just generally been hectic, so sorry for the delay on posting these up.

Here's the head and the underside of the pistons, as requested, if anybody's still interested.









I've also started my build thread:

https://www.evolutionm.net/forums/ev...ld-thread.html

Thanks again for all for the comments.