[RESOLVED] What do you guys think? Lean?

[T is for TURBO]

Here is a little history, about a year ago I was driving my car to school one morning and as I was turning into the parking lot I heard a terrible rattling noise comming from the engine bay. Sounded like a handful of rocks in the oil pan, I figured I spun a bearing. Well, this weekened I finally got the engine out and stripped the block down. This is what I found; No bearings were spun, however there was a lot of play in the rods and the bearings did have a good deal of wear (not down to the copper yet). When I pulled the head, I found a LOT carbon flakes just sitting on top of the pistions. I also noticed a few dings in cylinder #4, which leads me to belive the motor was a t-belt victim (previous owner). But my biggest question is what caused the build up on the exhaust valves.
Finally, I still cannot determine what was causing the rattling noise, rod knock maybe?
here are the pictures.

Edit: Sorry, I don't have a picture of the dings in the piston, my dad e-mailed me the photos and that one didn't turn out.

 

[mach4g63t]

The rattling could be any number of things. It could be some hardcore piston slap, busted wrist pins, or any number of things. To properly diagnose that, pull the oil pan and drop the crank. You should find out fairly quickly once you remove the rods and pistons.

We thought the same about my buddy's motor (rod bearings), but we found out all the bearings were cherry. Pulled the pistons and the sides of them looked like that had been beaten with a jack hammer and chunks of metal were missing from the bottom of the pistons. So, you can't really know for sure until you completely disassemble the motor.

As for all the oil caked up on the valves and pistons; I sould say bad valve seals most likely. That's how my old head looked and it was really nasty. Are the intake/exhaust ports caked up and gooey with wet oil too? If so, that's a really good indication.

Overall, I would keep disecting the motor and find out if you problem is in the bottom end. How did all the lifters/rockers look?

 

[1fastlaser]

looks like you need some rings, valve seals or both. I would say you would have to mic the crank and rod ends, and also check for grooves or anything bad. Plastic gauge and maybe do a half rebuild if your not trying to build it right now.

 

[SBR Joe]

looks like you need some rings, valve seals or both. I would say you would have to mic the crank and rod ends, and also check for grooves or anything bad. Plastic gauge and maybe do a half rebuild if your not trying to build it right now.

Or a popped headgasket, coolant pushing into the cylinders would explain the edges of the piston being pretty clean.


Joe

 

[T is for TURBO]

Well, the head gasket appears to be intact. I took a few more pictures of the block, however, I haven't taken the pistons out of th block yet, that comes this weekend. I'm very impressed with how good the cylinder walls look, very little wear and still has the cross hatch. (btw this motor is going to be fully rebuilt, but I'm just looking for thoughts on possible failures.)
If you look at the first picture, you can see the dings I was talking about on the piston.
Also, whats the deal with 1G heads having a copper color were 2g heads have a aluminum color? At least every 1g and 2g head I've seen...
(btw, this motor is out of a 92, and supposedly rebuilt 60-65K ago)
Still haven't found where the rattling is comming from. But like I said above, pistons are still in the block.
What do you guys recommend for a head rebuild? I'm shooting for 400hp, but building the bottom end for 600 incase I want to higer (and when I get an AWD) I was thinking 272s, but I know little about valves and springs? Should I stick with the 1G head? or should I get the 2G head I have machined for the 1G block and port the crap out of it?

Thanks!
-Shawn

 

[mach4g63t]

From those pics, everything looks good to go. Similiar to how my motor was when I pulled it apart. And I am looking to make the same power on pump gas, but with meth injection on higher compression 9:1 pistons. From what I read, it should not be very difficult on a 6-bolt head (no port work) and BC 272's. That's what I am going with.

As for those dings on the pistons, maybe something got sucked into your turbo and blown into the head. There was no real damage to your vavles or the combustion bowls, so not too sure on that. Couldn't be the valves. I had a spark plug detonate completely blowing off the lower end INSIDE of the cylinder and it went through my exhaust valve. Did no dmg to my head, pistons, walls, nor turbo (was at full boost so assuming it went through the WGate). Maybe you had something similar happen and got lucky that it did minimal dmg and was blown out without doing any real damage.

I rebuilt my motor with Eagle Rods, Wiseco 9:1's, ACL bearings, .02 over bore, and that's about it. What turbo you going with? Your turbo and tune will be the overall deciding factor for your outcome of power for the motor. With all the deals going right now, it shouldn't be hard to find some good forged pistons and eagle rods for cheap. Dont' forget to use ARP mains and head studs while you're in there to ensure you don't have to worry about it down the road and your motor is rated for the long haul.

Let us know how the bottom end looks when it all gets done. The cylinder walls look fine, but maybe the crank will need some attention (polishing at least). Hope everything comes out okay

 

[T is for TURBO]

Crank will most likely be replaced. I'm probably going to go with eagle rods weisco pistons (8.5:1)
It's going to AMS probably next weekend for the build/machine work, so things may change when I talk to them. So far I'm unsure about the turbo. Mine just run the T-28 for a little while since it only has about 10k on it. But I will probably go with a 50, or 60 trim... not sure yet, I've got some more research to do.

 

[T is for TURBO]

Found the culprits. Thrust bearing was destroyed. Is the hole in the trust bearing supposed to line up with the hole in the block for oil? mine was pretty far off.

But the big issue: This was the first piston I pulled. As soon as I got it out, I just started laughing.