xt6 motor blown headgasket how to evaluate block

[joe5]

I'm currently working on an XT6 project. I got the car with the motor out of the car with the heads off. Previous owner said headgaskets went which is why he pulled the motor. I can see clearly the heads are damaged. There are cracks between the valves on 3 of the 6 cyclinders. On one of the pistons, there are lots of little pits, like perhaps a little chunk of metal got in there and got smashed around a bit. There is also yellowy milky stuff around the motor in general which goes along with the blown headgasket story. Based on what I see, I don't plan on using the heads.

 

So my question is this: Any thing I can look for to evaluate the block? I have an extra pair of heads that look good. It'd be nice if I could throw them on and get a runner out of it. But I don't wanna do if the crank bearings or other are damaged. Anything I can look for to clue me in on what the inside of the block is like without actually splitting it? If I turn the crank, I can see that all the pistons at least move as expected without any grinding sounds

 

Thanks in advance!

[SoobDood05]

If the heads are off you can put a straight edge on the deck surface to make sure it isnt warped. Chances are if the heads got that hot so did the bearings. Id say they probabley dont look too good. You could youll off the oil pan and take off a rod cap to see what the bearings look like. Coolant in the oil eats the bearings. Good luck!

[ccrinc]

If you have oil and coolant mixed in the engine, it needs rebuilding.  The bearings are now damaged, as are the internal o-rings and gaskets.  New piston rings too.  

 

The good news is that this engine uses the same parts (in general) as an EA82 SPFI engine with a few additions and differences.  The heads are even probably rebuildable.

 

Emily

[joe5]

Hi guys thanks for the feed back. I actually have another block already torn down I was just hoping to avoid a full rebuild if possible. But I guess thats not likely. I think I'll go ahead and take off the oil pan and have a look, but sounds like a full rebuild is ahead...

[TomRhere]

Got to agree with Emily on this one. Bearings are toast now.

 

If, it had been addressed soon after the headgasket went, you may have been good to go.

 

But sitting around with the "Milkshake Oil" in it hasn't done the bearings any good.

 

And cracks between the valves isn't a problem unless they go deep.

 

Just recently tore down an ER27, so if you need pieces/parts, I have "Some" good items available.

Let me know what you need and I'll check. Some parts are basically scrap, so......

[Numbchux]

Yep, IF it wasn't run/stored with coolant in the oil, the bottom end is probably fine. But since you bought it that way, you have no way of knowing. I would pull it apart, and visually inspect bearings and rings/cylinder walls. If things aren't too scored up, I'd throw a quick DIY hone on the cylinder walls, assemble with new bearings and rings, and run it.

 

 

Also, I assume the ER27 heads have the same "problem" as the EA82 heads where they get surface cracks that have fooled many a reputable machine shop. As long as they pass a pressure test, don't worry about the cracks.

[idosubaru]

Also, I assume the ER27 heads have the same "problem" as the EA82 heads where they get surface cracks that have fooled many a reputable machine shop. As long as they pass a pressure test, don't worry about the cracks.

 

correct.  identical valves and structure.

 

the "cracks" actually aren't "cracks" in the typical sense. nearly every XT6 (and EA82 4 cylinder) on the road today has those cracks between the valves - they are normal.  they are benign surface cracks which do not continue down into water jackets or exhaust ports so they run 300,000 miles like that without issue.

 

they "can" crack deep enough to extend into the exhaust ports - but that is very rare and usually only happens with overheated EA82T's - 4 cylinder turbo engines.