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Tearing down engine Qs

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Ok, I replaced the head gaskets and only bummped the comp ratio from 30 to 90. They're supposed to be around 150. :-( So, looks like I might have cooked a ring or two. Not buring oil or anything, just poor compression. So........ can I get the pistons out without splitting the halfs?

Ok, I replaced the head gaskets and only bummped the comp ratio from 30 to 90. They're supposed to be around 150. :-( So, looks like I might have cooked a ring or two. Not buring oil or anything, just poor compression. So........ can I get the pistons out without splitting the halfs?

 

yes they only go in from the deck. the wristpin snaprings subaru uses are a pain to use though

Have to remove the engine from the vehicle, but yes it is possible to remove the pistons without splitting the engine. It's definately not easy or reccomended as it's difficult to push the piston out the top without making special tools to do it through the wrist pin hole. Frankly if you are tearing it down that far, you might as well split the block. You'll need a special tool to remove the wrist pins.... you can make one by making a hook out of some round stock.

  • Author

Ok, that answers that question. Thanks!

Next question, Can I borrow one of those wristpin removers from Autozone or Napa?

Use a grinder to make your own pin puller from a long bolt. It just needs to reach around and grab the pin. I've torn down several motors using this tool to remove the pins and it works fabulously.

Get your valves and valve seats done also while you are at it. No need for fancy step grinds; just get them to seat properly again and get the pits out of the faces.

  • 3 weeks later...
  • Author

My current engine state: http://usmb.net/gallery/view_album.php?page=1

 

The heads are currently at the machine shop having the valves looked at. Why I didn't have them looked at before....donno.

Now, if I can only find somthing to get those wrist pins out. My current large nail clamped with a visegrips only worked for one pin. Oh, what joys!

Took piston no 3 out and the rings look ok to me. Corse, do I even know what I'm looking at? No, but I'm going to learn!

It's really easy to take the pistons out without splitting the case. I accidentally forgot to put one of the pin-retaining spring clips in once, and after much head-scratching I came up with this method:

 

Using care not to scratch the cylinder wall with the connecting rod, turn the engine until the rod pushes the piston almost all the way out. Turn the engine until you can put the pin back into the connecting rod, then continue turning the engine until the piston is pushed all the way out. Ta-da!

 

 

That said, unless your engine is very new AND it was not run for very long with a blown headgasket, I would take the block apart and have a look at those bearings. It would SUCK to put it back together and have a rod knock.

  • 5 weeks later...
  • Author

I FINALLY got those pistons out without splitting the halves. I picked up some steel rod and ground the edge out and used that to get them out. The pistons all look the same and there's no sign of breakage that I can tell. The cylinder walls look good.

However, I did have a cracked head and will be replacing that one with one off the parts car. The guy at the machine shop said that the valves had scuffing marks all the way around them. He also said a number of them were burned too.:-\

Here's some pics of the pistons. I'm going to take one to the machine shop and have him look at it. He sould be able to tell if there was any damage.

http://usmb.net/gallery/view_album.php?page=1

Looks fine to me. At least no obvious damage, and it doesn't look like you were getting any significant blowby either (I assume you haven't cleaned the pistons yet).

  • Author

With only 9k miles on it, they shouldn't have too much blowby on them.

Yeah, they look fine to me too. I took one of them to the machine shop today and he said that the skert has callapsed slightly. He also noticed that there was scuffing on them too, possiby because the piston was rocking slightly in there. He said that will not allow the rings to seat properly and may cause trouble down the road.

I took some more shots of the other three. The middle one deffinately has some scuffing on it. Like I said earlier, the cylinder walls look fine. Or are they? I'm really not sure. Prolly will take the halves down there and see if he sees anything funny.

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