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"ridges" on cylinder head mating surfaces?


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Replacing the head gaskets on my 97 Outback 2.5, and after cleaning the heads and their mating surfaces on the case, I can feel a ridge in the head and a matching "valley" on the case. I should be getting the gaskets and other parts in the mail in the next couple of days, and I'm contemplating having the heads resurfaced. I checked with a machine shop a friends Honda/Acura repair shop suggested and they say they can do it no problem at $25 each. I'd rather leave the valves in the head, they said it wouldn't be a problem as long as they are below the head surface.

So I'm trying to decide about the machine work. Not so sure the gasket wouldn't seat better with the "ridges" as they are, or to go ahead and have the machine work done. Realizing this is going to "bump up" the compression, and I wonder what the deck height is from the factory? I've got the factory numbers for the maximum amount to be surfaced as 0.012" if I remember correctly. Also, I'm the second owner of the car, I bought it at 38k without a history. I'm noticing on one head, on the inside surface (towards the center of the engine) near the exhaust port there is a stamped "W", and the top of the head at the intake has some stamped numbers that are not the same as the funky Subaru font like on the top of the case. The other head doesn't have the "W" or anything stamped in that spot, and no other numbers at the intake other than the funky Subaru font. Could this have been a replacement/remanufactured head?

I tried the "search" function for "resurfacing heads" etc. and didn't find a whole lot. So, to machine or not to machine? Any takers?

 

Thanks!

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The "ridges" were definitely high enough to catch a fingernail, and the grooves as well. The grooves are in the case and the ridges were on the head I believe around the outside perimeter of the cylinders. Here is a photo I took when I removed them---I should have taken a few shots after I cleaned them up----but today I took them to the machine shop and they surfaced both of them 0.004" (four thousandths) each. They have an absolute mirror finish to them, I'll see if I can get a picture of them to this thread in the next day.

 

Anyway, here is where I think the gasket failed, below the front passenger side (I'snt that #1? I don't have my manual handy and it sure isn't the same as the air cooled VWs and Porsches!).

 

 

<img src="http://i4.photobucket.com/albums/y141/Huffmeister/IMG_0680.jpg" alt="Image hosting by Photobucket">

 

 

And the offending gasket!

 

<img src="http://i4.photobucket.com/albums/y141/Huffmeister/IMG_0682.jpg" alt="Image hosting by Photobucket">

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