WJM Posted April 11, 2005 Share Posted April 11, 2005 So i was looked at my 4 heads today...and picked out two of the better looking ones....a gen1 which is bare, and the cracks are BRAELY noticable between the valves. It came out of a 93k mile engine in which the HG was blown on the other side, and the engine was not overheated. The other came off of....uhhhm...what was it....i cant reember, I think it was the junkyard engine in the RX when i frist got it that we didnt reuse the heads...one crack is really noticable, the other one is not. The first is a Gen1 head. The second is a gen2. Had the subie techs looking them over...the old guys who were working on the EA81's and EA82's when they first came out...they said it didnt matter which head I used as long as they presure tested fine. Me: "But, this one is a Gen2 head, its better..." Them: "No, there are no differences in them other than the casted designation. SUBARU never said there was anything better about the gen2 and 3 heads...they are all the same regardless." That being said, Ive seen the same amount of ruined gen1 vs gen2 vs gen3 heads, and ive never had issues with any Gen1 heads Ive had. Ive had several sets of Gen2s as well. That and Ive never seen any documentation that Gen2 and Gen 3 are any better than Gen1. Just part number supercessions....ofcourse the HG's have the same number of redesigns as the heads....some parts have 7 redesigns and look the same/function the same as the first design. Opinions? Facts? Flames? Link to comment Share on other sites More sharing options...
GLCraig Posted April 12, 2005 Share Posted April 12, 2005 It looks like the techs at your dealership were not paying attention at update school. There are differences in the heads, however none of them address the crack between the valves. Here's the TSB that covers that issue. Http://home.comcast.net/~c.moe/heads.pdf The crack issue that is addressed by the different generation heads is the crack that develops in the exhaust port where the runners meet. This is the one were coolant will drip from the head, into the exhaust header. why must I repeat this every few months? why can't people search for this info. Link to comment Share on other sites More sharing options...
WJM Posted April 12, 2005 Author Share Posted April 12, 2005 so why is it that the WORST cracks Ive seen are on the gen 2 and 3 heads? the Gen1 heads are basically hairline cracks. I'll have to measure tomorrow see if the distance was actually increased. Link to comment Share on other sites More sharing options...
thealleyboy Posted April 12, 2005 Share Posted April 12, 2005 I took this up with a Subaru Dealer Master tech with 20+ years... He said the dealer paid very little attention to the gen. Unless the meltdown was major, they just resealed the heads, and ran them thru. No machine shop work whatsoever. Straight HG job. My thought is that any cylinder head that is going on partially rebuilt motor should get a second opinion. Small price to pay for another "thumbs up". In my experiences, at least 50% of heads used turbo heads have passed the machine shop test. Either way, you have a decent chance that the heads are usable. My advise is that you ignore gen's - unless you have a good supply of parts to choose from. I'm sure that 3's have been engineered better than 2's or 1''s. Not sure I'm convinced that the refinements between each series are significant to the average derelict, however. good luck, John Link to comment Share on other sites More sharing options...
Do It Sidewayz Posted April 12, 2005 Share Posted April 12, 2005 the differences are in the exhaust side. I believe the gen1's were really thin. The gen 2's were much thicker. the gen 3's were thinned back out a little bit. In reality. i don't think it matters much....as long as they aren't cracked when you put them in....And go get them decked anyways Link to comment Share on other sites More sharing options...
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