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building ea81, gasket and shaving questions


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So i bought my ea81 hatch for 1200, came running with 140k, a junkyard motor and a motor fresh back from the machine shop. Well cases and heads. Heads seem tobe shaved 20 or 30 thou, so my question is with the heads shaved do i need to have the crank and cam ground? I am thinking of doing the cam to 16/56, because ive read good things about that grind and my motor feels gutless as is. My dad has rebuilt many motors, hes teaching me on this one so forgive me if these questions are idiotic. I am looking for spfi pistons to put in. My other question isthe gasket kit, ive read different opinions on this, should i only go to subaru? Or use a standard one and get specifics from soob. Thanks for your time gurus

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I used Subaru OEM for everything but the HG, I used PermaTourque for that. I used the Delta cam torque grind for mine, they use a hydro lifter cam because it has a bigger base circle and it plays very well with 30 thou off the heads. I also added EA82 SPFI pistons to the mix and it certainly works well but getting knock and ping tuned out took some work with the timing advance curve and I am running a mix of 93 octane and 100LL. Performance is great but if you want a much less complicated setup I would suggest going with either 30 off the heads or SPFI pistons. Rock auto had the EA82 SPFI pistons when I was building my motor about 2 years ago. Do a good valve lap job, clean up the ports, and use an EA82 intake manifold. Lastly, if you do have 20 or 30 off the heads you will need to slot the intake manifold bolt holes so that they line up, and don't forget to match the intake port to the manifold. Just use some machine blue or other light paint and wet the manifold and install then remove it and you will see the mismatch that you need to create a smooth transition on.

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The last motor I built I did the shaved heads with a five angle valve job and Weber carb. I did not touch the bottom end at all since it had 55k miles when I put it together. I also had a 2 inch stainless exhaust the whole way back. So to answer your question no you don't need to do anything more if you don't want to. You will get more lift from the cam with just the head shave. My old Subaru really moved well for having a stock grind cam. Surprised quit a few people.

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Advice for creating a smooth transition from manifold to head subarubrat? And hatchsub, did you redo your y-pipe? Or did you just go 2" from y pipe back? I have a e.c.c. model y pipe im trying to put on but i have an exhaust stud stuck in the asv, but im putting that pipe so i have a 02 sensor bung for my spfi swap. Been looking at exhaust systems at pap, but everything is huge

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The last motor I built I did the shaved heads with a five angle valve job and Weber carb. I did not touch the bottom end at all since it had 55k miles when I put it together. I also had a 2 inch stainless exhaust the whole way back. So to answer your question no you don't need to do anything more if you don't want to. You will get more lift from the cam with just the head shave. My old Subaru really moved well for having a stock grind cam. Surprised quit a few people.

could i maybe get pictures of your exhaust?
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The last motor I built I did the shaved heads with a five angle valve job and Weber carb. I did not touch the bottom end at all since it had 55k miles when I put it together. I also had a 2 inch stainless exhaust the whole way back. So to answer your question no you don't need to do anything more if you don't want to. You will get more lift from the cam with just the head shave. My old Subaru really moved well for having a stock grind cam. Surprised quit a few people.

 

I am curious how you figure you get more lift from a cam by shaving the head or deck. Surely once you adjust valve to rocker clearances you get the same lift ?

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I'm going to attempt to explain it and see if I succeed or not. Since the heads are shaved the rocker is now closer to the base circle of the cam. The pushrod length didn't change so when the cam comes around and moves the pushrod if is now pushing that rocker a tiny bit further than before (the amount you shaved the heads). For the lift to remain the same as it was you would need to shorten the pushrod the same amount that you shaved the heads.

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So additionally, what kind of clearance problems am i going to run into with decked heads? And my dad swears we need to go from hydro to solid lifters, any input on this? I know solids need adjusting which isnt a problem, but is there anyone who can tell me whats better for this motor and why?, what sucks is the heads have the valve in already, like the shop that shaved the heads put them together, but i dont know if they lapped them or anything. Pictures coming

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Had a whole reply typed and hit the wrong key and erased it. Blah. My exhaust was a custom y to a full catback. 2 inch from the head to the tailpipe. Solid lifters are fine you will just need to close down the valve lash settings slightly. Get permatoque headgaskets and be done with it.

 

I did some searching and found this video of my coupe from years ago. Exhaust sound clip

 

Edited by hatchsub
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