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Probably my last EA Rebuild - an EA81T


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The thread started here with some pics of the tear down. I think I have some more if there is any interest.

 

EA81T Block and Head pics

 

I decided to save this one because it's a Turbo block with Hydro lifters and rebuildable EA's are getting REALLY hard to find. Here are some pics of the case parts just back from the machine shop bored .020" over, deck squared up and cleaned, ect.

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Here are a few more shots of the rear housing and the new oversize pistons.

 

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The original crank is pretty badly damaged from a failed rod bearing. I have a replacement crank going in for a mic and polish soon. Then I need to decide what to do about the cam. I'm not sure what a Delta grind would do for a Turbo motor or if I should just put it back in stock. The hydro lifters all look perfect. This engine only had about 144k on it when the bearing went.

 

More to come...

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Where did you find .02 os pistons and who did you have bore the block. Most of the shops around here will not touch Subaru blocks. I would like to save one of the engines in one of my Turbo Coupes that has a slight rust ring in one cylinder.

Edited by silverhelme
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They are actually oversize EA82-T pistons, but they will work in the EA81-T just fine. I found them on Ebay from Thompson Engine.

 

The machinist I work with has expensive equipment to do blocks like these - They do EJ's too. I know there are special concerns when doing Subaru blocks. I think the case halves were torqued together first - I am not sure but they might have also used torque plates as well. Piston to cylinder wall clearance is .0016" and they took about .005" off of the deck on each half to clean them up.

Edited by Crazyeights
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Action Machine Shoreline, WA (206) 546-2082 ask for Rob. Pull the head studs first to save their time and your money. They will also need your new pistons for measurement when boring the block and the bolts to torque the case halves together. Do any cleaning you want to the case FIRST before you send it to them. They will do a final wash after it's done.

 

Good Luck, and PICS!

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Hey,

 

Just wanted to add here, as this is what I'm doing right now. The EA 82 pistons you're using should give the EA 81 more compression and less piston to head clearance. Exactly how much I don't know, but you could measure it. Less piston to head clearance is better for detonation resistence.

 

I put a flatop EA 81 piston in an EA 82 block and with a .060 thick Genuine Subaru headgasket, and have .100" piston to head clearance.

 

I put a 9.5:1 CR SPFI EA 82 piston in the same EA 82 block with a .060" thick Genuine Subaru headgasket, and have .059" piston to head clearence.

 

I put a 7.7:1 MPFI Turbo piston, like the ones you're using in the same EA 82 block, a with a .060" thick Genuine Subaru headgasket, and have .041" piston to head clearance.

 

Now, the lowest I'd want to go is about .025 piston to head. Right now I have that .041 piston to head in the motor I'm working on.

 

Could you measure how far your piston sticks above the block deck with a dial indicater. And let me know how thick your headgasket is?

 

It's all good unless the piston smacks the head or valves:) I've got about .140" clearance piston to valve at TDC with a stock cam.

 

Sincerely,

 

Doug

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  • 2 months later...
It looks like the turbo that came on this engine is oil cooled only. I have read that Subaru had a campaign for water cooling the turbos on these. Should I just grab a water cooled one with hoses/pipes from an EA82T at the wrecking yard or use the original one?

 

Yes, a EA82T will bolt right up.

 

What about putting a wrx turbo in it? Might as well make that lil ea81t a Honda stomper. Just to wipe the grin off those stupid ricers faces. I wish I could find a ea81t.

 

The TD04 is not a direct bolt up, need to cut the flange off a WRX up-pipe and weld it onto the EA up-pipe then deal with the DP back exhaust.

And expect this engine to grenade within 100mi (or less).

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  • 2 months later...
Action Machine Shoreline, WA (206) 546-2082 ask for Rob. Pull the head studs first to save their time and your money. They will also need your new pistons for measurement when boring the block and the bolts to torque the case halves together. Do any cleaning you want to the case FIRST before you send it to them. They will do a final wash after it's done.

 

Good Luck, and PICS!

 

Rob is still there? I haven't been over there in fifteen years or so, they did really great work for me in the past, which I am sure they still do.

 

Ben

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  • 2 months later...

Well, it's been on hold for a couple reasons. First I lost a cam lobe on my daily driver (EA81 Wagon, EA81 with SPFI, 5K on a fresh HP build, torque cam, decked block, head work, solid lifters, the works). I took a few months and just EJ swapped that car and I am VERY pleased with the results.

 

Secondly I wanted to search out an EA82T water cooled turbo for it since the original one on this seems to be only oil cooled. Every EA82T car I found in the local yards were just BAKED beyond belief, sloppy turbo shafts, cracked housings, seized up, ect.

 

Before I shelved this project late last year I picked up another set of pistons (exact same oversize) but 9.5 SPFI flat tops. I have all the parts to assemble the block either way (N/A high compression multiport EA81 or low compression EA81T). I need to figure out what to do about the cam also. I don't want another early cam failure with a noisy valve train and poor idle quality. I'm open to suggestions;) No, I don't have a shell for it yet. I had planned to find a hatch body for it originally.

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