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Tycho

EA82 rebuild digest

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Smooth ports are a result of cosmetics selling (you illustrated why). I did a quick radius of the short turn on both intake and exhaust and removed the valve seat machining flashing remaining in the chamber.

 

As long as you get the shapes and cross sectional areas you want performance will be equal. Cartridge rolling the ports yields zero flow benefit...and polished chambers don't allow for proper carbon formation.

 

Port 1 and 2 flow have equal flow in both quality and fuel atomization.

Port 1

Port 2

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So you didn't repair the cracks, just did some cosmetics?

 

Nice job! I have to do the same now...

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Ball peen hammer to the cracks=problem half assedly solved :)

 

Do you think this is a long-term solution? Because I'm just reassembling my engine, and if this "repair" is enough, I'll go with that.

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Peening will keep the seats from dropping (at the very least).

 

There was no water or oil seepage through the cracks so beyond their effect on the seat I am not concerned (Miles Fox passed on his experience and he's the man with the soobs so I'm sure it will be fine).

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Nice.

 

 

How much $ to have those piston skirts coated?

 

Were the valve seats cracked in the heads as well, or were my eyes just playin' tricks on me? A cracked head is usually harmless, but a cracked seat might cause a problem later.

 

Nice engine, though. ea82's are bulletproof except for that funky head cracking thing.

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Nice.

 

 

How much $ to have those piston skirts coated?

 

Were the valve seats cracked in the heads as well, or were my eyes just playin' tricks on me? A cracked head is usually harmless, but a cracked seat might cause a problem later.

 

Nice engine, though. ea82's are bulletproof except for that funky head cracking thing.

33 bucks per piston for skirt and dome coating (moly skirts, ceramic domes) from Polymer Dynamics (PolyDyn). 3 day turnaround.

 

The cracks extended all the way down to the casting line inside the ports...the seats themselves showed no damage so I wasn't too worried.

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Looks like you've learned a bit from TOO and crew. ;) Very nice job, I wondered if you were indeed the same person from over there, now I know. Do you have/access to a flow bench of any kind to work from when you did your porting? Also interested in who did the coating of the pistons/price. I'm looking into rolling my own bench so that I can start dissecting porting results, any sugestions? I look forward to the results of your build up, it should be interesting. I really hate the single port heads, you should have invested in the mpfi heads if nothing at least marginally better then you could have gone to the 'spider' intake. - and I agree wholeheartedly with your 'drunken flunky' mech eng comments in another thread about these heads, but I would like to get as much as I can out of them for my builds as well. Have you made any changes to the cams? Boy I could talk with you all day about applying TOO knowledge to these little engines, I have thought about contacting them to see if they would even touch one. :D Awesome work dude!

Yes...I am a "Widmerist" for sure. I don't have access to a flow bench off hand...but there is one in the fluid mechanics lab at school (I'm in electrical engineering however so getting in there is a bit more trickey for me). This is the third head I've done (have done 2 saturn 16v heads in the past) so I'm getting a feel for what works/what doesn't. This head was done rather quickly as the intake ports are such a restriction big gains can't be found. I was looking for more mid lift flow by deshrouding the chamber and applying some radiuses to the horribly tight short turns. If I make more torque down low I'll be pleased (that's the only place the manifolding doesn't restrict anyway).

 

For this build the goal was longevity and milage. -.010 on the block to bump the C/R and fight detonation a bit (more effective quench), radiused valve reliefs to fight detonation, cermaic coated domes to fight detonation, moly skirts to resist scuffing on cold start and keep the pistons square (promoting square ring wear and lower leakdown), RTV'd everything with the Loctite black stuff (we'll see if it can keep the oil in...EA82s are pesky buggers). Pretty standard issue. ~.0015 on all the mains/rods (.0013 to .0017), everything meticulously clean during assembly...etc.

 

As such, the stock heads and cams were fine. I have other engine platforms if I want to make power (EG33, LL0, 4AGE...).

 

Hit me up on instant messanger sometime...I love to BS about the stuff discussed on the ENDYN forums.

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As to the head cracks, my heads had a bridge crack in one cylinder on each side. I tapped them down a bit, and those heads lasted just fine on the first engine for 5,000 miles until it threw a rod (long, painful, and expensive story). I re-used those same heads on my current engine, which has around 7,000 miles on it so far without any problems.

 

I wonder about doing any porting on the EA82 heads, as they are fragile enough already, and removing metal will likely result in less ability to take heat.

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Full on porting yes...keeping it confined to work around the valve seat/chamber area results in a minimum of material removed with a maximum return in flow gains.

 

If one wants more port flow...the 2 port heads are the way to go...with light seat work and some minor bowl work.

 

Porters who hog the runners out generally don't have a clue what they're doing (and it's certainly not helping flow). It's been said that 90 percent of the gains are to be found in the bowl/seat area...and if you think about flow and the valves...it's pretty easy to accept that statement.

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hehe i see in the eg33 and prob ej's subaru stopped putting a gudgeon/wrist pin plug in under the waterpump, I am still fighting that on my ea81 :banghead: rusting under there since the colourful 80s.

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