southwest2118

well my 7AFE in a corolla has been turbo'd since march of 2006 i believe. its my daily driver first i started at 5psi and worked my way to 12-15psi. haven't ran into any major problems with it. about 6 or so months ago i started getting smoke at the tail pipe after sitting at idle for a while. then as time progressed the problem got worse. Three months ago i did a compression test because blow by was pushing out oil out the breather hose and found cyl 3 and 4 to be out of spec after putting a lil oil in it it shot up which meant rings. The problem got worse, i had oil being pushed of nearly every seal that could leak. On 3-30-08 Sunday when i was in Houston it started smoking so badly it became undriveable, i left it there went back the next weekend 4-5-08 and stared tearing it down.

Damage found - on cyl 3 in between the first and second rings the piston broke(i guess you can say the ring spacer) i was able to take a peace of it out with my hands in one of the pics you can see this area missing. on cyl 4 there are two cracks in the same section as cyl 3 piston. visual inspection of rings shows no damage. visual inspection of cyl walls shows no damage.

(i know pic quality sucks )



















































































as of right now 4-9-08 i'm waiting on the guy from the machine shop to come and pick up the head and block, do some measurements and see what i need to do. I'll keep this updated


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seerex

Yes your pic quality does sucks. Wait car is auto/ boosted WTF I say time to do a 5-speed swap. Oh BTW ring lands own you.

southwest2118

i'll put the 5 speed in it after this one gives. ..

rings lands..
oh is that the technical name for that area..

jwbetley

Ringlands are the grooves around the circumference of the piston which seat the rings. These are typically the weakest part of the piston becuase the metal is the thinnest in between these grooves. Ringlands can crack and break when too much pressure (often from boost) is put through the piston. Your compression goes to hell due to this, and you'll usually comsume a lot of oil.

Get new pistons.

themadhatter

If i was you I would take this as a chance to improve on my motor and build a 7age which if you don't know is a 7afe block and crank with 4age pistons and a 4age head. Go look on mr2oc.com for more info because it makes a decent little upgrade and its cheap if your already doing a rebuild

turbo4age

ive broken ringlands on at least 4 stock pistons in my boosted 4ag. i just upgraded to gze pistons to cure the problem. why dont you just do a 4ag swap from an mr2, the gze pistons swap right in and only cost about 200 bucks (8:1 forged and ceramic coated).

southwest2118

i don't want to do the 4ag swap due to the fact i'm broke.

the 4ag pistons are full floating? and also read it will increase CR to 11.something?

toyollAZ86

not true.

check my www.whyturbothat.com

my buddy from tucson. he'll try anything.
you can go to the junkyard and get the 4ag head harness and ecu for dirt cheap. if not you can find it all online for
dirt cheap. people practically giving it away.
just go 7age. read that write-up on the website link. its pretty informative.

fe3tcourier

the only 4age that is 11:1 is the black top 20v. fitting those pistons below a 16v head (45deg included valve angle) will probably give you lower than 11:1 compression. I have to say, I'm impressed that your 7afe rods took 15psi with what is obviously a non optimal tune. they are pencil thin things aren't they. Good to know they can take it. I have a 7afe car outside that I may fiddle with at some point.

southwest2118

Well yesterday(4-25-0 i got my block and head back from the machine shop.
i think i'm getting better at talking pics with this $50 dollar camera



i couldn't resist the urge to paint it




allow me to reintroduce the 7A







in the pics it looks like i missed some areas










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el cheapo ITM pistions
























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this is where the magic happens


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the turbo came off of a volvo - anybody know if this is a standard 5 bolt down pipe flange?
so i can buy something like this http://i35.photobucket.com/albums/d198/bre..._flange_obx.jpg and go external wg?