AE92 Corolla SR5 - GTS goodies swap-in mini-build-thread

Dropped off the car at the shop a couple days ago so I should find out exactly what broke pretty soon. The drive over there was the first on the new spark table, it felt more torquey and was idling higher.

After the near-overheat at the track I think the radiator needs a 2-row recore to stand up to track use. It was still creeping up a bit even with the richer fuel map. It's probably 25 years old too. Unless the engine needs some catastrophically expensive work like an overbore/sleeves I'll try to get this done while the engine is out.

Here's one more thing I set up on the ECU, a temperature-based rev limiter. A 5500rpm rev limit will definitely catch my attention. I'll have to test it when the engine's running again, as a first guess I set the high-temp limit to kick in at 221F.

I've been thinking about trying the progressive fuel cut (and return) as well.

Got the radiator out last night but I'm waiting to hear exactly what the damage is today before I take that in for a recore. If there's any damage to the pistons or cylinder walls it will be the most expensive damage ever incurred to a thing in my life.

Hooooly E36 M3 am I ever berkeleyed. I went with a mild NA build because I didn't want to risk ever being this berkeleyed, and yet here I am, completely berkeleyed.

And yes the cylinder is scored too. The options are an overbore of at least 0.040" or a used block and used pistons. The cost of new performance pistons or importing a block is too high to consider, so any replacement block will have to be sourced locally and pistons will have to be used or cheapos.

Edit: Maybe cylinder sleeves and used pistons could be an option.

ouch......... I can honestly say I've never seen a stock 4AG piston get burned that badly....

How do all the other pistons look???

Do you know what your AFR's were?

You have the most preserverance of anybody i have ever seen. Most would have lit it on fire and walked away by now.

Im not sure if i i envy your preserverance, or question your sanity.

There was no damage to the other pistons. Don't know what AFRs were but they should've been quite safely rich, judging by the MS' settings and the fairly quick rate of fuel consumption. Never heard any pinging since the engine went back together with the new crank. If I had to guess at what caused this, I'd think it's this:

Dusterbd13 wrote: You have the most preserverance of anybody i have ever seen. Most would have lit it on fire and walked away by now. Im not sure if i i envy your preserverance, or question your sanity.

It doesn't take that much perseverance. If I could pick up a better car on the next paycheck I would indeed set it on fire and walk away. But throughout the course of this thread I've sunk easily $15k into this car, and to buy a car in good condition that's this quick and this streetable would cost at least $20k along with increased ongoing insurance and fuel costs. It would be a heavier and theoretically more expensive to run car, whatever it is. So fixing this car is not a terrible deal, certainly a better deal than a brand new Suzuki Celerio which is something like $23k here.

So it looks like there are no cheapo pistons of sufficient overbore available, and they're all much lower compression. Solving this problem in the 3rd world on a 3rd world budget will probably require a relatively exotic solution - I'm thinking either sleeves and 20v pistons (looks like they don't interfere in an otherwise stock redtop and increase compression, but how safe is this?) Or a mighty 83mm overbore with Mazda BP pistons (and how much is an 83mm overbore "asking for it?").

May have stumbled right past a workable solution - these pistons right here:

http://www.rockauto.com/en/moreinfo.php?pk=4802601&cc=1275331&jsn=418

They're just $23 a piece, compression ratio is close to stock for this engine. But the maximum overbore size they're available in is slightly below the mechanic's estimate for what's needed. He's going to do some measuring today to see if 0.030" overbore could be enough.

The big downside with overboring is that I'll probably need to switch to a "wideband" (digitally tuned) knock sensor.

Ah, less terrible news! Those pistons can work! Now I just have to rush-ship them in.

Edit: I'm trying to figure out if the ITM RY6446 has the right wrist pin diameter before I order them. Can't find much info yet but this could be the bubble-buster. It's specified for 4AGEs found in US model 85-91 Corolla GTSes and 90-92 Geo Prizms. Were the 20mm wrist pins used as far back as '85?

Edit2: In this big pic I don't see any clips holding the wrist pin in, that's a bad sign. 18mm wrist pins were press-fit.

Edit3: OK looks like only bigports came with 18mm wrist pins, smallports came with 20mm throughout the entire production run. So any '90 or '91 Corolla should've had a smallport and therefore 20mm wrist pins.

GameboyRMH wrote: There was no damage to the other pistons. Don't know what AFRs were but they should've been quite safely rich, judging by the MS' settings and the fairly quick rate of fuel consumption. Never heard any pinging since the engine went back together with the new crank. If I had to guess at what caused this, I'd think it's this:

I wouldn't suspect the high-rev/low-load area of the map at all. When is the engine actually operating in that range anyway? On decel, maybe, but the throttle is basically closed there anyway.

What are you using for load indication? MAP? TPS?

If your rings were gapped too tight, you could see that mode of piston failure.

Using MAP for load indication. It would go through there on decel and when shifting at high revs. That's the only area of the map with significantly more than stock advance. But again, I'd think I might hear some pinging before detonation blows a chunk out of my piston, if that's the cause.

Another bit of info I've turned up on the RY6446 pistons, RockAuto doesn't list them for this model on any year before 1990, which is a good sign.

In this little side-thread on the problem, oldeskewltoy pointed out that TC2989s are a clone of the factory high-compression pistons. They have the wrist pins held in with clips instead of pressed in too. The engine needs 0.5mm of overbore so 0.020 is still enough. So these are my top choice now, gotta see how soon I can get these shipped in.

Radiator re-core will have to wait until next year I think. It's fine as-is for street use and autocross. I'll at least do a little fin-straightening by hand before I put it back in.

Should have the TC2989 pistons sometime next week if all goes well. In the meantime I need to get the injectors tested, maybe the injector drivers tested, and finish up straightening fins on the radiator. The engine block will go in for machining late this week or early next week so it'll be ready for the pistons when they get here.

I've spent about an hour on the radiator so far using jeweller's screwdrivers (most of the spots that are bent are so bad that a fin comb would do nothing), it'll probably take about 3 hours of work in total.

GameboyRMH wrote: Ran across a pic of what the planned wheel size I'm looking at would look like. Mmm yes This car belongs to Hiro Protagonist on rollaclub. He said fender rolling might be a good idea but isn't necessary. I'd consider some kind of fender mod, especially if the wheels end up projecting past the fenders even slightly. I know how much more muck that kicks up onto the sides of the vehicle from experience with my Samurai. These are 15x8 +25s on an AE92 hatch, which is the same car suspension-wise. The tires are 195/50/15 which would be my emergency fallback size, ideally I'd run 225/45/15.

I ran 15x9 +36 wheels w/ 225/45/15s on the front of my AE92 SR5 and they fit completely fine other than some small rubbing on the control arm at full lock. even the miata hubcentric rings are a perfect fit :)

rears were 15x7 +25 w/ 195/50/15s

Interesting, I've been thinking about squeezing on 15x9s with the new 245/40/15 size that EPS tires are starting to come out in.

Aw E36 M3 I berkeleyed up again, TC2989s can come without rings even though the model number is the same, parts sourcing nightmare here we come. Hopefully the money i spent on rush shipping wasn't for nothing.

Looks like no overbore rings are available locally, so I wasted at least $100 and a week and a half of time with that mistake. But it also looks like there may not be any head gaskets available locally, I bought the last one the dealership had back in December, and I've been calling around checking for them along with the rings, and not only does nowhere have an MLS gasket, but most shops said they have none for the 4AGE 16v at all.

In reply to GameboyRMH:

As to the rings... check Honda Prelude

For a gasket Cometic makes a few MLS for the 4AGE - Cometic Import gasket catalog page 27

Already ordered the Prelude rings, had to go with a regular head gasket for cost reasons.

Got the rings and and HG yesterday (although it turned out one local shop did have a HG), luckily there was a customs mistake in my favor and they categorized the parts as "replacement parts" with no duty applied, saving me around $60. Dropped those off at the shop along with the pistons:

Here's some booty that came in a couple weeks ago, and installing it will be one of the electrical mods done as soon as the new engine is running, along with wiring up the knock sensor:

I've been lurking this thread for years. It's always been a source of inspiration to not give up on these chassis. You don't have a spare (pre-facelift) Trueno bumper by chance do you? My cooling requirements call for a larger frontal area opening.

Only one I have that I can sell is the one on the donor car, which is a very late model, and it has a lip fiberglassed into it. You can see it in my Rides section. If you're desperate I'm sure I can find a few more bumpers locally, one might be the kind you're looking for...shipping will be expensive though.

You might want to consider ducting your radiator stack, something like this:

It might give you the boost in cooling airflow you need without changing bumpers. Of course getting rid of your stock front license plate mount will help too.

Mechanic's getting the block back from the machine shop this morning, also I have to get a new knock sensor because the one that's only been on the engine for less than a day of runtime got a crack in it, probably due to the high-temperature incident at that last track day.

Looks like the best knock control solution is the MS3's addon knock module, a Bosch 0-261-231-008 sensor and possibly a custom mechanical adapter piece to put that onto the block. Can't do that until around the end of March though, so for now I'll just have the WBO2 sensor, temperature-based rev limiter, and safer new fuel and spark tables keeping the engine from trashing itself again.

And just like that the car's pretty much ready to go. Ran it a bit tonight. Break-in driving starts tomorrow night with these settings:

Damn, your mechanic is quick! I'd still have the engine on the stand. LOl