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DannyJ
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[*] posted on 28-3-2006 at 09:12 PM
3ac options


I have an 85 tercel 4wd wagon with the 3 ac engine(FREEEE). The engine makes a terrible clatter at all rpm's and my compression is below 120 on all 4 cylinders. I have heard that the 4ac is a direct swap. My question is is it cheaper to rebuild the 3 or buy a used japanese 4ac? What are the hp differences-haha-between the two? Any help would be appreciated as I got the car for free and don't want to dump a lot in it.

Danny
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[*] posted on 28-3-2006 at 09:22 PM


4AGE or 4AFE from the early 90's would be better I would think, anyone have anymore imput?



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ARCHinSTL
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[*] posted on 5-4-2006 at 01:37 AM


Join our Tercel 4WD Wagon-exclusive club, at http://www.tercel4wd.com.
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P.S.____T.S. was a St. Louis boy as well.
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[*] posted on 2-5-2006 at 08:27 AM


3ete?
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[*] posted on 2-5-2006 at 02:21 PM


Any A motor will swap easily in, so it's a matter of finding what's right for you.

For the Tercel, I'd think about building a 7A for it.

The 7A block came in 93-97 Corollas and 94-99 Celica STs. It's 1.8L and will provide you with the largest displacement you can have short of building a custom stroker. A 4A-F or 5A-F head should bolt on there without issue. They're both carbed.

You'd end up with a stroker that will keep your stock fuel system in place and provide you with better power and torque for good drivability.

The best place for info is from the Tercel4WD guys as this is only an educated guess.




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Typrus
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[*] posted on 15-8-2006 at 01:43 AM


You run into some issues with a blown up tranny with the 4AGE and 4AFE if you aren't careful.
Yes, the 4AC is a near-direct swap. Very little has to change.
I believe these are accurate....

3AC- 65HP@4200RPM, 73ft/lb@2400
4AC- 78HP@4200RPM, 85ft/lb@2400

Its been a while since I've looked....
Anyway, its close to a 25% boost in power. Several of my fellow Tercel4WD members have done the swap with much fanfare.

As for cost-effectiveness, I'm spending close to a grand on my 3AC rebuild. But I'm getting my head ported, polished, and decked. I'll be using performance valve springs, a hi-perf camshaft, the Somender Singh's Grooves mod, and an Engine Kit from Importperformanceparts.net with a high volume oil pump and race-style bearings. I'll also be using either a Weber32/36 carb or a Weber 38/38.
I should be seeing (hopefully) from 80-100 HP.
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[*] posted on 17-8-2006 at 01:39 AM


3A-C - 62HP@4800RPM, 75 ft/lb@2800 (some specs say 76 ft/lb)
4A-C - 70HP@4800RPM, 85 ft/lb@2800

Nice list on the rebuild. You'll probably get the HP you're expecting.




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Typrus
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[*] posted on 17-8-2006 at 10:38 PM


I'm just afraid of WHERE I'll get the power I'm expecting. The 3AC head had itty bitty ports (smaller than the 30mm outer and 32mm inner intake port sizes on the gaskets) to start off, so I'm sure their low-RPM velocities were pretty nice... However, they were very irregularly shaped I must admit. So I might see 100HP, but will it be closer to 4800RPM or 6000? And where will my torque be? Those are my big concerns.
The engine bores are fully stock. It only had to be honed, no boring involved. Not bad for a 184,000 mile engine, eh? Had the crank re-ground by .01 on the mains and .02 on the con rods. It spun a rod when my sis ran it out of oil, thus the rebuild.
So far the crank and clock have been hot-dipped to shiny goodness. The block is now "Grabber Green" enameled. Its rather shiny. The engine has around 9.0:1 compression stock, and I'd like to see anywhere from 9.6:1 to 10.2:1 on Regular. 86 Octane around here is regular if I remember right. Thus the use of Somender Singhs grooves and soon.

I'm looking into a custom intake and exhaust manifold setup, but dunno how realistic that is. The intake'd be FAIRLY easy. Use some velocity stacks (32mm ID x 120mm tall) attached to a further maybe 60mm of tube, hopefully tapered down to 30mm on the ones needed. Those'd be attached to a flange piece. If I were interested enough in it, I could create a sleeve here to allow the removal of the 60mm section to later install injectors. Doubt I'd put a MegaSquirt on this though. Unless I bought it, learned how to tweak it on the Super-3AC then used it on a 4AGE. Anyway, on the other side they are attached to 4-inch exhaust pipe that acts as a plenum. Dunno where the carb goes yet though. The 32/36 and 38/38's can't be side-drafted, so a rather tall hood-scoop would be needed probably.
If all else failed, I could ditch the velocity stacks. However, I've read that they can provide up to a 25% increase in airflow.
Anyway, a tube-type header would complement this intake manifold. The ends would have to be formed to a rectangular-oval shape to match the ports, then bend sharply down (mandrel, of course) and likely go into a 4-2-1 collection system. Cyls 1 and 4 and Cyls 2 and 3 paired. 180 degrees off from each other. Equal-length would of course be attempted. Probably extend to just before the current cat position, giving... Jeeze, I dunno... 3 feet of header length? Hopefully boosting low end torque. Shorter might be used, depending on where the engine lays with the stock mannie. Anyway, likely through a flex-pipe it would connect into a 2.25 inch Random Technologies Catalytic Converter (might go so high as 2.5") then into a Y-pipe 1-into-2 muffler where it branches out to 2, 2.25" pipes that exit out the sides just pre the back wheels. Using the dual 2.25's would allow for the use of these pipes in up to a 3 inch exhaust system, to allow compatible flow rates. The 3 inch coming from the possibility of using a Highly turbo'ed 4AGE later. Might as well make provisions just in case.

Heh... I need better use of my free time sometimes
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[*] posted on 18-8-2006 at 04:28 PM


Actually, heres a link to the type of intake I've been looking at. Even with the brand of Velocity Stack.
http://www.velocity-of-sound.com/velocity_of_sound/images/finishedm...
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[*] posted on 19-8-2006 at 02:47 AM


You probably won't change the characteristics of the 3A-C enough with just those mods to move the powerband, so just shy of 5000 RPM is where the HP should be, and the torque will still be in the midrange, perhaps slightly higher than stock. The compression probably won't change much, if any, either. Your biggest gains will be simply because of the weber, since the stock carb has always been the bottleneck on the 3A-C and 4A-C. With the capacity to dump lots of fuel, and the engine in prime shape to run wide open, the motor can finally show it's stuff.

I wouldn't suggest going into custom intakes unless its for sidedrafts, racing, or just experimenting. A downdraft weber is pretty capable of being jetted to deliver more than enough fuel through the stock intake manifold.

A header would be a good mod even without the custom intake. The 4-2-1 would go with the engine's design and be an improvement on the 4-1 stock manifold, but don't make it too long since you'll kill the high/mid for low-end that isn't there. I don't suggest using exhaust tubing any larger than 2 inch. In the meantime, if you're not getting a new exhaust, hopefully you've got a higher flow muffler or will just remove it.




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Typrus
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[*] posted on 19-8-2006 at 12:05 PM


I have a 2.5" stock-style muffler. So much higher than stock for flow. But I am thinking about doing that dual system.
One of my concerns with a header is the fact that with the way the intake meshes with the exhaust, a pretty sharp angle down would be required. Might even have difficulty fitting a decent sized tube in there. Let alone the fact that the first few inches have to be shaped to the rectangularized oval that is the exhaust ports.
So in a 4-2-1 for our engines, a 1-4 and 2-3 pairing is recommended, right? The cylinders 180 degrees off?
Anyone know how long up the header the 2-1 should happen? Then how much longer until the pipe?
You don't think that a cam, porting, decking down maybe 3 thousandths, doing the Somender Singhs Grooves, and the Weber won't necessitate anything bigger than 2"? Not even 2.25?
One of the big reasons I'd like to do the custom intake is for the velocity stacks. They'd ramp my flow up a bit. According to some places, upwards on 25%. Are you sure that stock intake'll flow what I'd like it to? I'm port-matching it for the first few inches, so that might help some. Well I suppose it would be kind of a pain to source all that aluminum.

I'm a little bit worried that the extra power might make my tranny finally kick the bucket.
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[*] posted on 19-8-2006 at 12:38 PM


according to people over at club 4ag.. who've had work done to thier 4ac's

by work i mean up to if not all, weber , p+P, cams , dual springs and a blue top bottom end lightened fly wheels etc .. 2" is all you need.. many who got 2 1/2 say they lost what low end torque they had.. thats the 4ac though but i'm assuming the 3ac may suffer the same way..

again this is based off of what i've read not personallyu experienced




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Typrus
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[*] posted on 19-8-2006 at 02:46 PM


Huh. Well, I still like the dual idea. Maybe I'll just get the 2.25 inch in /2x2.25 out and use a 2 inch front pipe and cat? Leaves the option open in case I decide to go 4AGE later on. Maybe not. I dunno.

So I pounded on an old trampoline pipe... I got a recta-oval shape out of it, but its rough at best... Would it be best to purchase a vice and squish that way? Or are there pipe-forming tools?
I'll let you all know if I can think of any more issues.



EDIT:
Okay, I measured the Circumference of the exhaust port hole in the mannie gasket. More or less 4.125 (4 1/8") So the closest exhaust pipe inner diameter is 1 5/16" for each exhaust runner.
So a 1 1/2 inch exhaust pipe with a wall of .065 is roughly 1.37" inner diameter. thats about .0575 too large.
Useless margin?

Other than pounding the crap out of the pipe I still dunno how I'd form it....
I do have a 1000F heat gun?
BTW, I do appreciate this. I keep asking these kinds of questions back at Tercel4wd.com and I get cricket-chirps. But ask about a vibrating back axle and you get 40 ideas. lol.

[Edited on 19-8-2006 by Typrus]
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[*] posted on 20-8-2006 at 12:41 AM


A dual-out muffler is useless for performance purposes on a 3A-C. The best performing exhaust would maintain high velocity throughout the system, and thats easiest to achieve with a single 1 7/8 to 2 inch exhaust. The cosmetic effect of dual outlet pipes might be nice if you want it, and you could probably do a 2" muffler with dual outlets if you wanted.

The header would need to be just as you're thinking it should. Pacesetter actually made one for awhile, it was total crap like all their other stuff, but gave a general idea of a possible design. Before starting out though, I'd suggest doing alot of reading and research on exhaust design, you'll probably be able to come up with something killer if you really put alot of though into it. I'd do the non-sequential pairing like you said, but without much room to work with, the header length is going to be restricted by the space you have to work with, so based on that measurement, you can choose the diameter of the tubing to get the best flow. Don't build an exhaust using a vice to form the pipe. You'll want to choose the pipe diameter and get the tubing, have it cut, and then expanded and machined to match the ports. Mandrel bends on the whole thing, too.

The mods you're doing don't require anything bigger than a 2", and most 1.5-1.6 L engines don't need large exhausts. The only reason you'd need to step up to 2.25" or 2.5" would be dumping as much fuel as the engine could possibly handle with dual sidedrafts or some custom injection system or something.

You can use velocity stacks on anything you want. Make an upside-down bell and stick it on the stock carb, a downdraft weber, a sidedraft, anything. It helps suck air, but generally they're for racing use since you want an air filter on there to prevent the engine sucking down solid particles while driving around. If you're feeling up to it, make a custom velocity stack and a hood scoop for your carb. The stock intake is absolutely perfect for the Weber 32/36, if you wanna go wild and get the 38/38 and make an intake to go with it thats fine, but I'm not sure you'll gain a whole lot from it.

I don't think you need to worry about the tranny other than how you drive the car. Use some good synthetic fluid in it.




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Typrus
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[*] posted on 20-8-2006 at 10:31 AM


Get it expanded, cut, and machined? What? How will that bring it to a proper shape? Maybe I just have to talk to my local exhaust shop...
I don't want to have to use a 1 3/4 inch pipe and lose velocity with the extra 1/4 inch or whathaveyou.
So then, assuming 1 1/2 is proper for the initial runners, what would be appropriate for the 2nd stage of runners? 1 3/4? 1 7/8? The final length would be made to 2 inches to match.
The duals is more of a thing for interestingness. That and it prevents the annoying excessive bending required to go around the rear axle. Though I suppose a single outlet might be more practical. I dunno. That and I was curious how a Flowmaster 40 Delta Series would sound.
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