worth it?

[skulley]

So I was just wandering how difficult it would be for a well versed mechanic to swap out the 3ac for a 4a.. and is that the biggest engine that can fit in our little cars? My mechanic says that he could do the swap for me for around $800 including the engine and labor cost. So my other question is that from what I've read the transmissions on our cars are hard to find so why put a new engine in if you can't replace the tranny?

[Petros]

If you need an engine the 4ac is an easy swap. It is worth it. A more powerful fuel injected engine such as the 4AGE or 4afe could also be make to fit but it is a lot more work.

Is your tranny bad? A lot of miles does not mean it is bad, some can run up to 400k miles if cared for. It is still worth it, you can find used trannys, but they are less common than they used to be, but still available. You just have to keep your eyes open for them in the wrecking yards.

Good luck.

[skulley]

Thank you Petros! My tranny seems ok. What are the benefits of going with the 4ac? How much more power do you get? Is it about the same mpg?

[Petros]

I think I recall about 16 hp, the North American 4ac is claimed to have 90 hp (vs. the 62 for the 3AC) according to Wiki, but that seems way too much for just having 135 cc more displacement (and everything else is the same).

I would suspect the fuel economy would be similar, it takes the same amount of hp to push the car at fwy speeds no matter the size engine that is in it. So it should use the same amount of fuel.

[takza]

If you look at some of the older car manuals that cover the 70s ... 80s...90s...you can see that as they "improved" the top end (head-intake-exhaust) on various 4 banger engines...the torque rating drops some...while the HP rises...when the displacement stays about the same? I think the 3AC was derated to pass emissions...since I tested around a 20% gain in "power" by advancing the ignit...though if you advance it too far you will lose mpg.

The car is really inadequate HP wise as it is set up...while I can shift at 2500 rpm with no problem now....most of the time.

With some of the later engines...the power is more up top...and you have less grunt power.

[Petros]

The 4ac uses the same head, valves, and a very similar carb as the 3ac. So it is an easy swap, and easy hp gain as compared to going to the more modern 16-valve EFI designs of the 4afe or 4age.

I think the 3ac and 4ac represent an earlier (and obsolete) design for small engines, there were contemporary cars with much better head, intake, exhaust and EFI set-ups. Unfortunately when they finally got around to putting a better engine in a small 4x4 car/wagon, the car also was "modernized" into something undesirable, and the sales fell off and the Corolla all-trac was discontinued. You would think they would learn from the popularity of Tercel4wd, instead they went even larger with the Rav4 and they ended up switching customers. I think most of the Tercel4wd buyers have switched to the Suzuki 4x4.

[onelungderryl]

Why not a 4agze or a 20 valve 4ag? I did one in my 1985 toyota corolla, they sell kits for the waterlines and for the distributor. Or ofcourse you can figure out how to run coil on plugs like I did or just bash your firewall.



the ae86 came with a 4ac which is basically the same as the 3ac so im assuming a 4ag swap wouldnt be hard.

[Petros]

That looks hot Onelungdaryl! what is that intake set-up, is it EFI, if so how does that air cleaner work with the throttle. Where is the throttle located? is that distributorless ignition?

what is the horsepower out put? That could be made to fit in a tercel4wd, but it would be a lot of work. Custom flywheel, custom header to clear the steering shaft and rack.

[onelungderryl]

It cost me around 2000 to do myself. It is distributorless, im using the distributor as a cam trigger for the coils. Id say around 150hp. I was reading about how the flywheel has to be machined or how a 6 bold crank should be used. If someone took initiative and built a 7afe bottom end with the bigger rods and the 6 bolt crank and throw a 4ag head on there it wouldnt be too hard (assuming the oil pan would fit). Or just use a ae86 subframe, front suspension and make it rwd...

I was also thinkig a 22r with the 4wd transmissor from the truck. I've seen the swap done before in corollas (with the rwd tranny) but as long as you have some kind of access to fabrication it'd be possible.

[onelungderryl]

Its efi, individual throttles. The intake is a pipercross that comes blank and you drill yourself.

[Petros]

Its efi, individual throttles. The intake is a pipercross that comes blank and you drill yourself.

I like it. Are they expensive? Do they make them for the 4age? I am slowing working towards doing a 4age (large port) swap, and have most of the parts I need assembled. I still have to rebuild the core engine. But with an intake manifold like that I would not have to alter my hood, it would solve one of my problems.

[onelungderryl]

venus auto in sac sells the silvertop for 500 with ecu, wiring harness, dizzy, sensors, manifolds, afm. but you want a blacktop or atleast a blacktop ecu, wiring harness, map sensor and ats so you can run the open throttles without a afm.

the swap is worth it 3x more power than a 3ac. only downside is the 4ag engines use a 8 bolt flywheel, which i read is problematic for these cars. check out club4ag.com under tech reference and also the 20valve section of the forum. hope this helped and inspired!