Welcome to the forum. I can add some to what SirFoxx already wrote:
ReverendRadical wrote: ↑Sun Aug 01, 2021 9:50 am
Questions:
1. Is there really a considerable difference between the 3.73 and 4.11 geared transmissions? If so, what is the difference in top speeds and fuel economy?
I owned several of each, it is a give and take for each: the earlier 3.73:1, what you should have in yours, is not so good in rough steep terrain, or starting from a dead stop on a hillside, but it is a bit more quiet at freeway speeds since the engine is at a lower RPM. also is better for a general daily driver I think. the 4.11 is good if your interest is mostly for rough/off road performance, and good from a standing start. If you want to do a performance up grade to the engine, the lower 4.11:1 is better, or if you want to build a high torque engine for low speed/off road use, the 3.73:1 is better for mixed on/off road use I think.
Both get about the same fuel economy as reported by others in the form, and as I have found on cross country road trips in Tercels with both final drive ratios.
I have a 4ac swap, with a few tweaks to get a bit more power out of it, and find that the 3.73 is not a major drawback for rough roads and steep hills with the extra power, and I still get a lower rpm hwy speeds for more pleasant highway cursing. the 4ac has fairly good low end torque as well, so the higher final drive does not suffer as much as it might with a stock 3ac. I have a project tercel4wd, building it up for a 4age swap, and will use the 4.11 final drive because the 4age is a high rpm engine, with out as much torque at lower rpms, so I think that engine is better suited for for the 4.11:1 final drive.
So you can make either work for you, it just depends on your long term plans, and your intended use, as to which one is better. it is a costly undertaking to swap out both front and rear diff/transaxles, so if you want the 4.1:1 I suggest you find a good candidate for your project car with the desired 4.11:1 ratio and either sell your current one, or keep it as a daily driver, or stay with your current set up if you want to keep the 3.73:1 ratio.
ReverendRadical wrote: ↑Sun Aug 01, 2021 9:50 am
Questions:2. I know that the most popular engine swags are other A series engines, but I REALLY love the 2zz-gte engine in my old Celica gt-s. I know its a transvers engine and it would have to be mounted longitudinally and use a different trans or just make the car fully fwd which would also take a lot of work, but it should still be possible... right? If I do all the fabrication myself at least I guess.
the 2zz is a great engine, and anything can be made to work, but it would be a major undertaking, with lots of special fabricated parts, to have it bolt into the Tercel4wd drivetrain and engine compartment. you would need a custom flywheel, custom made oil pan, special custom made engine mounts, an adapter ring made for the bellhousing, special coolant fittings, a whole new (from scratch) ECM and EFI set up (this can be done with factor parts from a wrecking yard, but it will be a lot of work sorting it out). I would advise against a 2zz swap unless you have done such major undertakings before and know what you are getting into. the most likely outcome would be it would sit for many years incomplete, too costly to complete, and/or too time consuming. It may never get done, and you end up selling a partly modded car at a great loss, few would want to take it up, and you have ruined any collectable value for a decent factory configuration Tercel4wd. Even if you did sink many thousands into it (even if you had the skills and access to a well equipped fab shop), the finished product would not be worth the extra time/cost/hassle. you would be on your own to make it all work together, special parts, mounts, electrical, etc (not an easy task to sort out). you would have to become a self educated automotive engineer, specializing in doing such an obscure swap.
Stay with one of the many good A-series engines, you have some excellent ones to choose from, and many performance parts are available and fairly inexpensive for custom parts. At least half of the swap issues are easily dealt with on any A-seiries engine, you will still have custom exhaust, fuel system, and the EFI conversion to deal with, but those will not be so overwhelming. the 4ac, 4age, 4afe, and 7afe area all excellent up grade engines to select, with good availability of both engines and parts.
ReverendRadical wrote: ↑Sun Aug 01, 2021 9:50 am
Questions:3. While I like the ideas of engine swaps, ive never done one before and id like to keep the idea of the tercel in the tercel with the 3A. Is there any way to slightly bump up the power numbers from the roughly 62hp to somewhere between 70 and 80hp? Could the carb be adjusted enough to produce that kind of power or a bigger/better carb or do I need to go to electronic injection?
what is the point of the previous question? if you have never done an engine swap, DO NOT EVEN think about trying to get a 2zz to fit. While the 3a engine is underpowered and has a poor head design for tweaking it for more power, it is okay for reliability in stock form, but nothing more. I tried to get just 20-30 more HP out of a 3ac engine for ten years, and kept having major failures and finally gave up on it. it is not suitable for boosting the power out of it, it is not durable enough. I have extensive experience with both performance engines, up grades and car modifications, and I have worked as an automotive engineer for a factory backed, fully sponsored racing team, to let you know that when I state the 3ac is not suitable for tweaking, it is from a lot of professional experience. It is okay in stock form, but trying to get more power out of it will only lead to disappointment when it fails.
Best, least costly, and a more reliable thing you can do: Go get a 4ac out of a corolla, add a few tweaks to it (street performance cam shaft, clean up the ports, custom exhaust, lightened flywheel), and perhaps go with a weber carb, and you will get a reliable 90hp+/- out of it, and it will all bolt up without any special parts needing to be made. it will drive well and you will not feel under powered as you do with the factory 62hp. This forum has many good threads on doing exactly this simple engine swap/up grade. Stay with what works and you will enjoy it for many years to come.
ReverendRadical wrote: ↑Sun Aug 01, 2021 9:50 am
Questions:4. Other than common maintenance items, is there anything that I should be ready to replace or fix? The car has 270k miles on the body and about 100k on the trans.
change out the gear oil in the trans, follow the procedure in the repair guides section of this forum. Make sure you get all 4.1 quarts of gear oil back into it. if there are any leaky seals, fix them right away. you must protect that transmission from low gear oil and leaks; it is very durable transmissino, but only if the gear oil is kept topped up and fresh. if you run it low on gear oil, it will trash the trans. And it will be hard to find a good replacement. parts are no longer available to fix a broken one, you have to search the wrecking yards nation wide, and parts cars, to get a replacement transmission, and hope it is not as badly abused as your wrecked one.
On a car this old, almost anything can be worn out and need to be replaced. fortunately for most all other parts of the car (besides the transmission), replacement parts are available and usually doing the repairs yourself is not too difficult. fortunately the Tercel is a very simple car to fix and maintain, and good for learning to DIY car repair. likely there will be other things to fix, but it is impossible to predict what that could be. Rubber bushings on the suspension, ball joints or tie rod ends, all should be carefully checked, and replace as necessary. Brakes seals and bearings, if necessary, replace as needed. Struts and shocks can be shot, or might be fine. a common issue with an other wise good running engine is the valve stem seals leak oil into the intake, not really harmful, but smoky starts are annoying. those can be replaced without removing the head. a leaky or compromised head gasket is common on the stock engine (poor head design), so keep an eye on your coolant level. if it is using coolant, and you have no obvious leaks, likely you will need a head gasket soon (if you need one, follow the head gasket procure over I wrote up in the repair guilds section fora more reliable headgasket installation).
In the repair guide section, as I recall, there is a thread listing all of the items to check on a newly purchased Tercel4wd. go check it out.
Good luck.
