Tercel Engine swap questions

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MicronMilleniaPro
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Tercel Engine swap questions

Post by MicronMilleniaPro »

Hey all, So i'm looking at an '85 (the one in my profile pic), and ive got a couple questions about engine swaps. I've heard 4ac is the easiest, but I've also heard those are barely an improvement over a 3ac. I've also breifley looked at 3a-su's. And back on the 4ac topic, will a 4ag also fit in bolt-on? so basically my questions are

1. Will a 4ac be able to cheaply make 110hp?

2. Can i bolt on swap a 4ag?

3. Are 3a-su's good motors? if so, are they able to make 100+ HP?

4. Are 3a-su's easy to find parts for?

5. If a 4ag is a bolt on, what kind of power am i looking at stock, and what are the best mods to do?

6. Will i see a drop in mileage with any of these?
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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Tercel Engine swap questions

Post by Petros »

1. possible, but not likely cheap. the stock north American 4ac is rated for 74 hp, you can likely get up to about 85 hp with minor and inexpensive tweaks done along with a rebuild (over over bore, raised compression, new cam, header/exhaust, possibly weber carb, etc.) that would be a big improvement over the stock 3a 62 hp.

2. No. the hard points on the block will bolt up to the trans and engine mounts, but you will need a new custom exhaust (or jury rig a tubo ex manifold with an adapter), alter the flywheel to bolt up to a 3a flywheel (6 bolt, vs. 8 bolt), and than get a costly side draft carb set up, or rig up a fuel injection system for a car than never had EFI.

3/4. the Japan DM 3a-su is a rare bird in north America, it is rated at 86hp, the highest hp 3a in the inventory. I have a lot of experience with the SU carb and think they are great once you know how to tune them. I would love to have a Tercel with SU carbs, but I have never seen 3a-su in the states. there were a few that were imported as crate engines I think, but I have never seen one, likely they are rather rare. You can likely buy parts for the carbs mail order, the long block parts will be the same as the north American 3a, except perhaps the camshaft. routine maintenance parts should not be a problem for the 3a-su.

5. stock north American 4age is 117hp (with factory EFI), many have tweaked them to well over 200hp, one I heard got 450hp (that is not recommend, and likely cost a lot of money to do). again however, the swap has been done into the tercel4wd, but it is major undertaking. time consuming and many costly custom parts to fabricate.

6. that is mostly a matter of your driving style. when you have more power available most tend to stomp on it more. but I know of people that installed the 4age with the factory ECM and improved their hwy mileage to about 34 mpg. the 4ac usually drops a bit, one or two mpg, but I think that is mostly a matter of driving style, heavy foot or light foot on the pedal. I would not know about the 3a-su, I would think it would improve slightly if you drive it gently. if you have one available, install it and let us all know. if you have one available, and are not going to use it, I will take it off your hands.

Good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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