engine overhaul vs. swap

General discussion about our beloved Tercel 4WD cars
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engine overhaul vs. swap

Post by toddmott@gmail.com »

I've got a Dead number 2 cylinder . Wondering if overhaul Would be more Difficult versus engine swap out ideas suggestions on alternative Motors to the 3A or 3 AC 4 86 SR5 4 x 4 wagon .

Any help ideas influence Or perspective would be greatly appreciated
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Re: engine overhaul vs. swap

Post by NWMO »

The 4A is the only "easy" swap and provides some (albeit not a lot) additional power. Fuel mileage will likely be a little less with the 4A as well (1.6L vs 1.5L). Other engine swaps have been tackled, but require significant modification and fabrication. If the 3A isn't in bad shape, you may just want to rebuild it.
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Re: engine overhaul vs. swap

Post by simon84 »

I have the 4a with weber. I just did a bunch of other stuff to the rebuild the car (trans, suspension, 1" strut spacer lift and 1/2" drop to crossmember and trans mounts, new exhauast system -no cat and cherry bomb for a "muffler" and some body work etc) including ditching power steering and installing manual steering rack and set timing to 10' (it was around 8' before). I'm noticing that it's a bit peppier than before. Maybe it's just the growly rumble from the exhaust and that my 3 yr old keeps referring to the tercel as the "sports car".
I'm sure that some of the other fuel injection engine swaps are great but the 4a is simplest.
Driver: 87 Tercel SR5, white, 4ac, weber carb (aka the Tercedes)
Road Tripper:95 Mitsubishi Delica L400 2.8L Turbo Diesel
Motorbike: 94 Kawasaki Ninja ZX6
Project Car:Red 68 Plymouth Sport Fury III
Previous Tercel:Orange 84 Tercel 4wd (aka the pumpkin)
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Re: engine overhaul vs. swap

Post by Petros »

first of all, likely you have something wrong with the head gasket or the exhaust valve in #2, it runs the hottest and typically developed problems first. it is far easier to remove the head and fix it rather than swapping a whole engine. and you may also find that the replacement engine has a lot of other problems only after you install it and get it running in your car.

remove the head and take a close look at the piston top, if is clean and shiny compared to the others, it means it was "steam cleaned" by the coolant from a head gasket leak. the other place to examine is the exhaust valve, they often get heat fatigue and they lose a piece of metal, sometimes the whole valve head breaks off (and results in lots of damage to the engine, including bent connecting rod and crank shaft), but you would know if that happened. I have seen once the wrist pin comes loose and than drifts to gouge a deep groove in the side of the cylinder, if that is the case you have to replace the engine. the other situation is a severely damaged piston that will not allow compression. either of these last two also has lot of oil consumption and blueish smoke.

pull the head off first, it should only take you about an hour or two, and get a look at the valves and head gasket. I would recommend you replace all of the exhaust valves, they get heat fatigue and can break apart. but pulling the head will make it easier to pull the short block out of the car anyway, if you find the lower part of the engine is bad. go read up on my head gasket replacement guide over in the repair guide section.

if you are going to get another engine, than get a 4ac, there is no reason to just buy another 3ac. unless you know it is in good shape (not based on the sellers claims, but rather from running it or testing it), I would advise to rebuild it before you put it in the car. so it makes the job even bigger, but it is well worth the cost and trouble. you might get another engine all in and running find out it has little to no oil pressure, rod knock, or a bad head gasket, or worn out piston rings. and you get it do it over again, and rebuild it.

even if you know it is a good engine, you will have to swap over the oil pan and oil pick up from the 3ac so it fits in the Tercel, you can just remove the #3 and #4 connecting rod caps and carefully inspect the bearings and the crank journals. if good and shinny, put them back the way it came off, and retorque it. replace the rear main seal (you will likely have to swap out your flywheey anyway) and install a new clutch unless you know your old one is recent.

it is far easier to pull and fix a problem in the head, rather than swap out a whole engine. more diagonsis might help you make the decision. put an air fitting in the #2 spark plug hole and attach compressed air to it with the #2 at top dead center. if you hear air leaking out the exhaust pipe (put your ear up to it), it is a bad exhaust valve. if you get air pressure and bubbles in the radiator, it is the head gasket. if you can hear air leaking into the oil pan (listen at the oil filler), than usually the lower part of the block is bad, you will have to pull it apart to see exactly what it is. might only be bad rings, though it is really rare only #2 goes out, more likely damaged cylinder walls or piston.

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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