hi just sighned up to get some info im about to purchase a fwd corolla 4a-ge 20 valve silvertop for my tercel 4x4 wagon and have some questions i have searched but would like to clarify some things
the bell housing will bolt on?
i can machine down the 20 valve flywheel to accept the turcel ring gear and use the 20v clutch?
engine mounts bolt on?
does the sump bolt on or do i modift the 20v sump?
apart from those things i should be ok with the rest ill be running a aftermarket ecu bigger injectors fuel surge tank setup and a small t3 turbo off a rb20 on hopefully 10 psi 2.5 inch exhaust and a small intercooler with a custom front facing plenum setup how strong are the turcel gearboxes? also im planning on modding the front hubs to accept lock in units so i can leave it in 4wd but have a rwd car or 4x4 with the front hubs locked in its all for a laugh really my mates give me shit for owning a tercell all the time so i just want it to be a little bit faster i have plenty of spare turcells for diffs and gearboxes
Larry McGrath installed a 20-valve into his Tercel. The short block is almost identical and all of the "hard points" for bolting bell housing, engine mounts and oil pan are identical. Larry cut down the 20-valve flywheel to take the 3a ring gear, fits okay but bell housing may need some minor clearancing to allow the larger clutch to fit. Welding in 4 of six bolt holes, and than machining 8 bolt holes in 3a flywheel has also been done, but it means you will have to use the smaller 3a clutch.
Gear boxes not really durable enough to take that much hp, I would advise going without the turbo. Unfortuantly there is not really any similar trans to upgrade to, the T4wd trans is unique to this car. Some have considered have gear clusters treated to make them stronger, but that is a very costly experiment. I would suggest not running more than about 120 hp through it, or if you do keep it rare and only in 4wd so the load is spread between front and back drive train. Consider this drive train was designed to push this car w/o the rear drive train, and the rear axle is from the rwd corolla, also designed to push the car without the front drive train. So you should be able to about double the hp, if you drive it nicely. Tripling the hp might be too much for the trans. You can go with a corolla GTS rear axle (AE86), which has a larger diff, and has an LSD option, but the trans is going to be your weak link. Use a freshly overhauled trans and use the best synthetic oil in it is about the best you can do, and do not abuse it, shift nicely and smoothly, and accelerate smoothly, should be okay, for a while anyway.
It might be nice to find a CV axle that uses same splines but with larger CVs, not sure if any area available, but if you are changing the front hub it might make a heavier axle a possibility.
If from Australia reason for going turbo was really just because I have all the parts laying around and the ecu I have will be wasted using it on a na engine it's off a Nissan sr20 I'm planning on mounting the crank angle sensor throttle position sensor and the 4 coil packs on the 20v and the 20v I'm looking at has no ecu so it works out for me plus I will use the engine in a buggy when the turcel dies I won't be driving it hard or dumping the clutch just using the power smoothly I have 4 gearboxes anyway knowing the gearbox is weak I should probably just turbo the 3a but I don't know enough about carbs it would have to be draw through then I can't use a intercooler and on 10 psi it will probably ping
This sounds like real fun, first off im larry i just put a v20 B/T in my tercel 4x4. to start off the 3a oil pan wont fit on 20v side bolt pattern has a 1" indent in the side of the pan ,you need to mod oil pan in 3 places the trany,and engine mounts line up,altinator bracket needs to be shimed about an inch to clear front of engine the 3ac harmonic balencer needs to be machined down so it slides farther back to line up all the belts p/s,alt,a/c. I took a 8 bolt 4age flywheel turned it down instaled the starter ring from the 3ac and used a 98 corolla clutch and pressure plate and a stock throwout bearing . If you look in the forum under gallery (Larrys tercel gets a v20 B/T) you'll find a complete wright up on this mod. this mod realy makes the car fun to drive if you go easy on the trany, the clutch seems to actualy work better than the stock set up. Where in austraila are you located ?
Tasmania so do you use the 3a alternator and brackets or? I'm a fitter and turner so machining won't be a problem at all also the engine looks higher will it hit the bonnet at all? Do I need to shim the subframe? How is your gearbox holding up I have spares I don't plan on rebuilding them just changing them when they break
I put a1/2" steel piece of bar stock under the cross member,started out with 2" piece of box tubing, it was too much, realy screwed up the angle of the axels. made it steer like you were driving a Marshallow on wheels. stayed with the 3a alternator. had to mod serge chamber for hood clearence.
the 3a head is unsuited to turbo or any other kind of up grade, Toyota messed up on the 3a head water jacket, it does not cool evenly and every attempt I have made to get more power out of it has resulted in blown head gaskets. The obsolete 8-valve head also really limits breathing and power output, turbo or not. That is why I am swapping to the 16-valve 4age.
About the best you can do with the 3a is to put a weber carb, clean up the ports, and do the modifictions to the gasket I have outlined over in the repair guides section for replacing the head gasket.
You are much better off to just swap out the engine to a more modern, more powerful and more reliable version. I am not sure I would go to the trouble of a turbo charged 20-valve (the idea had occurred to me after my 5th blown head gasket), but I opted for the more tame 16-valve naturally aspirated 4age.
thanks for all the help im moving my other tercel with a thrown conrod to my house soon to pull the engine out and start fitting the 4age also picked up 2 more spare gear boxes
