The
Oldcorollas FAQ
An FAQ dealing with KE1x to KE7x Toyota Corollas
Supplement to http://groups.yahoo.com/groups/oldcorollas
More and more people are asking the same questions about modifying
Oldcorollas, in order to save some time and to compile the most
accurate information, I've made this page to address some common
conversion questions. If you have anything to add or correct, please email me.
Before we start - you need to
at least know about a few webpages:
Matti Kalahati's Toyota Info - http://www.geocities.com/MotorCity/Pit/9975/tm_index.html
Jonny Rochester's Old Corolla Site - http://www.geocities.com/jonnyr_1973/
Toymods - http://www.toymods.org.au/
Club4AG - http://www.club4ag.com/
Registration and Engineering
Before you spend one cent changing the motor in your car, speak to your
state's motor vehicle registration department find out if it needs
approval from an engineering signatory. If so, find one in your area
and discuss what you want to do with them. They may require you to make
changes in a certain way (ie: modification of transmission tunnel to
maintain structural integrity of the floorpan) or to upgrade other
things in the car to handle the force of a more powerful motor (such as
brakes). There's no point, and it would really suck, to put a whole
heap of money and/or effort into your project car only to find you
can't drive it on the road.
Differential
Once you start making over about 80hp in one of these cars, you really
need limited slip to get the most of out it, or you'll just be doing
single wheelers everywhere. If you drive sensibly (no hard launches or
burnouts) then your stock diff will last, Angela from Adelaide has a
KE10 with a 225bhp turbo 5K and has never changed the stock 5.7" diff.
Of course if you drive hard, which is really why you're doing the car
up, right? You'll kill it. Nothing better bolts in, so it's time to get
custom. For a drive-in-drive-out conversion, expect to pay about $1500.
If you get a diff the right width, you just need leaf spring mounts
welded onto it. The pinion angle of these is pretty important, as is
the strength of the welds, if you don't know about either of these
things then pay someone to do it for you. Most stronger diffs are from
larger cars, and are hence wider, so you might need to get some things
shortened. It's easier to shorten a diff a lot than a little.
Some people use a Hilux diff, but this is known to be pretty heavy and
perhaps a bit of an overkill unless you're making huge power. That
being said, these are very popular diffs due to 4WD enthusiasts, so
there is a large range of ratios (i've heard of a 5.7:1) and Limited
Slip centers available.
A popular choice is the Borg Warner LSD diff from an R31 Skyline. These
are an unequal-length housing, so you get one axle and one side
shortened so it's all the same, and it should be about right for a
Corolla. The Skylines had 3.6 or 3.9 ratio gears, auto Pintaras in that
series had 4.1 gears, these are desireable. You can use the LSD center
from anything with the same type of Borg Warner center, some examples
are EB-onwards XR8 Falcons, and VN-onwards SS Commodores, they are the
same LSD as the Skyline, just cheaper. You use Skyline axles because
they are the same wheel stud pattern as KE30/55/70. Unfortunately,
these LSDs aren't really known for their quality or for lasting a long
time.
Probably the best choice is a Toyota T series diff. These came with
drum brakes on everything but the Japanese AE86, and those disc brake
diffs are very expensive. TRD LSD centers and 4.3 gears (although
pretty bloody rare) are available for these diffs, and are a Torsen
type so they work really well and last for yonks. If you use a TA22
diff, it's the same width drum-to-drum as a KE30/55 diff, and probably
a pretty decent size for a KE20 with not-too-wide wheels or flared
guards. If you have a KE70, a T-18 diff should bolt straight in, now
just get the LSD center. There are plenty more cars that these came out
of, check Matti's page.
Things This Article Doesn't Cover
Wiring - An EFI engine
obviously has alot more wires coming off it than an old carby engine,
sensors and ignition systems and what not. Phil Bradshaw's webpage
(http://home.clear.net.nz/pages/phil.bradshaw/)
will be useful to
people doing a 4AG conversion. Toyota dealer service are usually
friendly enough to let you photocopy wiring diagrams if you ask nicely.
A
carbed 2T should be able to just drop in and you match up the
alternator wires.
EFI fuel system (if applicable)
- I don't really like EFI so I've never bothered to research much into
this. At the least you're going to need a high pressure pump, bigger
line, use the stock line as a return, and probably an unleaded filler
neck restrictor. Lots of people fit a surge tank too.
Hydraulic clutch conversion -
You will need to do this for any gearbox with a hydraulic slave
cylinder on it. Check Jonny's webpage.
Front brake upgrades - Your
engineer might want you to do this if your new engine is sufficiently
powerful. There's a KE70 Tech article on Toymods about using Cressida
brakes. Jonny has upgraded his front brakes by swapping in Corona
struts. Mal McKiggan made a post on Oldcorollas about using Camira
rotors on KE Corolla hubs,
2T, 2T-G, 3T
Corollas in America and Japan came out with 2T motors, these are 1600cc
alloy-head crossflow four cylinders, or which there is a higher
performance, twincam variant called the 2T-G. There is also an 1800cc
version called the 3T. In Australia 2Ts came out in TA22 Celicas and
the like, 3Ts were in T-18 Corollas. Some people say a 2T is "too
heavy" for the front end of the light Oldcorolla, I say you set
anything up properly and it can handle well, there's a KE20 racecar at
my local hillclimb track with a 327 Chev in it and it gets around just
fine.
Jonny's webpage has a complete conversion howto for this engine and T50
gearbox into a KE30 or KE55.
If putting it into a KE10, they have a very small engine bay and
narrower mounts on the engine crossmember, they are also missing the
second set of holes for the gearbox crossmember, so you've got some
custom fabrication to do. Factory automatic KE10s had a larger
transmission tunnel which fits a T50 gearbox without a problem,
apparently factory manuals had a smaller tunnel that requires
modification.
KE20s do have the other chassis rails holes, so your gearbox will fit
up. The engine mounts on a KE20 crossmember are the same width apart as
KE10 ones, but the crossmember is a total different shape. Again, time
to do some custom things.
If you've got a KE70 and want a T motor, I would be inclined to just
find a T-18 engine crossmember from the wreckers and use that, I
believe it's all bolt in, but you might want to double check the
struts, steering rack, control arms, steering arms, etc will fit.
1G (GTE/GZE)
This is a 2L inline six cylinder Toyota engine. Yes, a 1G will fit in
the engine bay of a KE70, KE55 and KE30 Corolla. I'll bet you could
even stuff one into a KE20 or KE10 if you moved the radiator forward.
You will need to englarge the transmission tunnel to fit the gearbox
in, and make custom engine mounts. I know someone who used to have a
KE70 wagon with a 1G-GTE, he says it was great for doing burnouts and
going in a straight line, but the nose was a bit heavy to corner well
at speed.
4A (GE, GZE, GTE)
These popular 1600cc engines are in RWD config in AE71 and AE86
Corollas. These use a T50-type gearbox, but with a different
bellhousing and internal bits and output spline to a T50 from a TA22.
Despite rumors to the contrary, you cannot use an AE71/86 bellhousing
on a TA22 T50. Well you can, but it leaks oil because the input shaft
bearing is a different size, and it shifts like crap because there are
some internal spacers that won't fit anymore. The best thing to do is
probably use an AE71/86 gearbox and have your tailshaft modified to
suit the different output spline.
If you use a newer engine - such a a 100kw Smallport from an AE92, or a
4AGZE, or a 20 valve - these were only available in FWD config, so you
need to change things to suit such as mounts, cooling system, intake
plenum and custom exhaust bits. There is plenty of information relating
to this in Toymods Tech Articles and on Club4AG.
Apart from that, you just need to mount the engine. You'll need to make
new angled rubber brackets or modify the mounts on the engine
crossmember for any KE10 to KE55 Oldcorolla you put this engine into.
If you have a KE70, then try to get an AE71 crossmember and 4A-C engine
mounts (actually the whole engine, that will make it alot easier to
change a FWD motor to RWD). If you have an AE71 then it's a pretty
simple bolt-in matter, lucky you!
Something Stronger than a T50 Gearbox
The next step up is a W55/6/7/8 gearbox,
which will
need transmission tunnel mods due to their larger size, and an adapter
plate (try Dellow?) or new bellhousing
(niteparts.co.nz make a good one for A motors). Check Matti webpage to
see which Toyotas these gearboxes come out of .
Mazda Rotary Engine
Rotary engines are light, I believe even lighter than the original K
engines, and they can make BIG power if you build them right.
All the KE Corolla rotary conversions I've seen use custom mounts (or
ones chopped off a Mazda crossmember), welded onto the angled brackets
at the front of the engine bay that house the castor rods. I've read
that you can position the engine so that a Mazda gearbox bolts up to
the Corolla gearbox crossmember. I've heard a rumor that Series 2 RX7
and earlier gearboxes are small enough to fit into a Corolla
transmission tunnel, but Series 3 onwards boxes require spreading from
the firewall back to the shifter hole. I
don't know what the output spline on a Mazda gearbox looks like, but it
wouldn't surprise me if you need to get your tailshaft modified to
suit. You'd probably also need custom extractors so your exhaust
manifold doesn't hit the steering components.
Keep in mind that in Australia, rotaries are considered as an engine
double their actual capacity, so double check your legalities. You can
not put even a measly stock naturally aspirated 12A in a KE20 or KE25
in New South Wales, they are 4kg short of the weight requirement, which
is based on original tare weight and cannot be changed at a
weighbridge. I don't know how 13B Turbo drag KE20s such as GRIMAS get
registered, and nobody is really willing to share the secret.