Introduction - That Tired Old 18R-C.
you've found yourself driving an RA model celica with a
clapped out 18R-C? you tell your friends "hey its a
classic", and if they are quick they'll reply "yeah,
a classics POS", then blow your doors off in their
ricey excel, lancer, or even worse, an auto VL commondore...
Ok sure its fun to pull up at the lights next to grandma
and grandpa and scare the beejeezus outta them with that
death rattle coming from your timing chain, but at the end
of the day this truck engine (yes that's right truck
engine) is VERY uninspiring. Well, not much left
over pocket change... what are your options?
1 - Rebuild the 18R-C.... big webber carburettor,
aggressive cam, headwork, extractors, dizzy remap, what
do u get? A an engine that's an absolute pig in
traffic, drinks fuel like its going outta style, and
its still gonna be a truck engine. A wise man once
said, "you cant polish a turd".
2 - Zoom on down to your local engine importer
and buy yourself a 1G.
Engine - What's a 1G You Ask?
cylinder (and 8 cylinder) Toyotas in Japan come with a 2
litre engine option due to taxes on engine capacity, so
these engines found their way into supra's (GA61/70),
soarer's (GZ20), cressida's (GX63) and crowns (GS11?) from
factory. There aren't many examples of these on
Australian roads, I know of one GA70 in Melb, but that's
soon to be converted to a JZA70. Ok so its an
unpopular engine in Japan, a 2 litre engine hauling around
a 1600+ kg MK3 supra, not an enthusiasts 1st choice, but that's
good, it means more of them are going to wind up at your
local engine importer. These engines are excellent
replacements for the 18R/21R and reasonably straight
forward to fit.
|| The 1G-GE is a 2 litre,
inline 6 cylinder, twin cam, with EFI, and it comes in
naturally aspirated, supercharged and twin turbo versions...
it was sort of the black sheep of Toyota
engines in the 1980's and early 90's.
The G-Series Engines - Decisions Decisions...
click to enlarge
Twin Throttle butterfly (TVIS)
sensored, Single Throttle Butterfly
direct fire ignition, supercharged (SC14)
direct fire ignition, supercharged (SC14)
distributor, twin parallel turbo (CT12), water/air Intercooled
distributor, twin parallel turbo (CT12), air/air Intercooled
What To Buy - Browsing At The Local Importers.
The easiest way to start an engine conversion is to purchase a front cut, this is pretty much just the front half (or back if the engine is mid-mounted) of a car with the engine sitting in the engine bay as if it was complete and running. This can allow you to organise a battery fuel pump and start the engine at the importers before you buy it, this is a handy way to see if your
buying a dud engine. If your unable to organise to start
the engine make sure you check it for as much as you can,
when I purchased my front cut it was missing a starter
motor. Another good reason to buy a front cut rather than
just an engine is that it will come with a HEAP of other
handy parts ie throttle cable, a HEAP of nuts and bolts
and you will also get a heap of good parts to sell to any
MA70 owners you meet on the street, (yeah I used to
approach them in parking lots), but hey I made over AU$500
back from selling the left over parts, which is great
especially when I paid AU$950 for the front cut, hows that
for a good deal. Ok so your forking out for that
front cut, MAKE SURE YOU GET A
RECEIPT, or else you will
run into A LOT of trouble when registering the car and
trying to prove that you actually own the engine that's
sitting in your engine bay. Now "how the hell
do I get half a freakin car back to my place" u ask?
Well your on your own there pal, your going to have to
think for yourself on some things.
Hints Before You Buy::
Pull out the glove box
and find the ECU, you'll need that.
Ask about warranty.
You will need an engine
that has a 'Mid-Rear Sump' bulge, if its going into a
RA series celica.
Do a general check on
engine, oil, plugs, coolant etc etc.
Try and get the ID
plate that sits in the engine bay, engine and chassis
numbers will come in handy, when ordering parts from
I managed to buy a GA70 front cut for $950 which had a late
model MAP sensored 1G-GE, that's naturally aspirated, a good
choice if you want to avoid high insurance premiums and
expensive brake upgrades.
So you've managed to get the front cut home, time to strip
it, take off everything u can and DO NOT THROW ANYTHING
AWAY, you will find that the most trivial thing will come
in handy (proof of this will be in the section of setting
up the throttle cable and accel pedal). An easy way
to get the engine out is to put the front cut on stands
and with a block and tackle lower the engine (still attached
to the cross-member) onto the floor, then with 3 or 4 mates
you can lift the chassis up and junk it. That's the
stripped shell in the background.
Engine's Out Now - I Just Chuck It Into The Car Right??
this is the time to put the engine onto an engine stand and
service it. Everything is accessible so why not make
it easier for yourself. Ok a few things to do, take
the cam covers off check the cams for damage or a thrown
shim, also take note of the colour of the oil and any
residue on the underside of the cam covers. Take the
spark plugs out and check for symptoms of oil deposits,
detonation, mechanical damage etc. While the sparkies
are out try and have a look inside each cylinder, remember
the engine may have been turned upside down during its
travels to Australia. If it looks good inside the
cylinders take a note of what spark plugs it was running
(buy a new set) and put the old plugs in until u can get the
new ones, same with oil, fuel, and air filters. Now
take off the timing cover and take the timing belt off get a
new one (even if it hasn't done many, km's) you never
know how long it has been sitting at the wreckers getting
all hard. Behind the timing cover replace all of the
front oil seals (that's 2 cams, front main, oil pump, and
water pump) and also replace the rear oil seal. WARNING:
make sure you buy the exact same seals that are on the
engine, go down to a good bearing shop and get them matched,
and PAY ATTENTION TO THE ARROWS
on the seals. You do not want to finish up an engine
conversion only to find out that when you started the car
all of the seals were spun out and pissed oil
everywhere. Next thing is to go get those injectors
tested and cleaned. Ok don't let me hold your hand too
much, do what else u can to prepare the engine before you
put it in, you will be glad you do this while its out, now
its time to start the conversion.
Engine Mounts - Please Can We Put The Engine In.
Sorry not just yet, but, its
safe to say that the conversion has officially started.
The engine mounts can be bolted to 2 locations on the 1G
block. Rear Position and Mid
Position, the mounts will need to be bolted to the
mid position. If the mounts are on the rear position you
will have to move them but when moving the engine mounts to the
mid position the bolt pattern on the block doesn't suit the bolt pattern on the mount, the mount on the exhaust side
of the engine can fit with some bending and stretching but the mount on the
intake side of the is harder to fit, you will need to
redrill them. Now they are in the correct location to
be bolted directly to the celica crossmember. All
you need is a 10mm Spacer plate to go between the 18R rubber
and the engine mount. You should be able to find some
aluminium off cuts at you local steel yard. If your
going to run a 1G-GTE it would be wise to cut the mounts
from the crossmember and re-weld to the crossmember into the
proper position, then get new rubbers, this will lower the
engine and give some well needed room between the top of the
engine and the bottom of the bonnet. Be sure to keep
the engine on a ~15 degree tilt to the passengers side or
you'll have turbo to steering box clearance problems. NOTE::
notice that the engine comes mounted on a tilt from factory
Sump - Pass Me The Hammer...
did you homework you got an engine with a mid-rear sump
bulge, this will be the easiest to modify as only a steering
linkage is in the way, bashing it with a hammer is an easy
fix but risky business, it just wont shape out like you want it to and it may
end up with a hole, I was lucky with mine as it survived. if u want to spend more time for a nicer looking sump then
I suggest getting it
cut and re welded. images below::
Gearbox Mounts - Whoops Need To Go Back To The Steelyard.
left:: The original
gearbox crossmember can be used (lucky you got a front cut
aye?) you will need to make a slight modification, now go
find someone who can weld.
Installation - Time To Just Throw It In.
4 chassis stands, a trolley jack and a engine crane comes in
VERY handy. Once again self explanatory, just watch
You will find that
depending on the car and engine the shifter position will
do either 2 things, sit perfectly centre in the hole of
the floor pan or sit too far back, if it sits too far back
(it will only be an inch or 2) then you will have to cut the
floorpan, be sure to weld a plate covering the original
hole to stop any noxious gases seeping into the cabin, see
The Left Overs - Its Time For Some Ingenuity.
If you want it to clear the air conditioning compressor
you have to get the radiator moved 10mm forward which
means just getting the mounts resoldered, any reputable
radiator shop can do this. I also compared the celica radiator with the
front cut radiator and noticed the nozzles were on opposite sides of the tank so
you can asked the radiator guy to swap the nozzles over as
well. While all this is happening I strongly suggest to
get a triple core put in, most radiator shops stock a triple
core replacement for the tanks on a celica radiator and
all up (mounts, nozzles and core) it will cost around
AU$350. Once this is done the bottom hose that came from the
front cut will fit perfectly, you will have to find a hose
for the top, I used two bends joined with a thermo-fan switch.
Slave Cylinder:: The supra gearbox slave is on the other side of the
bell housing than the
18R box so a rerouting of slave cylinder plumbing was needed,
you can use what was on the supra front cut, you can bend it
to suit it will not crimp or pierce unless you play with it
too much. Once again lucky you kept those front cut
Hoses:: Once again use what you had from the front
cut and 18R, if you cant then its not hard to buy some
suitably shaped hoses.
Cable:: The accelerator on the 18R isn't a cable so
what I did was cut the top off the front cut pedal and weld it onto the top of the
existing celica pedal so the cable could be connected to it.
NOTE: the depth or throw of the
18R pedal was far more than the throw of the throttle butterfly
on the 1G so a steel stop has to be fixed to the floor under the pedal to
prevent the accelerator cable snapping,
rummage through your front cut parts, once again wasn't it a
great idea that you kept them.
Fan:: No more room for
that so go out an buy a GOOD
quality electric fan, use your imagination and the left over
front cut parts to mount it either in front or behind the
Cable:: The existing
celica one will screw right in without a problem..
The existing celica tailshaft will connect up with the
gearbox without a problem, God I love Toyotas, its as if the
1G was meant to be there.
:: Fuel System - Mr Simpson The Fumes Are Making Me Dizzy...
Ok bare with me here, this pic is a mock up of the fuel
system you will need. Why? Well your carby 18R had built in
mechanical fuel pump, this fed a small reservoir in the carburettor,
this means that if you ever got air in the fuel lines (fuel
tank is not baffled either), the car will not suffer from
fuel loss as it can feed from the little reservoir.
Now if you are hooking up an EFI engine to an unbaffled fuel
tank you will need a surge tank to be sure the engine will
not starve when air gets into the fuel lines, this causes to
engine to stutter and can most likely happen during a time
when you are low on fuel while doing some spirited cornering
on your favourite mountain pass, not good.
Ok so why
do you need two pumps, well high pressure pumps that feed an
EFI engine don't like to suck, this means you need a low
pressure lift pump to lift fuel from your FUEL
tank into your SURGE tank.
then from there the high pressure pump can feed the
engine. Follow the little arrows in the picture,
notice how the fuel returns from the engine into the surge
tank and then returns once again from the surge tank to the
main fuel tank. You can buy surge tanks from your
local performance parts shop, if you are handy u can make
one by welding closed the ends of some steel pipe then
putting in the 4 nozzles. Another quick note, the size
of the surge tank depends on the engine (N/A or turbo), they
range from two thirds of a litre to about 3 litres, I ran my
naturally aspirated 1G with a 2/3 litre tank with no
troubles at all, I do recommend going larger with the GTE
though. Hey Rob I own a RA65 with a 22R-E in it.
Well good for you, you've already got what you need for an
EFI fuel system. Hey Rob I own a RA60. So go
grab an RA65 fuel tank and pump and bolt it straight in.
Exhaust - Please For God's Sake Be Reasonable.
Unlike the 18R, the 1G has
a crossflow head that means that the exhaust will be coming
out the side opposite to the 18R. Any reputable
exhaust shop can fit your exhaust and then cross it over
to the passenger side of the bottom of the car (dont
forget to install a cat converter too now your running
unleaded). I recommend you cross the exhaust under
the tailshaft, and remember to get the exhaust flanged. I can't tell you what size to use, what
type of muffler or whether to go over or under the
axle. However if you do go the naturally aspirated
route don't go overboard with the size, or else you will
lose a lot of low down torque, which, is one thing the N/A
1G-GE really needs. My choice was a 2.25 inch witch
puts out a relatively humble 88db, gives me ample low down
torque a nice and free revving top end and an awesome
sound, yeah that's right I reckon bigger doesn't always
sound better, but you can be the judge of that with the
Wiring - Okay Now I'm Stumped.
This is where I'm going to
have to leave you hanging, you can either do as I did and
leave your car in to a performance shop to get wired up
(never again, my God some people are shoddy, and they were
people I trusted), or you can find yourself a wiring diagram
and hook into it yourself. Just a word of warning, it
is better that you use the factory ECU with these engines as
the after market ones will give you nothing but trouble and
an empty wallet (spent on dyno tuning). Same
sentiments for intercooler plumbing your on your own, but it
isn't really that complicated.
Brakes - Dad I Broke The Brakes.... You What?
Different engineers will
require you to do different things with your brakes, it is
best to talk to your local engineer (yes you need one to be
street legal) they will tell you what you need. An
easy upgrade for the RA23/28/40 is a set of RT132 corona
brakes, grab the whole complete front strut off it and bolt
it right in, it will come with 10.5 inch solid discs and
twin piston sumitomo calipers. The RA60 and 65 have
larger vented discs with single piston callipers and the
corona struts will NOT bolt in.
That's About It - I've Held Your Hand Long Enough.
time for you to get your
hands dirty, though I do stress that this is not a step by
step recipe for a 1G, but rather a rough guide, you will
encounter your own problems and you will have to overcome
them yourself. As I said I have held your hand long
enough, if you still have a hundred questions to ask me then
well its probably best you shouldn't be doing an engine
conversion in the first place, you still need to be
mechanically minded, and willing to just get in and do
things. I also accept no responsibility for any wrong data
or bad advice, I spent a good chunk of my spare time writing
this for everyone to enjoy and learn, this is not my job so
I give you all this information in good will, if you stuff
up, if you buy a dud engine, and if you fart in front of your
mother in-law its your problem mate, with that said, happy
driving, hope to see you on the road some time soon.