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NOTE: The following article was initially written in early 1993 and published in ‘Sports Car Talk’, the magazine of the Sports Car Club of NZ. I have given the article a once over and corrected a few minor errors. It relates to my initial installation of a 4AGE in a Lotus 7 type car. All prices are in NZ$. 
 
 

THE TOYOTA 4A-GE ENGINE

OR

(ALMOST) ALL YOU EVER WANTED TO KNOW ABOUT EFI

By Phil Bradshaw (with a little help)

INTRODUCTION

In 1992 I constructed a Leitch Supersprint kit car, which is a replica of a series three Lotus Seven, and of a similar build quality to a Fraser Seven. The kit was supplied by Leitch Industries in Invercargill. Early on in the piece I had to make an engine choice, and after seeking advice, I ended up with two options: a 1600 pushrod English Ford Escort motor with twin 40 DCOEs and about 130 horsepower, which was available via my brother in law who was selling the Mk I Escort Rally car it resided in, or a Toyota 4A-GE 1600 16valve DOHC. The pushrod went like a rocket but needed yet another rebuild, and I was a little dubious about the engine's reliability after having killed three more sedate versions in the previous two years in my own Escort.

The 4A-GE was a completely unknown quantity. I had read articles in New Zealand Car magazine about their Fraser Seven, complete with twin 45 DCOE fed 4A-GE, but didn't know anything more. To cut a long story short, I ended up with the Toyota motor. And while I do not claim to be an expert, I know considerably more than I did a year ago. So, if you're thinking about building a kit car, repowering your present car, or just plain curious, read on. Hopefully this article will answer a few questions that I know I certainly had a year ago, yet had great difficulty in finding answers to. While this article deals specifically with the 4A-GE, the principles apply to many modern EFI motors.

THE TOYOTA 4A-GE

The Toyota 4A-GE has an alloy head, double overhead cams, 16 valves, a cast iron block, and multi point electronic fuel injection. It also comes stock with a sump windage tray. Displacing 1587 cc it is commonly found in a number of Toyota's hotter little cars, in a variety of configurations. It first appeared on our shores around about 1983 in the front engine, front wheel drive Corolla DOHC GTs, followed by the very well received rear engine, rear wheel drive MR2. Nowadays it resides in many used Japanese imports, commonly FX-GTs, Levin and Trueno DOHC Sprinters and the occasional Celica.

SELECTING AND BUYING AN ENGINE

All the engines are basically identical, regardless of application, which means you can buy a front drive engine and mate it to a rear drive gearbox. Care must be exercised however because the shape and length of the inlet and exhaust manifolding varies slightly with application, as does the external plumbing of the cooling system. The east/west engines have a remote thermostat as well. Some engines, typically supercharged models, have the starter motor on the right hand side of the engine, which may cause problems with footwell clearance. Additionally it is wise to ensure that you have ALL the little bits and pieces you require or else you may find yourself spending a lot of time and money tracking down obscure little parts to get your engine to run.

Any "A" series gearbox (ie normally used with an "A" series engine such as 4A-GE) will fit, however I use the stock T 50 gearbox from a Levin. This measures 650 mm from the front of the bellhousing to the centre of the gearlever housing. Some rear wheel drive gearboxes have the hydraulic clutch mechanism on the left hand side of the gearbox, which have prevented me from having to grind the end off my clutch fork due to it interfering with the driver's footwell (it is too hard to hacksaw easily). Basically any engine can be mated to any suitable gearbox but you may find a lot of minor modifications are required in order to get it fully fitting and functioning. The Japanese domestic model gearboxes have a larger diameter output shaft, so ensure you get the matching drive shaft yoke.

If you want to go really fast, there are turbo and supercharged models, but I intend staying to what I am familiar with. The naturally aspirated engines come in four basic types, however it must be remembered that changes were made piecemeal and one type may include later model features. The age of an engine can be identified by the year printed on the spark plug leads. The month of manufacture is additionally recorded on the clutch and brake hoses.

Early engines tend to have all black lettering on the cam covers, and develop around 118 horsepower. These engines have a smaller crank with 40mm big ends and 3 small vertical ribs on the inlet side of the block. These were followed by blue and black lettered engines (which I have) which are also from 1983 and develop the same horsepower, but many seem to have a bigger crank (42mm big ends). After these came the red and black top engines with 89 versus 88 kW, from about 1987-1990.

The latest has all red lettering, is 91 onwards and develops 135 horsepower (100 kW). These engines have a different cylinder head with smaller inlet ports and an external oil return at the rear right corner from the head to the block. If you were at the last motorkana you would have seen my car making a very effective smoke screen as I completed about 30 seconds of 7000 in first gear whilst turning hard left! Basically the oil pump was pumping the oil into the head faster than it could drain back, the cams submerged and the oil then went out the breather into the inlet manifold and my car became a 2 stroke. Apparently I went rather pale... Anyway, I think the advantages of the external oil return are now obvious! As an aside, I went on to use second gear and win the event.

Additionally these later engines have bigger gudgeons and oil cooled pistons, along with a bigger oil pump and larger clutch and different flywheel, which will still fit the into the standard gearbox bellhousings. Unfortunately at this moment in time these engines are very rare in NZ as most cars so fitted are still on the road, even in Japan. All of these engines develop maximum horsepower at about 6500 rpm and in stock form lose power rapidly above 7500. If you get very lucky, there is a 4AGE-20 which is in the latest Corollas in Japan. This beast has 5 yes 5 valves per cylinder and 160 horsepower in stock form. The supercharged version delivers 195....

I have been seen and been quoted prices from around $1000 for an early motor, box, computer and loom, and about $1500 for a newer one. As with everything, shop around, and I would strongly recommend dealing with an importer who knows the engine and its application in kit cars etc. There is apparently a 4AGE-20 running with an aftermarket computer in the South Island which cost $3500 all up...Daryl Jeffares of Telford Equipment, who was very helpful with data for this article, is very knowledgeable about 4A-GE engines and may be able to help with sourcing you one. Barry Leitch of Leitch Industries or Neil Fraser of Fraser Cars could probably point you in the right direction. A word of advice: most importers I have talked to do not hold 4A-GEs in stock, so allow for lead time in your project planning. This is because the engines are fairly popular in NZ, Australia and Japan.

The supply of north/south engines and gearboxes is not getting any better, with the last such units produced in 1986. What this means is that if you want a late model (ie front wheel drive) engine but mated to a rear wheel drive gearbox, you may find that you are effectively paying for the rear wheel drive engine as well, as they do not really sell on their own. Be warned that it may get very expensive. The good news is that the relationship between exhaust ports, bellhousing mounts and engine mounts is identical on all engines, so interchangeability is pretty good.

Another option is buying a front cut, which depending on your project may be a better option, despite the added cost. This method virtually guarantees the provision of all the hardware, intact looms (engine importers tend to cut them either side of the firewall, which results in a lot of time, effort and heatshrink being expended to rejoin the 30 odd wires), and possibly better front struts, brakes, instruments and steering etc than you currently have. Scott Orr has recently put a two litre Sirius Dash turbo motor into his Cordia, sourcing a front cut from an Eterna (I think) less exterior panels, struts etc for a reasonable price. Once again, do your homework, shop around and negotiate. Front or half cuts now attract the same import duty as whole cars, ie $1500, which may not make it so attractive. Scott reckons his engine etc owes him about $2000.

The third option, which I took, and personally recommend, is buying a complete car that has been written off. The disadvantage is that you will not get a warranty. You can argue that you are buying a crashed vehicle which has unknown hidden secondary problems, but then again how much do you know about an imported engine's background? All engines newer than 3 years are generally from written off cars, where as older ones ex Japan tend to be from intact "retired" cars. Be careful with recent engines as front wheel drives have a habit of cracking the blocks around the engine mounts in major frontals.

MY EXPERIENCE IN BUYING A WRECK

I am a great fan of the Trade and Exchange, which is where I found an add in March 1992 for a 4A-GE engine for $600. I telephoned and enquired if he had the gearbox as well, he replied he had the whole car. I went for a look at what was a very bent Toyota AE86 Levin 16 valve GTV that had lost an argument with a lamp post whilst sliding sideways. Suffice to say it was a little worse for wear. It looked reasonably ok, despite the left hand front strut tower being virtually impacted on the engine.

The radiator was impacted against the thermactic fan, but was not ruptured. It was full of corrosion inhibitor, there was an NZ oil filter fitted and the oil was in good condition. I hooked up a battery and turned on the ignition. All the warning lights came up and the fuel pump cycled. After sitting for three months, the engine fired after about 10 seconds of cranking and then settled into a slightly rattly idle, until the oil circulated when it quietened down. All the warning lights went out and I turned it off before the fan got hot enough to try turning against the radiator. After noting the absence of exhaust smoke I decided to buy it. I bought the entire car for $1100 cash and it cost $45 for it to be towed from Henderson to Takapuna.

The car ended up donating engine, gearbox, entire wiring loom, all engine ancillaries (less air conditioning which I figured was superfluous in a convertible), drive shaft, rear disc brakes, hand brake complete, fuel pump (which sits in the tank), aftermarket Panasonic 40W stereo and clutch master cylinder. I would have kept the rear end, but decided to use an Escort one which now wears the Toyota discs, but that is another story. Even better, I sold off the rear of the car from the B pillars back, along with a mint driver's door, perfect front and rear bumpers and lights, front seats and all rear trim, one front strut, two wheels and all the stock air intake trunking and filter. The rest was dumped due to damage sustaned in the accident. I can recommend using a circular saw fitted with a carbide blade for cutting up cars; it is cleaner and neater than a gas axe and has less effect on the surrounding area.

I placed an add in the Trade and Exchange and to my surprise sold the whole lot to the first caller for $600 - which means that my motor etc has only set me back $545. While I may have been lucky, I do believe that even if you paid $2000 for a wreck, depending on the damage and condition of the parts surplus to requirements, there is much potential to sell the remains over a period of time for a good return. When you consider that models like the Levin are reasonably popular, particularly amongst the rally set, and parts are not that common, it has to be a seller's market. In my case, due to the car's damage, I had a complete undamaged set of headlights, front bumper and indicators etc available, likewise a mint door and rear hatch, tail lights and bumper. How often are those type of parts in demand after a minor accident? Apparently a new front bumper alone is $800 from Mr Toyota...

I recently answered an add in the Trade and Exchange for a Toyota 3T-GTEU 1800 16 Valve 8 Sparkplug Twincam Turbo Engine. These are apparently good for almost 200 HP. It was for $350 due to it having blown turbo seals. The engine had covered 120,000 km and included computer and half the engine wiring loom. I was quoted between $150-350 for a turbo from various engine importers, and $850 for a complete engine. Of course you still need wiring, computer and gearbox, alternator, startermotor etc. Importers seem to neglect to include GST in their prices too... I didn't buy the engine, but it is good to be aware of what is available. I also established that the chances of getting an engine manual and wiring diagram in english were virtually non existent, which means you may have to pay some Guru to sort it out.

PARTS, MAINTENANCE AND REPAIR - EXPLODING A FEW MYTHS

The next step was preparing the motor and gearbox. I went to Vital Books and bought the Toyota 4A-GE repair manual. This cost $99 and includes the engine mechanical components, EFI, cooling, lubrication, starting and charging system. The manual contains 450 pages and deals with the engine, etc only. I was always under the impression that an EFI engine had to be repaired by a dealer with expensive main frame type computer equipment. This notion, which had been fortified by various car magazines, had always put me off EFI.

The truth of the matter in Toyota's case could not be more the opposite. The engine computer has its own inbuilt diagnostic programme and in the event of a fault produces a check engine warning light. If this occurs, you then short across a connector in the wiring loom and turn on the ignition to the run position. The warning light will flash a number of times, this code corresponds to the fault condition. Cross-Reference with the book will show that code 8 (for example) is generated by an open or short circuit in the throttle position sensor signal. The book then tells you what to check and even how to check the computer system out with a volt/ohm meter, via a very straightforward flow chart. The end result is positive identification of the broken bit. The manual also has a very good general trouble shooting guide similar to what we are used to in Haynes manuals.

My engine had covered 84,000 km when I bought it, and was suffering from a small oil leak. The sump was also dented from the accident, so I paid a visit to North Shore Toyota. I have never owned a Toyota before, but I have been very impressed with the support network. A new sump, which is common to all 4A-GEs, was $120 which I think is very reasonable, and I also managed to get all the crank seals and cam cover, etc seals that I was after. Due to cars being sold NZ new with this engine, the parts backup is very good, and if it is not in stock, it tends to arrive within two days from the national parts centre. I also found out that a few Levins were actually sold new in NZ and as such Toyota has quite a surprising array of parts available - I managed to get a new set of rear disc brake seals, and could have bought new discs if mine had been damaged. One word of caution however - Japanese domestic model engines specifications vary slightly from NZ or export models, but the majority of specifications are identical.

It is strongly recommended that you put a new cam belt on the engine as soon as you get it - Daryl talked of one that parted after only 40,000 km. He changes his annually.

FITTING THE ENGINE

I had the inlet manifold shortened in height by 30mm by Leitch industries which is why my car does not have the bulge in the bonnet that Frasers have when fitted with a 4A-GE. It is possible that I have sacrificed a few horsepower at the top end and my idle may be a tad lumpier than stock due to the inlet runners no longer being as they left the factory, but it is not really apparent: anyone who has been for a ride will tell you, my car certainly has sufficient power and does not feel compromised. What this means is that you can get away with a little cutting and shutting if you find that the inlet manifold you have just will not quite fit.

I used the standard 4 into 2 cast exhaust manifold, and then went to a custom 2 into 1 system with a single straight through muffler. I decided against extractors on the grounds of added cost and that I wanted to run the engine with the oxygen sensor which sits in the cast manifold. Additionally there is not a lot of room in a Leitch for extractors. Whilst the manifold looks quite presentable with the heatshielding ditched, flashings removed and painted, there is nothing quite like a 4 into 1 for visual appeal and getting all the available power out of the engine.

All standard engine ancillaries were used with the exception of air conditioning which was unnecessary. I used the Leitch engine mounting brackets which use Mini rubber mounts, and the standard Toyota gearbox mount. A Cortina radiator with a heavy duty core and thermostatic fan keep the engine cool, although I use an overflow tank as the radiator cap is inaccessible. The clutch is hydraulic, and uses a 5/8 inch master cylinder. It is wise to use an oil cooler, particularly with oil cooled piston models, or if you are going seriously racing.

INSTRUMENTATION AND FUEL SYSTEM

I chose to use a full sweep of Smiths instruments in my car as I like the look of them. They came out of a Triumph 2500 PI and cost $112 from a wrecker for the mint set of imperial gauges. The rev counter was incompatible with the Toyota ignition system, so I had appropriate rev counter internals transplanted into the Smiths housing. Due to the tight confines of the Leitch tunnel, I have a VDO angle drive against the gearbox driving a custom cable that is hooked up to the Smiths speedometer. The speedo and tacho work was done by Robinson Instruments in Auckland City, who charged me $434 for the complete job, including rev counter, speedo and odo calibration. This may seem expensive, but it is a little cheaper than using procol instruments and a lot cheaper than VDO, and personally I prefer the Smiths dials. The thing to bare in mind is that most transplant operations will require a custom cable and a speedo recalibration. Although an angle drive at $100 will not always be necessary, it will probably still cost around $150 to match up a speedo to an alien gearbox.

The temperature gauge is hooked up to the Triumph PI sender, which despite being an imperial thread, screwed straight into the Toyota housing with a whisker of thread tape applied and doesn't leak a drop. Triumph PIs do not have an oil pressure gauge so I liberated one from a Mini ($5 from Pick a Part) which I fitted with a PI bezel to match the others. The gauge dial is slightly different, but you have to really study it to notice. Toyota use only an electronic oil pressure gauge, so I bought a T piece and fitting kit for the Smiths gauge for $26 from Strong Brothers Mini Parts which screwed straight into the block. Care must be taken not to crack the block as the block is relatively weak at the pressure tapping boss. Also most T pieces tend to snap off if you cantilever an electric sender off them, the solution being to remote mount the T piece on the chassis and connect it via a flexible tube. I used a bourdon tube gauge, as that was what I had. It is important to use the correct olives with plastic pressure tubing as copper tube olives will cut the plastic tube when tightened. Any decent auto electrical shop should stock the right type should you need them. My oil warning light is driven by a generic Toyota oil pressure sender which again screwed straight in.

The fuel gauge is slaved to a Austin 1300 tank sender as this is vertical mounting in the tank top as opposed to the tank side PI type. If you use the EFI system, then you will need a high pressure (ie 80psi) fuel pump, although the system runs on about 35 psi. I used the tank mounted Levin pump because I had one, but I have heard of EFI Commodore and 280Z external pumps being used. If you use a tank mounted pump, you will need a steel cased high pressure fuel filter, which are about $80 from Repco. Again, I already had one. If you use an external pump then any in line filter in the suction line will do. The 4A-GE uses three fuel lines, I used braided hose and anodized jubilee clips for the supply and fuel regulator return lines, and just normal fuel hose for the tank vent/overflow. I used an air hose fitting with a copper washer to join the supply hose to the HP filter and the standard Toyota hose runs from there to the engine. Provided you have the fuel rail fitting you can cut off the factory crimped Toyota hose and just jubilee clip your fuel line to it.

DIFFERENTIAL RATIO

I use 185x70 13 inch steel radials on my car, with an Escort 4.44:1 differential. The Toyota comes stock with 185x60 14 inch tyres and 4.1:1 or 4.3:1 diff, so its geared fairly short from the factory, but the engine is so free revving it doesn't seem to strain at all. I have a self imposed redline at 7000rpm to save engine wear (and because that is as high as my rev counter goes!) but I have heard of people pulling 8500 (allegedly) and living to tell the tale, although unless you change the cams there is apparently little to gain. The EFI system has a built in rev limiter that cuts in around 7500, but I rarely encounter it unless I get something wrong! My car will do 100 km/h at 7000 in second, about 145 in 3rd and 170 km/h at 6300 in 5th. (I do not know how fast it will go, although I would be surprised if I got over a genuine 180 without removing the windscreen) I am led to believe the engine develops maximum power at about 6500rpm, and is certainly on song at 4500.

INJECTION, CARBURETTION AND POWER CHIPS

I decided to use injection because I had the whole system and it was the cheapest option. You may have lots of money, but I am not that fortunate! As with all engine decisions, it is important to match the engine to the car and the type of driving you do. The Leitch is my only car and I built it for the open road, which is why I don't have exotic rubber or huge horsepower. But what I do have is an engine that starts first crank every time, hot or cold, that is relatively quiet, very smooth and easy to drive, and has not let me down yet in the 9000 miles it has been driven since November 1992. It has ample get up and go, yet runs on unleaded and returns over 30 miles per gallon at a 70 mph cruising speed, even though it regularly gets up to 85 when overtaking.

I have discussed power chips with a couple of people and their opinion is that unless the computer comes with a carrier for plug in chip replacement, there is very little to be gained. The 4A-GE is in this category. It is the computers that have the carriers that have the potential, as often the road car has a slightly detuned engine compared to what it is capable of in order to prolong engine life. I have also been told that for $300 I can cut a second off my quarter mile time and gain 25 horsepower. I must admit to being a little confused over which to believe, however that was from the same experts that managed to connect a speed sensor to an air conditioning input on the computer. I wonder why they closed down... I think that the best option is to buy the engine that has the power output closest to what you are after and take it from there.

I run the complete, stock fuel injection system, on unleaded, with the exception of some of the emissions hardware and the exhaust sensor. I have an inductive speed sensor fitted to the driveshaft (in the Toyota it is part of the speedo) which was sorted out (in the wake of the Experts) by Wayne Gum of Electronic Research and Development, who I personally recommend for any electronic/EFI work. He is one of very few who actually knows what he is doing as opposed to those experts that think they know but actually don't. Apparently the sensor can be bypassed, but I do not know the details. I use a large K&N filter attatched directly to the throttle body.

If stock is not enough and you want to play with your fuel injection, or you do not have the correct computer, the best bet is to run with a complete, adjustable aftermarket computer such as a microteck, which will set you back about $1230 and includes wiring, but will not yet run the stock distributor, (see below) although a model soon to be available should be able to.

Weber Specialists have set up a number of 4A-GEs on twin 45 DCOEs, and maintain that you get an extra 20 horsepower, however the standard distributor must be replaced with one from a 4k engine or similar, as the 4A-GE dizzy is fully electronic. Neil Fraser had a number of black boxes made a couple of years ago that for $300 would run your dizzy with carburetors, but I do not know if these are still available. It will cost you about $1250 for 2 Weber 45 DCOEs, $230 for an inlet manifold, $200 to set up each carb with correct throats and jets, in addition to getting a spark, linkages and air filters. However it may be an easier (and cheaper) option than trying to get a late model engine running on EFI. Then again, you may prefer carbs. Weber Specialists certainly know what they are doing, and they strongly believe that carbs are best, but then so they should!

I hope this article has gone at least part way towards removing the fears like I used to have that fuel injection for Kit Cars was "too hard" and something to be avoided like the plague. I am anything but an electronic or computer wizz yet I am comfortable with my engine and actually feel more able to work on my EFI system than on carbs... It is not as bad as you think. Electronic Fuel Injection is practical for kits, specials and homebuilts. Welcome to the 90s!

I am very grateful to people like Daryl Jeffares, Jamie Ailslabie, Barry Leitch, Neil Fraser, Wayne Gum and others who were willing to give me their time and benefit of their experience in many areas of this article. Like them I am happy to help anyone with any questions they have, although I stress I am not an expert, although I have tried very hard to make this article as up to date and accurate as I can.

Next: 4AGE 20 Valve Car Club Magazine Article

 
 


Copyright © 2000 SpeedTECH Last modified: January 23, 2000