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The Stock 4AGE Description Page

In this page I talk in some detail about the different types of 4AGE, and a little about which cars they come in.
The Toyota 4AGE engine started life in 1983 as a logical progression from the 2A and 3A single cam engines. There was also the single cam 4A-C engine, which initially shared an identical block & very similar internals as the twin cam version. The 4AGE soon progressed to having stronger internals, and so they diverged from there.
The twin cam 4AGE is basically a road going, mass produced version of the Ford Cosworth BDA twin cam racing engine. They share the same bore and stroke (81mm x 77mm), the same size valves (29.5mm & 25.5mm), and in some versions of the 4AGE very similar port shapes & sizes. When fully prepared for racing, they both produce similar hp figures at similar revs, so it would seem that Toyota has done an excellent job with them.

This is a 2 litre BDA ( B elt Driven, series A engine), which is basically identical to the 1.6 litre BDA.

The parallels continue - The 4AGE is the first twin cam that Toyota made with a rubber drive belt for the camshafts, as was the BDA. The 4AGE was a development of the single cam 2A, 3A. & 4A  engines, but I guess Toyota must have planned to make the 'A' series engine into a twin cam, perhaps again following the 'A' series Cosworth engines.

Quick link on this page to -
- The first 4AGE, RWD & FWD
- Brief summary of the different types
- 4AGE heads
Next page -
- 4AGE manifolds, 4AGE blocks, 4AGE cranks, con-rods, and pistons
On the last page -
- 4AGE oil system, 4AGE water system, 4AGE EFI, 4AGE other stuff

The total variants of the 4AGE are, to the best of my knowledge -
- Very early big port TVIS 16 valve, with black lettering & 6-bolts holding the flywheel on.
- Big port TVIS FWD/RWD 16 valve, usually with blue lettering on the cam cover and 'TVIS' on the inlet plenum.
- Big port TVIS FWD 16 valve, with red lettering. They have a seven-rib block with oil-squirters.
- Small port non-TVIS FWD valve.
- Silvertop 20 valve. Early & late type, minor variations in inlet system & VVT operation.
- Blacktop 20 valve.
- Early supercharged 4AGZE, low compression big port head, distributor.
- Mid-aged supercharged 4AGZE, higher compression big port head, crank angle sensor type ignition.
- Late supercharged 4AGZE, higher compression small port head, crank angle sensor type ignition.
More information on these engines below.

The first 4AGE, RWD & FWD
Anyway, the 4AGE started life as a twin cam head fitted to the single cam bottom end, though the crank was a bit stronger, the pistons also stronger, and a windage tray fitted between the sump and the block. The clutch and clutch plate are identical as the single cam 4A model.
The versions with MAP (Manifold Absolute Pressure) sensors make 127hp in standard trim, and red-line at 7700rpm. Some countries have the AFM (Air Flow Meter) sensor versions, which make 115hp. So how to tell the two apart? Well, the MAP sensor versions have a small black box that is attached to the inlet manifold by a rubber pipe. (This pipe lets the sensor sample the inlet manifold air pressure) The MAP sensor usually sits on the firewall, and looks like this -

And here's the AFM type, where the AFM sits between the throttle body and the air cleaner. The AFM is simply a sprung flap that swings back more and more as the engine sucks more air, thus making more power.

This is the Air F low Meter on an MR2

Brief summary of the different types
4AGE's come in both front and rear wheel drive form, and although they are very similar, there are a number of small differences that make swapping them over not quite as easy as it would first seem. I won't be getting into that area, as a good friend of mine, Phil Bradshaw, has already written an excellent page on doing just that. Please note that the engine types described here in the next few page are of Japanese production, other countries may vary on these specs slightly.
With the RWD types, they came out in big port versions only - no small ports - in basically two types as mentioned in the previous paragraph. These can be found in the AE-86 Corolla and AA-63 Celica, with the AFM one having 115hp and the ones with MAP sensors having 127hp. The FWD ones are much the same, coming in the AE-82 Corolla, but with the AE-92 Corolla the small port 4AGE (non-TVIS) made its debut, with 100kw or 134hp.
Two odd types -
- I have also heard that there was a very early (1983) and now rare 4AGE TVIS FWD that had black lettering on the cam cover, but the main difference is that the crank only has six flywheel bolts verses all the other 4AGE's that have eight and so it looks like it has a 4A-C single-cam type crankshaft.
- Another odd 4AGE is one that has red lettering on the top, is fitted with TVIS & a big port head, but has a seven-rib block & a 42mm bearing crank. There are much easier to find around the world. They also appear to have no oil squirters on the inside of the block, unlike the regular small port types which do.

With the arrival of the AE-101, things changed a great deal; The naturally aspirated 16v 4AGE was no more - replaced by the new 20v 4AGE - and another newcomer was the supercharged 4AGZE. The 20v started with a claimed 165ps and the blown 16v 145hp, though the 'Z' had a great deal more torque, but was a lot less 'revvy'.
The AE-101 came with the slightly improved claimed 170ps 20v 4AGE, and there was also the options of two 4AGZE's, both with 165ps. (The later one having an integrated ignition coil pack system)

Many people seem to define the different types of 4AGE by the colour of the letters on the cam cover, but I think that this is not a reliable method, as from what I've seen different countries have different colours, cam covers have been repainted, and sometimes swapped. I only recognise the different types by them being a big or small port, RWD or FWD, AFM or MAP, and the number of valves.

4AGE Head Types
There are two types of 16 valve heads, and the one 20 valve - The majority of 16v 4AGE's have what's called the 'big port' head, and the remainder (only found on the AE-92 FWD Corolla) have the 'small port' head. The small port head is the prefered type for performance in a road car, as they are easier to get up to about 200hp out of. (More than about 200hp the big port is best)

Here's a pic of the big port head

And another of the small port
And to compare the two properly, here's both together. Note that these pictures where taken from slightly different angles, and so the port divider isn't the same position in the top & bottom of the picture, but the actual port faces relative to each other are pretty much correct

This is what the combustion chambers look like ...

... and they are quite efficient, able to make a good 100hp/litre with very few mods

Here is a cross-sectioned 16v head

The rest of the head is much advanced over the 'old' BDA, in that it is a single piece design and it also doesn't require to have the camshafts removed to get to the shim adjusters when working on the valve clearances. (The BDA's head comes in two large pieces, and it splits horizontally just below the cam bearings to make it possible to get to the shim adjusters. This makes the head castings a LOT more expensive, less accurate, and potentially unreliable)
The 4AGE's use a 'shim over bucket' system for valve clearances, and by doing this it allows you to alter the valve clearances without removing the cams, unlike just about every other twin cam engine. Note that Toyota want you to use a 'special tool' to get the shims in & out with, but it's easy enough to do it with a couple of small screwdrivers to push the bucket down with.

16v 4AGE head, completely dissasembled

16v 4AGE heads specifications -
- Valve included angle (angle between the inlet and exhaust valves) - 45°
- Minimum valve spring seat pressure to allow for 7,700rpm - 35lbs, or 16kgs
- Inlet valve diameter - 29.5mm
- Exhaust valve diameter - 25.5mm
- Both valves have 6mm diameter stems.
- Cam bucket diameter 28mm, shim diameter 25mm
Cam Timings - (Japanese spec) Inlet Cam IVO  BTDC IVC  ABDC Duration
Lift (mm)
'Big port'   51° 240°
'Small port'   44° 232° 7.1
4AGZE   44° 232°
'Big port'   51° 9 ° 240°
'Small port'   44° 232°
4AGZE   44° 232°

The 20v head is a very different beast indeed!
The obvious difference is that they have three small inlet valves instead of the more common two. This is intended to give the engine better breathing, and as the 20v is about 145hp it seems to work. For lots more pictures of the 20v head, please check out the second page of my 4AGE Mods page.
The other differences are that the inlet port has a much better angle onto the inlet valves, and that the valve included angle is a good 10° less than the 45° of a 16v head, which is a good thing for making power. The exhaust side of things are very similar.

20v 4AGE head specifications -
- Valve included angle (angle between the inlet and exhaust valves) - 35° (I think ...)
- Inlet valve diameter - 26.5mm
- Exhaust valve diameter - 26mm
- Both valves have 5mm diameter stems
- Cam bucket diameter 23mm, with very small shims between the valve stem top & bucket
Cam Timings - (AE101)  Inlet Cam IVO  BTDC IVC  ABDC Duration
Lift (mm)
VVT <4400rpm & >~7000rpm   70°  250°
VVT >4400rpm   30° 40° 
   Exhaust Cam EVO BBDC EVC  ATDC 250°
    54° 16°

Cam Timings - (AE111)  Inlet Cam IVO  BTDC IVC  ABDC Duration
Lift (mm)
VVT <4400rpm & > ~7000rpm   65°  250°
VVT >4400rpm   35° 35° 
   Exhaust Cam EVO BBDC EVC  ATDC
    54° 16°  250°

(See the '4AGE Other Stuff ' section for more details of the VVT system, and also my ' VVT Vs VTEC ' pages for a complete description)

Continue on to -
- 4AGE Manifolds, 4AGE Blocks, 4AGE Cranks, Con-rods, and Pistons

And on another page -
- 4AGE Oil System, 4AGE Water System, 4AGE EFI, 4AGE Other Stuff

Back to the Car Index page

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Page & contents where applicable © Bill Sherwood