The Modified 4AGE Page, page three

This is a standard 16 valve 4AGE disassembled into its components

4AGE 16v oil and water system schematics. Click for a bigger pic 

Note that the 20v water system has the cold water from the radiator going into the head first, opposite to what the 16v engine does. 

Big port oil pump on the left, small port & 20v & 4AGZE on the right - though this is not always the case, as the type of pump can vary even within the same engine type
 

A cross sectioned 20v 4AG head on the left and a 16v on the right
 

Here's a pic of the big port head

And another of the small port, standard on the left and my modified one on the right

Here's the big port and the small ports together so you can see the difference. The actual edges of the ports are pretty close to what they'd be if you cut the heads to make them meet up like that, it's just the difference in the camera angle that makes the background appear at a different angle

Here are the two 20 valve inlet ports, the silvertop on the left and the blacktop on the right. The silvertop is dead stock and the blacktop has had only a light clean-up to get rid of the bumps in the casting. You can see down near the valve seats that the blacktop has better dividers to each valve
   

This is the small port 4AGE inlet manifold I made from a few pieces of aluminium, for about Aus$50
 

Here is a standard 4AGE combustion chamber
 
 

This is my 185hp 4AGE that's going into my Starlet
 
 

This is a Formula Atlantic 4AGE head, and it makes 240hp
 

This is a pair of 20 valve silvertop combustion chamber. Rather different to the 16v
 

This is a 20 valve blacktop combustion chamber, and you can see that it's far more open than the silvertop's, and so has a lot less squish area. In this regard, I think that the silvertop's chamber is the better one
 

Here are the two 20 valve exhaust ports, with the silvertop on the left and the blacktop in the middle. Again, the silvertop is stock and the blacktop has only had the bumps cleaned up and the valve guides shortened. On the right is what they look like compared to each other. As you can see, the blacktop's is a bit bigger
 

Here's a couple of close-ups of the 20v's valve seat areas. Silvertop on the left, blacktop on the right
 

This is the two 20v's, again silvertop on the left and blacktop on the right. Note that the blacktop has deeper 'fences' around the cam bucket holes to try to keep more oil in, and it also has shallow cut-outs to allow for cams with more lift to be run without the cam lobe hitting the cam bucket support

20 valve 4age inlet manifold. Very nice indeed
 

A pair of the shim-under type buckets for the 16v
 

4AGE con-rods. Note that in the photo on the left the rod on the left has a groove cut into the side to squirt oil up onto the bottom of the piston to cool it, while the one on the right has the conventional small hole. They both end up doing the same job, though the one with the slot would tend to help cool the piston more and also make the rod a little stronger. Both rods have a small hole in the little end to also help oil lubricate the gudgeon pin
 

Here's a pic of a standard cam wheel, (on left) a vernier cam wheel, (middle) and a fully adjustable one
 

Alternate way of running the ignition, coil-over-plug units from a 1GGZE
 

A friend of mine faxed a series of dyno runs to me the other day, and so I thought that some people may be interested to see some actual horsepower figures for performance 4AGE's
 

This is a forged steel racing crankshaft - a rare item indeed
 

A Group A racing con-rod. Quite similar to a standard rod
 

A TRD/Mahle racing piston, as used in the Formula Atlantic 4AGE's
 
 

Another forged piston, from RMSport in the UK, and a Formula Atlantic TRD/Carillo con-rod
 

You can just see the small butterflys in every second port in the Air Control Valve plate on this factory inlet manifold

Here's my own 4AGE, which was finally fitted to my AE-86 in April 2002. It has quite a lot of good bits in it, and makes about 185hp. As well as good performance, if I drive carefully I can get up to 42mpg @ 100kph on the highway.

I have collected some information on the Formula Atlantic 4AGE engines, and it's all in the one 352kb zip file. It contains pretty much the entire TRD list of parts & part numbers to build one. There's also some specifications for clearances and so on. A few pictures of the engines as well. To be found here.