Weldspeed Billet 4AGE intake: https://www.weldspeed.com.au/product-...

A MASSIVE THANK YOU to Bill Sherwood (Billzilla) for maintaining his 4age website that's a true wealth of information on the 4AGE engine.

Check out MRP for awesome 4AGE performance parts and builds: https://www.mrpltd.co.nz/
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The 4AGE started it's life in 1983 and was produced until 1998. What does 4AGE even stand for? 4AGE is the 4th revision of the A block. G is a performance cylinder head and E is electronic fuel injection. When it comes to the 4A family, the first members were far less impressive and performance oriented than the 4age, the first engine being the 4ac, which was a single overhead cam 8v carbureted engine outputing around 70hp. The next evolution of the 4A family was the 4AFE which introduced double overhead cams and fuel injection. After this came the 4AGE, which was the performance option for the Corolla, Celica, MR2 and other mid-sized Toyota vechicles of the time. Interestingly enough you can also find the 4age in the GEO Prizm and Chevrolet Nova, which are basically rebadged versions of the Corolla AE92. When it comes to the power output the 4age started with 112hp in it's first generation and ended with 165 hp in it's last generation.

The engine the 4age shares a lot with is the Cosworth BDA. BDA being belt drive a type. It was one of the first racing and production engines to have both cam gears driven by a rubber toothed belt. The 4age was also toyota's first engine to have both cam gears driven by a rubber toothed belt.

This was a racing engine designed in 1969 by Mike Hall for homologation purposes for the Ford Escort RS1600. The original BDA spawned numerous different variants which were very succesfull in many different fields of motorsport.

The 4age has a bore of 81mm and a stroke of 77mm. The bda has an identical bore and stroke. From this we can see that the 4age is a very oversquare design which means it's an engine capable of handling high rpms pretty well. A large bore allows for some nice large valves and in stock form the 16v 4age comes with some healthy 29.5mm intake & 25.5mm exhaust valves. These are also of an identical size on the Cosworth bda. So the 4age is basically a mass produced version of the cosworth bda.

What about tuning? The 4age has been around for more than 30 years so everything posible that you can imagine being done to it, has been done. Everything from Crazy high revving formula atlantic builds to turbos, to twin charging to carburetor conversions to whatever else you can think of..Somebody likely already tried it.

The 4age is a good enggine, and while there are engines from the same era that may have an edge over it when it comes to engineering and performance, the 4age is capable, has undenieable charm, and is perhaps one of the best sounding 4 cylinder engines ever made.
The 4age engine has a total of 5 generations and you can sort of tell them apart by the valve covers. But that is honestly very unreliable and you can't really tell what's inside a 4age until you actually take it apart.

Remember how we said the A series engine had more generations after the 4a? An important one is the 7afe engine. It was a 1.8 liter with the same bore as the 4age but a larger 85.5mm stroke, and good way of getting more torque from the 4age, both in NA and forced induction modes is to take the 7afe a block and 4agehead and build something called a 7age. However there is also something called a 9age. This is a total frankenstein of an engine that boosts the 4ages displacement to 1.9 liters and is capable of serious power, especially if you go for the 20v valve cylinder head, which has a narrover intake angle compared to the 16v.

9age you need parts from 4age (16v/20v), 7afe block, 1zz/2zz crank, 2zz connecting rods (con-rods) and custom pistons. For this guide I'm going to assume you all ready have a stock 4age 16v and we will start building from there.

If you're interested in this engine, a company called MRP in New Zealand is basically a sort of a 4age mecca and they can build one for you. It will not be cheap but it will be insane. MRP can also build basically any kind of 4age for any kind of application you need.
So to sum it up, the 4age is a good, small reliable and capable engine. It's short and it's a great swap into older toyotas and any other light cars! It is outdated and squeezing very large power figures from the 4age will take a lot more effort and money than getting those same power figures from more modern iconic engines such as the 2zz or Honda's K series for example. That being said it's novice frienldy engine that is still relatively plentiful and it's fun and easy to tune and work with. The sound it makes is the icing on the cake.

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