Ford Essex V4 / V6 Tuning Guide
This Ford engine can be viewed as a kind of scaled down American V8 and it certainly weighs as much! Originally introduced in 1965 in even more scaled down form - V4, the Essex was available with 1663 and 1996cc. ‘66 saw two extra cylinders added, resulting in 2494 and 2994cc. However, the engine most are concerned with is the Post-1970, uprated unit, which is very similar to the previous units BUT, there are plenty of parts that aren’t interchangeable. So, be careful and make sure you have the correct engine before you throw money at it.
The 3 litre Essex appears light on BHP at 138, especially compared to the engine that replaced it - the Cologne, which weighs in at 160bhp. But, the 3 litre’s biggest strength is bucket loads of low-down torque with tuning potential reaching almost 300bhp. At this level though, it gets a touch temperamental, so be warned! Before you really go mad, there’s two areas you need to pay attention to - first, the engine runs on 4-Star so unleaded seats need fitting. All our heads can be supplied converted, which is a good excuse to upgrade to a pair of performance heads too. The second consideration is the fibre cam timing gear, which can easily shred with more power piled in. We stock a steel replacement cam gear and again a good plan is a steel gear upgrade plus cam swap at the same time.
For starters though, the 38 DGAS carb is capable of fuelling the engine to 180bhp with re-jetting plus an electric fuel pump. It is a touch thirsty being a double pump type rather than a vacuum secondary like the 40 DFI5 Weber replacement. You should get better economy with the latter but, no matter what stage you start, replace the restrictive airbox for a K&N filter.
So, a pair of Stage 1 heads should see an extra 8-10 bhp, Stage 2 another 6-8 but, combine the latter with a Kent V63 cam and you’ll see around 180bhp. Go to our biggest valve sized head, plus a Kent V66 cam and power will be close to 200bhp.
Alternatively, the Burton cams range will give you similar performance but in a different way - these tend to conform to the ‘old-school’ low lift, long duration theory, which is perfect for historic track use but not brilliant when it comes to emissions control.
To obtain higher levels of engine power, you need to uprate the induction because the limit of the DGAS will have long been exhausted. Here it can get expensive although extremely good looking! We can supply a manifold to fit triple 40 DCNFs, which should power the engine to around 240bhp. More capacity is fairly common although the largest safe bore size is plus 0.060". We stock Accralite forged pistons that allows up to 3161cc.
There are a few weak areas on this engine - the timing gear we’ve already addressed but, if you intend revving past 6500, it is advisable to have the crank cross-drilled for better lubrication.
However the rev limit is around 7500 with heavy duty rod bolts. The press-fit of the pin in the small end is also a problem area.
Balancing this engine can be tricky since it’s a V engine and any removal from the flywheel weight will mean a complete internal balance of components.
At the top of the engine, the pressed steel rocker arms pivot on a stud that’s pushed into the cylinder head. Serious engine power needs these replacing with threaded inserts and stronger roller rockers fitted too.