Ford CVH Tuning Guide
Introduced in the front wheel drive Mk3 Escort in 1980, the Ford CVH has been available in both normally aspirated (N/A) and turbo forms and it’s been tuned to produce daft power using both methods.
Most common capacities you’ll find are 1117cc, 1296 and 1597. However, the 1300 was dropped in 1986 and replaced with a 1392 (1400). This was also a significant year since the oil pump system was revised for use in the Mk4 Escort. The only rear wheel drive version was available in the Sierra in 1800cc format. Sierra engines were based on US-spec 1905cc units and share few components with the smaller CVH engines. However, their thicker block was popular with 1900cc conversions, particularly RS Turbos.
Cars you’re likely to find a CVH fitted to are, Fiestas, Escorts and the aforementioned Sierra. Early Mk5 Escorts carried the engine but it was phased out in favour of the Zetec. Ford’s early range also included the very special RS1600i, which differs from regular cars since it has fuel injection, solid lifters, plenty of motorsport features and the highest N/A power, 115bhp.
CVH stands for 'Compound Valve-angle Hemispherical' and as such featured a ‘Hemi’ type combustion chamber. But, there are differences because the later ‘Lean-Burn’ series has a heart type chamber so you need to be sure which one you’ve got - the only sure way is to take it off because casting numbers can be misleading. Either head type can be tuned although the ‘Hemi’ will generally give the most power. Your head will need inspecting since some feature oversize cam bearings and lifter bores.
The combination of a Burton Stage 1 head and a Kent CVH22, should release about 15bhp extra and you can use the best standard type carb from the XR3/early XR2 (Weber 32/34 DFT) in conjunction. These engines are very cam-timing sensitive and really do need a vernier pulley to see the best.
Stage 2 and a CVH 33 should see another 5-10bhp although you’re best now switching to twin choke Webers. Most common are DCOE side draughts - either 40s or 45s for more top-end power. However, these can cause space problems so the rarer DCNF down drafts are more suitable.
The bottom end is pretty strong although there is a rev limit of 6,000rpm but this is more to do with the lifters rather than the rods - better bolts ensure they’re safe anyway. We’d recommend solid lifters beyond the limit of 6,500rpm, which is when you really need to consider forged pistons too. Standard Mahle pistons will go to 10.2:1 by skimming the head although this needs to be checked to avoid valve contact. Accralites are recommended beyond this level although these are to special order only.
At this stage we’d also recommend our Farndon H-section rods and if you’re really serious a steel crank as well - however there are plenty of CVH engines racing with the standard cast crank.
Turbo engines are reasonably simple to tune to around 180bhp, which is normally achieved with a Bayjoo chip, -31 actuator, air filter and stainless exhaust. These modifications will allow around 1BAR of boost. Beyond this and you’ll need a larger intercooler to drop charge temperatures plus a hybrid turbo to hit 200bhp.
You’ll get a touch over this with a Kent CVH34 cam as well as reaching the limit on the standard pistons, for which we stock Accralites to better handle boost pressures. These come with finished crowns and a CR of 8.0:1 but can be machined for lower compression ratio.
We also stock all you need to perform the ZVH bottom end conversion, which will give you a 2.0 litre Zetec bottom end and the potential to go beyond for true monster power.