The cvh engine was introduced by ford in the mk3 escort in 1980 and was made in 1117cc, 1296cc and 1597cc, the 1.1 was dropped in 1983 and the 1.3 was replaced by the 1392cc in 1986. in 1988 a 1769cc CVH was fitted to the sierra and although a similar engine share virtually no interchangable parts with the 1.6 model.
The most inportant factor on rebuilding these engines is not to mis match head, pistons oil pumps or cranks all of which changed in late 1985
Also if using a performance cam shaft in these engines an adjustable pulley must be fitted as timing is of up most importance to these engines.
the injection cvh engines can be modified to fast road spec with a cam and head change exhaust change and a chip. The earlier carb'd engines can be tuned to fast road spec using the XR2/XR3 carb ( hte early Weber DTF is better than the later Weber TLDM) The carb engine can be taken further using a twin carb setup and solid lifters. a very similar setup is seen in the RS1600i. A twin DCNF carnb setup is ideal but Twin DCOE's can be used although space for a decent air filter is tight in the engine bay
CVH turbocharged engines are much easier to tune, with an increase in boost and modified chip you will easily see 170 bhp wil no other changes, Higer power outputs can be achieved but you will then have to lower the compression ration to prevent detonation and allow higher boost to be run. A must is an uprated intercooler when boosting anything above 1 bar (14.7psi) as if using std pats there will be an increase in charge temp resulting in a serious power loss.
All versions of this engine are safe to use std followers upto 6800 rpm, engines that rev over 7000 rpm are advised to use anti pump followers, any thine above this will result in the need to use solid followers and with this setup CVH engines can be made to rev to over 10000rpm
There are alsdo facilities to convert the CVH engine to use the Zetec E bottom end this hybrid engine is known as a ZE-VH engine