Kent Cams

When talking about Cam shafts amongst performance and modified Ford enthusiasts one word is without doubt going to come up - Kent.

Kent have been producing cams since 1980 so they know there stuff, years of development and testing have helped to ensure the highest possible power gains whilst keeping as much driveability and durability from the average drivers point of view.

The Cam we are testing is the CVH 33. This is the highest listed cam for a CVH engine using a carb (or carbs!). That is not to say by any means that they don't go wilder - they do! You just have to ask specifically.

The reason for this article is to show the likely gains, drawbacks and benefits to fitting this cam over standard and a more mild variant.

The picture above shows the engine that was used for this article, the spec is as follows:

1596cc CVH rebuilt and overbored to 1646cc (+1mm) , Specialised Stage 2 Big Valve Head and skimmed 20 thou, Kent CVH 22 Cam, Magnex manifold and system, Weber twin 40 DCOEs

The above setup was rolling roaded at 110bhp @ the wheels @ 6100rpm running 32 chokes. (this setup was also rolling roaded with the same spec. and 36 chokes and made 116bhp @ the wheels - but was not driveable other than in a race situation)

The CVH 33 cam in this case was obtained in the kit form, which contains the double valve springs which are needed due its rev happy nature, lube, gaskets, anti-pump followers and the cam itself. The cost of the kit varies but expect to pay £220 upwards.

With the cam fitted and run in properly (this is the most vital part of installation and if not done correctly can cause premature damage if not worse to your cam) It was time to take it to be setup and rolling roaded again.

The results:

At idle it is fairly lumpy but if you were at the state of tune the above engine is in, it is not bad at all and hardly any different to its CVH22 little brother, and it is also to be expected anyhow.

Anyone who has used twin carbs and or played around with cams will know the sort of judder and lumpyness I am talking about but even from standard I would imagine this not to be too much of a problem to the majority of recreational drivers.

Low end is obviously slightly off from the old cam although not too bad again, It is suprisingly pleasant around town and idles / drives from low rpm superbly! This is not to say there is power from low revs as there is not - However, it is smooth.

where the cam really excels and where you would expect it to is between 4000rpm and 6500rpm - It really does pull through superbly and adds a noticeable increase in power and torque.

Noise levels increased. This was because of the increased lift on the valves, hence there also being more audible valve noise.

The limiting factor in this test was not the cam itself but the twin 40's. The reason for this is that at present to keep driveability they are set with 32 chokes and where the cam would like to continue pulling through ie 6000rpm-7000rpm the chokes are not allowing enough air through to make use of the extra duration and lift the cvh33 is providing.

CAM	CHOKES	BHP @ Wheels	BHP @ Flywheel
Standard	n/a	77	90
CVH22	32	110	127
CVH22	36	116	134
CVH33	32	114	131

Flywheel figures are given with an approximate transimission loss of 15%.

From the table we can see that simply changing the cam and nothing else gave an increase of 4bhp @ the wheels at 6200rpm. As explained above this figure will greatly increase when the choke sizes are incresed and that restriction is then removed.

From driving the car it is obvious that the power gained is not all at peak power either - 4000rpm upwards has without doubt seen an increse in bhp and ft/lb to the previous setup and a worthwhile one at that.

In conclusion it is an expensive means to gain power but Naturally aspirated tuning always is. If you you use the car every day do not go for more than a CVH33 or you will have problems with driveability. If you intend to use it as a weekend recreational car or for track days and the like then speak to Kent directly and ask them for something a bit wilder!!!

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For more information about KENT cams see there website at http://www.kentcams.com