Nick Rogers
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| posted on 16/12/06 at 06:13 PM |
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Camshafts
Guys,
i am building a 2.0l zetec 1993 with R1 carbs. i am currently at the stage of engine rebuild and was thinking of putting in some 'fast road
cams'. Anyone tell me what i need as power bands differ abd so do prices, also do i need to do anything else whailst changing these over.
Thanks for your help, hopefully santa will bring these if i am very precise with part numbers.
Nick.
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oliwb
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| posted on 16/12/06 at 06:41 PM |
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The only two bits of info I can give you are that:
- if you go wild with profiles you'll need new uprated followers so that the valaves open fully, and
- rally spec cams are a good bet for road cars as they lack a bit of horswepower but give a lot more torque over a much bigger power band (better for
road use)......Oli.
If your not living life on the edge you're taking up too much room!
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ROO
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| posted on 16/12/06 at 11:02 PM |
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Hi Nick..
Ive built loads of modified engines so here's a little advice.
1st decide what you want out of the engine. A road engine has to idle and not overheat and do sensible miles to the gallon. As soon as you start
asking for more power you will loose some or all of these atributes. The wilder the tune, or camkit in your case, the harder the engine is to live
with. Sometimes, like when you have melted your motor on the side of the road in the rain for instance, having a full race engine in your road car
seems so overkill. . . . .
But!, if you must tune... (and you must tune, right?), the simple rules are try and match your induction (carbs or fuel injectio yeah?) with the
exhaust side of things. (decent manifold and system). Once you have decided on these you can choose your cams acordingly.
Also, remember that to get more fuel/air in and out of the engine (thats the key to tuning) the camshaft lobes, AKA profiles, need more lift and
duration designed into them. That means that the valves will open further and stay open longer than the original spec cams. This means that valve to
piston contact can happen. To reduce that risk, pockets can be machined into your pistons, increasing the gap between valve and piston. Dummy building
your engine is essential. A piece of plasticene on the head of the valve will compress against the piston leaving you with a clear measurement of the
gap.
My advice to you would be call a camshaft company, tell them what inlet/exhaust combo you have and ask them to recomend a kit for you based on your
requirements. Then all you have to do is fit them, time them perfectly and away you go......
Ask a silly question.... Merry Xmas Bud.
If it aint broke... fix it 'til it is!!
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