As per title.
Probably a dumb question but I see lots of cam specs include the term ''Lift at TDC''. Surely there is no lift ?(on No1) at TDC.
Im new to this so go easy on me.
As per title.
Probably a dumb question but I see lots of cam specs include the term ''Lift at TDC''. Surely there is no lift ?(on No1) at TDC.
Im new to this so go easy on me.
thats where your wrong my friend, in order to have an inlet valve open a worthwhile amount when the piston starts moving down the bore on the induction stroke you have to start opening it when the piston is going up the bore on the exhaust stroke.
Remember the valve has the whole chamber depth to open before it smacks into the piston at TDC. Trick is to get valve as close to the piston at TDC and follow it down to max lift
I think I got it, so on an exhaust stroke the piston is on its way up the bore with the Ex valve open.
As it reaches TDC the Ex valve closes and Inlet opens?
Surely that causes a degree of pressure going into Inlet tract? Which I would have thought is bad for flow.
Looking at my Std Pinto cam it looks like there is a fair way after TDC before inlet opens i.e the piston has started to go down the bore on induction stroke.
Still a wee bit confused.
The inlet will start opening before the exh. has closed - yes some inlet charge flows out exhaust - its a juggling act!
4 stroke cycle = suck, squeeze, bang, blow.
Interestingly after the valve has got fairly close to the piston @ TDC on the (suck) stroke the valve actually chases - and gets closer to - the piston as it continues down the suck stroke for a short period of time!
Generally speaking the hotter cam, the more lift is present at TDC.
it shouldnt, on a std pinto cam the inlet will be open slightly at TDC, that is assuming the cam is timed correctlyLooking at my Std Pinto cam it looks like there is a fair way after TDC before inlet opens i.e the piston has started to go down the bore on induction stroke.
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