TDC Question

[rlees85]

right this isnt quite micra related but its a generic question relating to some work me (and a few others) have been doing on my brothers fiesta (zetec)...

if the camshafts (both) are locked (not positioned but positioned and locked) in their TDC position.... are ALL the valves 100% CLOSED or are some open/slighlty open??

strange question but if anybody knows will be really useful.. thanks!!

 

[frank]

rlees85

slightly open

 

[rlees85]

open enough to be introduced to mr. piston??

 

[frank]

rlees85

mr inlet and mr exhaust will both be about 1-2mm open at tdc
on a standard cam

 

[rlees85]

i know this might make me stupid, but is that likely to strike a moving piston or not? thanks btw

 

[frank]

rlees85

not stupid at all
if the valves are at the top of the combustion chamber, and the piston reaches the bottom of it, there will be some clearance between mr v and mr p

 

[rlees85]

good good reason i ask is: whilst the cams were locked in place (bang on TDC) the crank was rotated a few times trying to remove the an old cam belt... anyway now all the work is complete it will not start...

just making sure that no valves could have got bent during this as i cant think of much else what is up with it....

thanks for the help

 

[frank]

rlees85

if you push the car in 2nd gear you should be able to feel the 4 compressions equally spaced, if so, mr v,s are ok !

 

[rlees85]

cheers, will look more into it tmr ...