Page 1 of 1
valve guides height
Posted: Sat Jan 24, 2009 5:30 pm
by bones
hi all, ive measured the height of the valves and from the top and they range from exhaust 35.97mm to 36.50mm and the inlet 36.06mm to 36.25mm . these are ok arent they,?
rich
Posted: Sat Jan 24, 2009 7:27 pm
by kiwicar
Er OK for what?
they seem about as equal as you will get them from pressing them in (not machining them in situe) if that is what you are after. As to whether they will clear your collets and retainer on full lift you will only when you measure it
.
Mike
Posted: Mon Jan 26, 2009 4:03 pm
by bones
i had them fitted along time back and never checked them, collets never hit them, im just checking things to see if anything is way out, or abit to close for comfort, port matched the exhaust side and do inlet later, will get some pics up soon of heads ,and i didnt realise just how much i had opened them up,
rich edit again, just noticed there are 2 different collets, 8 are flat at the top and the other 8 have a small step around the top edge, are they 1 for inlet and other for exhaust valves if so what ones for what,? or doesnt it matter,
rich and i know these are boring questions,
Posted: Mon Jan 26, 2009 4:46 pm
by katanaman
You shouldn't port match the exhaust ports, you need a step there to stop wave reversion.
Posted: Mon Jan 26, 2009 4:55 pm
by bones
a step what side .head or manifold, and step as oneside is smaller ?, problem of being bored ,i start messing about, and hoped it would help the nos get out quicker,
Posted: Mon Jan 26, 2009 7:29 pm
by kiwicar
The step is from the port (smaller) to the manifold (larger.the step should be at the bottom with a smooth transition at the top and either a slight step at the sides or a smooth transition here aswell, The important thing is to have a very gradual flair in the port in the head until the step. on the inlet side you need a steady taper down to the point where the bowl is formed behind the valve, it is vital that there are no sudden changes in area. On the rover it is easy to make the mistake of using the gasket as a template and opening the both sides out to match it, this makes this bit of the inlet tract too big an area and the inlet tract flairs out to the join then it tapers rapidly to the pushrod pinch area. The double change in area and abrupt taper causes alot of turbulance and ruins flow.
Mike
Posted: Tue Jan 27, 2009 7:25 am
by bones
the exhaust port is opened up at the valve end and just made a smoother flow and took more out the top of it, the manifold side is not as big as the head port but i angled them as they were flat so angled upwards. And i was mainly trying to get them in-line, but must admit i have opened them up afair bit, i will try and get some pics up of them
rich