Valve Timing - some Dumb Questions
Posted: Tue Feb 25, 2020 3:51 pm
I have been rebuilding a big valve engine, (sorry it is from a Europa), for some time. Now retired, progress on the rebuild is dictated by finances which are generated by selling "stuff" that I collected over the years by having access to more money than sense. I am now at the stage where I am ready to offer the head back to the block and embark upon (I think) the dark art of checking valve timing. I have read this well discussed topic at length on the forum AND made dog eared pages within the Miles Wilkins "Byble". I "think" I am beginning to understand the approach but I have the following questions I am still uncomfortable with regarding definitive answers.
1. To prevent any valve/piston contact, BEFORE initially offering up the head to the block I assume I have to have No.1 piston at TDC AND the inlet and exhaust sprockets so positioned with the timing marks facing each other - correct?
2. I understand the significance of establishing an accurate TDC and not relying totally on the crank pulley and timing case marks to achieve this, but can I rely on the camshaft sprocket indicators (marks) or do I have to go through the inlet/exhaust camshaft Open/Closes BTDC/ABDC dance....?? (Note: this is a road engine I am building and I am using vernier sprockets)
3. Finally, in Miles Wilkins book, page 146 at the bottom it reads, "When setting the valve timing, make sure both camshafts are rocking on number four cylinder". That does this term "rocking" mean exactly? Does it mean when the cam lobes are "just" making contact with the cam follower? (Cigarette paper test..?)
Thanks in advance for your help.
1. To prevent any valve/piston contact, BEFORE initially offering up the head to the block I assume I have to have No.1 piston at TDC AND the inlet and exhaust sprockets so positioned with the timing marks facing each other - correct?
2. I understand the significance of establishing an accurate TDC and not relying totally on the crank pulley and timing case marks to achieve this, but can I rely on the camshaft sprocket indicators (marks) or do I have to go through the inlet/exhaust camshaft Open/Closes BTDC/ABDC dance....?? (Note: this is a road engine I am building and I am using vernier sprockets)
3. Finally, in Miles Wilkins book, page 146 at the bottom it reads, "When setting the valve timing, make sure both camshafts are rocking on number four cylinder". That does this term "rocking" mean exactly? Does it mean when the cam lobes are "just" making contact with the cam follower? (Cigarette paper test..?)
Thanks in advance for your help.