Pressed steel rocker - How it oils the pushrod and valve tip
Posted: Fri Mar 20, 2020 5:56 pm
I did a total engine rebuild last year but didn't do anything to the rocker assembly.
After running the engine for 20 miles I noticed that the valve tips and rocker contact pads of valves 7 and 8 were dry of oil.
All other valve tips had loads of oil as did all 8 pushrods tops.
This got me trying to work out how the valve tips and pushrods get oiled.
The pushrods are easy because of the oil way through the adjuster to the opening in the
central pivot bush.
The valve tips are more difficult so I wanted to check out where oil was released from the rocker.
Firstly I tried pumping oil through but couldn't get enough pressure.
So I decided to pump air through. To do this I cut up an old push bike tyre valve and used some washers one side of the central pivot and another bit of rubber tyre tube and a two pence coin for the other side. This picture shows the equipment used:
This was secured using two pairs of mole grips:
This was attached to a foot pump:
The rocker was put under water and air pumped through.
(This picture is not very good because it was taken from a video file.)
This clearly showed air only coming from the adjuster end but from two places:
1. From the end of the adjuster which impacts the pushrod
2. From the tiny hole under the adjuster nut
So my conclusion from this is that some oil comes out of the tiny hole under the adjuster nut and travels down the groove in the top of the rocker to the valve end and works down to lubricate the contact pad and the valve tip.
Am I right in my conclusion or do the valve tips get oiled some other way...by oil splash for example.
Any other theories?
After running the engine for 20 miles I noticed that the valve tips and rocker contact pads of valves 7 and 8 were dry of oil.
All other valve tips had loads of oil as did all 8 pushrods tops.
This got me trying to work out how the valve tips and pushrods get oiled.
The pushrods are easy because of the oil way through the adjuster to the opening in the
central pivot bush.
The valve tips are more difficult so I wanted to check out where oil was released from the rocker.
Firstly I tried pumping oil through but couldn't get enough pressure.
So I decided to pump air through. To do this I cut up an old push bike tyre valve and used some washers one side of the central pivot and another bit of rubber tyre tube and a two pence coin for the other side. This picture shows the equipment used:
This was secured using two pairs of mole grips:
This was attached to a foot pump:
The rocker was put under water and air pumped through.
(This picture is not very good because it was taken from a video file.)
This clearly showed air only coming from the adjuster end but from two places:
1. From the end of the adjuster which impacts the pushrod
2. From the tiny hole under the adjuster nut
So my conclusion from this is that some oil comes out of the tiny hole under the adjuster nut and travels down the groove in the top of the rocker to the valve end and works down to lubricate the contact pad and the valve tip.
Am I right in my conclusion or do the valve tips get oiled some other way...by oil splash for example.
Any other theories?