Leak down testing? (1 Viewer)

[sodafeld1]

Been looking at leak down testing, this guy is thorough to say the least.


Am I understanding correctly that valves can be adjusted by the listening of the leak?

When I adjusted valve lash, I felt it was a bit robotic to the fsm specs. The specs would mostly apply to new valves and seats wouldn't it?

But then, do worn valve seats and/or valves require a different gap on the fsm spec lash to fully close?

I guess factors like carbon, sludge, lifters etc would come into factor too..

 

[sodafeld1]

geez, then there is this one!

wish I got my endoscope sooner..

 

[lacalvette]

As long as the valve seat tight and still within spec. Doesn’t really matter if they recess. The valve lash need to be pretty close to the FSM. Beginning start with the cam lobe, if the valve lash is less, the valve will start opening earlier. On those engine the piston come near the top of the bloc and the head is flat. There is a risk of contact. Exhaust lash is usually twice as intake because exhaust gas heat the stem and this one extend.

If the exhaust valve leak, it will melt very shortly

In doubt, examine the rockers contact tip, if there is a « hole » the valve lash will be false or a hit and miss..

 

[sodafeld1]

Interesting stuff..I much to learn