General hydraulic lifter question

BSTKN

MEMBER
1970 FORD MUSTANG
160,000 MILES

If a lifter were bleeding down, not pumping up or partially pumped up, could a valve partially open?
This is a general hydraulic lifter question. There was no category.

This is for a one cylinder engine with hydraulic lifters. Engine will not start and all other factors have been addressed. If valve were not opening fully it could explain lack of combustion. Have spark and fuel, carburetor is clean.
The oil was contaminated recently, lifter could have contamination.

1 Reply

JACOBANDNICKOLAS

MECHANIC
108,205 POSTS

Hi and thanks for using 2CarPros.

If it is totally collapsed, chances are it will not open the valve. However, here is how you can tell.

First, disconnect the spark plug wire but leave the plug in the head. Turn the engine over as if trying to start it and feel if there is a vacuum being created at the carburetor. If there is, the intake valve is opening.

Next, do the same thing, but put your hand over the exhaust. You should feel compressed air exiting the cylinder when the exhaust valve opens.

Try that and let me know what you find.

Joe