Soaking Hydraulic Lifters-Yay Or Nay?

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Never made sense to me, I don't do it, never had a problem.

If your pushrod length is correct, hydraulic lifters are in between the ends of their adjustment range with the valvetrain at zero lash. That would also mean that if you filled a lifter without preload, putting it in it's max extended position, the lifter can hang it's valve open.

I prefer to install the valvetrain and prime the lifters with the engine's oil pump.
 
emmett442 said:
Never made sense to me, I don't do it, never had a problem.

If your pushrod length is correct, hydraulic lifters are in between the ends of their adjustment range with the valvetrain at zero lash. That would also mean that if you filled a lifter without preload, putting it in it's max extended position, the lifter can hang it's valve open.

I prefer to install the valvetrain and prime the lifters with the engine's oil pump.
Click to expand...

This. I prime with the oil pump after re-assembly.
 
Even if you soak the lifters in oil, with a non adjustable valve train, you’ll just bleed the oil out of the lifter when you bolt the rocker arm down. Whatever travel is left of the plunger, in theory, should still be filled with oil. I’ve never had a problem soaking them in oil prior to installation on any engine I’ve built.
 
One of the most important parts of the lifter is the check valve. It can't bleed out the oil unless the check valve isn't seated. Else, the lifter couldn't do it's job.

A good lifter will hold pressure almost indefinitely.

Bleed down would happen via malfunction, not by design.
 
emmett442 said:
One of the most important parts of the lifter is the check valve. It can't bleed out the oil unless the check valve isn't seated. Else, the lifter couldn't do it's job.

A good lifter will hold pressure almost indefinitely.

Bleed down would happen via malfunction, not by design.
Click to expand...

https://dannysengineportal.com/valve-lifters-hydraulic-and-mechanical-what-is-the-difference/

“It is extremely hard to compress any fluid. This makes the lifter now act, almost as if it were, a solid design. A predetermined and closely held clearance, between the lifter’s plunger and its body; permits a minute amount of oil to escape from below, moving past the plunger.”

“

This movement of the plunger, with respect to the lifter body; after the check valve is seated is called, leak down or bleed-down. As a result, it consists of the oil, draining out. As the lifter returns to the base circle of the camshaft; oil fills the high-pressure cavity and the cycle begins again.”​


Direct from the article.

You obviously will rotate the engine over several times once you bolt down the valve train to make sure everything is moving properly. You will have some some bleed off from the lifters doing this. If what you say is true the valves would never be closed if you prime the lifters as it would never compress. Every single time I have bolted a rocker arm down I have never had that happen. The plunger always compresses
 
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Always primed the pump after camshaft replacements and rebuilds. A few squirts in the lifter with an oil can just made me fill good. After zinc was removed, a flat tappet cam engine needs all the help it can get. Crane Cams had a moly cam lube that I really liked. Never had a cam go “flat”, even with aggressive cams and performance valve springs. The initial start up and break in (20 minutes) is critical for a cam and lifters to live a long life. If soaking is how you’ve done it with success then carry on.
 
CarbonSteel said:
Back in the day, I put them in a pan of clean oil and pumped them a few times, but this was done more to ensure there was lube inside the lifter versus "pumping them up".
Click to expand...
yeah, anything moving inside an engine without lubrication is bad.
 
PontiacHO said:
Always primed the pump after camshaft replacements and rebuilds. A few squirts in the lifter with an oil can just made me fill good. After zinc was removed, a flat tappet cam engine needs all the help it can get. Crane Cams had a moly cam lube that I really liked. Never had a cam go “flat”, even with aggressive cams and performance valve springs. The initial start up and break in (20 minutes) is critical for a cam and lifters to live a long life. If soaking is how you’ve done it with success then carry on.
Click to expand...
After cam break in (2K RPM for 20-25 minutes) change the oil and filter. 500 miles OCI again. Another 500 miles OCI again. Then I recommended every 3-5K miles.
I used SAE 30 wt. (Pennzoil and/or QS) for ALL of my cam break ins.
Rhoads lifters and COMP CAMS had a great cam lube for breaking in a cam.
 
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Years ago I used to work in a machine shop and have put together a few hundred valve trains, we never pre-filled them. They did have some kind of fluid in/on them in the package but I always assumed that was so they wouldn’t rust. Never had issues setting lash or anything and the engines were always pre-lubed once installed in the vehicle.
 
Jimmy_Russells said:
Years ago I used to work in a machine shop and have put together a few hundred valve trains, we never pre-filled them. They did have some kind of fluid in/on them in the package but I always assumed that was so they wouldn’t rust. Never had issues setting lash or anything and the engines were always pre-lubed once installed in the vehicle.
Click to expand...
My dad was an awesome race engine builder. He's the one that taught me to soak/fill lifters with oil.
 
Break in is more critical for flat tapper lifters/camshafts than hydraulic rollers.
 
BlueOvalFitter said:
After cam break in (2K RPM for 20-25 minutes) change the oil and filter. 500 miles OCI again. Another 500 miles OCI again. Then I recommended every 3-5K miles.
I used SAE 30 wt. (Pennzoil and/or QS) for ALL of my cam break ins.
Rhoads lifters and COMP CAMS had a great cam lube for breaking in a cam.
Click to expand...
When I worked as a line tech for a Chevy dealership we used a can of GM EOS lube for new cam lube. The 305 engine kept us busy with cam and lifter replacements as well as pulling heads for worn valve guides. I had a 305 in a new (79) Camaro I bought my wife. I used Phillips 66 Trop Artic 10w40. Never had either cam or valve guide failure. Loved that oil…
 
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