Soak new hydraulic lifters?

[EngineerDoug]

Hi guys,

Got a question about installing new hydraulic lifters (flat tappet cam). It used to be the conventional wisdom was to soak them in oil so they would fill prior to installation. But now I am reading some folks recommend you do not do this. We need the engine to fire as quickly as possible and rev to >2000 rpm for proper break in. I will pre-oil the system with a hex shaft into the oil pump, of course.

Bottom line - what do you experienced builders do? No soak? Soak but do not pump up?

Thanks!

 

[Ski 61701]

I take my lifters apart to make sure there is no machining gunk inside. Ive had a few over the years where I found weird residue inside and to err on the side of caution, I check these now. Read my other post responding to the gentleman having problems with his 440. It pertains to checking for lifter rotation. If they all rotate properly, just prior to inserting them I just oil them up and slide them home. I take out the distributor and hex gear and prime the motor with a speed wrench and turn the motor over to make sure you have oil coming out of the rocker shafts. Use the proper oil and get the rpms up to break the cam in properly

 

[Challenger340]

That's a tough one for me because I don't use Hydraulic Flat Tappets much anymore, but when we do it's just a bench check with a pushrod to make sure we can move the plunger a little, any stuck or easily collapsible we either dis-assemble to make sure not stuck, or take note of "where" we install them, then run the Engine Oil System on a primer with the Rockers/Pushrods on and the Intake Manifold off, rotating the Engine as well, to insure they are pumping up(air bubbles out around the inner Lifter plunger while on Cam base circle), looking for at least some plunger position preloading, and don't completely bleed off to collapsed at Lift.
Long story short, we don't soak them, although it wouldn't hurt I guess ? But my understanding is Hydraulic Lifters are filled with a silicone fluid for testing at manu's before leaving ? or were in days gone by ? so who knows now ?

Maybe somebody with more Hyd Lifter savvy can chime in with what they do ?

 

[dieseldazzle]

I soak them atleast 4 hours in Lucas zdpp additive and Lucas break in oil. Can't say it helps but never have I had a flat cam

 

[ZR9B]

I always soaked and pumped new lifters...this last time I actually read the instructions and they said not to soak or pump and I didnt....It took what seemed like forever to stop ticking, but I wonder if the less pressure on the new cam may helped it break in???

 

[khryslerkid]

I always soaked and pumped new lifters...this last time I actually read the instructions and they said not to soak or pump and I didnt....It took what seemed like forever to stop ticking, but I wonder if the less pressure on the new cam may helped it break in???

I'm thinking that's why they don't want you to soak them before installing. To have less pressure on the new cam on initial start up.

But when you prime the engine before start up, you're filling most of them...

 

[dieseldazzle]

My lunatis recommended soaking them and my crane and Harland rockers said to soak them too

 

[miller]

If you read the overhaul book, all it tells you on tappets is...oil them, before installing.
Outside, inside, what? Just says to oil 'em!
But if you understand the fact that, when the tappet cup moves up and down, that action is what pulls oil into it, and pushes the oil back out. Do ya say that's the hydraulic end of the deal??? Hehe.
I've always pre-lubed my tappets, not by soaking, but in a can of oil, moving the cup through it's movement. Simply gets some oil inside. Clearances on those tappets are 'real close', will push oil back out as easily as it pulls it in. Of course, while your at it, you take note of free movement, or if it's hanging...if so, then needs a closer look.

 

[65-440]

I let mine sit face up in oil for a few days while finishing the build. During pre-oiling whatever air was still in there was pushed out buy the push rods. Zero issues with cam break in, and zero lifter noise at first start up ....

 

[lewtot184]

don't pump the lifters up. make sure they're clean and coat them with assembly lube before installing.

 

[Ranger16]

I installed a new cam & lifters (flat tappet) last May. I submerged the lifters overnight in oil. No ticking at start up. To me it's only common sense to soak them.

 

[lewtot184]

you never want to pump up a hydraulic tappet before installing. pumping up the tappet extends the plunger to full travel and basically turns it into a solid that can create piston to valve collision. a fully pumped up tappet has to bleed oil off to put the plunger in it's proper preload position. the tappets have a type of one way check valve that tries to prevent bleed down. all new tappets that i've worked with lately do have some oil in them that will bring the tappet into a pumped up state quicker. i don't know of any cam grinders who recommend pumping a tappet up before installation. soaking/dipping a tappet in oil is not the same as pumping it up. assembly lube would be better than motor oil when using new parts.

 

[dvw]

you never want to pump up a hydraulic tappet before installing. pumping up the tappet extends the plunger to full travel and basically turns it into a solid that can create piston to valve collision. a fully pumped up tappet has to bleed oil off to put the plunger in it's proper preload position. the tappets have a type of one way check valve that tries to prevent bleed down. all new tappets that i've worked with lately do have some oil in them that will bring the tappet into a pumped up state quicker. i don't know of any cam grinders who recommend pumping a tappet up before installation. soaking/dipping a tappet in oil is not the same as pumping it up. assembly lube would be better than motor oil when using new parts.

Exactly

 

[moper]

x3. When the engine is assembled and lifters preloaded you pre-oil. That fills the lifters - no reason to soak.