Hydraulic cam followers

[rah rah 986]

So is it accurate to say that a properly functioning lifter can be pumped by hand, allowing oil to pass in and out?

Is it normal for the lifter to pump to a state of being solid once it has filled with oil?

And, if after being out of an engine for several months would a healthy lifter be solid, or would it be soft, enabling it to be pumped by hand?

I read posts that refer to lifters "draining down". I interpret that to me that in an idle state, the lifter drains of the oil that had filled it while in operation....the engine running. Is it normal for the lifter to drain down, or should it retain the oil, keeping it rigid?

Sorry about all the questions...I know some seem redundant. But, with my engine apart and ready to reassemble, I am concerned about understanding how to to best evaluate the condition of my lifters. I have picked up bits and pieces of information, but, nothing that really summarizes just what to be looking for in the behavior of a healthy lifter....or, an unhealthy lifter.

Thanks

[JFP in PA]

Originally Posted by rah rah 986

So is it accurate to say that a properly functioning lifter can be pumped by hand, allowing oil to pass in and out?

Is it normal for the lifter to pump to a state of being solid once it has filled with oil?

And, if after being out of an engine for several months would a healthy lifter be solid, or would it be soft, enabling it to be pumped by hand?

I read posts that refer to lifters "draining down". I interpret that to me that in an idle state, the lifter drains of the oil that had filled it while in operation....the engine running. Is it normal for the lifter to drain down, or should it retain the oil, keeping it rigid?

Sorry about all the questions...I know some seem redundant. But, with my engine apart and ready to reassemble, I am concerned about understanding how to to best evaluate the condition of my lifters. I have picked up bits and pieces of information, but, nothing that really summarizes just what to be looking for in the behavior of a healthy lifter....or, an unhealthy lifter.

Thanks

When you pump them up by hand, as they become full, they feel solid, because the oil is not compressible, but this may bleed off over time if left to sit as the oil drains off. Because of their design, the oil has to go in and out thru the same opening.

A healthy unit should pump up a appear to hold pressure by feeling rigid. I never like to put any engine parts in "dry", so giving them a pump up will help on start up.

How are you planning to pre oil the engine before start up?

[Gilles]

Originally Posted by JFP in PA

How are you planning to pre oil the engine before start up?

Hello JFP,

What is the most prsctical way to pre-oil the boxter engine after reassembly?
Do you crank it without the fuse for the oil pump?

Thank you!

[JFP in PA]

Originally Posted by Gilles

Hello JFP,

What is the most prsctical way to pre-oil the boxter engine after reassembly?
Do you crank it without the fuse for the oil pump?

Thank you!

No. We use a small pressure tank (air over oil) filled with break in oil to pressurize the entire engine without having to spin it, sort of like an over sized accusump set up. Once wet, light it off.

[Gilles]

Originally Posted by JFP in PA

No. We use a small pressure tank (air over oil) filled with break in oil to pressurize the entire engine without having to spin it, sort of like an over sized accusump set up. Once wet, light it off.

Cool, so you connect the hose from the pressurized tank to the oil filter housing?

[JFP in PA]

Originally Posted by Gilles

Cool, so you connect the hose from the pressurized tank to the oil filter housing?

You can use a modified filter housing, but I prefer to use the oil pressure sender port, and the oil ports on the cylinder heads so that the filtration system is wet as well.

[rah rah 986]

Originally Posted by JFP in PA

When you pump them up by hand, as they become full, they feel solid, because the oil is not compressible, but this may bleed off over time if left to sit as the oil drains off. Because of their design, the oil has to go in and out thru the same opening.

Does it then mean that, if a lifter that has been out of a car for an extended period of time and remains rigid, there is a problem with that lifter since it did not drain down and become compressible again?

[JFP in PA]

Originally Posted by rah rah 986

Does it then mean that, if a lifter that has been out of a car for an extended period of time and remains rigid, there is a problem with that lifter since it did not drain down and become compressible again?

Yes. Two things will keep these units rigid: They are mechanically jammed and therefore useless; or the oil ports a plugged with debris and are hydraulically jammed.

Some years ago, Jake posted a procedure for "cooking" stuck cam followers in Marvel Mystery Oil to free them up (if they can be), or determine which ones need to get tossed and replaced.

[Gilles]

Originally Posted by JFP in PA

Yes. Two things will keep these units rigid: They are mechanically jammed and therefore useless; or the oil ports a plugged with debris and are hydraulically jammed.

Some years ago, Jake posted a procedure for "cooking" stuck cam followers in Marvel Mystery Oil to free them up (if they can be), or determine which ones need to get tossed and replaced.

JFP,
I also remember seeing a picture posted by BYProdriver where he is 'cooking' the lifters submerged in oil but cannot remember if you are supposed to push them several times while they are submerged in hot oil to 'prime them' and fill them with oil before being installed.

[JFP in PA]

Originally Posted by Gilles

JFP,
I also remember seeing a picture posted by BYProdriver where he is 'cooking' the lifters submerged in oil but cannot remember if you are supposed to push them several times while they are submerged in hot oil to 'prime them' and fill them with oil before being installed.

When being "cooked", the object is to pump them to clean them out. When done this way, the heated oil often comes out completely black and full of crud.

[BYprodriver]

Originally Posted by Gilles

JFP,
I also remember seeing a picture posted by BYProdriver where he is 'cooking' the lifters submerged in oil but cannot remember if you are supposed to push them several times while they are submerged in hot oil to 'prime them' and fill them with oil before being installed.

Yes once they are purged of old oil, pump them up in fresh oil prior to install.

[Gelbster]

"Cooking the NEW Lifters"
Now that new Lifters are only $17 instead of $60+++,why clean old ,suspect Lifters?
Some commentators(You Tube) now claim cooking/priming is potentially damaging/unnecessary for new Lifters. I am confused because new lifters come oil-filled and the package is often soaked in leaking oil.So why not replace the lost oil by soaking & cooking?
Is it possible the over-fill the tappet so the dome is so high it causes valve lift/seating problems?
Or would the excess just bleed out harmlessly on start up ? New/old Lifters are different in this respect?
Bleeding Lifters
There are vids showing INA style lifters(ignore the Harley & GM) being vacuum-bled .The author shows the stream of air bubbles rising from the small orifice in the side of the Lifter bucket. But that is just air from the bucket(?) ,not air from the Tappet.The Tappet has a check valve that would prevent any trapped air from escaping? If it did not, the ball/seat would be dirty/defective and it would never hold a full charge of oil in use.It would go soft quickly.So what is the point of bleeding NEW Lifters ? INA does not give an Instruction to do so.
Does 'cooking' bleed air from just the bucket ?How could cooking get air out of a soft Tappet ?
This is a previous version of our INA Lifter to help clarify :
https://www.youtube.com/watch?v=ZCucAyf56Ik
Evaluating new and used lifters
There are credible reports of defective new INA & Porsche Genuine Lifters.see link below
There are references/videos to test rigs that identify defective(leaky) Lifters- new or old.
https://www.youtube.com/watch?v=XvEQ9vIjgy8
The critical leak point is the ball/check valve not the overflow/fill hole in the side of the bucket
https://rennlist.com/forums/996-forum/975059-rebuilding-valve-lifters-can-it-be-done-well.html
INA installation/pumping/priming Instructions
INA do not show any cooking,or priming or filling. The video link below shows a version of the INA procedure.Go to 1.50.
https://www.youtube.com/watch?v=XwTfFesA-yo
To evaluate NEW Lifters I am experimenting with simple rig that others may find helpful.
Use a 12 pt., 1/4 drive, 9mm(11/32") socket plus a 1/4" drive x hex extension. Fit in a drill press.Use a weight on the Press arm to apply a specific amount of pressure on a "solid"(but not jammed) Tappet in a Lifter for several minutes.Measure the Tappet height before/after.
See Post 61 here for a better version:
https://rennlist.com/forums/996-forum/975059-rebuilding-valve-lifters-can-it-be-done-well-4.html
To test your rig - first dismantle an old Lifter and clean(if necessary) leave the Retaining Ring off the Tappet for the test just to make it easier to remove after the test is complete.
Any Tappet that compresses more/much more quickly than the best of your sample is suspect.
Yes it is a crude ,comparative test but it is easy to replicate on many Lifters if you are methodical.
To test the rig further , select a 'soft ' Tappet. Dismantle, clean, refill both the Tappet and bucket with oil.Reassemble. Omit the little spring wire Retaining Ring. It will probably be a leaker and compress too much ,too quickly. Measure the Tappet height before/after to confirm.The amount of oil dribbling out of the fill/weep hole is unimportant.The bucket is just that - a reservoir.
Failure to pump up
One of the most likely failure points of either a New or Used Lifter is the ball seat for the check valve.If you identify this before the engine is reassembled - just clean to remove dirt/swarf.Then retest on your test rig for leakdown.Despite what you read from experts ,the INA Lifter contains 2 springs ,not 1.The spring often shown is inside the tappet and helps it expand.There is also a tiny spring under the ball seat, retained bu a cage.That is where (I think) the problem lies.There are some tight tolerances/clearances there.The slightest defect will cause leakdown.
A 'good' Lifter may fail if it can’t keep it's reservoir(the Bucket of the Lifter) full. If oil pressure is generally low or if oil supply to that part of the Lifter Carrier is obstructed.The Tappet of the oil-starved Lifter may have tested 'good' on the test rig but will tick after a few hours(?) of running.The oil will have been squeezed out of the Tappet into the partially empty reservoir(bucket). The tappet will get air in it and be soft. Until the oil pressure/supply problem is fixed, every Lifter in that location will fail .#4 is particularly vulnerable because of it's position in the oil circulation system(according to credible sources). There are claims that using a (Band-Aid?)10W-50 may help if the problem is slight Lifter Carrier bore wear or similar issues.
The same problem(with the same Lifters) affects BMW also - see M52 and M54 engines.Lots on You Tube
Lifter failure often causes Misfire codes that are misdiagnosed and lead to ineffective parts replacement. The engine cylinder corresponding to the collapsed Lifter(s) may accumulate liquid (un-burnt) gas because of low compression.This liquid gasoline may get purged into the header ?You will then see gas leakage on the header gasket
An unusually loud(but O.K.?) fuel Injector may be confused with lifter tick(see BMW vids). Confirm by interchanging with quieter injector from another location.Much easier than Camshaft removal to chase ticking Lifters!
________________________________________

[Gilles]

Originally Posted by BYprodriver

Yes once they are purged of old oil, pump them up in fresh oil prior to install.

Hello Bill,

When you purge them again in clean oil, does the oil has to be hot well?

Thanks!