Hydraulic cam followers

[Gelbster]

Hopefully my just-rebuilt M96 is not sacrificed on the altar of Hydraulic Lifter Wisdom.:ah:
If it does, the world gets access to $9 lifters instead of $40++. From the original source. It saves $400+ on a lifter replacement job.

[rah rah 986]

Originally Posted by whitecliffs

Is there anyway to test the hydraulic cam followers once there out of the engine, ive got two sets, one set came from a running engine which was nice and quiet, and another set is untested.

Both set are all solid with no movement, is that the way they should be or should there be some spring movement

I'm hoping some one could respond to the op's question and give some clarity. It does seem that lifters removed from a fresh tear down vary in their movement. some have a fair amount of spring travel, and some are completely ridged with oil pressure. Which is correct? And if reassembling the engine, should the lifters be installed without being pre-pumped with oil-allowing full spring travel, or, should they be pre-pumped with oil making them ridged upon reinstalling?

[JFP in PA]

Originally Posted by rah rah 986

I'm hoping some one could respond to the op's question and give some clarity. It does seem that lifters removed from a fresh tear down vary in their movement. some have a fair amount of spring travel, and some are completely ridged with oil pressure. Which is correct? And if reassembling the engine, should the lifters be installed without being pre-pumped with oil-allowing full spring travel, or, should they be pre-pumped with oil making them ridged upon reinstalling?

Where to begin..........these lifters/cam followers have a "dead end" oil passage design, meaning that once oil gets in, it often cannot get out again, leading to degradation in place, not to mention becoming a receptacle for any debris that is in the oil galley. This results in some lifters becoming solid objects that won't pump.

But now to get to your question, and that of the poster you quoted; you should not be mixing lifter/cam follower locations when using used parts from one engine, or taking them out of one engine and putting them in another. These units take a wear pattern to match that of the cam lobe they have been riding on, moving them to another lobe means they need to re-wear to their new location, which is not a good idea. Both Jake and I commented above on the criticality of the "crown" of the lifter, which promotes proper rotation and reduces wear on both the follower and the cam itself; wearing in the lobes and followers a second time can be very bad news to both.

When disassembling one of these systems, you should be keeping the followers in the correct order to put them back where they came from, or tossing the old units and using all new. In either case, I prefer to hand pump them before installation, and always coat the wear surfaces on the followers and the cam lobes with a good quality flat tappet break in grease to limit excessive wear on start up and break in. Every cam company sells this stuff, so it is easy to find.

Scrounging up used pieces from multiple engines to make one good one is never a good idea, that is how Frankenstein got started, and we know how that worked out.

[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!

[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?

[Gelbster]

The only problem I encountered were stuck tappets.They were impossible to release with reasonable methods. So, if they are solid - they need to be replaced IMHO.
I am on a tight budget with this car but replaced all 24 parts. Why? Because of the stupidity/ignorance/cheapskate tax that Jake mentions.
These cars are complex ,with lots of quirks that will puni$h you if you don't take the time to study the many issues an ask questions here that indicate you've done some research and are ready to follow advice.
The information is scattered over innumerable Posts,websites and Blogs. So it requires some diligence to understand these issues in any depth. The lifters seem expensive until you contemplate having to replace the re-purposed/used ones after you've run your rebuilt engine for a few thousand miles. There are many other mechanical issues with the M96 that are like this. I suspect that is why some owners just give up ,sell them cheap and buy a Mustang/Miata/Z4. Those cars are less trouble and seem more forgiving so owners get less dollar-fatigue repairing and maintaining them. My Jag is way cheaper to keep running then the Boxster S but eventually I shall get to the end of the Boxster's to-do list and have a great car !

[Smallblock454]

Hello,

if the lifter is filled with oil and is soft it's gone. Especially if you pull him out of a "running" engine.

There is a spring and ball mechnism in the lifter that in general stops the oil getting out of the lifter chamber. If the spring is worn the ball valve can't work and the lifter will be soft. So the lifter won't be able to generate the correct height for a correct valve play.

If the lifter is new or was a long time out of the engine, just press him and put him in an oil bath (completey covered with engine oil) for some time so he can soak oil in. If the lifter is OK in in general it will work than. Also it will be hard. If it will stay soft something is wrong.

Regards, Markus

[Smallblock454]

rah rah 986: Did you understand how these hydraulic lifters work? Just do some research on the internet. Easy to find.

Regards, Markus

[rah rah 986]

Actually, I have done much research and reading prior to posting my questions here, up to and including you tube videos that show disassembly and cleaning of lifters. (For what it's worth). What I have not found until now (sort of) are answers to some of the questions that I have posed here, which are really a matter of trying to judge whether a lifter is functioning normally, or needs replaced. After sitting for many months, I have lifters that are completely rigid, and lifters that have the ability to be pumped. Nowhere have I found an explanation as to whether one of these conditions, or both are ok. I have tried not to burden this forum with meaningless questions, or questions that have already been answered elsewhere. But, in much of my reading, readers have been forewarned of problematic lifters and the high percentage of these cars that have malfunctioning lifters. So, while I am not a seasoned mechanic, I am a hobbiest with more than average mechanical skills and aptitude who is learning as he goes, and is in the process of reassembling my engine after having had a valve job performed. I am trying to be clear on this lifter issue so that I don't overlook the importance of reassembling this engine with properly working parts. Thanks

[spendy]

rah rah,
I went thru a similar situation. I had some heads rebuilt that were from a working engine that had been out of the car for about a year. When testing the lifters, I found that -all- of the intake lifters felt a bit spongy. Most of the exhaust valves were firm. I know the engine did not have any apparent lifter problems before storage. A possible explanation of this is the orientation of the lifters in the engine. The cup of the intake lifters is tilted downward, while the exhaust lifters are tilted upward. This might explain why the intake lifters leaked down more than the exhaust.

hth

[Gelbster]

So, if they are solid - they need to be replaced IMHO.
*I now believe this may be partially wrong based on dismantling many old M96 lifters. Sometimes the tappet assembly is solid in the bucket because the tappet and the bucket is full of oil.
Proof = Dismantle all the Lifter parts,and carefully reassemble with no oil - the two halves of the tappet move freely. Install the tappet in the bucket WITHOUT the retaining ring - everything still moves freely. Install the retaining ring - ditto. Fill the tappet and the bucket with oil and reassemble completely - Rock Solid to finger pressure.
But remeber ,the lifter will only stay "rock solid"to any degree if the engine oil pressure is sufficient.If the Lifter carrier bores or cam bearings are worn -not so much ? *