Macster

even manages to run long enough. By that time any codes are thrown the engine has likely hammered itself to bits inside.

Sincerely,

Macster.

Macster

and variable lift) but not the standard M96 lifter. I dare say all hydraulic lifters work similarily and the interesting stuff's inside that housing.

I got to take some better pictures of the insides of an M96 engine lifter and post.

These zero-lash valve lifters are fantastic devices. We don't appreciate them enough I think. Well, as some who's done his share of valve adjustments I think I appreciate them.

Sincerely,

Macster.

ivangene

So,
have any engines had issues with the lifters getting weak due to exessive wear from age? In other words the parts end up allowing the oil to leak out and thus not remain in contact with the valve (ie...ticking, like the old days with manal adjustments?)

second, Those dont look to hard to change, I am guessing there is a bit more to it than meets the eye with relation to the cam shafts/chains and timing... (I have never seen those exploded views or pictures)

And on another note.... I read up a few about a bad IMS bearing, What would one look for, listen for or have as a way of determining if the bearing needs replacing - then of coarse, how would you aproach that job.

AGAIN, I really am just interested in these things and NOT trying to pee all over the thread with stupid questions. My thoughts are more preventative maintenance. I think if some of these could be done in conjunction with other "normal" issues like replacing a clutch or something, it might be well worth the effort to do.... just ideas

cdodkin

As I mentioned above, I did a set of hydraulic lifters in a GTi, and this was specifically because they had become noisy.

Based on the assumption that increased noise indicated the lifters were no longer pumping-up onto the cam correctly - and that this would quickly translate into increased cam wear - I initiated a complete swap out.

Cam removal/refitting and timing settings were the key issues - the lifters themselves were pretty straight forward, they just needed priming with new oil before fitting.

The old lifters showed some scoring on the outsides - not excessive, but definitely there after the 100+ thousand miles of use.

Certainly far superior to the manual setting of days gone by!

ivangene

VW GTi ??
I have done them on a Chevy 327, so far nothing on my P-car equates to those days except the little thing I use to inflate the tires with. The Cam and variocam (which I have no idea what is or does) frankly sound a bit scary to work on. (which might help explain why not many people have worked on them) The IMS is another WTF part for me and I hope to gain an understanding of it....(again, anyone who has had problems, had the motor replaced so there may not be much info on these areas.)
Not that your info isn't good, I just want to know about the M96

The pictures are great to look at and study, thanks to the OP!!!

cdodkin

Yep VW GTi - just using to illustrate what to listen for when hydraulic cams need replacing due to high mileage.

Maybe someone here can post M96 specifics.

ivangene

cool -

ivangene

OK I am going to shut up...... I just spent over an hour watching this guys vids on youtube. There are about 12+ vids each one is about 4 minutes. Here is what he did:

He had a bad Boxster, he rebuilt the motor, he video taped it. Made a lot of his own tools (obviously not an amature mechanic)

LINK (to one of the series)

So I know its not the same animal BUT there are some things I can see that cross over. I think the info is amazing and I see now what some of the parts are in the motor and how they are installed.

This is a cool look at the entire build of a motor - worth watching IMHO

gota911

Ed, thatnks for that link. His rebuild and documentation was awesome! I now know why these engines fail. It is because the chain guides are held in place with rubber bands.

I could do that, if I stay at a Holiday Inn Express for the next 6 years!

ivangene

Yea, the one showing the chain assy is pretty hairy... and like you say, those rubber guides (not the bands LOL) have to wear (like he shows) and at some point must become less effective. Cheap and easy to replace as long as you already have the 6 years invested in a motel 6 !

I also liked the one that shows the upper end of the head assy with the lifters and cams going in, and the one where he is installing the wrist pins into the 4-5-6 cyliders, Thats some trick there too!!

salayc

The big trick is all of the specialized tools he made.
Do you get Variocam and the function of the IMS now?

ivangene

Oh yea, and I see how "easy" it would be to replace/service
The thing that I have in the back of my mind is there is also "electronics" that have to interface with all these things... that's where I get triple lost !

cdodkin

Ed great video series - it's still a M96 block like the 996, so very applicable.

judd944

I watched those videos too when I was looking for a video of a teardown of an M96 engine. This engine would not be so easy to rebuild at home....

Macster

getting weak (worn) and thus unable to maintain as much pressure and produce more valve clatter at least at startup. During engine running if a lifter noisy that's more than just wear.

These things fed from an oil passage fed by oil pump. They see high pressure oil all the time. The mating parts have some very nice sliding fits. By nice I mean given the diameter of the parts they fit together even with no oil so well that they have the abilty to even trap air and thus become an air spring. Assemble the two pieces together with no spring inside and I think you'd be hard pressed to separate the two without resorting to some method of gripping that would damage the parts. They fit together and slide very well.

My point is that it is hard to imagine a wear scenario that would see a zero lash device unable to retain sufficient oil pressure to function properly.

However, there's a check ball backed by a spring. Should this spring fail or the check ball develop a leak this would allow oil to flow out under pressure of the valve being opened and a noisy lifter the result.

The ball could develop a leak if a piece of debris got caught and prevented the ball from forming a good seal with seat.

Where would the debris come from? It would have to have entered the oil passage after the filter which is unlikely except in the case of a new engine.

More likely if the engine has some miles on it from dirty oil that is not going through the filter because the filter is full/plugged and the bypass valve is open allowing unfiltered oil from the pump to flow directly to all bearing interfaces.

The noise can of course come from another area. One possibilty is the lifter and cam lobe interface starts to wear. The zero-lash adjusters can only deal with a relatively small amount of lash take up.

Another possibilty is the lifter in its alumum bore wears the bore and the clearance becomes too great and oil flow and pressure that would otherwise flow to the zero lash device in the lifter housing instead follow a less restrictive path, the zero lash device becomes noisy at least under low oil pressure conditions because it has insufficient oil pressure to keep it pumped up against the normal bleed down that occurs during operation or after extended periods of no use.

The lifters can be changed. Whether it can be done with the engine in the car I don't know but I suspect not. Alot of dissassembly has to be done to expose the lifters. They live under the camshafts and to remove these requires removing the chains and this requires removing front and rear engine covers and well a change in lifters in the M96 not a quick or easy job.

For IMS bearing failure symptoms I know of no real advanced warning barring something turning up in the oil.

The transistion from a properly functioning IMS bearing to one that is not functioning properly is a very quick event. Seconds if that. If there is an advanced warning one may not have time to react to it before it is too late.

I know of at least one owner who detected something amiss and shut off the engine and apparently this limited the collateral damage and the engine was torn down and deemed rebuildable. I have pictures of this engine apart. I do not know the details of what the owner heard, what signal/sign he got other than something the mechanic said about noise. Probably just some horrible sounding noise that would make a person so alarmed as to shut the engine off first then think about the noise. Or better yet, not think but simply have the car flat bedded -- with no engine start/running -- to dealer for diagnosis.

As for preventative maintenance all I have to go by is my experience with an 02 Boxster with nearly 214,000 miles on its and its original engine. Frequent oil/filter services.

Mr. Raby does not like Mobil 1. He has covered this and I won't arque with him. There very well could be something about Mobil 1 oil that contributes to IMS failures and maybe other internal engine problems as well.

However, based on my experience with Mobil 1 oil it has served me and my engine well. I have used Mobil 1 mainly 0W-40 but sometimes 15w-50 and even 10w-40 exclusively since buying the car new. I do change the oil every 5000 miles along with the filter. Additionally I treated the engine to an early oil/filter service at either 1000 or 2000 miles, then again when the odometer read 5000 miles and every 5000 miles after.

Even at this stage of my Boxster ownership I'd change oil brands if I knew what to change to. But I don't and I am not in a position to buy an engine from Mr. Raby or have him redo mine in order to learn the better oil he has found.

Sincerely,

Macster.