stuttgart46

What is the highest mileage you guys have seen? I've heard of a couple with over 200K miles on them and still running strong.
I just bought a car with 176K on it and I was just curious.

Macster

My 02 has over 255K miles. Original engine. Original IMSB. Original clutch. Damn driver's side floor mat is shot though. Crap German floor mat engineering.

Sincerely,

Macster.

stuttgart46

That is awesome.
I went through a few motors running a Spec Boxster so I am little gun shy. On the other hand, I ran the crap out of our first Boxster when it was new on the track doing DE's and it never blinked. I don't think they like sticky tires unless you go to accu sump. That'll be the first upgrade for this one.

KNK123

I'm curious, how much use did you get out of the engines in your Spec Boxster before they failed and what failed? We're you running an accusump?

trem816

I just purchased a 2000 boxster with tiptronic it has 145k.

flyingpenguin

My 1999 2.5 has a little over 140k miles and throws a variocam tantrum when driven hard. This started happening just recently and I suspect it is because of the variocam ramps being heavily scored. When I redid the top end of my 2000 996, those ramps were scored / pitted after only 60k (admittedly hard) miles, but with very short oil change intervals on M1 15W50.

Got this Boxster with 110k miles, so don't have its full history, but with 140k expect the ramps to be in bad shape.

stuttgart46

No accusump as this was one of the early cars built for the series. Looked to be IMS or D-Chunk every time. I sold the car with a re-manufactured from Porsche and to my understanding it is still running strong.

Macster

The ramps come 'scored' a bit to 'guide' the chain/position the chain. The pitting is just the wearing away of the slick/solid outer surface of the rail which exposes its porous interior, the pits.

The pits are there to help retain oil which lubes the chain rollers as they move over the rail.

By following the pre-scored rail (the other rail is not scored and not pitted due the very light load it has due to the way the VarioCam system works) after a (short -- more on this below in parentheses) while the chain rails wear a groove deep enough the rails make little to no contact and the chain is supported by the rail against the rollers. This results in nearly zero wear.

(How short a time does it take those rails to develop a nearly zero wear surface for the chain? Well, here's an idea: When I changed the oil in my 08 Cayman S at 750 miles the oil filter housing oil and oil filter were filled with trash, some of it tiny pieces of the chain rails material. At the 2nd oil change at around 1400 miles there was no sign of any rail trash/debris.)

Here's a pic of a not new but not very worn actuator (I was not able to get a pic of the new one before it went into my Boxster):



Here's the old one out of my Boxster with IIRC 230K miles on the thing.



BTW, the ramp was still in real good shape according to the tech. We had talked about possibly replacing the other bank's solenoid/actuator if this side turned out to be worn but the tech was quite firm in his advise the other side didn't even warrant the removal of the camshaft cover.

The reason the actuator was replaced was it was bad, inside. The unit is 'sealed' and not rebuildable. Without access to a machine shop I'm unable to even try to disassemble/cut the thing apart.

Oh, the tech and I surmised the actuator wore out probably due to a bad solenoid that had erratic activation which caused the actuator to be continously (or quite frequently) activate then deactivate. Over the miles this just wore out the actuator. The one on the other side of course is still working just fine.

Might just as well mention the 996 and its VarioCam behavior might have been due to the 15w-50 oil which is probably not the best oil for satisfying the hydraulic fluid requirements these engines require of their engine oil. Which is why 15w-50 oil is not approved for these engines.

Sincerely,

Macster.

flyingpenguin

I like your theory. One question though; Why would the original design of these ramps not call for a deeper cut / scoring in the first place?

Macster

What does a deeper cut/scoring buy? Just a faster worn out part.

These rails are essentially not serviceable items so it is to Porsche's benefit, and more importantly the owners' benefit, that these rails deliver maximum service life. A deeper initial scoring works to shorten the life of the part.

Sincerely,

Macster.

flyingpenguin

At the risk of highjacking this thread, want to share some more thoughts.

Today the CEL came back on (on the 1999 / 140k miles Boxster), after it disappeared several times by itself. Pulled P1539 (camshaft adjustment bank 2) and P0154 (O2 sensor ahead of cat bank 2)

Activating the camshaft adjustment with Durametric results in a grinding noise. Wondering if my diagnosis of the variocam ramps being totally shot is correct...

I guess it's time to get serious on pulling the engine..

Macster

P1539 camshaft adjustment bank 2. No triggering of the actuator nevertheless active position [sic].

Possible causes: short to ground; actuator defective.

Also, if (big if) the solenoid or more likely just the actuator is 'bad' the engine does not have to come out of the car. 'course, if you are doing the work you can drop the engine. The engine out is easier to work on.

And if you have to go deeper (chains/tensioners perhaps) the engine may have to come out.

Might add that the techs I spoke with when my Boxster's solenoid acted up told me that so often both the solenoid and the actuator are bad that they replace both. In the case of the actuator you can't tell this is bad until after you have replaced the solenoid and buttoned up the engine.

To dive down to the actuator means doing the solenoid job again, and then some. The actuator adds around 4 to 5 hours to the job and of course the camshaft cover must be resealed (and new microsealed bolts used) and so on. So, you might consider replacing the solenoid if you have to replace the actuator.

The 02 sensor error might be explained by the fact the VarioCam system is not working right. A side effect is the #2 sensor reading will not be what the DME expects.

The DME will attempt to address this by adjusting fueling. (I observed some pretty wild short term fuel trim values on the 'bad bank'. The tech when I told him of this said that this is another sign of the VarioCam system not working right.)

The adjustment may drive the #1 sensor into an error state (flat lining between 0.4 volts and 0.6 volts for more than 5 seconds without any interruptions).

I'm sure you're way ahead of me, but just to finish my thought: I think the primary focus now is to id the cause of the P1539 error and get this fixed.

Afterwards drive the car and see if the sensor error comes back.

Sincerely,

Macster.

flyingpenguin

Thanks Macster.

From what I read there is not a sure fire way to bench test the actuator, correct?

Macster

This is what I was told or deduced from what I was told and have observed.

In the case of the Boxster engine (and I believe this is true of the 996 engine but my experience/exposure to these items comes from my Boxster) the actuator can't be tested on the bench. It operates via oil pressure/flow that is controlled by the solenoid and supplied by the engine's high pressure oil pump/delivery system.

The actuator can only be tested in situ and with a properly functioning solenoid.

This is why, I was told, that it is SOP to replace both the solenoid and actuator if the solenoid (or possibly the actuator) was bad.

The techs told me too many times repaired cars come back with the same/similar symptoms and the cause was a bad actuator that was masked by a bad solenoid. Now these repairs the bulk of them were under warranty so the cost was about the same, so it was not a cost saving action to skip/skimp (so to speak) on the replacement of the actuator, nor when the decision came about to replace both a cost padding measure, but simply a customer satisfation issue.

No one likes to have his new (under warranty at least) car in for this serious of a repair only to get the car back and within days maybe hours have the car back in again for as best the layman customer can tell is for the same thing.

Might add briefly as possible that in my Boxster's case the actuator was not replaced, at least initially. I've coverd the details of this before and won't repeat them but if you PM me with a request for more details I'll provide them.

Anyhow, shortly after I got the car back the symptoms/error codes returned. Back the car went and the tech eliminated a faulty new solenoid and said the actuator was at fault. He said there's no way to test the actuator until the solenoid is replaced and the engine buttoned up.

But of course if the actuator is found bad at this time, quite a bit of the cost to replace the solenoid is required to get to the actuator.

So, I was told if the solenoid is bad that replacing both the solenoid and the actuator is the best course of action.

I do not know if it is possible to identify a bad actuator (while the engine is still together) and if so then is it also SOP to replace the solenoid 'while there'.

I might add I closely examined the bad actuator and spotted nothing that even hinted it was defective/bad. The rail coverings were not very worn at all, to the point the tech didn't even recommend going to the other bank as a preventative measure replace if not the solenoid/actuator the actuator rails.

Also, all internal engine components exposed in this repair: the camshaft lobes. bearing diameters, the camshaft bearings in the head/camshaft cover, the lifter bucket tops, the chain/sprockets of the cams, everything showed no signs of any wear.

Even the interior surfaces of the engine were quite free of any sludge/varnish buildup.

I have pics of the above and can provide you with copies if you send me a PM that can accept the pics as attachments to emails.

Sincerely,

Macster.

lilredpo

Not very high, but a milestone.....just turned 55,555 yesterday.