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I wish my 2002 cab would have lasted to 125,000 miles...
I'd sure look at changing out the cam chain and tensioners. Mine failed at 72,000 miles and the engine grenaded at just 2500 rpm under no load. Sold it as a roller for $5K.
I wish my 2002 cab would have lasted to 125,000 miles...
I'd sure look at changing out the cam chain and tensioners. Mine failed at 72,000 miles and the engine grenaded at just 2500 rpm under no load. Sold it as a roller for $5K.
Bill
I wish my 2002 cab would have lasted to 125,000 miles...
I'd sure look at changing out the cam chain and tensioners. Mine failed at 72,000 miles and the engine grenaded at just 2500 rpm under no load. Sold it as a roller for $5K.
Bill
My roller ($4K) also an 02 lost one of it's chains at 124K miles before I got it.
Hopefully dropping the sump will provide more information. I keep going back to your filter photo. I know you said you ran a magnet over it and thought maybe these were air bubbles. These images look more irregular in shape than a symmetrical air bubble? Maybe they are tensioner pad material?
Last edited by 85eurocarrera; 03-19-2019 at 09:13 PM.
Hopefully dropping the sump will provide more information. I keep going back to your filter photo. I know you said you ran a magnet over it and thought maybe these were air bubbles. These images look more irregular in shape than a symmetrical air bubble? Maybe they are tensioner pad material?
You've seen the photos of the filter material after I cut it open, correct? If those were not bubbles, where did they go?
Brought the trailer to work with me today. Will haul "Smokey" home later. Need to replace the master cylinder in Nico, then I can get Speedy on the lift again. Ordered up a manometer, Loctite 3900 and an oil filler cap. Won't be running the engine enough to perform a crankcase vacuum test, so the tools will be saved for later. Studying how to drop the engine. Chances are good that will need to happen, even if the sump is clean.
Last edited by Scott at Team Harco; 03-20-2019 at 08:49 AM.
I've been investigating more deeply the AOS and its replacement. Came across a few threads here where it was suggested that it could be modified and never again cause a problem. Haven't found enough detail as to exactly how to do this. Do any of you guys have such detail? Would make a good subject for a technical thread.
Didn't come across it specifically in the 101 Projects book, but Wayne has an article at the Pelican site. Found this very interesting:
When the separator fails, you will begin to see a large increase in the overall vacuum in the engine crankcase. In the most extreme cases, the air-oil separator fails to separate the oil from the air, and oil is then sucked into the intake manifold. Oil in the intake system is not healthy for the engine and it can foul spark plugs and destroy catalytic converters at the very least. The failure of the air-oil separator is often but not always, accompanied by huge amounts of white smoke exiting the vehicle's exhaust and a generally poor running engine. You may experience a check engine light (CEL) as the oil being drawn into the intake can affect the mixture level. The oil cap may be very difficult to remove when the engine is running due to high vacuum levels. In addition, you may hear a high-pitched squeal from the engine when it's running because air is being sucked in past the crankcase seal due to the extreme vacuum inside the case.
This has me questioning whether the sound I have been hearing is actually the AOS and not an IMS related noise. Is there anyone here that has experienced this? I may need to start a separate thread to get more eyes on it. I did encounter oil in the intake when I had the front plenum off, and the plugs were oily/sooty. Both consistent with the above issue. Will check plugs shortly after getting the car on the lift. Should provide a better picture of how bad things are. If the oil and sump look good, I may just do the AOS and some other basic - while the engine is out - things. Which leads to...
Further questions: Can the chain guides be replaced without removing the heads? My guess is that it may be possible for the IMS to cam chains but can't tell about the crank to IMS chain. The only ones I am certain of are the pads on the cam to cam chains (5-chain engine). What about the chains themselves? Are they known to be problematic. It looks as though only the cam to cam chains are serviceable without tearing completely into the engine.
Last edited by Scott at Team Harco; 03-20-2019 at 05:31 PM.
I've been investigating more deeply the AOS and its replacement. Came a cross a few threads here where it was suggested that it could be modified and never again cause a problem. Haven't found enough detail as to exactly how to do this. Do any of you guys have such detail? Would make a good subject for a technical thread.
Didn't come across it specifically in the 101 Projects book, but Wayne has an article at the Pelican site. Found this very interesting:
This has me questioning whether the sound I have been hearing is actually the AOS and not an IMS related noise. Is there anyone here that has experienced this? I may need to start a separate thread to get more eyes on it. I did encounter oil in the intake when I had the front plenum off, and the plugs were oily/sooty. Both consistent with the above issue. Will check plugs shortly after getting the car on the lift. Should provide a better picture of how bad things are. If the oil and sump look good, I may just do the AOS and some other basic - while the engine is out - things. Which leads to...
Further questions: Can the chain guides be replaced without removing the heads? My guess is that it may be possible for the IMS to cam chains but can't tell about the crank to IMS chain. The only ones I am certain of are the pads on the cam to cam chains (5-chain engine). What about the chains themselves? Are they known to be problematic. It looks as though only the cam to cam chains are serviceable without tearing completely into the engine.
Yes I have seen the AOS cause the RMS to make noise. The car had came from an Indy who had misdiagnosed it as a failing T/O bearing, then replaced clutch, flywheel, and T/O bearing, noise came back, was brought to the Porsche dealer where I found the AOS was the culprit..
The IMS chain guides cannot be replaced without complete disassembly. The cam chain guides can be replaced without complete disassembly. The IMS to cam chains can be found in a master link type, but I would recommend measuring the chains to see if they are less than 1% wear first. If less than 1% percent I would not run the added risk of using the masterlink type chains. There are special tools to measure chain wear.
I have more if you're interested in anything specific. As others have mentioned, get some durametric time and you'll be able to verify a lot of things. Wish I had got mine sooner.
Yes I have seen the AOS cause the RMS to make noise. The car had came from an Indy who had misdiagnosed it as a failing T/O bearing, then replaced clutch, flywheel, and T/O bearing, noise came back, was brought to the Porsche dealer where I found the AOS was the culprit..
That is a little encouraging. The noise only occurred at high vacuum (off throttle/ idle). If I applied throttle the sound would go away. I may investigate doing the AOS without removing the engine. Maybe dropping it lower at the rear (removing the engine mounts) a little might help. Then again, that may have the opposite effect. Will have to see what I think after I get a good look and consider options.
Regardless - the valve seats have been well lubricated...
That is the thread I found to be the most interesting. I bookmarked it at work today. Need to breakdown the information the Dutch guy was describing. A catch-can might be simple and effective. I'll need to educate myself on this. Or... take the 'easy' way out and buy a new AOS and install it. Might be good enough to outlast the useful life of the car.
Originally Posted by Porschetech3
The IMS chain guides cannot be replaced without complete disassembly. The cam chain guides can be replaced without complete disassembly. The IMS to cam chains can be found in a master link type, but I would recommend measuring the chains to see if they are less than 1% wear first. If less than 1% percent I would not run the added risk of using the masterlink type chains. There are special tools to measure chain wear.
Good information. I'll dig into this. I have seen the masterlink style chain in my searches. Definitely makes sense to verify the need before going that route. I am a little worried about the IMS chain guide. The black 'sludge' I found in the oil filter may be pad material from a guide such as that. Could explain the noise as well, but certainly not the oil smoke.
I have more if you're interested in anything specific. As others have mentioned, get some durametric time and you'll be able to verify a lot of things. Wish I had got mine sooner.
That's a lot of debris. I'll make no predictions on what I will find in mine. I will definitely let you know if I have questions. Great to have so many good people that are willing to help out and provide their experiences. Looked at pricing for a Durametric. Less than $300 seems like a good investment.
Safely home...
...and, of course, it's rainy and crappy out. Should be able to get it back on the lift by the weekend.
Scott, you can disconnect the AOS from the TB plenum and plug the vacuum side to test and see if it is also your source of noise and smoke. ( which I think it could very well be)
Then decide to replace or do the mod above in Coopduc's post. My AOS has been bad for a year and a half (Tip, so it's a b^&ch) and have been running a catch can mod.. Just have to empty the water out of it about every 4 months or so, holds .3 liter moisture.
Scott, you can disconnect the AOS from the TB plenum and plug the vacuum side to test and see if it is also your source of noise and smoke. ( which I think it could very well be)
Then decide to replace or do the mod above in Coopduc's post. My AOS has been bad for a year and a half (Tip, so it's a b^&ch) and have been running a catch can mod.. Just have to empty the water out of it about every 4 months or so, holds .3 liter moisture.
Tech - that's a good plan. I'll definitely do that first. Need to check diagrams - but maybe you can tell me if you are referring to one of the circled items in the photo below? I assume you are referring to the red one.
I'd be very interested to see how you modified your system. Do you have any photos or diagrams that you can point me to?
03-19-2019, 03:33 PM
