24 Valve VR6 - Timing chains and measuring blocks

bigfoot_ev

I have recently been diving down the rabbit hole of how our 24 valve VR6 variable valve timing system works and if there is anything I can do to make up for past sins and extend the time until timing chains, guides, tensioners, etc. need replacing.

Unfortunately for me, I followed the VW recommended oil change interval of 10k miles for the first 80,000 miles. Fortunately I used, almost always, full synthetic. The van was purchased used with about 25,000 and had full records. I suspect the oil change interval is the primary cause of issues with the 'timing chain'. If I was really adventurous I would pull the valve cover off and take a look at things. Maybe I will, since I now believe that is the best way to evaluate the condition of the whole valve train.

Before I did anything of note, I broke out my VCDS and logged some measurements. All measurements are taken at idle with the engine warmed up to 80 deg C. Since we don't have an oil temp sensor that I know of I used coolant temp. And since there is an oil cooler that uses coolant I figured this was a good proxy. Subsequently, I have been driving the van to warm it up sufficiently since I have read this is a better practice.

In VCDS, Select Control Module, 01-Engine, enter measuring blocks 208, 209, 90, and 91. As an aside, it's probably a good idea to do an auto scan periodically while you're in VCDS. I am by no means an expert with VCDS but here is the best I can determine what the measuring blocks mean.
Please, anyone correct me or add to our understanding.

For 208 & 209, I really don't know where this measurement is coming from. What sensor is this?

These look like cam position sensors based on the output. I have read that the exhaust cam, at idle and below 1200 RPM, is set to 22 deg of adjustment. Can anyone confirm what sensor this is?

Here is what I logged with all my years of poor oil changes:

The numbers are not good, but also not an immediate concern either. The spread between 208 & 209 is 3, right on the edge. Time for an oil and filter change plus I added 8 oz of Seafoam to the engine oil. I drove the van for about 40 miles. Then logged the measuring blocks again.

The notable thing here is that there is NO change. So, another oil & filter change plus I added 6 oz of Seafoam to the engine oil. I started to cut back on Seafoam because I wasn't sure if it was too aggressive. I drove the van for 50 miles and logged the measuring blocks again.

Now we see a change! The 208 measurement has come down and now the spread is 2. I'd say that is moving in the right direction. Around this time, I confirmed to myself that Seafoam is probably too aggressive for what I'm trying to accomplish. I discovered a company called High Performance Lubricants that sells an engine cleaner that is supposed to remove sludge and varnish but at a much slower rate so as not to cause stress on filters. This is particularly important because of the screen located in the control housing where the cam adjuster sprockets are attached. Many have discovered this screen blowing out and leaving shrapnel inside the solenoid valves which really messes up your valve timing.

So, another oil & filter change plus the HPL engine cleaner. I drove the van just 10 miles and logged the measuring blocks:

Okay, this is interesting, 209 went up! But the spread also dropped to just 1. Is this good? Or, is this bad? I really don't know.

So that's it for now. I'm going to run this oil for around 3,000 miles and probably change it. I will probably change the oil filter between now and 3,000 just to take a look. Once I drain the HPL cleaner and just before my next oil change I'll take a sample and send it off to Blackstone. I wish I had thought of that before I added the Seafoam.

kourt

Good thread--I'll be watching for your updates. I have been planning the exact same analysis and interventions. My 2001 AXK has 235k miles and sounds great, but I want to push out the inevitable timing chain service as far as I can.

If you have a source for the HPL product, please let me know.

kourt

bigfoot_ev

VanGeek

Good thread -- I'll be watching it! bigfoot_ev -- pls share the results of your next oil change. Curious to see if you have subjectively observable darker oil from deep cleaning-off of deposits when they drain oil after using the additive. Reviewing the thread you shared, it sounds like some users clearly see it and others (perhaps with already clean internals) see no difference.

bigfoot_ev

A quick update, not much to say. I thought we would have put on more miles during our shoulder season outings but I have only put 1,329 miles on since the last reading. No changes. We don't have any outings planned, but I've been contemplating a snow camping trip. We shall see. Here's the output.

kourt

I'll play. My numbers today. 2001 EVC with 240,000 miles on original engine.

Group 090: Power enhancements - exhaust camshaft
680 /min Engine speed
ON Operating conditions
21.5°KW Camshaft adjustment
Bin. Bits

Group 091: Power enhancement - intake camshaft
680 /min Engine speed
16.9 % Duty cycle
0.0°KW Specified angle intake cam adj.
0.5°KW Current angle intake cam adj.

Group 208
680 /min RPM
135 Count
-9.0°KW Idle Stabilization
00100100 Bin. Bits

Group 209
680 /min RPM
133 Count
-7.0°KW Idle Stabilization
10110100 Bin. Bits

I'm going to do some cleaning as suggested above and will report back in a few weeks.

kourt

bigfoot_ev

Fantastic! Great to have more data points.

I'm thinking about adding Seafoam again, but this time at half strength. And then run that for at least 1,000 miles. The way I'm driving the van these days that will take until middle of next year, lol.

kourt

I'm going to do Seafoam just before the next oil change, then do HPL engine cleaner for two oil changes, and then see what happens. Perhaps measuring along the way. More later. Glad we got this thread going. I'd love to see more VCDS users chime in with their data points.

kourt

jjvincent

I suggest a few things.

1. Listen to the back of the engine. If it's growling, they you have a problem that Seafoam will not fix. Seafoam might fix one issue but if there is another (chain and guiderails) then you are just doing a bandaid treatment which will come back to be a major issue down the road (i.e. it skipping a tooth).

2. That screen can get jammed up in the solenoids. No amount of Seafoam will solve that.

3. Maybe try the electroshock treatment. It's this is simple. Pull the connectors off the cam solenoids and then apply a 9V battery to them. Keep reversing polarity a few times. Since the solenoids work off of 5V, a 9V battery will not burn them up.This forces the solenoid to move the pistons for the cam timing oil passages to it's full extent. If you see no improvement, then you are out of luck. You have another issue.

I have done a number of VR6's and the timing issues. The EV is no different. It's that people were willing to try anything except for fixing the real problem. Then they have to determine if they just want to bend all of the valves in the motor and have a much bigger bill or just go smaller and fix it properly.

I just did an Audi TT with a VR6 and the forums told him the Seafoam trick. I told him that it was too noisy and it was a chain issue. The forums won and he went that way. I won because I got to remove the engine and trans, yank the head, do a complete valve job (as it bent a bunch of valves and did the whole chain and rail change. Than you forums for making me money.

kourt

Regarding Seafoam, I've had a change of heart. My readings on Seafoam don't support using it at all. The best medicine, short of doing the actual timing chain service, is good quality motor oil, changed at reasonable intervals. I will still do the HPL engine cleaner and remeasure, but Seafoam is out of the picture for me. Thanks for the post.

kourt

bigfoot_ev

I don't disagree with anything that jjvincent has said. And I certainly don't want other unsuspecting EV owners to think that a timing chain service can be avoided with a bottle of magic elixir.

But I do want to reiterate the purpose of this post. Specifically, it is try and remove varnish and sludge build up from years of poor oil decisions, whether that be long intervals (ie 10k mi) or cheap oil or both. I feel there are benefits to the vvt by having it cleaned out and then continue to use quality synthetic oil changed at reasonable intervals, perhaps 5k mi, but oil analysis would be the best gauge. Secondarily, I'm hoping keeping the internals clean and well oiled will postpone the need to replace the various plastic parts related to the timing chain.

There is such a wide range of miles that EV owners have put on the 24V VR6, something has to account for that. Maybe this is one of them.

jjvincent

I have seen this too. People just use too much Seafoam and the grenade the motor. #1 reason is that gunk goes into the pan, then plugs the screen on the oil pump. Thus pressure drops low when on the highway. Lack of lubrication makes it starve for oil volume and thus it kicks a rod out of it.

I will tell you, 90% of that gunk is up in the cylinder head and is easy to see when just pulling the valve cover. VW is not exclusive of this.

bcolins

[email protected]

It took me a good weekend, a lot of stuff has to come off.
Get a good gasket kit for when you put it back together
_________________
2001 eurovn weekender 207k fresh batteries

bcolins

Just to confirm, this thread is about attempting to insure that the variable valve timing of the VR6 engine is functioning optimally,....and not insuring that your VR6 cam chains, guide rails, tensioners etc,.....do not fail or at least live a longer life.

kourt

Fundamentally, this thread is about measuring your variable valve timing values in VCDS and posting them, along with your mileage, so that we can build a trend and compare values among vans to help manage our future maintenance expectations.

kourt

bigfoot_ev

Yes, the more data we can collect and analyze together the better off all of us will be. Along those lines it would be really helpful to include information about oil change intervals, oil filter condition, and type of oil used. If you know your history about these oil topics, even better.

And pulling the valve cover and posting a picture of the insides would be great!


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