Variocam thoughts and questions
 

Ok, so I did my homework and I have read through a a lot of threads and articles on this variocam fail topic and I learnt a few things that were new to me but maybe obvious for most of you all. I still have some questions that I thought are worth to share. First, what I learnt: 1) The actuators are all the same in all 5 chain engines, from 2.5 to 3.4, or at least they have the same part number. 2) The two units are different though, variocam 1-3 and 4-6 move to the opposite direction when they actuate, and it seems only actuator 1-3 has this large green O- ring that has a tendency to disintegrate. At least in all the threads I`ve looked at the first sign was the appearance of green rubber O-ring fragments. Actuator 4-6 has no such large green O-ring shown on the few pictures available on the web.

I noticed that when the actuator is not filled with oil the piston moves freely between the two endpoints. When the camshafts rotate and the valves open and close the load alternates respectively between the small chain`s upper and lower side, resulting in tugging the actuator`s piston between the two end points pretty badly. I uploaded a video of this here:

https://www.youtube.com/watch?v=F069qIpI3_U

When I fill the actuator with oil with a syringe, the piston no longer moves. So I assume the tugging is gone once the actuator is pressurized. Also, normally the oil can`t escape from the actuator easily, because there`s a check valve in the actuator`s oil pressure line which rectifies the oil flow. So, is it possible that the check valve remains open because of dirt or something and the tugging at start up eventually destroys the O-ring?****

In this case, dying of the actuator should be preceded by a rattling noise at every startup. Is that true?

Why is it that only the 1-3 actuator fails (if that`s true)? I`ve read some hints somewhere here on the forum about that in engines with****DOF****where the IMS is punched through, the actuator may be more vulnerable and more likely to fail. This makes sense to me because oil might leak through the IMS at the pump and the oil that gets lost has to be pumped back at startup. So, is there a real statistically significant relationship between DOF and actuator failure? And again, why only actuator 1-3?

Opinions?

Very nice video. Just to clarify does your question of 1-3 actuators pertain to 5-chain motors or 3-chain?

5-chain. As far as I know 3-chain engines have a completely different system.

Just following this discussion as my car had the green debris in the oil filter

What concerns me is;
1) IF the green debris (in oil filter) is just an O ring mashed up then the potential risk of future issues (of oil feeds clogging) is relatively minimal (as clearly, my old filter had done its job and there was about an O rings worth of tiny bits) and claims that I need to "tear down the entire engine and have it rebuilt" (from some UK specialists) may be an overreaction?

2) If the one O ring is now gone and the actuator is still functioning then how long will it continue to function without the lost O ring? And in what way will it react (wear or break) over time OR maybe it will go on working because there are also other internal seals in the actuator?

3) Add the massive cost of the brand new OEM parts and the labour to fit (£2-3k?) in a £4K car that has a RMS leak and will need a clutch and maybe the dreaded IMS doing soon costing £1.5k+

1) I agree, tearing down the entire engine is an overreaction. If you clean the sump and the strainer you should be ok. You would have to pull the valve covers anyway, clean the internals while you are there.

2) Good question. Perhaps others will chime in who had the same problem and know the answer. I wouldn`t use the car for too long like that, you can see in the video what happens if the actuator works with no oil. Probably your actuator is not there yet, the remaining O-rings may still hold the pressure? The small timing chain rail bits in the filter on its own would be a good reason to pull the valve covers to prevent future failures.

3) Yeah, tough decisions you need to make here. If you want to keep the car for long it`s worthwhile to fix all these issues. If you are a DIY person. If you are not, I`d consider selling the car to someone, who is...

Yes, I agree with those points. I do some DIY but probably not capable of replacing variocam actuator, as it involves timing, etc. If I knew the one that was failing and the exact part number I'd get a good used one and get it put in...Done a few trips totalling 70 miles now and engine exactly as it was. Got recovery cover for a year as back up too. Plan to check filter again after a few hundred miles and see what it has in it.

An easy thing you could do is to remove one of the green plugs on the camsafts on either side and take a peek into the gap. You can see the actuator from an angle and one of the pads. If you ask somebody to rotate the crankshaft with a wrench (clockwise) you can inspect the actuator if there`s any movement. There should not be anything, and probably there isn`t, because it would rattle otherwise, but at least you would get an idea if things look ok. At least things that you can see there. I`m not sure actually what you can see with the engine in the car, my engine is on a stand now. If you have a boroscope that may help.

Yes that seems a good idea - nobody has suggested looking into it to check and I am guessing a bore scope would help see the actuator condition. Or maybe just listen with a stethoscope on the cam cover when it's on tick over and at 1,500 + revs? As the failed one likely to be on 1-3 bores drivers side for a UK car I may even try taking off the cover and have a look.

First, I`d suggest just taking out the plug at the intake cam. The plug is not reusable if you remove it so you will need a new one but it`s cheap. If you want to remove the cover, you will need to lock the camshafts and hold them down using a tool, otherwise you may damage the camshafts or the bearings. There`s a good tutorial about this in Wayne`s book, available online on Pelican`s website for free.

Timely post for me. My 2000 2.7 just threw a 1341 error code (cam timing). The newly remanufactured engine was just installed last fall after Sitting in a garage for years. After reading this thread, seems conceivable the O-ring could have dried out and failed. I am still holding out hope it’s the sensor or solenoid, but after reading this.... probably not.

Yes I believe oil pressure issues will not affect the actuation of the old style. They are straight solenoid based: on off. Oil will affect wear though

It should affect both. In the old, 5 chain system, the solenoid`s pin moves about 2 mm total, this operates a small plastic piston that opens and closes small oil passages inside the actuator. Oil flowing in these passages will control to which direction the large piston will move.

Thanks for this and good to know...had assumed it was only 3-chain that was affected

Sorry to hear... Can you tell which bank threw the code?

Bank 1-3 unfortunately.

Have you checked your oil filter? That may tell a bit more about the issue. Keep us posted!

Unfortunately I changed the oil a week before I found this discussion. I am pretty sure the “rattling” is becoming louder Tho, when starting the car cold. Once it’s started it runs well and subsequent starts are normal.

I am not clear on the work to replace these 0-rings and the actuator. Is this something a competent shop can do with the engine in the car? Is this a $3k repair or $6k?

Just to make sure your actuator is failing, I would still pull the the filter and cut it apart to see if you have similar green rubber debris to that of shown in several threads in this forum. I believe the replacement can be done with the engine in the car, it`s difficult though because of the limited room. It`s quite straigthtforward with the engine out of the car on a stand if you have the right tools. No clue how much the labor costs, the actuator unit is around $1000 new.

Ok, I don’t get this. Just received my new OBDII scanner yesterday. I cleared the 3141 error code (Camshaft Adjustment Bank1 below limit value) that threw the CEL. I cleared the code with the engine running. The moment the CEL cleared, the engine idled down maybe a hundred rpm. In addition, when I start the car after the CEL was cleared, the car does not really “rattle” the 1st second or two after starting as it had. Other than this anomaly, it runs normally otherwise.

Why does the car start and idle differently with the CEL on than off? Why would the chain “rattle” be different? Is that the nature of the 3141 code?