My local mechanic said I might have a faulty cam variator. Anyone has this problem? please advise?
Cam Variator
msrt
81 - 100 of 225 Posts
Joined
·
4,647 Posts
I was under the impression that its the lifters making the noise on start up
Joined
·
1,273 Posts
No the variator sound is not the lifters. The variators are much more aggressive (louder, more metal-on-metal) and louder than a lifter noise. From what I see, the variators are functional based on hydraulics. The variator uses engine oil pressure (essentially using engine lubricant as a hydrolic fluid) to maintain a certain cam position. The change in position at various RPMs (the functional aspect of VVT) is triggered by the solenoid. When you start up your car with a "bad variator," the device fails to have adequate pressure to keep the internal parts of the variator in a fixed position, so it in turn rotates slightly from left to right making the noise. The inner piece of the variator is connected to the cam shaft, and the cam will move slightly out of sync during the rattle, sometimes causing a misfire warning, however the movement will only be within the rotation limits of the variator, ultimately keeping the valves safe.
Many people think it is similar to the problem of a snapped timing belt (in a Porsche, for example) in which case the cam shafts spin freely in relation to the crank shaft. This is absolutely NOT the case.
As far as the cause, it is simple understanding the effects of mechanical parts controlled by hydraulic pressure - the more pressure, the more effectively the variator will operate, the more the small seals within the variator will receive proper lubrication, and the more control the system will have over the cam position. This is why I am a firm believer that the QPs suffer the most due to the owners' willingness to only shift the car in the low RPM range during normal operation thus not allowing adequate oil pressure to effectively operate and/or lubricate the VVT system. This is especially true when in AUTO mode, which is the default setting for the QP. Now, couple that with an AUTO car without the oil check valves and you really have a nightmare, which is the case with the 07 model year wet sump cars. This also explains why the majority of the two-door cars, which default to the manual position on startup, have no problems.
If you own a QP, shift the car in manual mode and high in the RPM range, between 3500 and 5000 in normal driving conditions. I can almost bet my life you'll have far fewer, if not any, problems going forward.
Many people think it is similar to the problem of a snapped timing belt (in a Porsche, for example) in which case the cam shafts spin freely in relation to the crank shaft. This is absolutely NOT the case.
As far as the cause, it is simple understanding the effects of mechanical parts controlled by hydraulic pressure - the more pressure, the more effectively the variator will operate, the more the small seals within the variator will receive proper lubrication, and the more control the system will have over the cam position. This is why I am a firm believer that the QPs suffer the most due to the owners' willingness to only shift the car in the low RPM range during normal operation thus not allowing adequate oil pressure to effectively operate and/or lubricate the VVT system. This is especially true when in AUTO mode, which is the default setting for the QP. Now, couple that with an AUTO car without the oil check valves and you really have a nightmare, which is the case with the 07 model year wet sump cars. This also explains why the majority of the two-door cars, which default to the manual position on startup, have no problems.
If you own a QP, shift the car in manual mode and high in the RPM range, between 3500 and 5000 in normal driving conditions. I can almost bet my life you'll have far fewer, if not any, problems going forward.
Joined
·
3,431 Posts
Don Lorenz, on your car it probably is lifter noise. The noise the QP guys (mostly) are talking about is different. Think ball bearings in a coffee can.
lifters?
What is the most time consuming part of the job? 30 hours is a very long time.
Given that the cam timing depends on the oil's ability to pass freely through the cam phasing solenoids, It's completely possible that a cleaning agent could fix the issue. Assuming that the issue is related to the solenoid and not the stator on the end of the cam of course.
If there is buildup in the solenoid which blocks the oil, then your cam adjustment will suffer.
Another option if they are blocked off is to pull them and place them in an ultrasonic jewelry cleaner. This apparently works really well and the jewelry cleaners aren't terribly expensive to purchase.
I know on VW W8 engines, there is a filter screen which deteriorates and causes the cam adjusters to hang up. Now, this is a little different insofar as the issue is that the cam adjuster itself can't move, but you probably get the picture.
FWIW, the fix for the W8 adjusters is to apply bursts of a 12V current to the adjuster. They're designed to work with a 5V signal, so the extra voltage jars the adjusters loose.
***PS:****
Here's a link to the maserati factory guide to overhauling a 4.2L https://www.scribd.com/doc/201140054/4200-Wet-Sump-Engine-Overhaul
It's a great document and there are also a bunch of factory training resources for the electronics, cambio transmission etc...
Joined
·
86 Posts
Having read this topic with great interest, i was wondering; has anyone ever changed the little brass oilfilters in the oil supply lines to the the variators?
And are there no known problems with the accumulator?
A leaky accumulator could cause the pressure being lost quickly, causing slow pressure built up to the variators.
the brass filter (F variant);
Ferrari Enzo, 430 - Oil Filter (cyl head), Ferrari #180266 | eBay
And are there no known problems with the accumulator?
A leaky accumulator could cause the pressure being lost quickly, causing slow pressure built up to the variators.
the brass filter (F variant);
Ferrari Enzo, 430 - Oil Filter (cyl head), Ferrari #180266 | eBay
Joined
·
1,273 Posts
What you're stating makes complete sense. The only issue I have is the fact that variators fail at anywhere from 20K to 100K, which makes less likely that any buildup or blockage is the cause. Otherwise, it would be more proportional to use and mileage, correct? Additionally, I have yet to witness a unilateral variator failure - it's always both sides at the same time. The only common denominator I have found is driving habits. Now if the pump / accumulator were to fail, then that would likely cause both to fail at the same time by starving the variators of oil. However, if you were to replace the variators in a motor with a bad pump / accumulator, then the variators would quickly fail I suspect and that doesn't exactly happen.
Also, do you, or does anybody, know where I can find a similar manual for the dry-sump engine?
Joined
·
1,521 Posts
The most time consuming part would be R&R of the camshafts. Between the physical process of disassembly to get the chains off and on, and R&R of the cams, then resetting the base mechanical timing of the camshafts, it's a lengthy process.
Joined
·
77 Posts
Hoping some people who have had the variator work done or estimated can give us some ideas of costs they are being quoted. I am looking at potentially doing this work proactively and have started shopping around at dealers to get pricing/estimates.
Also - my dealer originally told me over the phone that they replace the worn variators and quoted something around $4K. I asked about the machining process and sending them out for that work (as I have read here) and to install a check valve and they knew nothing about that and claimed ignorance. So either they are confused or not in the loop or maybe there are other ways to go about addressing this issue. I certainly don't want to just replace worn variators that will only wear again in the same way for the same root-cause issue.
AndrewT
Also - my dealer originally told me over the phone that they replace the worn variators and quoted something around $4K. I asked about the machining process and sending them out for that work (as I have read here) and to install a check valve and they knew nothing about that and claimed ignorance. So either they are confused or not in the loop or maybe there are other ways to go about addressing this issue. I certainly don't want to just replace worn variators that will only wear again in the same way for the same root-cause issue.
AndrewT
Joined
·
28 Posts
That is insane. I am thinking of filing a class action lawsuit. I have driven my 2011 less than 10,000 miles and I had to pay to get mine fixed.
Joined
·
10,413 Posts
On the variators...there seems to be a lot of confusion on this so maybe I can clear that up some..You basically have one motor that looks the same, but its rather different in operation..
Dry sump: all coupes, GS, Spyders, and QPs with F1....These have a 4.2 with high pressure VVT system using a helical gear in the VVT unit and aux. oil pump driven by LH camshaft .They have check valves installed from the factory...
Wet sump: Granturismo, QP automatic transmission....These are either 4.2 or 4.7...blue or red valve cover...These have a low pressure VVT system using a vane type VVT unit...They do not have check valves and Maserati would later update this with a check valve installation and a new variator assembly that has a large spring to return the unit to home position...
The cars we see with the most noise are the automatic QP cars..They most likely have the older style VVT unit fitted...regards...Jason
Dry sump: all coupes, GS, Spyders, and QPs with F1....These have a 4.2 with high pressure VVT system using a helical gear in the VVT unit and aux. oil pump driven by LH camshaft .They have check valves installed from the factory...
Wet sump: Granturismo, QP automatic transmission....These are either 4.2 or 4.7...blue or red valve cover...These have a low pressure VVT system using a vane type VVT unit...They do not have check valves and Maserati would later update this with a check valve installation and a new variator assembly that has a large spring to return the unit to home position...
The cars we see with the most noise are the automatic QP cars..They most likely have the older style VVT unit fitted...regards...Jason
so basically once things started to wear, the oiling system couldn't make enough pressure to return the timing back to the idle position. Hence, why a spring was retrofitted in.
I really don't see how someone with mechanical experience and a camera phone can't do this at their house.
Get a paint marker and make marks while the engine is TDC and make sure the cams aren't 180 deg out. Take some pics and get at it.
Joined
·
10,413 Posts
Well, because its a good bit of work and beyond most DIY guys..Your removing the cowl, the intake manifold, the cam covers, the front cover and its like 10 different length bolts...Once you get all that apart you hope the balancer doesn`t get stuck.. When you finally get to the chains you`ll need a special tool to remove the variator on DS(dry sump) cars...Then you got to get the whole thing all timed again with a degree wheel and dial indicator as there is no TDC mark on the crank..If your off by too much its gonna set a check engine light and you can take all back apart again...Still want to do it in your driveway? I have done a dry and wet sump car in last month..Its a good bit of work..I think people forget how much the parts cost..its not 5K in labor..The price of a DS variator is over 1000.00 and you`ll need 2.....regards..Jason
I'll give you that one, some people really struggle with basic math/physics type things.
If that's the worst and most critical part of the R&R then I don't see why a Maser tech from a local dealer wouldn't take a couple hundred in cash to time it up for you after work one day.
Joined
·
10,413 Posts
Most guys are not gonna want to do that as they would be married to your DIY project and you could wear out their cell phone along the way...Worst case something goes wrong and you get pissed and go tell the service manager at the dealer about what happen...Might lose your job for a few hundred bucks...Jason
Joined
·
77 Posts
I have had the occasional rattle on card start-up when not driven in a while - primarily when its also cold outside though the car is garaged. No big deal and I have figured I could wait things out - see if it gets a lot worse over time before putting out the big dollars for the repair.
Yesterday, after it was warm and been driven for 45 mins, I noticed a quiet fluttering sound when decelerating and revs reached around 1K RPM. I found that if I rev'd it at idle and then took foot off the gas - as the RPMs declined to 1K or so I would hear the flutter which sounded like a very muffled version of the variator noise. Never heard this before and could get it to repeat at will. On one occasion the idle stumbled and then caught when the fluttering happened. No code was thrown but I'm pretty sure I could have gotten one if I kept doing this. Is this also a symptom of the variations going?
AndrewT
Yesterday, after it was warm and been driven for 45 mins, I noticed a quiet fluttering sound when decelerating and revs reached around 1K RPM. I found that if I rev'd it at idle and then took foot off the gas - as the RPMs declined to 1K or so I would hear the flutter which sounded like a very muffled version of the variator noise. Never heard this before and could get it to repeat at will. On one occasion the idle stumbled and then caught when the fluttering happened. No code was thrown but I'm pretty sure I could have gotten one if I kept doing this. Is this also a symptom of the variations going?
AndrewT
Joined
·
86 Posts
The engines with the high pressure VVT system using a helical gear in the VVT unit and aux. oil pump driven by LH camshaft...... how much pressure is being used in this system?
If the variator (in my Gransport) makes noise for one or two seconds after starting up, after a long period not being used, couldn't this just be a matter of wear at the rubber o-rings around the variator, causing oil leaking away, pressure being lost in the accumulator?
If not, what exactly is wearing in this type of variator?
If the variator (in my Gransport) makes noise for one or two seconds after starting up, after a long period not being used, couldn't this just be a matter of wear at the rubber o-rings around the variator, causing oil leaking away, pressure being lost in the accumulator?
If not, what exactly is wearing in this type of variator?
Joined
·
10,413 Posts
Honestly, I`m unsure of the pressure, but I remember maybe Lorenzo hooking a pressure gauge on a DS car one time..The variator for both cars wet sump and dry sump really contain no rubber parts..On the DS there is a copper bushing that the cam runs in and I have seen them wear groves in them...Requires entire disassembly of front of engine...There is no magic to fixing these ...
81 - 100 of 225 Posts
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
