Hey guys,

Looks like I'm having rattle like sounds from my VTC intake sprocket. I have an 04 coupe so I only have the 2 intake cam sprockets. I know I need to replace one. From what I would think, if I have to replace a VTC sprocket, I might as well do the chains, guides, other sprocket, etc...at the same time right? Unless, there is a way to do the sprocket without removing everything else.

That being said, how much time will take a shop to do a job like this? I plan to buy all the parts and have a shop install them. I was just going to go OEM through a dealership, but if someone has a recommendation on where to get the parts, I would appreciate that as well.

Depending on the answer, will determine whether I'd get my engine built as well. In my opinion, if the replacement of the timing system is only a few hours short of doing a whole build...I may go the build route.

Thanks everyone.

 

Does anyone have any info to help me with this?

 

Before deciding to replace timing chains, sprockets and guides it maybe just the oil tensioners.

The VQ Timing chains are designed to last life of engine 275K-300K miles.

If the noise only occurs on start-up than its probably the tensioners going bad.

Main tensioner can be replaced through Timing Chain access cover on passenger side.

Camshaft Chain tensioners require TC cover removed.

It will be very costly to have a shop or stealership replace the timing gear.

 

How severe and what is the quality of the noise? What causes it? Is it consistent or intermittent? Is it dependent on engine temperature? Before thinking about a rebuild I'd try a lot of simple things first. I would change the coolant, painstakingly properly bleed the coolant system at least 5-10 heat and cool cycles with the nose up, heater on and keep the overflow reservoir topped to FULL. When you have it properly bled, I'd elevate the front end on ramps after a long commute and have the radiator fans kick on and off at least 3 times. Second, I would change the oil at the same time as the coolant while you're under there. Third I'd run the car at least on a full tank with Redline Fuel System Cleaner. That stuff works and won't do harm to our VQ motors. Run that until the low fuel light turns on before refilling the fuel tank. Fourth, I would reset the ECU using the manual ignition key and throttle pedal method.

My reason is because sometimes the sound isn't always what people make it out to be. I've heard everything from a fuel line buffer ticking, low oil level in the crankcase, to carbon deposits in the valvetrain, to the ECU needing to be reset in order to recalibrate the variable valve timing. I've heard the cooling system having an air bubble can actually cause a loud sound echoing in the motor due to improper bleeding technique or low coolant level. The most severe cause of these weird sounds could also be the good ole nylon VQ timing chain guide and tensioner failure. If nothing good comes to this then so be it. The motor needs to be opened up and it will cost a grand or two. If you do these little things first you may have a better idea on what it really is.

I have gone 10 weeks with a horrible tick when the motor is warm or restarted luke warm. In those 10 weeks I searched and searched on forums, search engines, youtube. I wanted to do a lot of things first without having to resort to a professional diagnose and open up the motor. A lot of times it could lead to a misdiagnosis and may save you thousands. It has been over 2 weeks with the motor whisper quiet under all types of operating conditions (crosses fingers). Good luck and have faith in these nicely built motors.

 

Thank you for the replies.

I know my original post was short, but it seems when a post is too long....people lose interest and either do not read the post or get about halfway through before moving on. So....I've mentioned this issue in a few other posts.

Before I go further, my coolant was drained an filled at 147,500 miles. No issues with the rattle sound at that time. I figure if it was a coolant issue it would have shown up within 2.5k miles of driving before my intake mods were added. At 150K miles I added a z-tube, rev-up airbox, and a 5/16 plenum spacer. After these intake mods is where I noticed the sound. The sound was barely noticeable, but noticeable

I asked the shop about the sound, but they must have thought I was talking about something else. They suggested I get a tune. They must have thought I was talking about the pinging. I don't know what pinging sounds like, but that is what they must have thought I was referring to. I was referring to the rattle like sound. Anyway. I did get a tune and it smoothed out my engine a bit. The rattle was still there though. It wasn't noticeable to the shop I got my tune done at, but it was noticeable to me.

I drove with this sound for several thousands of miles. I drove on the autobahn at 150mph at 10-15 min increments. No issue with the car, just the rattle like sound between 2-5.5K rpms.

Later.....

I took it to a a different shop. The mechanic there thought to be something from the transmission. On the lift, it seems as though the rattle is coming through to the large well of the transmission. The transmission was dropped and a new clutch was put in since it needed one anyway. A worn shaft piece was replaced, which was thought to possibly cause the issue. This part was replaced, but the noise was still there. Needed the clutch anyway and my flywheel was still good. I changed that 60K miles prior to single mass SPEC steel flywheel. Condition still looked good though.

Much later.....approxmately 17K or so since the first tune...I returned to the shop that did my first tune. I wanted to get a re-tune since I added a motordyne exhaust.

This time the shop did hear the rattlelike sound and refused to do the tune. This shop did not do an in depth diagnosis though. They listened to my engine for a few minutes or so and said that they have heard the sound before. In their opinion, it was a bearing go bad. The said the big end bearing to be exact. This shop is in the UK so maybe they use different terms here.I told them that sound was there since the first tune, but they said they would have noticed it the first time. The rattelike sound has increased in volume a bit so it was a bit more noticeable as well.


Note: It is a similar sound you hear if these cars get low on oil. I kept up on my oil changes and constantly added oil when needed. There was a time it did get a little lower on oil, but I added oil as soon as I heard a sound. I've heard the low oil rattle from time to time throughout the years. Once I added oil, the sound was gone immediately.

Still no problems with the car so far. I was a bit depressed thinking it was a big end bearing going bad. Took it to a third place since I was thinking about going forced induction if I had to rebuild anyway.

This third shop was very helpful. They wanted to hear the sound anyway. In their opinion, they were almost certain it wasn't a big end bearing since my car was still running 17K miles later, and being driven at high speeds. The did some simple tests and used a screwdriver to listen to various parts of the engine. They are not VQ specialists, but do specialize in race engines on a much more expensive scale of cars that mine. They showed me that the rattle sounded like it was coming from behind the timing cover exactly where the camshaft sprocket is located. It was is the top one on the driver side. They do not know the VQ engine, but this shop said it probably has something to do with my timing gear, chain, etc. They also suggested oil samples to help diagnose if it was a bearing problem or not.

The diagnosis was free of charge. The results came back negative. Absolutely no signs of any bearing wear at all. In fact, my engine was in excellent condition. Samples were taken after 1500 miles of use.

Basically, I get the startup rattle when the engine is cold. It lasts for 2 seconds or so. If the engine is already warm and needs to be restarted, there is no rattle. The rattle starts at 2K rpms. The rattle is consistent and intermitten at the same time...if that makes sense. I mean it doesn't hit on the same sound every single second or so. It kinda fades out and in, but quickly. Hard to explain. To most people it would sound consistent though. I can hear sounds differently at different frequencies so maybe to me it sounds like some parts of the rattle are softer in sound than others. The rattle sound is there when the car is moving or not. I can be in idle and revving the engine and it will be there. Now, it only rattles when I'm pressing the gas. So, say I rev the engine then hold, you can hear the rattle. When driving, if I rev the engine and let off the gas...the rattle sound isn't there. Its only when I'm pressiing the gas between 2-5.5K rpms.

Besides this rattlelike sound, the car is performing normal. No abnormalities whatsoever. The only thing different is that I had problems getting over 150mph on the autobahn. Normally I can get up to 156 or so, but I figure this could account to my engine having high mileage, the larger 19inch wheels I added (18 inch were stock), or what I'm about to explain next.

So from some research, I was told that it was probably my intake camspocket being worn. The 2-5.5K rpms rattle was the cams trying to adjust themselves with the work camshaft. I've also been getting random cyclinder 4 misfire. The CEL light comes and goes when it wants. I've already changed the plugs and packs around. Still the same cyclinder 4 misfire. Again, no change in engine performance though.

I've heard that it is possible that my misfire could be linked to my rattle and worn camshaft sprocket.

Anyway, that's about it. This is more a chain reaction of events. If it is my VTC cam sprocket, I might as well change the whole assembly right? I mean if the entire timing cover has be taken off then I might as well change all the parts.

My thinking was that I have a very reliable car for the most part. I have 167K on it right now and my MPG has actually increased. I put a new alternator in it last week and cleaned all the ground wires. Strange....anyway....if a timing chain assembly replacement is going to take say 10 hours to do....and rebuild would take 50 hours....I could see the timing chain job offsetting the rebuild job. Then the rebuild job would offset the forced induction install job, and the forced induction/rebuild job, would offset the install of upgraded twin clutch to handle the extra power. Just one thing leading to another really. I'm just trying to weigh my options.

I'm either going to just do a full timing gear replacement job, or go all the way with FI and supporting mods. What do you guys think? Thanks

 

Meh, I say drive it if it isn't giving driveability issues. Did you manually reset the ECU btw? I'm telling ya, before spending a sh*t ton of money do all the small stuff first.

 

Yes the ECU has been reset. In fact, I had the rattle like sound before I had my Uprev Osirius tune. Tune was 17K ago or so and have done multiple manual resets and removal of ground wire resets for other reasons. Car doesn't drive any different. Its definately timing related though. Everything that has been done relates to the timing. Not necessarily timing chain, but a bolt tensioner could account for the start-up rattle, a faulty chain guide could be the culprit I suppose, but the VTC cam sprocket seems likely since I get the rattle between 2-5.5K rpms when pressing on the gas. I could be at 4K rpms and let off the gas and the noise goes away. From what I understand, the rattle at those rpms stated could be because the VTC is trying to self adjust itself and with a work cam sprocket....I'm getting a rattle. If anyone has any other ideas please let me know. Thanks.

 

Yeah, it seems like the severity and condition as to which you experience the noise is different than mine. Mine occurs only at idle. I have since gotten a hint of sound after the warm motor has been sitting for half an hour or so. This has happened twice since my small interventions. That's an improvement considering it used to happen all the time as soon as the motor warmed up with me idling at a red light or parking. I only have about 73k on the odometer so I'll monitor it.