Valve Lash Adjustment for QR25DE

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LiquidSchwartz

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I would like to know if this is a good thing to do or not for my 2011. I've gone through the Nissan forums and the answers are always different…piston slap, solid lifers, valves, etc. The manual says to adjust at 60K “if noisy.” But what is noisy and when? I am the kind of guy that doesn’t mind doing something for my cars even if it isn’t necessary with the goal of a smoother and more reliable ride.

This motor is a bit noisy and noisier when cold. At cold idle it sounds normal but at light acceleration I get a mild diesel-like sound I guess for a couple of minutes down the road then it sounds fine. It only sounds different when cold and under light acceleration for a mile or two, other than that it’s ok. There is no rattle at startup either and there are not any other performance issues that I can tell.

Thanks to anyone who wants to give advice.
 
It's probably list piston slap, but it could be the valves. If your engine requires valve adjustments, it could be that they're slightly out of "tune". I've done it twice on our CR-V...not because it really needed it, but I like checking on things under the cam cover and it's just fun to do. I'm a gearhead; I like that kind of stuff.

Edit: given the info posted directly above, it sounds like it's not easy to do on that engine, and that's a shame. Many of Toyota's engines are the same way...it's a direct-acting bucket design that requires removal of the camshaft to change lash.
 
Thanks guys. I've looked my Chilton manual and, yes, it does not look easy at all but the dealer I go to has been pretty good to me and my wife's car so maybe they could quote me a decent price.

Wouldn't piston slap be heard at idle as well? It doesn't sound like that from all the youtube videos I've seen. There are quite a few Subaru vids online with pretty bad slap at idle and under acceleration.
 
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My KIA also recommends a valve check at 60k, if noisy. I plan on taking the valve cover off measuring valves at 60k regardless. Its really not hard to do.. to just check the valves it will likely cost you a valve cover gasket, and a feeler gauge. I think this is a good measure to take in any car that has solid lifters.

On another note.. newer cars are just noisy.. with the injectors clicking, and variable valve timing, then if you throw solid bucket lifters into the fray, it makes for a loud engine. If you check your valves, and they are all in spec, the cam lobes look good with no scuffing, and you don't hear any loud droning knocking I wouldn't be too concerned as long as maintenance has been kept up properly.
 
I would be surprised of noise in this type of valve train. These usually tighten up with wear. The valves receding. Also I wonder if dealer swaps these around . Like shim motorcycle set ups. Not having to purchasing new buckets.
 
I suspect a valve adjustment job on this car is going to pure gravy to the assigned mechanic.

How would you know if the job was actually done or not?
 
I think I could definitely take the cover off myself but I have a baby and the wife works shifts. So I would opt to have the dealer do it if the price is right.

Your right Vikas, how would I know? I guess if the engine was quieter then I would know. But they could just say that's how the engine sounds. I'll email the dealer and see what they quote.
 
Originally Posted By: Vikas
How would you know if the job was actually done or not?


You don't, that's why it's better to do things like that yourself. Why people spend hundreds of dollars for a valve lash adjustment is beyond me. A factory service manual would pay for itself real quick in that situation.
 
I have the same engine in my Sentra, it's never been a quiet engine but also never really loud, even with my deleted pre-cat and other mods that might affect NVH. I actually like its distinct sound at idle and especially when you get on it.

I've never heard of anyone doing a valve adjustment for this reason, especially on the newer QR's which are supposed to be much more refined.
 
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If the manufacturer expects you to do valve adjustment, they would have put lock-nut and screws on them. Nobody ever does adjustment with shims and buckets.

Don't even bother calling the dealer. If he is honest, he will flat out tell you that service is not needed. If he is not, he will take your money and you will receive an expensive "wall job". And if by any chance the mechanic actually tries to adjust the valves, the chances are it will be a botched job.

You are asking and paying for unnecessary trouble.
 
LiquidSchwartz

Apparently the whole entire factory service manual for a 2011 Nissan Altima is available for free download off the internet. I took the liberty of already downloading it. Send me a PM with your email address and I'll send the whole file to you.
 
Some cars with bucket lifters place the shim above the lifter. Sometimes the dealer will have a specialty tool that enables replacing the lash adjustment shim without removal of the cam.

However, some cars have what is called "Shim under bucket" and in those cases, the cam has to be removed, the lifter must be removed, and a spacer between the lifter and valve must be replaced. I have read that is is common if an engine runs high RPM or has aggressive cam profiles.
 
This car the buckets come in different sizes. A very expensive proposition I suspect.
 
Unless there is a distinct tick tick from the valve cover area leave the valves alone.
Getting the adjustment spot on with aluminum heads with this type of adjusting mechanism (replacement) is difficult even for experienced mechanics.

Clearances vary a good bit with temp change. The easiest do it with a successful outcome is to measure the known quiet ones and take an average, then set the loosest one to that.
The exhaust will usually be tighter and rarely make noise, do the same thing but reverse.

Once you have the measurements of +- you need just get the buckets for those. You use the book measurements as a guide only. To do this job and get it right takes experience and a good feel.
I come across many engines that have been done by independents and dealers alike that were louder after the adjustment on many engines.
 
Not familiar with this engine, but have a lot of experience with this technology on motorcycle engines. This first thing I'd do is visit some forums that are specific to this engine, to see what others have experienced with valve clearance checks/adjustments. You may find that in spite of clearance checks, the clearances never move, or you might find that they really do need checked and frequently adjusted. I didn't recall seeing how many miles you had on the engine. My experience on bikes is that they will usually tighten up, unless there is something abnormal going on with cam / lifter wear. There is a significant amout of subjectivity and feel involved in checking these as far as using the feelers gauge. Use a good set of metric feelers gauges, because the shim, bucket selection will be in metric units, so it saves a lot of time horsing around with conversions. Also on bikes, regardless of how the shim is marked, I mike them at the wear points just to make sure they are face value. Typically they are. As stated above, many times people will shim them for max clearance, which is not the best approach, since that will increase valve seat hammering and noise, and may require more frequent checks due to the valves receding in the seats. Based on my measurements on brand new bikes, Yamaha sets the valves to be at nominal or tighter after break in, not at the max limits. I'd love to see how they do this during engine assy. Enough of me babling.
 
Thanks for the responses. I have gone through the Altima forums only to find one poster that was working on a QR that is about 10 years old. I have yet to find anyone that has brought their cars in around or after the 60K mark where the manual suggests a valve adjustment if noisey, everyone just complains of odd warmup noises for a few minutes. The responses are always "it's normal" for that engine and that they just need to warmup.

When my Mazda was in the shop we were given a '13 Altima and Rogue as loaners and I never heard any odd warmup issues in those engines which are the same as in my Altima. Granted those cars did have a third of the mileage I had on my car.
 
I would look at SER forums.Where people actually turn wrenches on their vehicles. Rogue and Altima people tend to not .I used that Google thing and this came up.

http://www.nicoclub.com/archives/inside-the-qr25de.html


A lot of work went into minimizing friction in the valvetrain in an effort to maximize fuel efficiency. Minimizing valvetrain mass allows the valve springs to be lighter, which reduces the amount of power wasted opening valves. To achieve minimum valvetrain mass, a direct-acting cam-on-bucket design is used. (See photo #7.) Unlike most direct acting valvetrains, there is no valve shim for adjusting valve lash. Instead, the entire bucket is available in different thicknesses when valve adjutments need to be made. Elininating the shim further reduces valvetrain mass. Valve adjustment isn’t likely to be necessary during the normal service life of the engine because of the very light valve springs, but changing cams will likely require valve springs and a more complex adjustment procedure than the hydraulically adjusted SR20, or the screw-adjusted Honda engines.
 
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