Honda K24 VTC Rattle help

Our 2008 TSX (k24a2, 5at, 215k miles) has developed the VTC rattle, where it sounds like a diesel at times.  Digging in to how to fix, I'm running into variable advice online - imagine that.  Most common suggestions:

• Replace VTC oil screens for spool valve, and off front of timing cover.
• Replace OIl control solenoid - this is usually mentioned in relation to oil leaks, not the rattle
• Replace VTC Spool valve - this is usually mentioned in runs poor/VTC error codes/MIL lit
• Replace VTC Actuator sprocket - this is most often tied to Rattle, but usually with the caveat "this is the VTC rattle that goes away after 2sec and oil pressure builds"

My issue is, the rattle isn't just at first cold start - it comes and goes, sounds rhythmic, can appear at low or mid RPM - cannot hear if it happens at high RPM as car is rarely driven there.  My other thought is stretched timing chain/worn guides/tired tensioner.

With how popular the K-Swap All The Things movement is, I was hoping some of our GRM friends may have experience with this, before I start throwing parts at it.  Thanks!

The VTC rattle is because the lock pin does not hold the mechanism together until the oil pressure builds.  If you are getting the noise while the engine is running and not just for a half second on a cold start, it isn't a VTC rattle.

At 215k it should be getting at least its second replacement timing chain.  They usually wear out at 60-110k.  If you got 215k on the original chain, congratulations!   Fortunately, Honda made this very easy to diagnose, as they have a timing chain tensioner access cover.  Three or four bolts, pop it off, and you can see if the tensioner is maxed out.

I bet you need to change the timing chain, tensioner and likely the VTC pulley. If you are pulling the timing cover to do so, you can change the VTC solenoid o-ring and manually clean the screens at that time , I doubt it (solenoid) needs replaced unless it failed or you can't get it clean enough. I don't know about the spool valve gasket/screen.

I am actually in the middle of changing the chain, pulley, guides and tensioner on my 10 tsx right now. 

Pete's advice sounds great, however I couldn't tell if my tensioner was maxed out ( indicating chain stretch) by pulling the access cover as it was incredibly difficult to see the piston (on the right of the picture). I could not see how far it is extended out due to frame obstruction of the view.

Since I'm going in for all new parts (leaky main seal high mileage etc.) I bought everything. I tried to document on the way in.

I have obvious chain stretch, it however did not set any codes. I do get the vtc rattle on cold start. I have 180+ k miles and timing components are origional.

Here is a picture of the intake cam lined to #1TDC: 

You can see the cam cap arrow and pulley arrow are aligned (or take my word for it)

Here is where the crank pulley wound up, it is slightly advanced, indicating cam chain stretch (the tensioner takes up slack on the back side of the chain, thus the crank advance or cam retard). I drew red arrows to indicate markers misalignment due to a less than ideal picture. 

Now that it is all apart the old chain is obviously longer than the new replacement. I would imagine your chain is in similar if not worse shape. Pulling the valve cover and lining the timing marks should let you know if your chain is stretched. 

Interestingly my chain guides look perfect.

Hope to have mine buttoned back up by tomorrow, if the tensioner window view changes with new components I will update this thread and let you know.

If you are leaving the motor stock-ish then get another RBB VTC gear.  If your plans involve cams or other notable mods in the future then this is a good time to get a 50 degree VTC gear for future tuning and power.  I put a 50 degree gear on my K24A2 before I swapped it into my Civic when I out on a new chain and tensioner, but left the rest of the motor stock other than intake/header/exhaust.  The tuner didn't use VTC timing outside of the stock 25 degree gear when making best power.  If I had a better intake manifold and better cams and reved over 7k then the 50 degree gear would have been beneficial apparently.  

Pete Thanks for confirming likely not a "clean some screens" easy fix.

Daytonaer Thanks for the pics, I was planning on pulling the tensioner cover tomorrow (waiting for rain to stop); but if that's minimally visible I'll likely pull the valve cover as you did to verify stretch, then order up new bits.

EDIT - how hard was breaking the crank pulley loose?  I've read varying amounts of frustration.  The rest of the replacement reads like one would expect - not that much off from doing a timing belt.

Sonic - unfortunately, this is destined for another 200k miles of daily commuter.  Though I have told my wife that if the TSX dies/gets totaled/other bad luck, that K24 is going to move over to the '96 Miata.  At that time, I'd do all the KMiata tricks like the 50* VTC.

I got our '04 TSX super cheap because of the common - cold start skipped time in the driveway issue. Since it had 230,000 miles & is an auto, my son & I got a JDM K24A(RBB) & an auto trans. I replaced all the timing items before dropping it in. There were some other things to change over from the us to jdm motor also.
The front pulley was probably the hardest part. The big 1/2" drive impact would not free it. Took a long bar & creative holding.  I bought a 50* gear but decided not to install it because it's more involved on the 1st gen car & it's auto. 
The motor was only $750 & trans was $250.  
Since the rest of the car was perfect & it had a full Mugen $1500 suspension it made sense. Plus got the car for $1400. 

If you have an impact gun, a weighted crank damper bolt socket (weighs about 5lb) is magic.  That or you may need to heat up the bolt until it is dull orange before you zip it out.

Autozone sells the magic sockets.

Pete. (l33t FS) said:

If you have an impact gun, a weighted crank damper bolt socket (weighs about 5lb) is magic.  That or you may need to heat up the bolt until it is dull orange before you zip it out.

Autozone sells the magic sockets.

I got the harbor freight 1\2" earthquake xt, ran it at 115 psi from a 10 gallon tank compressor with less than ideal hose setup with an Amazon weighted socket. 

it struggled, alot, but won in the end. I just held the gun on until the compressor psi dropped below 60 psi then waited for it to build up pressure again. Rinse and repeat for 5 or 6 minutes (including small compressor recharge time) I'm sure with a good tank and hose setup this would have gone quicker.

Socket

I thought about getting one of these : Power bar!

Also, in the past in a Toyota I resorted to breaker bar wedged in frame and bumping starter to loosen the crank bolt, but that makes me nervous something (else) may let go.

Right now I'm taking a break, I found the valve last tedious as I couldn't fit feelers in well. Last night I tried to put the timing cover back on but managed to scrape all the silicone off the mating surfaces and onto everything that shouldn't have any...

there is a reason shops charge a couple grand in labor for this job... I still enjoy this hobby :-)

The PowerBar is not as good as an impact with a regular socket.  It is good for some things, like Subarus when you don't feel like pulling the radiator for impact access.

When I took mine apart the first time it was out of the car on a furniture dolly and my big Makita impact wouldn't budge it.  I had to bolt a 2x4 to the flex plate and then use a breaker bar with a pipe on the end to break it free. 

Pete. (l33t FS) said:

If you have an impact gun, a weighted crank damper bolt socket (weighs about 5lb) is magic.  That or you may need to heat up the bolt until it is dull orange before you zip it out.

Autozone sells the magic sockets.

I can vouch for the magic socket. It worked for me when a normal impact socket would not.

Reading this thread is making me realize I still have the original chain on my K24 at 230,000. I guess that's one more thing for the to do list.

Edit: I replaced the tensioner about a year ago, should I pretty much just need the chain?

In reply to gearheadmb :

I have never seen guides or tensioners go bad, but I have always replaced them while in there.  Not to say they can't fail, but the chain seems to fail first. (As opposed to the V6s where the tensioner leaks its oil out before the belt is due)

Replacing the VCT sprocket often involves removing the camshaft and dealing with it on the bench, just for clearance reasons when trying to loosen the bolt.  The last two I did I was able to get the bolt loose in the car.

I have never replaced anything in the oil pump drive, which is cool because you have to drop the pan to do that, and I use a short 18mm socket wedged between the pan and subframe to hold the engine up.  Why 18mm? You don't need it on a Honda...

New parts: cant.see.the tensioner piston, but check out the different orientation of the shipping/ installation latch vs old pic above.

The VTC Gear spring is usually what wears out. The timing chain tensioner also has a spring that wears out. There is a spring-start vtc repair kit available for a lot of Acuras and Hondas so you don't need to change the VTC Gear, you just replace the worn spring in the VTC gear. With long term cold start rattle issues, usually the chain tensioner is defective too because a lot of stress is put on it from the VTC gear slapping back and forth. Those cheap easy fixes usually stop the cold start rattle. In the odd case they don't, you may have a stretched timing chain.

Canoe.

BUT.

By the time you remove the gear, which requires dropping the timing chain that is probably stretched and should be replaced, and often requires removing the camshaft so you can wrap it in a towel and clamp it in a vise so you can get the VTC bolt out, and buy the special 5 lobed sockets to disassemble the VTC ($140-ish at NAPA, have not seen for sale anywhere else)... you may as well just put a new one in there.  They aren't that expensive.

You do not remove the gear, your simply remove the 6mm VTC Gear cover bolts. Spring-Start has the proper VTC access bits for under $10.

There is no risk of putting your car timing out either.

 Replacing the worn spring in a quality OEM VTC Actuator in about an hour seems like the right step to take. Why put some after market VTC Gear that retards / advances your timing and affects performance in your vehicle?

I've taken apart many old OEM VTC Actuators including RAA, RBB, RBC, R40,5A2 and R5A and compared them with brand new OEM VTC Actuators. The common theme is that the spring in the old VTC Actuators is shorter and has less spring force than the new ones. 

I have yet to see a damaged VTC Actuator although it does happen occasionally. 

Replacing the defective VTC spring is a lot easier and more cost effective than replacing the VTC gear in most cases. 

If you are unfortunate enough to have a stretched chain, and have money to burn, replace the chain and the vtc actuator if you like, if not, replace your chain and the VTC spring.

There's an improved VTC Gear spring being launched in January 2023 for the TSX and Civic Si that fits RBB and RBC VTC Actuators. It has improved metalurgy and spring rate. Google springstart vtc

springstart said:

There's an improved VTC Gear spring being launched in January 2023 for the TSX and Civic Si that fits RBB and RBC VTC Actuators. It has improved metalurgy and spring rate. Google springstart vtc

 

aging youthfully? 

hmmm

Good luck with your business :-)

In reply to daytonaer :

Thanks for the good wishes! Here's the link, #1 just above in the screenshot you posted.

We definitely don't have the spring to fix that!

This is now the second broken VTC Actuator we've seen. A mechanic from Maryland attempting to use our kit to fix a Honda VTC rattle found a broken one in a 2010 CRV as well. The noise was very different than the typical worn spring rattle.

It happens in less than 1 in 1000 cases and obviously you need to replace the VTC Actuator in that rare case.

Usually it's just the locking pin spring that wears out which takes us about 20 minutes in K20s and K24s.

Still baffled by what causes this on a stock engine but on the rare occasionit does happen.

We believe that installation with the locking pin engaged is the prime culprit but hard to be certain. 

spring-start.com