Timing rattle after fresh build

[The_big_dill]

Yes I did a lot of reading but have a bit of a unique situation.

Recently rebuilt engine.

All new OEM timing components were installed. Engine starts great and sounds good while engine is cold. The warmer it gets the more rattle/tapping/light knocking I hear from the valve-train area. (sound at camshaft speed)

After 100km of driving, I pulled the VC (cold engine) and at TDC, chain is tight. I spun the engine by hand and tension feels good all around.

There was a TSB showing that this could be caused by a loose timing chain, and the condition (under 2k rpm when warm) match my conditions. The only problem is the chain feels right when cold.

There are 2 things I am going to try:

1. Re-time it without pulling timing cover.
a. I did not align the VVT to anything, just threw it on and tightened it. I don’t think this is required, but seems like a controversial topic.
b. I am also pretty sure I tightened the cam sprockets before releasing chain tension. From my understanding, this usually results in a loose chain, correct me if I am wrong.
2. Re-check/adjust Valve lash. I had to do a lot of correction for machine shop mess from grinding the top of the valves. Should I aim for low or high end of valve lash? I set it in the middle.

Any help is appreciated.

Phil.

[Vansquish]

I think that your assumption about the VVT orientation may be incorrect.

HOW-TO VVT

How-To: VVT Actuator Swap

[The_big_dill]

Originally Posted by Vansquish I think that your assumption about the VVT orientation may be incorrect. HOW-TO VVT How-To: VVT Actuator Swap

I read through those 2 guides and noticed they have different procedures. One of them tightens the exhaust cam sprocket after the tensioner is released and the other tightens both cam sprockets before installing on car and releasing the tensioner. Which one is correct?

In addition, one of the guides says to mark the old VVT to the cam cap and then transfer that marking to the new VVT. With something as sensitive as timing, how can transferring the marking of the VVT sprocket by hand/eye accuracy be sufficient to ensure you line up with the original position? I understand it has worked, but maybe those are lucky cases?

I found another thread describing my sound:

https://www.mazda3forums.com/66-mazd...vw-diesel.html

There is also a video there now, last post reported with a replacement of the VVT... Perhaps my new VVT is defective?

[Ced2142]

The FSM indicates to release tension then torque down the exhaust cam sprocket. Which makes sense to me since you want the sprocket to spin freely when letting tension off the chain so the cams and the crank are timed (this is with the cams and the crank at TDC with the SST's)

[The_big_dill]

Originally Posted by Ced2142 The FSM indicates to release tension then torque down the exhaust cam sprocket. Which makes sense to me since you want the sprocket to spin freely when letting tension off the chain so the cams and the crank are timed (this is with the cams and the crank at TDC with the SST's)

Thanks for the reply.

I actually released the tension after tightening my cams.

The noises I was hearing was from the balance shaft and light weight flywheel. It sounded as if someone threw a bold in the oil pan and it was just bouncing around. I bet it it was due to the flywheel and the aftermarket rod/piston combo.

I deleted the balance shaft and the engine sounds much better.

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[The_big_dill]

The only thing I forgot to mention is that the noise sound like it's coming from theVC area in the center and closer to the HPFP. Timing cover/VC chain area doesnt sound like that.

[Vansquish]

Yeah, it definitely sounded worse by the HPFP in your video than when you moved the camera over to the passenger side of the engine. That said, it still sounds pretty loud. I know our injectors are loud as hell when firing, but it almost sounds like there's something loose inside the HPFP.

But...before you go taking the HPFP off or anything like that, I have a couple of quick questions.

- How long has the car had upgraded HPFP internals? (Miles/KM are probably more relevant than length of time.)

- Have you ever done the Key-On Engine-Off (KOEO) test for the High Pressure Relief Valve on the fuel rail? If not (or even if you have), you should probably run it again just to see what the crack pressure of your HPRV is.

The reason I ask is that when the HPRV fails, it can cause a huge amount of clackity-clacking that sounds like it is coming from the HPFP housing, but actually isn't.

I took a video of my HPRV when it failed years ago, but I think it has long since been deleted. It sounded quite a bit like your HPFP does now though.

[The_big_dill]

I rebuilt this engine at 232000km I have no history before that as I bought it and drove it to the shop on 3 cylinders. HPFP internals went in with the rebuild.

I took a look at some videos with a failing hprv and it doesn't sound the same. Could just be the mic.

I am also questioning valve lash because it's only making noise when warm.