Loud Ticking on JDM motor

Hi all,
Just got done doing a JDM swap on my 95 4x4 3rz (dad blew up my old motor, long story). The swap was pretty straight forward and went pretty smooth. The new engine runs and performs great, the only issue is a very prominent ticking noise when the motor is warmed up. The ticking is not always there, but it is loud when letting off the throttle and at idle, though it sometimes just comes and goes at idle. It appears to be coming from the back top end of the motor, though even with a long screwdriver I can’t pinpoint it anywhere. I know the Tacoma tick is a thing but there is no way this is it.

Like I said, it is quite loud and driving me insane as I am pretty paranoid about blowing another motor. The inconsistency of it makes it sound like something loose or an exhaust leak, but I cannot pinpoint it.

I originally thought it was a valve issue, so I pulled the valve cover off and checked clearances. The intake side was good, all shims were in spec, however almost every exhaust shim was out. So I removed the exhaust cam, bought some new shims, and rearranged some shims and brought everything back to spec.

Well the noise is still there.

I checked the spark plugs, swapped the injectors from the old motor over, and re torqued the header bolts, so it can’t be any of these things.

I should also mention that this motor must have sit for a while (makes sense for a JDM) and when I first got it some of the cam lobes had slight surface rust on them (see image). Could this be a cause? Like I said it only seems to be coming from the back, but there is defiantly rust on the front cam lobes as well.

What could it be? I may be able to post a clip of the sound soon.

Would additives help, I have tried sea foam in the intake, gas, (not in the oil yet), higher octane gas but nothing changes.

I haven’t really driven it that much, so will driving it more help?

Sorry for the long post but I am very frustrated…

 

Noises are tricky !!

Do you know what a bearing knock sounds like? You did remove the rust on the cam before cranking ??

Enough rust can wipe a cam bearing .

My first step would be a mechanical oil pressure gauge to check oil pressure .

You have ruled out the popular cracked exhaust manifold or leaky exhaust or poorly supported exhaust ?

Good luck!

 

Listen closely to the purge solenoid. Drivers side, by the firewall. Should be in a rubber isolator. I hear mine all the time and it comes and goes.

 

I bought a used purge valve.....
......it sounds like an old 22R ticking.....
you can hear it real loud in the driver seat......

 

So I reused the intake manifold from the old motor so the purge solenoid/valve is the same. I haven’t ran the truck yet but I discovered a few days ago that one of the vacuum lines into the solenoid was disconnected. Could this be the problem or could I have the vacuum lines on backwards?

 

Might as well hook it up and see what happens. A vacuum line that is switched with something else will most likely cause idling issues or a CEL light.

 

Update: I connected the vacuum line and ran it with the lines connected both ways (I found the correct way on a diagram so I have it in the correct order now).

However, there is no change to the noise.☹️

 

Can you post a video of the noise?

 

Sorry, keep forgetting to get a video. When I get home this evening I’ll record it.

 

"It appears to be coming from the back top end of the motor, though even with a long screwdriver I can’t pinpoint it anywhere."

Possible valve train chatter?

 

Thank you all for the input

Here is a video of the sound

I’m only worried because the old motor did not do this, however the old motor had over 300k on it. I’m wondering if maybe this is just normal for valves that are in spec, just need some other opinions
https://youtube.com/shorts/LYaPow-OgXc?feature=share

 

Between my old ears and cheap speakers I might hear an exhaust leak.

 

That could be. Almost sounds like valve train though as it seems to be at a certain rpm.

 

I had a 3rz that sounded Iike this, made me panic but it ran fine for the 2 years I had it. When I took the engine apart I found it to be the chain guide. The one on the tensioner side (long one) the ear that the bolt goes through broke off and was hanging on for life by the one lower bolt. It would slap when the chain would slack at certain rpms. I know it's in the front of the engine, but it's amazing how sounds will travel in an engine bay.

 

My money's on this being OP's problem^^^^