Sooo this has been driving me crazy. Ive spent a ton of time trying to isolate it, and still cant come up with anything, maybe someone else has seen this possibly?

My engine build...

Wiseco 9:1 Pistons
BC Rods
BC Valvesprings and Retainers
PTuning Head Studs
Cometic HG

Motor currently has just over 1k miles on it, and everything is running perfectly other than this noise/issue.

Symptom - When engine low idles (600 rpm ish) a loud noise will eminate from the head that sounds like a sticking valve or sticking cam follower (bucket). As soon as I give it ANY gas (even if to only 1200 rpm or so) it will go away.

It is kind of strange how it goes away though - at first the noise will speed up with rpm, than itll just dissapear when it hits about 1000 rpm. When I let off and the rpm goes back down to low idle, 99% of the time it doesn't come back.

It doesnt affect performance at all - Im revving the motor to 7000rpm and everything seems perfect. Also no CEL.

When does it occur? Only when hot and driven for quite awhile. Even then it doesnt always occur when it drops to a low idle. One evening I spent ALL night trying to get it to do it, but I couldnt.

Here are some steps Ive tried to take to isolate it...

1) Used a screwdriver as a stethoscope - moved it all across the head/valve cover - the noise is uniform all the way across :/

2) Removed valve cover and checked for abnormal cam/follower wear and checked valve clearances. NO abnormal wear and all clearances were spot on where I set them when I built the motor.

3) Changed oil (it needed to be changed over to synthetic anyways - built motor now has 1k miles on it) - no debris in oil - oil looked perfectly normal, almost new. (Issue also still persists with new oil)

4) To insure it wasnt tranny or clutch related, Ive tried pushing in the clutch when the noise occurs, no change.

5) I thought it was possibly that rear motor bracket for the pass side CV axle - everythings tight.

6) Checked all motor mount bolts - all tight.

This has just been driving me crazy, Im hoping maybe someone has seen something like this and can chime in. Let me know if theres anything else that I could possibly due to isolate it. Also for those of you who dont know me, I have built many motors,everything from V8's to small engines (125cc-600cc) including 4 2AZ-FE's now, unfortunately Ive seen nothing like this, and neither have any of the other mechanics I know :/

 

vvti gear.

 

Whats funny, is I was actually thinking that could be the case, I have a second set of cams just laying around, butman its gunna be a _____ to change with the engine in the car though - usually when its stuck you get a CEL for intake cam over retard or something of that nature. If left like it is, what would be the eventual outcome?

 

Also, looks like I just found a diagnostic for this, pulling the vvti OCV plug should make the noise dissapear if its in fact the VVTI gear, will have to test this tonight - found a couple youtube video's of this issue and the noise is spot on.

 

Yup, just pull plug and boom =D It could be a lack of oil pressure going to it, make sure the oil filter gallery and screen for vvti gear is clean and clear.

 

Yup - I replaced that filter when I built the motor. Also everything was thoroughly cleaned before and during assembly. Think it could possibly be the OCV? That wouldnt be hard to swap so I may try one of the other like ummm 5 that I have laying around lol

 

Also, eventually will the gear just fail entirely and get stuck in the retard position, or will it continue to work and just make this obnoxious sound occasionally?

 

What you can do is connect your battery to your ocv and you should here a click meaning its working. If you don't here a click well then your ocv failed but then again if that fails you should get a retard code or advanced code. I have the same problem as you but I get the timing retard code but not when I here the noise it comes on when my car runs to rich.. But my noise comes accelerating from 1000 to 2300 Rpm. But I think its my vvti going back and forth to the retard and advance setting. I think its going so fast back and forth that the Ecu can't catch up to read it. I have another cam. But I am going to get a new o2 sensor and might get bigger injectors when someone confirms I can run id1000 with no fuel return and then get refined just for those big injectors and see if that code comes back.

 

Yea I think Im just gunna let it go until it throws a code and locks the cam in full retard Thats really the worst it can do, or it may just make the noise forever :/ At least I know now its not really a sticking valve or follower. Unless this happens... LMAO



But in all serious, I dont see that happening

 

can you post up a vid of the sound?

 

Ill try to - now I cant seem to get it to happen at all :/ My car is bi-winning. lmao
Still havent gotten any codes or anything of that nature... Only CEL I have is for the 2nd 02 sensor being gone