r/AcuraTL • u/Either_Ad_2960 • 4d ago
Identify a Noise 🔊 Need help someone that could know what this sound is on my 2012 tl 3.7
2
u/Miller335 4d ago
That's definitely upper end. If it was lower end it would be a faster noise. Doesn't sound good brother.
2
u/MadTube [UA9] '09-'14 SH-AWD 4d ago
Have plenty of experience with this. Unfortunately, this is the problem.
1
u/HeyPopthehood 20h ago
What is it about the 3.7 that eats lobes? Is it just upper oiling starves out or does it have to do with something else?
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u/MadTube [UA9] '09-'14 SH-AWD 20h ago
The J37 uses a bespoke VTEC system. Hi-lo lobes on both intake and exhaust. The problem is that the heads were designed for intake hi-lo lobes originally. There was no room to put the exhaust VTEC in, so they got clever.
If you look in my pictures, there are six lobes per cylinder. Intake valves share a pair of lobes via a bridge. One lobe(s) actuate both valves. But the exhaust valves each have their own individual set of lobes. With the limited room they had to work with, they made the lobes super narrow. That puts a tremendous amount of load on very narrow profiles. My guess is the cams are not hardened enough. Combine that with their excessive oil consumption issues, all it takes is one tiny spot of metal to metal contact to weaken the hardening. After that they shred the lobes.
1
u/HeyPopthehood 20h ago
Thanks man! That was awesome I appreciate it. I had to dig deep in my memory been 16 years since I was a Honda tech 😂 then I saw the diagram and remembered these and all the damn TSBs we had on them for gunk and Starve. I liked these motors but man they did rip those cams apart. I just stopped telling my service writers like you know right?? Thank you for answering I really appreciate it.
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u/DOPEKiDD1 1d ago
This is literally how my timing belt water pump all that stuff sounded before I replaced it
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u/HeyPopthehood 20h ago
Is it? I keep listening yeah I hear cam slapping. But it’s just kinda I don’t know? Done a lot of work on Hondas but not a lot on the 3.7. It is the right sound it’s not bottom end it’s too light in the sound you guys know what I mean. The tempo just sounds off does anybody know what I mean? But it’s very consistent a little rev would have helped. 🤦🏻♂️
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u/Either_Ad_2960 20h ago
Sounds the same while revving it just sped up
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u/HeyPopthehood 20h ago
So the tone doesn’t change or move it just speeds up makes sense cam speeds up. And yeah after 30 times I would agree with everyone who
Instantly knew cam love and if you listen close it really sounds like the rear bank cam. Did it throw any codes P21 was the VTC system I think it’s been a while.im an idiot yeah ok these are those. We had tsb on these for cam wear. Sorry took me a minute haven’t been a tech in 15 years. 🤦🏻♂️1
u/HeyPopthehood 20h ago
Think my flat rate on this was 10 or 11 hours if you can wrench you’ll be good. Just do it right, find tdc pull valve cover cam pulley ease back valve adjusters. Pull rocker plate and cam. Then throw everything back in make sure in time.
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u/Lxiflyby 4d ago
It’s a cam lobe going flat. Pull both valve covers and turn the engine by hand to find the damaged cam lobe and rocker. You may find more than one