A little over 6k miles on a DSI stage 2 engine with FAST EFI, 14.5 mm o-ring type injectors, 123 Distributor, and a not so great exhaust header.  Single gasket. 

Checked valve lash today with engine cold, followed by re-check with engine at operating temp.  All in spec.  Stage 2 cam with stock rocker arms, all other valvetrain parts installed by Eiji at DSI.  Not by me haha. 

This video is taken with the engine running post valve lash check after about a 30 mile drive.   Honestly, It's always sounded like this.  Even before I sent it to DSI.  It runs great, makes good power, has great compression and has no known issues.  It broke in quick, and I don't beat on it too hard.  4k RPM shifts and 3K RPM cruising speed give or take 500RPM. 

I have a feeling it's probably ok, I just want the community's opinion.  I'm thinking it's a combo of normal L28 valve train racket, exhaust leaks, or simply thin steel used in the header, or maybe a little injector noise.

I have the stock o2 port plugged with a bolt, and the EGR port plugged with a big bolt as well.  I've moved the o2 bung to the collector further downstream.

Been considering doubling the gasket on the header.

 

 

Sounds too fast to be an exhaust leak, it kinda keeps up with the valve train???

Have you tried the hose listening trick yet, poor mans stethoscope?

 

I stuck a screwdriver on the valve cover and listened to the rocker arms from the front to the back.  The noise is quite a bit more pronounced when listening with my ear at the end of the screwdriver.  Which I imagine is to be expected.  I guess I'm not entirely clear on how much louder it's supposed to be when doing that.  I've tried to watch all the videos I can find on you tube of these engines running.  Some sound like this, some louder, and some quieter.  Some stock, some built, some with the text in Japanese that i don't understand haha. 

If I put the end of the screwdriver on the exhaust runners of the header it isn't all that much louder. 

I forgot to mention an important point:

The engine only sounds like that as it starts to warm up and at operating temperature.  When it's cold it does not make that noise. It's otherwise quiet. 

Spray bar or self oiling cam?

Odd circumstances. If DSI did the head I can only think it's a leak. Metal expands when it gets hotter, right?

Head scratcher!

7 minutes ago, siteunseen said:

Spray bar or self oiling cam?

 

It's a P79 with an oiler cam only, no bar.

The last time I checked the valve lash(roughly 1 year ago) I went a bit tight on the adjustments just to see if it made a difference, and it had no discernible effect.    I didn't keep those tight settings of course, I reset to spec. 

Eiji told me that he runs his valve lash at .008 cold for both intake and exhaust.  I've run that and the factory spec .008 intake/.010 exhaust cold and the car seems to run better with the latter(factory spec), so I've been running that.  Noise remains the same.

Have you asked Eiji about running 40w oil?

Have you asked Eiji about running 40w oil?

I haven't. But I will email him and see what he says. Before I received the engine back from him I asked what oils he recommended and have been using the Driven dino 10w40 he recommended.

Sounds perfectly normal to me. L series engines always have valve chatter…..especially with a higher lift cam. I asked the Z Doc about this when he used to build my heads…..he said its the nature of the beast. You might be trumpeting it through the thin headers too. Enjoy it, drive it, L series engines are hard to break…,.believe me I’ve tried LOL.

Yeah Eiji said it sounds normal too. I appreciate the reassurance. I'll just drive it and enjoy it.