ben_g99

I've got a bad valve train noise that is bad enough to make me cringe.

I've been around DSM's and Evo's, 4G63's in general for years and I know this is not the normal valve tick. This noise occurs more likely the colder the car is and the colder it is outside. The really strange thing is this noise only occurs between 2500 rpm and 3700 rpm and only when I am at part throttle within a 10% range. I have not logged to see what my TPS value is when this happens, but I would guess between 40-50% or so. Any other throttle position and it will not occur. Also, when I do accelerate fast and release the throttle slowly, this happens again at about the same throttle position.

Now onto the noise - this literally sounds like someone is tapping mutliple screwdrivers against the inside of the valve cover. It's like metal is hitting the valve cover from the inside.

I can also make this noise happen when I first start the car and free-rev it a bit. When I do drive the car for 30+ minutes on the highway, the noise is pretty much non-existing at any RPM or throttle positon.

Now, when I first got this car (June?), this didn't happen. The only thing that has changed since is the oil. I've changed the oil and replaced the Royal Purple with Mobil 1 (full synth) 5w30 or 5w20 (I can't remember for sure).

I am absolutely clueless. In case it helps, these are the main mods!

2.3 Stroker
Wiseco Pistons
Scat H-Beam Rods
Balance Shaft Delete
Ported/Polished
Ferrea Valves
Works Valve Springs
Ti Retainers
Delphi 680cc Injectors
Denso Iw24 Plugs
Ports Matched
Walbro 255
ACT Street Disk
Tubular O2

Any help would be greatly appreciated!

240Z TwinTurbo

iTrader: (25)

Check the plugs to see if they are showing any signs in detonation. Without hear the sound it is hard to diagnose.

sparky

iTrader: (1)

Mine had a tapping sound inside the valve cover and it turned out to be a lifter. But we bled it with a paper clip and I think it must have had a small bit of crud in it. After bleeding , the noise went away.

barneyb

The oil weight you are using is lighter than any recommended by the maker.

Tsurugi-san

iTrader: (37)

Ben,

I'm thinking the light-weight oil is part of the problem as well. But I remember some of the mechanics here (NW Arkansas) commented on how little room there was (tight squeeze) for the WORKS valvetrain kit, and I'm wondering if the combo isn't the cause.

There are a couple of ex-mitsu mechanics that started a shop out at Lake Weddington, and they did the install on my friend's evo, and they might be able to help you out. Let me know if you need their number.

ben_g99

What weight oil do you both suggest I should try? I know the works valve train problem, it would not have been my first choice, however, the previous owner built the motor and this is what I am stuck with for now! Thanks for the help and please recommend a better weight oil.

Thanks!

Tsurugi-san

iTrader: (37)

Well, for starters, I'd try the OEM recommendation of Mobile 1 synthetic 10w30 --- you can get the 5 quart container at Wal-Mart for something like 23 bucks after tax. It wouldn't be a bad idea to call WORKS @ 415-641-9675 or even Buschur Racing and ask them what oil they use in their built 2.3 liter motors. Maybe they'll have some information on the symptoms as well.

Hope that helps!

ben_g99

Thanks, I appreciate the info!