Help! metal noise from engine..

[Hillkill]

I dont think it's a bent rod but here is what happened. I changed my oil from royal purpal10w30 to red line 5w30 the day before this happened. I drove for over an hour and drifted hard on a track for over five hours before this happend. But I was in second gear on redline when I think my IAC valve clip popped off. Then my engine started making a tank tank tank noise. So I shut her off and pushed her off the track. I plugged the IAC back and started it with the same noise. It seems to be coming from the head. I also noticed after I towed her home that one of my intercooler pipes wasn't connected. Please any info or thoughts are appreciated

[240sxbobbis]

ok im no expert but this is my two cents about it i think that the oil u have you have in right now is thinner than what u had in before , then you were drifting it hard for five hours it burned the oil up pretty bad . any one correct me if im wrong

[ccasey645]

more than likely the IC piping coming off did it. I've blown mine off several times and my ca wouldnt even idle let alone rev anywhere. I highly doubt you toasted your redline oil. That stuff is tough. Not uless it was 120 degrees and you had it to redline the whole 5 hours. Wouldnt hurt to check though. Reconnect it, id say the intake air bipassing the maf makes it sound like that.

[240sxbobbis]

i also believe that can be the cause also

[float_6969]

You could have simply toasted a lifter as well. I'm not a big advocate of sub 40w oils on turbo motors, unless it's cold weather. I'd say hook that pipe back up, and see what happens. We can go from there.

[Hillkill]

How would I tell if it's a lifter? I already drained the oil and it was pretty black for one days use. But there were no metal shavings whatsoever.
Modified by Hillkill at 2:40 PM 8/22/2006

[Hillkill]

If I can push the lifter down and feel a noticable differance does that mean it's bad?

[r34 gtr]

just pull the cams out and check the lifters, even with re-setting the timing it shouldnt be more than an hours worth of work. theyre hydraulic so you may be able to move them some regardless because theres no oil in the engine anymore. that CA head can take quite the beating, so i wouldnt think you would have killed something, let alone one of those incredibly stout rods.

- Tim

[Hillkill]

ANything else I should check if a lifter is bad?

[float_6969]

If you can press down on the lifters and feel them move at all, they're bad. I think the tolerance is something stupid like 1mm.

[Hillkill]

Should I replace the springs if a lifter is bad? or is there a way to test them without taking the head off. has anyone here ever bent a valve without breaking a timing belt or throwing rod. thanks

[ccasey645]

Ive bent valves by snapping a timing blelt, thrown a rod from over reving, and seen valves come apart mid stem because of fatigue and become lodged in the piston (but that was a pushrod engine). I'd start by takin off the valve cover(s) and just lookin. If your worried about a bent valve do a compession test or a leak down test. Its hard to tell if a valve is bent sometimes by just lookin at it. I snapped a timing belt on a dsm and after removing the head thought only 4 valves were bent. So i put them on a lathe to make sure and sure enough every one was bent. But I knew something was up when the compression test gave me screwy numbers. I would say compression test it. It will same you A LOT of work.

[Hillkill]

valve covers are off, engine is out, I don't have a spring compressor but I'm chancing not taking the head off because if I do I wont have the time to put it back together properly before saturdays drift event. I need some input, if not I'm going to toss in the 3 lifters that I ordered yesterday and hope nothing else is wrong