Weird engine vibration. HELP!

[al lkosmal]

This does not align with your rocker adjustment, but check your fan pulley. I had similar symptoms (mechanical vibration) and it turned out to be a broken fan pulley. The material between the smaller holes, surrounding the large mounting hole had sheared. This allowed the pulley to be off-center.

Regards,

Al

[Grady Clay]

I agree.

Since you have the plugs out and are rotating the engine to TDC compression on each cylinder for the valve adjust, it is easy to screw in the cylinder leak test adapter and take a measurement. It can’t take three minutes extra per cylinder.

Al has a good idea.
If you dissasemble the pulley, inspect the flats on the pulley half and the fan hub.
The 'cup washer' cannot be concave.
Remember - six shims total.

Best,
Grady

[carrera turbo]

hey there

i just noticed you have no mention of pulling the #4 plug out and checking it. this would be where i would start if that cylinder wasn't firing due to valve not opening this plug could be fouled and causing your miss.

just on a side note, if the problem didn't start until this rocker problem look at this area before you go off looking else where. a vibration that is caused from oil viscosity or such will end up being a sound before you can feel it. just my experience with these motors. a clutch coming loose could be the culprit, but what you have here i believe is a miss fire. turbos have lower compression and the misses aren't as harsh feeling at idle as a motor with 8-9 to 1 compression.

#4 plug first, then wires, i would go as far as to loosen all the wires on the cap so they pop off easy, then when at idle remove one at a time till you find the one that makes no difference, then dig in.

cheers ed

[pkracer21j]

Ok, first things first, thank you all for your quick responses and help! I dug into her today and changed the plugs, adjusted the valves, and took her for a spin. shes running smooth again. 175F oil temp and I spent some time from 5-7k. she was smooth again like she used to be. the intake valves were a little tight on 5 and 6 and the exhaust valves were tight(almost no play) on 1, 2, and 3. the plugs were richer then usual, mainly because Justin and I tweaked her a little bit to provide the excellent flamage videos during Okturbofest. but 4 was so rich it may have been fowled, and I think I have failing injectors on 2 and 5, as they were the lightest of the 6. The cams don't look great with some odd wear patterns, I'm not sure what to make of it.
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[pkracer21j]

Well the vibrations still there. its not as bad, but its still there. I'm wondering if its a sign that the cams and rockers are on their way out??? I cleaned the spray bars out again, we'll see how it runs this weekend.

[carrera turbo]

Plug wires

ed