Quote:
Originally Posted by makoshark
Are you running a pilot bushing or bearing in the end of the crankshaft? I had a similar vibration on a car once after installing a new clutch. I chased the vibration down by a damaged pilot bushing due to install. I replaced it with a bearing
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I don't know. I had a shop assemble the sub and they installed the pilot bushing/bearing. I'll know soon enough I think.
Quote:
Originally Posted by chr2002ca
I went down this road also Chad when I first put my GM crate motor ZZ454 in years ago. Same exact vibration problem, except I had an automatic. Did nearly all the same things you're doing. Compression check, fuel pressure check, spark plug and wires check(and distributor), harmonic balancer check, mounts check. I eliminated some vibration when I found a bad spark plug wire arc'ing over to my block causing a misfire. But still had some vibration so I then detached the torque converter from the flywheel and shimmed the transmission back to allow the engine to run while detached from converter. I noticed very little vibration then. So, to make a long story shorter, most of the issue was with my flywheel and how the converter was bolting to it, and a new flywheel solved that. I still had a slight harmonic vibration between 1500 and 3000pm after all that, but it was basically just a result of a big cube motor and I came to that conclusion when I sat in somebody else's ride who had the same ZZ454 and it felt exactly the same at the steering wheel.
It drove me nuts for quite a while so I hope you get it sorted out soon and it's something simple.  |
Thanks Chris.
I think I eliminated tune or engine running incorrectly as a cause of the vibration. I took the car for another diagnostic drive tonight and the vibration is there upon deceleration as well. I even turned the car off in gear decelerating down from about 3.5K rpms and its the exact same vibration. So I'm convinced it's mechanical, rather that anything else.
I have to go out of town this weekend but I plan to pull the motor next week.
Regarding the oil pressure I ordered an adapter for my other sending unit and can play with that next week too. However, when I did my test drive tonight I noticed that at cold oil temps I have a ton of oil pressure (50 idle cold and doesn't drop below 35-40 until a good 10 mins into driving (not idling). If I rev the motor with cold oil it will hit mid/high 70's PSI.