mikeman350z

My engine is making a metal grinding like clunk noise at low rpms and when I accelerate slowly. If I hold the gas pedal at a certain point I can make the clunking constant. When I am high speeds on the highway I never hear the clunk. Usually only happens when I am taking off also it happens almost every time I am going in reverse. Very confused to what this might be. Just recently installed MD iso thermal plenum spacer, not sure if that would have anything to do with it. I do have a bad ball joint or bushing I need to fix some people have told me that could be the issue. I personally think it is coming from the engine very nervous that something is really wrong.

please if there is anything you can think of let me know much appreciated!!!!

2bad240

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rcdash

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plenum is hitting strut tower brace. add a few washers.

iamjustincase

+1 on the plenum hitting the strut tower brace.
I had this issue, solved it by adding 0.200" thick washers underneath the strut tower bar, which then caused my bar to hit the hood so i added some washers to the hood aswell.

When you are checking it, it may look like there is clearance between intake and strut bar, but just remember that the engine moves a decent amount under load with oem engine mounts.

mikeman350z

thanks guys I will try that asap!!!! Just curious why doesn't the noise happen at high speeds just at low? I would think the noise would be louder if the engine is moving more.

iamjustincase

to mostly answer your question.
its not the speed of the vehicle that determines how much the engine will move.
but rather, how hard it is working, or how much load is being applied.

once the vehicle is moving, especially at high speeds, your engine does not have to work hard and there is little engine load, so it doesnt move around much.

when you first get the car moving however, there are higher levels of engine load, and especially when the load is first introduced. causing the engine to move a bit on the engine mounts, and relax back to its normal position once u are moving.

mikeman350z

THANK YOU ALL you guys are geniuses! Strut bar was rubbing, going to add more spacers took the bar off for now until I buy more washers. You guys are awesome thanks for all your help!