Just started up my 5 speed swap project -> Have a few issues

[SlideWise]

Well i bought this car from a friend and originally it was an auto car and the auto went bad so my buddy pulled the auto transmission planning to do the 5 speed swap and then the car sat for about 6 months. I bought the car about 3 weeks ago and just finished up the 5 speed swap tonight.

When i fired the car up it had a knocking noise in the top end (even though i pulled the valve cover and poured oil all over both cams and the entire head before starting it) which it never had before but it quieted down as it warmed up but did not completely go away. It sounds like a marble is bouncing around randomly under the front portion of the valve cover (in front of the front plug about where the timing chain is). The noise almost goes away or is not audible if the engine increases in rpm but when im off the throttle it comes back. Its not constant either which is confusing and it is most noticeable at an idle.

My second issue is the digital dash and heads up display. When i first turn the car on the heads up display and the digital dash work for about 15-20 seconds then turn off randomly. None of the other electronics are experiencing this issue as the rest of the dash works fine. The speedo will even read the speed of the car until those first 15-20 seconds have passed. Then it wont come back on until i turn the key all the way off then back on again. Of course it goes right back off after the 15+ second and im right back where i started.

Any advise on either issue is greatly appreciated!!

Edit: It is a 91 240 coupe with a ka24de with 201k miles in it.
Here is a video of exactly what it is doing. First i start it up and you really dont hear much then after it starts warming up from idling you start to hear it. Its most noticeable it the end of the video.
http://www.youtube.com/watch?v=HBkTKVw00DI

[S13_RB25]

The first problem is a chain rattle. Remove the upper and the driver side guides. If it doesnt go away your lower timing chain guide is done and needs a replacement. As for the heads display you messed up with the wiring somewhere. I can't really give advice on that since I got analog display not digital.

[moso]

heads up displays are known to have issues. they can have anything from bad capacitors to poorly soldered boards and after years of use they can die. google search for "240sx HUD fix" and you should come up with a dozen fixes for all different problems. and s13_rb25 is totally right on the chain rattle.