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Last night I finished putting together my first 350 (stroked to 383, injectors swapped to carb, dist swapped to HEI), and it started immediately, no problems.

But during the break in (running engine at variable RPM for 25 minutes) I noticed that once I apply a little bit of throttle, and bring the RPMs higher than idle (RPM gauge isn't working yet so I'm not sure the exact RPMS), the engine (or something around the engine, I'm not sure yet) makes this pretty terribly loud "rattle" sound.

I've checked the oil and the oil looks very clean wiped onto a coffee filter.

I also have a video of it starting and revving up, the sound in question starts at 0:10. https://www.youtube.com/watch?v=jWQd70ex3q4

Could this be something as simple as timing related? Or does this sound closer to having something inside the installed incorrectly?

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  • Is this a roller cam or flat tappet?
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Feb 18, 2019 at 19:43
  • @Pᴀᴜʟsᴛᴇʀ2 hyd roller
    – Brian Leishman
    Feb 18, 2019 at 19:43
  • For future reference, when starting a fresh engine, knowing the oil pressure is quintessential to the life of the engine. Without it, you are flying blind and could destroy the engine on first startup, with or without assembly lube. Really, knowing the oil pressure is that important.
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Feb 18, 2019 at 21:05
  • That definitely makes sense. The oil gauge worked for a second at the first start, and then the needle in the cluster got stuck all the way to the right, and then I started it once more to record the sound
    – Brian Leishman
    Feb 18, 2019 at 21:08
  • @Pᴀᴜʟsᴛᴇʀ2 Got a mechanical oil pressure gauge, and the oil pressure looks quite solid, it was around 60 when I started it, but the idle on the carb is really high right now, and the second start up it was already down to 55, which seems pretty good. As for the rattling, it might have been the piece of thin metal between the trans and the block, at the bottom, two bolts were missing, so I added them, and so far haven't heard that sound again. I'm gonna try with the belt again tonight
    – Brian Leishman
    Feb 20, 2019 at 20:13

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The rattle I'm hearing in the video doesn't sound internal to the engine. It sounds like a torque converter bolt or something along those lines. I don't know how to describe it, but I think if you went around and tightened everything up which is connected to the engine (on the outside) you'll probably find what the issue is.

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  • Just an update, that sound never came back, and the engine has run perfectly for about 500 miles now
    – Brian Leishman
    Aug 12, 2019 at 14:42

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