Weird engine noise under quick load. (Video links)

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Old November 17th, 2023 | 08:28 PM
  #1  
Pitbull2o08's Avatar
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Weird engine noise under quick load. (Video links)

Hey all, happy Friday.

I tuned the carb and idle for sea level and adjusted the timing to obtain a nice 20 pounds of vacuum.

car idles and runs greats. Had much faster pull.

but I have this weird noise from the engine bay under a quick load. So not a high load, like if I lean into a gear slowly and go up on the rpm’s, but quick throttle blips. At first I thought it was the carb, but it doesn’t do it in idle. I overfilled the power steering fluid and it oozed out when I got home, so maybe the lid under pressure? What about the tranny?

thanks for the help.

https://photos.app.goo.gl/WBoeCcoTptvT6Qm28

https://photos.app.goo.gl/1XYxXENCXP6nBWXD8
Old November 18th, 2023 | 11:07 AM
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This is good video of it with hood open and brake+throttle. Engine warm.

https://photos.app.goo.gl/ZReZet6psNGs3BNn6
Old November 18th, 2023 | 11:33 AM
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Neutral, no load. Revs fine

https://photos.app.goo.gl/d4gyFkJcq9UY71r3A

under load again, from passenger side, no air intake on

https://photos.app.goo.gl/KDivyckHYybGyvL4A
Old November 18th, 2023 | 06:53 PM
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Your first video scared the hell out of me.
It made me sick thinking that I’ve heard the dreaded rod-knock of an Olds.

But the last video sounds like extreme dieseling.
Old November 19th, 2023 | 09:59 AM
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Originally Posted by Rallye469
Your first video scared the hell out of me.
It made me sick thinking that I’ve heard the dreaded rod-knock of an Olds.

But the last video sounds like extreme dieseling.

I fixed it by backing down timing, I did so little by little until I didn’t get the clacking at near WOT.

I also changed the plugs and wires because they looked pretty old. Got NGK and Napa wires. They did well

car ran great today. So I’m happy.

i do have a decent leak at the bell housing which is new. The oil I put in is relatively thin, according to others (10-30)

so I was gonna do some thicker stuff but I’m in SoCal.

Old November 19th, 2023 | 10:44 AM
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Originally Posted by Pitbull2o08
I do have a decent leak at the bell housing which is new. The oil I put in is relatively thin, according to others (10-30) so I was gonna do some thicker stuff but I’m in SoCal.
10W-30 should be fine for a stock-ish engine with more-or-less factory clearances. How's the oil pressure? Regardless, I doubt that going heavier will seal up your leak. Out of curiosity, you didn't just switch from dino oil to synthetic, did you?
Old November 19th, 2023 | 09:39 PM
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I'm not sure what the PO used (It was his dads car who passed, but he was a proponent of synthetic himself) and I have always used Mobile 1 synthetic with high zinc content.

I heard from others on here to run 20-40 or something similar. The engine is factory, it was bored .030 over and has 455 components in it. Cam doesn't sound too aggressive. And compression is 179-181 all the way around.

Old November 20th, 2023 | 12:25 PM
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10W30 is fine. Check what's leaking. Heavier weight oil wont resolve a leak and could cause lubrication issues. 10-40 is also acceptable.
Old November 20th, 2023 | 08:19 PM
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Originally Posted by sysmg
10W30 is fine. Check what's leaking. Heavier weight oil wont resolve a leak and could cause lubrication issues. 10-40 is also acceptable.
I might switch to that.

I changed the valve cover gaskets, got a good look inside and checked the lash. And the oil pan bolts were pretty loose. I tightened those down.

so far nothing leaking right now. I’ll let the car idle tomorrow and see.

thanks for the feedback, you guys are great.
Old November 21st, 2023 | 03:43 AM
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I'm suspicious adjusting the timing didn't fix the entire issue. It sounds like a cracked/broken/warped flex plate or loose attachment bolts. I watched the videos carefully, it only happens under load while you're brake torquing the engine & in particular (while driving) it occurs under light load. Remove the bell housing cover & use a very bright flashlight to examine the flex plate & hardware. Look for any suspect areas. If possible, have someone in the car performing same brake torquing you performed while you listen in the area of the torque converter/flex plate/starter.
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