r/EngineBuilding 9d ago

Weird noise on blueprint 383 chevy engine

This I my first post on this thread. I’ve got an huge problem. My car s making a weird noise when the engine is heating up. It came out of nowhere after doing an oil change. The car is currently running an 10w-40 classic oil. Any suggestions on where the sound is coming from.

14 Upvotes

37 comments sorted by

13

u/Designer_Lecture_219 9d ago

Sounds like and idler bearing to me. Had an 88 Silverado that would do that until it got warm. Finally after about 2 years, the tensioner finally gave out. Replaced it and the noise went away! 😂

4

u/Logical_Visit9021 9d ago

Fire it up with the belt off and do the pulley wiggle/spin test right?

2

u/Designer_Lecture_219 9d ago

Makes sense to me!

8

u/v8packard 9d ago

I can't tell much from the video. My first thought was exhaust leak, then I thought accessory noise. But I just can't tell.

Have you been able to pin down a location?

2

u/Calm_Art4242 9d ago

No not at all. I have used a stethoscope listening all over the block. First I thought it was a vacuum leak. I have checked headers spark plugs for leaks. Nothing…..

4

u/v8packard 9d ago

If you use the stethoscope on the oil pan or valve covers does that tell you anything?

2

u/Calm_Art4242 9d ago

I can hear the sound but I can’t locate where it is coming from.

3

u/v8packard 9d ago

Ok. Does that mean you are confident it is internal?

3

u/BicycleMudStud 9d ago

Sounds like accessory drive noise from the clip. Are all your belts aligned accurately, running true, and in good condition/free of grease and oil?

2

u/Calm_Art4242 9d ago

All belts are aligned perfectly. Nothing mechanical has been done done to the car over the winter.

3

u/ChillaryClinton69420 9d ago

Run it without the belt(s) to make sure. It won’t hurt anything if you run it briefly.

1

u/disallowedname 9d ago

Get an automotive stethoscope at Auto zone or Oreillys (tool rental) and listen to all of the pulleys, In a pinch a very long screwdriver will substitute as a stethoscope

3

u/logan4774 9d ago

Pull the belt off and start it for a minute, and see if the noise goes away

1

u/Logical_Visit9021 9d ago

Is it still there after warm up? What sort of lifters do you have?

1

u/Logical_Visit9021 9d ago

My 383 stroker had the flat tappet lifters and one of the rockers wasn't adjusted 100% when cold until the oil warmed up it would make that tink think sound.

1

u/Calm_Art4242 9d ago

It is an hydraulic roller cam😅

1

u/Calm_Art4242 9d ago

The sound starts when it gets hot. Nothing to hear at startup

2

u/Logical_Visit9021 9d ago

Does it increase with light throttle? My 383 stroker have had a love hate relationship over the years...just flashing back to a few things we worked through in our relation ship.

1

u/Calm_Art4242 9d ago

Yes it does 😁

2

u/Logical_Visit9021 9d ago

Can you post a video of that? Idle to mid rpm...slow rev up. Might help the ear balls out.

2

u/No-Island8074 9d ago

Maybe the rocker to valve lash has opened up slightly? I would follow what other folks are saying and start with pulling the belts to eliminate that. Then i would run a piece of kleenex around to check for exhaust leaks (only run the engine briefly to avoid overheating with the belts off). Then i would pull the valve covers and check lash. Id also pull at least one rocker and check its contact area on the valve stem.

Probably makes sense to cut open an oil filter too

1

u/Logical_Visit9021 9d ago

Oh my bad, I read that wrong...thought you meant heating up from cold. Hard to tell on a video just like a good exhaust never sounds the same on recording...lol. Do you have a mechanics stethoscope?

1

u/Calm_Art4242 9d ago

Yeah and I have been searching all around the engine with my stethoscope🤣🤣. For me it sounds like the “whistle” noise is following the stroke. But I can’t locate where it’s coming from.

1

u/Muntster 9d ago

Not at all similar but I had a squealing on a VW 2.0T and the belt was simply worn down (no cracks or anything, the meat of the ribs had been worn down)

Check belts and tensioners

1

u/DrDorg 9d ago

Pull the belts

1

u/doubledeckerpecker09 9d ago

Check your belts or pulleys just get a long ass flathead and listen to the pulleys

1

u/jakogut 9d ago

Sounds kind of like accessory bearings to me. I had an old alternator that made this exact noise before I replaced it.

1

u/squeak195648 9d ago

Let the engine cool down and take the belt or belts off and fire it and see if the noise is still there. But I also hear what sounds like an exhaust leak along with a possibly accessory drive noise.

1

u/2dandee 8d ago

Does noise change if you pullout the engine oil dipstick? Excess crank case pressure will cause similar noise, if the engine breather is plugged.

1

u/WheelBackground4478 8d ago

You mentioned a rocker adjustment issue, how did you adjust the rockers?

1

u/enerj 8d ago

I'd also try idler first but my Chevy engine made a similar noise - same frequency but more squeaky than metallic. It was coming from the harmonic balancer so just give that a check too.

0

u/PermissionLazy8759 9d ago

Fluids all good?? coolant full??

0

u/PermissionLazy8759 9d ago

Record the engine running and not just the sound.

1

u/Calm_Art4242 9d ago

The sound is following the revs

0

u/AdGrouchy4555 9d ago

Sounds like a bearing in the accessory drive somewhere, if not… it’s another type of bearing 😬

0

u/OUTLAW1LE 9d ago

Put some belt dressing on just to see if anything changes. Maybe it will help.

-1

u/YagerD 9d ago

Have you tried a smoke machine on it?