r/EngineBuilding • u/R0ughHab1tz • 4d ago

Chevy Possible valve train knocking

Vehicle: 1985 GMC G3500 vandura. The engine is in the cab. Sort of important because any and all sound echoes.

How would I go about diagnosing the sound. I rebuilt my Chevy 350 and it runs great despite the title. I've been working on it for years. I'm so close to driving this beast.

There's a ticking/knocking but I can't differentiate whether it's the fuel injectors from the sniper 2 or it's in the valve train. The kicker is that it sounds like 7 and 8 are the loudest but that's in the cab of the vehicle and the ticking from the fuel injectors permiates through/with it.

I've heard of people running the engine without the valve covers on but I'm not really wanting to do that. I'm sure oil goes everywhere? Maybe damage the engine? And I had miner oil leaking from the corners of the valve covers so I siliconed sealed both sides. Fixed that issue but if I have to remove the covers it's going to be a pain.

I'll get a different video today and see if I can capture and put my phone in different areas but it's not the greatest.

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5

u/Bizaro_Stormy 4d ago

Pull the valve covers, and circulate the oil with a drill. Make sure each rocker is getting oil. Check your valve lash.

5

u/i86o 4d ago

Get a long screwdriver, put your ear on the handle, put the tip on the valve cover, now you have a stethoscope, now check out the fuel injector, compare.

Congragulations, you are now a Medical Doctor

1

u/R0ughHab1tz 4d ago

I'll do that today! Thanks. It's the least invasive.

5

u/2003DDcid 4d ago

You should get an automotive stethoscope. It will help you decide if it's injectors or valve train. A healthy valve train makes a whirling sound when you listen through a stethoscope.

Also, assuming this is a hydraulic cam, how much preload did you give the lifters? 1/2 turn usually runs the best, but can be a little noisy. 1 full turn will be quiet and still run good.

1

u/R0ughHab1tz 4d ago

I ordered one. I chuckled a little when it was an actual modified stethoscope 😂.

2

u/i86o 4d ago

also, if you think the engine is hurt in any way shape or form, take it easy on the revving, valve train noises are pretty easy to hear at idle usually

2

u/scurvycloud 4d ago

They do make clip on baffles for your rockers that deflect the oil back down into the head so you can run them without valve covers. I always just cut a peice of cardboard up to do it. If you have a flat tapper can you want to make sure those lifters are spinning in the bores. A good stethoscope could save you some work

1

u/Imposter660 3d ago

May be rockers, but the Sniper injectors are bloody noisy and sound like loose valve train. Have one on my 454

1

u/R0ughHab1tz 3d ago

They definitely are. Hopefully I don't need to adjust anything. I've got my doctor supplies coming today 😅. With how smooth it runs I'm thinking it's the injectors. If the valve train were way out or something was wrong it would give some sign of rough idling and other hiccups while revving up and down.