Ruh roh Raggy! I hear you knocking…

[Bextreme04]

That could be…
I was wondering about the speed. And valvetrain noise would be even slower, yes? Half the speed of crank speed?
I’ll ask them tomorrow. Thinking about it, it does make the sound - quieter, but it’s there - when it’s cranking. If it were a knock, I don’t know that it would do that…

Valvetrain noise and rod knock would be very similar speed, and yes.. much slower than that. That speed sounds like something hitting at crank RPM, but it isn't deep enough of a sound to be rod knock in my opinion. Sounds light and tinny to my ear in that video. Rod knock will be much deeper and shows up on one stroke only. Could potentially be valvetrain, easy enough to just pull the valvecovers and see. Mechanics stethoscope is dirt cheap and would help you narrow down exactly where the noise is coming from. My bet is if you put the stethoscope on the trans dust cover you're going to find that the noise is coming from right there. If so, take it back to the shop you spent the money at and have them fix their screwup.

 

[SquareRoot]

Not trying to knock ya but can't afford a hoist but can afford a shop fixing it?

 

[Disco]

Valvetrain noise and rod knock would be very similar speed, and yes.. much slower than that. That speed sounds like something hitting at crank RPM, but it isn't deep enough of a sound to be rod knock in my opinion. Sounds light and tinny to my ear in that video. Rod knock will be much deeper and shows up on one stroke only. Could potentially be valvetrain, easy enough to just pull the valvecovers and see. Mechanics stethoscope is dirt cheap and would help you narrow down exactly where the noise is coming from. My bet is if you put the stethoscope on the trans dust cover you're going to find that the noise is coming from right there. If so, take it back to the shop you spent the money at and have them fix their screwup.

I’m gonna see how much integrity the shop has. It’s still over there (it’s been a hell of a morning), so I’m gonna talk to the owner about having them double check their work, looking for something hitting the block or bell housing, as previously discussed. If I have it towed home and I discover it’s something they did, that’s another tow bill and a fight over who pays for it.

If it’s not that, then I’ll drain the oil, drop the pan, and start by looking for forbidden glitter…

 

[Bextreme04]

I’m gonna see how much integrity the shop has. It’s still over there (it’s been a hell of a morning), so I’m gonna talk to the owner about having them double check their work, looking for something hitting the block or bell housing, as previously discussed. If I have it towed home and I discover it’s something they did, that’s another tow bill and a fight over who pays for it.

If it’s not that, then I’ll drain the oil, drop the pan, and start by looking for forbidden glitter…

It's still at the shop? From when they did the work? And it didn't make that noise when you dropped it off?

I just went back to he first post and re-read it... so the shop did a clutch replacement, then when you went to pick it up it is making this noise... and the tech who did the clutch replacement thinks its a rod knock?!?!?! WTF

I absolutely would not take that thing out of their shop making that noise. That tech needs to go back and check his work and figure out what he F-d up... because it sure sounds like they didn't do something right and you now have something attached to the crank making contact with something else. Go down to Harbor freight and buy a $5 stethoscope and have them put it up on the lift for you. Start her up and track down that noise with the tech..

 

[DoubleDingo]

That does not sound like a rod knock, that sounds more like an exhaust leak at the donut. But it could be something hitting on a rotational item. Did they place a card on the shroud to hit fan or alternator? To me that engine sounds healthy.

 

[Disco]

UPDATE: I went to the shop and talked to the owner. He agrees that it’s unusual that a healthy engine suddenly starts making noise after having work done. I found a video of my truck running the last time I had it running and showed him. He said he will personally check it out. Fingers crossed.

 

[DoubleDingo]

UPDATE: I went to the shop and talked to the owner. He agrees that it’s unusual that a healthy engine suddenly starts making noise after having work done. I found a video of my truck running the last time I had it running and showed him. He said he will personally check it out. Fingers crossed.

That's good to hear.

 

[Disco]

She’s home. It was the inspection cover of all things. They went to go scope it. They took off the cover, the noise went away. They put the cover back on and it stayed away.

Thank you, everyone, for your suggestions and help!

 

[Ricko1966]

Ugh. Car forums…

I have never replaced a flywheel or clutch in a V8. The only experience I have in that area is from 20 years ago with a 73 VW Bug which has an engine small enough you don’t need a hoist; you can pull it out by hand. It weighs 80 lbs.
I wasn’t about to learn how to change a clutch and flywheel on a 350 that weighs twice as much as I do while laying on my back, by myself, with hand tools and a Harbor Freight trans jack, while a 3800 lbs truck looms overhead on jack stands.
So, yes. I budgeted for a shop.
A $300-400 engine hoist I will hopefully never need again and have nowhere to store is outside the budget.
I sold things to have the money to send it the shop, hoping that’s all it needed.
Foolish, I know, to hope that life would play fair and let me have a win. But no. It’s two steps forward, 3 steps back, and now I’m low on funds, out of stuff to sell, and I still need wheels to get me to work. I cannot afford a hoist or a shop.
I don’t have a garage; I have a driveway and a carport, both of which are under water right now. And I have a need of the truck and no experience working on anything like them. I’m learning, but I find no joy in the experience. I work on my own vehicles because of necessity, not as a pastime.

Maybe I should just sell the damn truck? Then I’d have money and no pit to throw it in…

A bug engine weighs about 225lbs. You do not need a hoist or even a transmission jack to do a clutch on a square. Next time you'll know. But more importantly if you had asked here first. What's involved in doing a clutch on a C series we'd have told you. So next time you have a problem ask first,do some research first because it might not be as big of deal as you think.

 

[Rusty Nail]

4) Thoughts? I don’t really know if there are questions I don’t know to ask…

I think that would suck.
At least they got some cool dudes - in here.

Pretty hard to undo damage caused by runnin old oil. Lol?? Might should have started there...

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Haha he said "don't be such a effin chump."

 

[mikeoverland]

I wish that you lived closer to san antonnio. I have a stand that you could borrow and I can get my hands on a hoist with very little problem.

Mike

 

[Disco]

I wish that you lived closer to san antonnio. I have a stand that you could borrow and I can get my hands on a hoist with very little problem.

Mike

I’d love to have some car friends around.

 

[JBswth]

Ugh. This hurts.

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So I bought my C10 2 years ago. She had spent 15-20 years sitting in a neighbor’s backyard, slowly sinking into the dirt. The engine rotated over by hand with good compression, so when I bought her, I pulled the plugs and filled the cylinders with a mix of ATF and MMO, then I put the plugs back in and let it sit for a week. After that, I pulled the old plugs back out and cranked the engine to blow the fluid out. Then I put in new plugs, dropped a fuel hose from the pump to a gas can, and filled the carb bowls with TruFuel, then turned the key. I kid you not that she fired right up on the first try and idled.

I did a few other things to it (brakes, bearings) and I got too busy to continue — plus it was 110+ outside for like a month straight and I was not working on my back on hot concrete. That was about 1.5 years ago that work stopped.

Fast forward to today. I decided that there were two ugly jobs I didn’t want to do holding up the truck from returning to the road: the clutch/ flywheel that needed replaced, and all the brake lines needed done. I decided I needed a shop to do those for me.
I just got the truck back today, and when I fired her up, she had a LOUD knock that wasn’t there when I last ran her. The tech thinks it’s a rod, a friend thinks it’s lifters, I think it’s bad news.

The friend who thinks it’s lifters thinks it just needs to run for a few minutes to build up oil pressure, and the noise should go away. I’m nervous that running it may end up with a hole in the side of my block.

So I need help. I’m just getting to know Chevy small blocks (she’s a 350) and my buddy doesn’t know them at all.

My plan was to bring it home and do an oil change right away. She still has Bush Administration oil in her. Part of that oil change was going to involve Lucas oil treatment to help her out. I believe she has somewhere between 70-80,000 original miles, so I know tolerances are starting to widen, and a bit of honey in the oil will help.
The shop is 1.5 miles away. I was hoping to drive it home.

1) Should I let her warm up and see if the knock goes away without a thunk?

2) Do I need to look into a bottom end rebuild and is that something I can do with the engine in the truck?

3) If the engine is toast, will a late 80s or 90s 350 bolt in? And will that engine accept the OE intake and exhaust manifolds? I don’t have the time, money, or expertise to start messing with FI swaps and I have a brand new Holley Q-jet carb for her.

4) Thoughts? I don’t really know if there are questions I don’t know to ask…

Hmm, possible that they put in a defective throwout bearing, or maybe lost one of the pressure plate to flywheel bolts, and replaced it with one that is too long and is striking something. Many years ago, I had my brother take my car to an acquaintance of his to replace a blown headgasket, (I was away on a political trip), and when I got it back, it was pumping oil. They scored the cylinder walls. I found out much later that they took it drag-racing and overheated it. Turns out it had a cracked head that I didn't know about, as it didn't ever overheat. It was a 66 Ford Galaxie with a 352. Doesn't sound so special, but in the early 80s, late-model cars were quite slow, and that car seemed like a hot-rod by comparison.

J. B.

 

[JBswth]

n

A worn out cam would cause a knock?
I would figure a bad cam would result in a no start condition. Is that not the case?

Is this even a knock I’m hearing?

A bad cam would, at worse, result in affected cylinders seemingly misfiring, especially at speeds above idle speed, and maybe noisy lifters, but not knocks.

J. B.

 

[Disco]

@JBswth, it was the inspection cover, apparently. They pulled the cover to check inside the bell housing area, found nothing of concern, put the cover back, started the engine to use a stethoscope to track the sound, and the sound was gone.
The only thing we can think is the cover was put on in just the wrong way that something inside the bell housing, something spinning at crank speed, was tapping it. I have had the engine running several times now, and the noise has not returned.