Ruh roh Raggy! I hear you knocking…

[Disco]

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…

 

[Disco]

Yes, she has oil. It’s old oil, but it’s there and it’s full.

 

[fast 99]

When draining oil look for metal particles. If present, you know what's wrong.

If ok, pull valve covers inspect for loose or broken parts. If vacuum gauge is available hook it up should be steady. It is also possible a chunk of carbon got dislodged, usually will quiet down if that's the case.

 

[Shorty81]

Pull a valve cover, roll engine over and see if valves are moving up and down. See if your cam is wiped

 

[Disco]

Pull a valve cover, roll engine over and see if valves are moving up and down. See if your cam is wiped

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?

 

[Ricko1966]

A flat cam won't usually result in a no start. Trying to diagnose an engine noise from a video is a pretty tall order. Rods and mains are more of a solid sound,valve train is more rattle, clicking type noise,efe valve can make scary noises. If it's at a shop and your mechanic thinks it's a rod. I wouldn't be taking chances. Tow it home pull the pan and pull up and down on the rod caps, if you find a bad rod bearing now its a cheap fix,after it eggs out the rod big end and destroys the crank and or the block,not so much. People used bring blown up stuff in to the shop and we'd tell them it's x dollars to take it apart and put it back together, plus any parts or machine work. A common reply was it shouldn't need much it was running great before it blew up. Well it should have been rebuilt before it blew up,that's when it gets expensive.

 

[Disco]

Ok. Thanks, y’all. I’ll have it towed and see what’s what. Hopefully it’s not too expensive and it’s something I can do. A camshaft, for instance, is outside of my capability. I don’t have an engine hoist and cannot afford one.

 

[CountKrunk]

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

 

[Bextreme04]

Ugh. This hurts.

xc_hide_links_from_guests_guests_error_hide_media

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…

My thought is that if you just had a shop do a clutch... did they maybe install too long of a bolt in the flywheel and its whacking something? dust cover bolts? It sounds too fast to be a rod and I'd be suspicious of the latest work being the issue.

 

[Disco]

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

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…

 

[Disco]

My thought is that if you just had a shop do a clutch... did they maybe install too long of a bolt in the flywheel and its whacking something? dust cover bolts? It sounds too fast to be a rod and I'd be suspicious of the latest work being the issue.

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…

 

[Disco]

My thought is that if you just had a shop do a clutch... did they maybe install too long of a bolt in the flywheel and its whacking something? dust cover bolts? It sounds too fast to be a rod and I'd be suspicious of the latest work being the issue.

They replaced the clutch with the same type they pulled out (the odd “heavy duty” one with the coil springs around the outside and the three levers, rather than the typical diaphragm type). I would assume they measured the flywheel and ordered the correct replacement as well…

I’m having a really hard time believing this truck could sit in a pasture for 15+ years and then run just fine with no odd sounds, but randomly start knocking after sitting another year and a half on a paved driveway with no new stresses on the engine.

I can totally buy into the idea that something else is causing the sound. Something that has changed recently.

 

[legopnuematic]

I’m with Eric on this, to me it’s suspect that the clutch gets changed and noise begins. These trucks tend to use a lot of fasteners that are pretty close in length, say 3/8x1” and 3/8x1 1/4” and it can be easy to put one in the wrong place, or replace a bolt with a new one that is “close” in length, but may be just ever slightly too long to cause an issue, or missing a washer or something like that.

It may be worth to slither underneath with a flashlight and pop the inspection cover off the bellhousing and take a good visual inspection at the flywheel and clutch and see if anything looks out of place. If it is a fastener hitting something there should be some witness marks.

 

[Mango]

Very Nice Patina cant make that up

 

[Disco]

Very Nice Patina cant make that up

Thanks!