Help. 3.4 V6 noise

shark2000 · 07-20-2021, 02:35 AM

Okay, after replacing the cracked head, suddenly, it is knocking. It would go away
After it warms up, but it took a long time to go away. My neighbor, whom does not talk to me since my wife complained about his dogs keeping her up at night, doesn't talk to me anymore. Before that happened, he suggested it was the connecting rod bearings. Suggested just replacing them with a standard size and it should be good to go. Finally, I get around to doing it and as I am working on it, I notice cylinder 1 piston seems to be making a noise. So, now I'm wondering if it is the wrist pin? Hopefully I can link the short video. It's hard to tell where the sound is coming from in the video, but it sounds to me, like it's the piston slapping against the cylinder wall or something. I'm not sure.

https://youtube.com/shorts/-xbEs3kU9u4?feature=share

Thank you for your input in advance.

Blue Bowtie · 07-20-2021, 06:54 PM

The rod centered in your video seems to have a LOT of excess play.

shark2000 · 07-21-2021, 12:39 AM

I just put new Connecting Rod bearings on. There is no play on the lower end. From what I see and hear, it sounds like and looks like the first piston. The others sound different. It it's the wrist pin, I don't want to have to pull everything off again. I should just do it now. It's just strange that it was knocking after changing a head. Didn't even have to take the bottoms end apart for that. I guess I will have to take the head off again. So irritating.

shark2000 · 07-21-2021, 03:17 AM

Come to think of it, that was the cylinder where the head had the crack.

xeroinfinity · 11-05-2021, 06:50 PM

yeah you've got some play down there thats for sure. If its sloppy enough Im sure that it extends past the top of the block thus hitting the head(s). It looks like its run low on oil one to many times or the oil pump is failing.

shark2000 · 11-05-2021, 08:41 PM

It would start to over heat when I got on it. But did fine if I didn't hot rod it. Originally, it was a lower I take manifold leak. It leaked coolant into the oil. I replaced it and check clearances on everything. Everything checked out good. So I put it all together. Come to find out, it had a crack in one head, between the valves. I changed out that head and when I started it, it had a knocking sound. Figured the I just needed the hydraulic lifters to pump up. It got a little quieter, but still sounded like one thing still making noise. Finally after the engine heated up to normal operating temperature, it final got quiet. I shut it off. Next time I start it, it's noisy again. It takes a while to get quiet again. Eventually it does. I wasn't sure if somehow the rod bearings went bad, so I changed them, plastigage shows clearance is fine. That's when I notice this clunking noise, just by turn the engine by hand, when the #1 piston is at top dead center.

xeroinfinity · 11-05-2021, 09:51 PM

Sorry i brought this up now, I just noticed it was posted a few months ago.

Yeah, coolant in the oil does a number on an engine. They usually overheat easy when low on coolant or oil. But its hard to say if the engine overheated, or the piston hit and cracked the head causing this mess.

So have you fixed this engine, or get a used one??

shark2000 · 11-05-2021, 11:53 PM

At least you replied. I've paused all work on this car, because I'm not sure what to do right now. If it's piston slap, I guess I just put it back together and run it the way it is. I was just concerned when I was torquing the Rod bearing caps and heard this noise. That's when I thought it could be something more serious than just changing out those bearings.

xeroinfinity · 11-06-2021, 03:44 AM

well that movement is pretty serious IMO. Are you able to turn the engine over by hand?
If so check the top of the block and see if the pistons extend above the block.

If it does, it's gonna need some parts, maybe everything in the bottom end?
I'd pull a cap off a couple rods and see how the bearings look. Might pull a crank cap and check the bearings by that piston you show in the video.

But personally i would not run it that way, or spend to much money on it, with out investigating further

shark2000 · 11-07-2021, 04:28 PM

Everything checked out good, when I replaced the head. It didn't make this noise until I changed the head. It was quiet when I shut the engine off, to change the head and gaskets. Thinking the noise was rod bearings, I just changed those, and noticed this noise while turning the crankshaft by hand, to change the bearings, and use plastigage, to verify it's within proper specifications. Which it is. That's just when I noticed this, in the video.

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