1G How do I fix a Rod knock?

[ANGELRAY]

I just got a 1990 Mitsubishi eclipse GSX and some people are saying I got a rod knock but if anyone knows how to fix it please let me know

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[CKOPOCT]

Unfortunately rod knock is only fixable by rebuilding the engine. Given the mods visible, your engine should be gone through very thoroughly. If the engine was properly built and driven and maintained well, you shouldn't have much of an issue. But if the PO beat on the car, didn't maintain it properly, or if the engine wasn't built to handle the power put through it, the rebuild might get much more expensive.

 

[danl]

Step one is the easiest. Don’t run the engine again until you rebuild it. You risk doing an insane amount more damage.

 

[curt-s]

^this

every time you hear that smack, that's the bearings into the crank journal at high speed.
Do not start that motor again unless you're ok with buying a new crank or sourcing a used one that hasn't been bludgeoned to death.

 

[danl]

Even worse if bearing material starts pumping metal through the engine. It ruins anything that oil touches. Crank, oil pump, cams, cylinder head, lifters, turbo. It’s all likely junk if it’s been ran like that for very long. Even the valve cover is junk.

 

[DSMPT]

Did you make sure it's rod knock? Rod knock sounds usually start occurring at low rpm after the oil temp gets hot and it would disappear by revving up the engine. And then getting worse and worse by time.
In the video, the knock sounds occur when you rev up the engine. This is actually opposite from the usual rod knock symptom. So if the sounds just start occurring, I would suspect balance shafts/its bearings or harmonic damper separation, hydraulic tensioner or so first.

 

[chrisman287]

That doesn’t sound like rod knock to me. Do you hear it more on the top end or bottom end of the motor? Sounds more like the top end.

 

[curt-s]

Now that I listen to it with proper speakers in proper volume, I'm not 100% convinced it's rod knock either. The clarity of the sound is making me think top end.
Pull the valve cover and see if you can push down any of the lifters.

 

[motomattx]

Thats rod knock folks.

 

[evil_eagletalon]

Sounds like our hyundai theta when they rod knock.

 

[curt-s]

Get somebody to rev it and listen from underneath near the pan. Could use a mechanics stethoscope to help narrow down the area.

 

[DrewmHolland]

100% Rod Knock, it's fixable but you better hope that your crank is in spec and the cam bearings aren't trashed. also if the bearing is spun you'll need a new set of rods

 

[Pjj]

if you dont want the work load of rebuilding the engine, let me know and ill buy the car off you, been looking for a white 90 gsx

 

[dwb]

Why not just drain the oil, cut open the filter and check for glitter? That way, if it is rod knock, you're not starting the engine again and further damaging it. If everything comes back clean, then at least you ruled that out and you can start checking HLAs, timing belt tensioner, etc.