My 63 225 wagon has got 171K plus miles on it. Engine is tired. Was driving faster than normal down the freeway (70mph), and started hearing knocking noises. Slowed down, but the noises stayed. Got off the fwy and drove residential streets, but the noise was still there and increased in cadence. At idle and lower engine revolutions, my oil pressure light is on. When I increase throttle, I hear knock, that sounds top end. Car is starting to run warmer. What's probably happening?

Lost bearings or oil pressure (gear?)

Richard

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Part of Tyrde-Browne Racing

Clean up the bypass on the oil pump. See if that helps.

CJ

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Part of Tyrde-Browne Racing

if your getting a engine knock with low oil pressure and you want to save the engine, better pull the base pan and check the rod bearings.

#7 rod bearing

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slant six's RULE!
http://www.usajon.com

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Thanks guys. Wasn't going to take a chance on driving it more since retaining the original engine in this car is important to me. Parked the car, had it towed home, so now it's back where I can work on it. Now comes the fun of tearing into the engine to figure out what's knocking.

#7 rod bearing???

I will be dropping the pan, though once dropped, I'll have to figure out what I'm looking at/for, since I've not done this before.

You will find it is easier to pull the engine.

Richard

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Part of Tyrde-Browne Racing

If I have to pull the engine, I might as well rebuild it. Hoping i don't have to go there yet.

engine out is easier, you will know which rod it is by moving them on the crank, if you have a bearing bad enough to knock it will have lots of play back and forth on the crank.

As terrylittlejohn said, once the pan is off just shake the connecting rods, if you are able to move them at all then you've probably lost a bearing. Sometimes you can also see a dark discoloration.

But before you pull the pan... have you checked your oil level? Also, probably want to smell the oil, if it smells like gas its probably time to replace the fuel pump.

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'66 Dodge Dart

Have smelled gas recently - wondering where it was coming from. Did replace the fuel pump within the last year, with an NOS one that seems to be working fine, with no obvious leaks. But I understand that NOS can present some problem, especially for fuel pumps (dried out diaphragms, etc.) so I wasn't counting on it to last a long time. Haven't had time to pull the pan yet to check it out. Don't have a cherry picker so I can pull the engine: will probably look into getting one for this, since I want to do it all myself, or as much as possible.

Dude. It's got 171,000 miles on it. It's at least due, quite possibly overdue.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan, you're correct of course. That still doesn't stop me from hoping I don't have to do it yet

So to update: the car has sat untouched for the last month . But too much time has gone by, so I now need to get this done, or at least start.

I will clean up the bypass on the oil pump as soon as I get my hands on some crocus cloth: apparently, not a very commonly sourced item at any of the hardware chain and independent stores I go to, plus I'm not so familiar with machinist supply houses in the area, so I'll have to figure out where to get some.

My engine does have a lot of mileage on it, but it wasn't exhibiting unusual signs before this last trip. With rod knock, are there any usual precursor indicators? Is it always: the engine is fine, and then it starts knocking?

The more I read about oil pump gear failure, I wonder... Again, I'm recounting what happened while driving on the freeway, replaying in my head to try and make sense of what the real issue might be.

As soon as I started hearing a whirring noise, it grew louder into more of a buzzing sound. Then, after not much time, it became a louder knocking sound and that was when I exited the freeway. The moment the engine slowed down in RPM, the oil light lit. So here's what I'm thinking:

If the oil pump gear stripped at high-speed, it might make that buzzing noise because of the sheared or split teeth on the helical gear, correct? Wouldn't a stripped oil pump gear at high speed cause a sudden loss in oil pressure, and a rapid (as in, about a minute) decline in lubrication of all moving parts? Since I was driving at 70 mph on the freeway, and the engine was especially warm and turning at high RPMs, if I lost oil pressure within about 30-60 seconds, wouldn't that lead to an immediate and significant increase in metal-on-metal friction, and a significant knocking sound?

Once I got the car off the street, I shut it off. It sat for the next 4-6 hours and cooled down. When I came back, I started it up, and it "mostly" sounded normal, though I didn't rev the engine or put any load on it. Winched it onto the flatbed, transported it home, got it off the flatbed, and was able to drive it to it's normal parking spot (again, no load other than idle). Engine was cold, sounded fairly normal, no knock.

Any additional thoughts before I dive in? I would pull the engine to take off the pan, but I've not done that before, so that's a bridge I'll cross only when I definitely have to. What about changing out the oil pump? Am I going to have to remove the passenger side motor mount and distrib and lift the engine up so as to be able to remove it?