It is deeper than it sounds in the video. I was going to pull it today but i would like some opinions before i do. Listen in the video how intermitent it is around 40 seconds. Could it be a lifter or a cam bearing? Maybe a wrist pin? I dont know.

But remember it is louder and deeper than the video makes it seem. Thanks in advance for all your help.

http://youtu.be/SebIKS_2FHk

 

Thats sounds pretty bad.

Its hard to diagnose when your'e not there. In your video at one point, the sound goes away..and comes back quickly. It could be the things you mentioned but here is what I would do.

First thing to do is rule out at least two other possiblites;

Loose/damaged flywheel. Look the area over real good including the torque converter.

Broken water pump shaft.

Maybe some others can help, with out a complete teardown...at this point.

 

I will not presume to be able to diagnose your sounds through the æther, but I agree, it sounds a lot like a rod knock.
Fortunately, you're pulling the motor anyway, and can get right to the "bottom" of it shortly after it's out.

Nice use of wire nuts.

... And isn't your fan belt a bit loose? You haven't been driving like that, have you?

Welcome to Classic Olds.

- Eric

 

Sounds like valve train to me.........What does the oil pressure do hot?

 

I can say that it did come after sitting for some time. And also it started as a squeak then turned into a knock type sound. I wonder if it is a fly wheel! It did make its first appearance after scraping the bottom of the car over a drive way inlet then burning out. at first i though it was the headers scraping on the frame or something because it was making such a high pitch squeak, but then it tuned into a knock.

 

id like to pull the motor if i dont have to.

LOL And the belt is loose because i had it all apart but i just threw a random belt on to charge the system a little while I was testing it.

 

I dont have an oil pressure guage hooked up right now. Do you think its a stuck lifter?

 

hard to tell . If you have a stuck lifter turn each cylinder to tdc and feel for slack in the pushrod when both valves are shut. Get a oil psi gauge that goes a long way.

 

79pont455: Man, I feel your pain!

I was at the Delaware Valley Oldsmobile Club Show in Downingtown, PA this past October, 2011. While driving to the show, my car started to make an out of this world, dreaded knocking noise.

The whole engine is toast. Sand found it's way into my block from the freshly sanded and painted valve covers.

Yeah, I know, It sucks big time!. I now have to have this beast rebuilt for the 2nd time! The whole motor is toast.

I hope that things are better with your engine!

 

Thanks Jaybird.

If i have to rebuild this thing it will be my second time as well..

 

If you hit the bottom of the oil pan, you could have bent it in enough to contact one crank throw, and it could make a noise like that. You could probably feel it from underneath, by pressing your hand against the pan with the engine running.

That's a recurring nightmare of mine.

- Eric

 

79pont455: I now know why many people replace their toasted Olds engines with Chebbys.

I really don't want to be one of those people.

Good luck with your rebuild!

 

While you're under there, feeling your pan, [sounds nasty!!] also feel the the cover for the torque converter, towards the front of the trans - more in line of the curb.

 

That's what I was thinking too.

 

WELP! I pulled the motor apart. How can you tell if you have a stuck lifter? All looks ok and none of the push rods seem to be bent. I think all of the valve springs look ok..

photo3.jpg

 

Wellllll... The engines' kinda got to be running to tell if a lifter is stuck.

A stuck lifter will not pump up with oil properly, usually because of a bit of crud stuck in it, and so will provide too much clearance at the rocker.

Since the heads are still on, you should be able to reattach the rockers and see if any of them has any slack at TDC, when both valves should be closed.

- Eric

 

Sounds like a spun rod bearing to me.

 

Well I pulled the motor. It almost looks like the piston was slapping on the head. I'm about the flip the motor over right now and see if the bearing is worn.. Gimme 20 min...
20120318_173351.jpg
20120318_173335.jpg

 

is there a step there on it . I think if it where hitting it would leave a pretty good indentation.

 

No not really.. Everything other than that looks good so far. If its just 1 bearing can i just change it? Or am i have to get a full bottom end rebuild?

 

you might as well spend the money and freshen it up atleast re grind the journals and add new bearings. since you already have it apart. That is assuming everything is in order.

 

Well poop. There sure is a problem, metal fragments in the oil pum pscreen. It may be a wrist pin, I will post that soon.

20120318_183032.jpg
20120318_183018.jpg

 

It looks like the bottom of the piston was hitting the crankshaft weight. Also is the wrist pin bearing supposed to be all to the side like this? The other ones dont look like that.
20120318_185211.jpg

20120318_185258.jpg

 

Also thats the same cylinder as the small marks on the head from the first pic.

 

What do the rod bearings look like on that cylinder?

- Eric

 

Here is a video of the bearings. Are they supposed to be like this? Or is that a problem also?

http://youtu.be/M4yLIFcEwTo

 

They seem to be tight. Should i take them apart?

 

Its toast. I just took it apart and its mostly gone. What should i do? Is it possible to change just the bearing? I just rebuilt the motor about 15,000 miles ago.

 

Unfortunately, the motor has to come completely apart.

You have to clean through every passage, nook and cranny (yes, even the crannies) again, to remove any nasty metallic debris that might be waiting to provide a repeat performance. Then, you can put it back together with a new bearing, provided that the crank and rod surfaces are undamaged. The rod bearing in question may need to be reground, and the rod may need to be redone as well. Also, it would be good to find out what caused this, if possible, so that you can prevent it from happening again.

If all else is well, you MAY be able to get away with just a bearing, but you need to get more information before you can even guess.

- Eric

 

With that much stuff floating around in the motor i would do a simple bottom end rebuild and machine what is needed.

 

That sucks. I wonder what caused it. Probly because i let it sit 6 months or so before a fire up without priming it. I dont know.

Here is a pic of the bearing just for the heck of it.

20120318_192838.jpg

 

That seems to be a little extreme for just not priming it something failed. maybe isufficent oil to that rod journal. it's just this one ?

 

I think its just that one. But i havnt taken the rest apart yet.

 

You have a typical spun rod bearing. You will have to remove the crankshaft to have it reground and remove the suspect piston and rod assembly to have the rod resized. The usual cause of this is over revving for an extended time or a lack of oil pressure. The initial squeaking noise and subsequent knock is a dead give away of a spun rod bearing. The knock was the piston hitting the underside of the head due to the excess clearance of the rod bearing.

 

Thanks 67442HT. So Can i just bring that piston, rod and crankshaft to the machine shop and be ok after they do their work? or should i take the entire thing apart and do a complete bottom end rebuild?

And how long can you rev the motor high? I did race it on the freeway against a street bike at high speeds for a minute or so reving to 5500 for 20 seconds i would say one of the last time i drove it before the knock came.

 

You're NOT going to get away with a quicky on this one!!
You've seen the metal and bearing material throughout the shortblock - how did it get there?? Through the oil passages!!
As mentioned - ALL THE NOOKS AND CRANNYS ARE NOW CONTAMINATED!!!
Reground crank, rebuilt rod, new bearings, including camshaft, boiling the block and the rest of the rods, inspect the rings and pistons, a gasket set, and I'd clean out the lifters and oil pump, gasket set, and probably more I'm forgetting - IT AIN'T GONNA BE CHEAP, PAL!!
And that's to do it right!

 

When you rebuilt 15000 ago did you check bearing clearances. Should have about .001 clearance when torqued down.

 

You can't rev an olds motor with a stock setup to 5500 rpm.
That's the equivalent of twirling a 20 lb. sledgehammer like a parade baton.

They are heavy rotating assemblies, the clearances are too tight, and the oil passages are bottle necked in the back of the block. I shift at 4800 max with mine during drag passes.

 

Unfortunately it it's not stock Ive already had it rebuilt once and he did a lot to it, oil restrictors and some other stuff. But oh well. Here we go again.