Hey Yotatech,

I just bought an 81 2wd and towed it home. I knew it had a rough oil leak when I got it and it was coming from the copper oil pressure line. Now, after starting it up it has a bad knock coming from the side of the engine closer to the driver. I assume this engine was driven low on oil at some point just because of how bad the oil leak was. Any ideas on what caused the knocking? Valve-timing? Need new rings?

 

Welcome to YotaTech!

I am not sure what copper line you are referring to.

Does the engine have more of a ticking noise or a hard knocking noise?

If it is a hard knock coming form the bottom end of the engine, then you are probably looking at rebuilding or replacing the engine. I am not saying that you need a rebuilt engine but from your description, a rebuilt engine looks to be in your future.

You never want to throw a set of rings at an engine. The rings will more than likely not seat correctly if the block is not machined causing more problems. Also, the rest of the engine is probably worn out and needs to be rebuilt. For the engine to work properly, not burn oil, and be reliable, you will need a complete engine rebuild. Plus piston rings will not solve a knocking problem.

Check oil pressure, timing ,and if you want, do a compression check.

It definitely could have been driven low on oil if no one really cared to fill the oil regularly with the leak.

Also, post a picture of your truck!

Sorry for giving you the possible bad news.

Good luck!

 

Thanks for the response! It is a hard knock coming from the top of the engine, which makes me think it could be valve timing. But I am unsure.

I'll upload a pic of my truck when I snap a nice pic tomorrow!

 

Is it a knock or a loud tapping?

The valve train in these engines are usually noisier than other engines.

I cannot hear the engine myself, but it is worth seeing if the rocker arms are contacting the valve cover. This can happen if the valve cover is on too tight. You do not need much torque on those nuts to over-tighten them. This is probably not your problem but worth a shot.

 

Here is a link I uploaded of what the engine sounds like:
Any ideas?

Edit: I also fixed the oil leak last night, so I know it wasn't low oil pressure causing the knock. Although, to me the knock sounds a little different than before.

 

wrist pins knocking. maybe something in top end too. but major knock sounds like rod slapin around inside pistons.

 

Late to the party. Timing chain slapping timing cover due to broken chain guide? More of a clack than a knock to me; also a little too present near the surface to be really deep internal problem. IMO.

If it were me I'd pull the valve cover and see what I could see on the timing chain & guides. And check the valve train for broken parts & valve lash while I was at it. Hope you get it fixed.