Rattling sound while accelerating?

[hambo]

I would go like this:

Drain the engine's oil into a clean container - and note the presence (or lack of) shiny metal particulates.

If any metal is observed, determine whether it is ferrous (iron/steel based) or non-ferrous. Do this by dragging a magnet through the oil. Only ferrous particulates will stick to a magnet.

If the magnet comes out of the oil covered in small pieces of steel, the engine has suffered severe damage.

If the magnet comes up clean (or with just a minor amount of fine dust), that would indicate that the metal in the oil is non-ferrous. It can then be safely assumed that the metal flakes are just pieces of bearing material - that have been wiped away from the shells. In that case, there is a strong possibility that the block has not been damaged and the engine can be rebuilt.

To investigate further, you might want to pull the oil filter and cut it open. Dump the contents of the filter into a clean container and inspect. Also look at the "dirty side" of the filter pleats - look for any large pieces of metal.

Okay. I'll do that. Is there any chance that if I see no metal whatsoever, I can just replace the oil pump and see if thats the cause of no pressure? Any chance that the engine would be okay to run if theres no metal in the oil?

 

[chengny]

Yeah, I suppose you could try to re-establish proper oil pressure, change the oil and filter and hope for the best.

But, I hope you got what I was trying to say - about the difference between wiped and spun bearings.

If you have damaged your bearings (and that is almost certainly the case), but they haven't yet spun - the engine can be rebuilt.

On the other hand, if the bearings have suffered severe loss of lining material (generally indicated by an engine knock) and the engine is continued to be operated, the bearings will eventually spin (and trust me, this will happen sooner than later).

At that point - without extensive shop work and parts replacement (e.g. line boring of the block, bearing cap modification, crankshaft replacement, etc.) the engine will be history.

 

[Skweegle89]

Just out of curiosity, how long/far did you run it with it making those noises?


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[hambo]

Yeah, I suppose you could try to re-establish proper oil pressure, change the oil and filter and hope for the best.

But, I hope you got what I was trying to say - about the difference between wiped and spun bearings.

If you have damaged your bearings (and that is almost certainly the case), but they haven't yet spun - the engine can be rebuilt.

On the other hand, if the bearings have suffered severe loss of lining material (generally indicated by an engine knock) and the engine is continued to be operated, the bearings will eventually spin (and trust me, this will happen sooner than later).

At that point - without extensive shop work and parts replacement (e.g. line boring of the block, bearing cap modification, crankshaft replacement, etc.) the engine will be history.

Yes I got what you were trying to say with the difference between spun and wiped bearings. Thank you for that explanation. Although since my knowledge is very limited I still dont exactly know what bearings you are talking about. The bearings on the crank? And I only heard the engine specifically knock once. The other times it was just that rattling during acceleration. And also, would I have to pull the whole engine for a rebuild? And how hard is a rebuild? I know its probably a ton of variables but Im just looking for a general idea and cost because I really dont have the money for a shop to do it. I would rather do it myself and learn, but Im just afraid of screwing something else up.

Just out of curiosity, how long/far did you run it with it making those noises?

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Well the engine knock I only heard one time and then I think it went away. But I drove it with the rattling for maybe 5 days. I dont know if the rattling/knock are the same thing or mean the same.

 

[hambo]

I still don't exactly know what bearings I need to replace. I think its the crank bearings? I was going to buy a rebuild kit off summit for $230 like this one: http://www.summitracing.com/parts/fem-205-6086m022/overview/year/1987/make/chevrolet/model/r20 and also an oil pump because mines probably bad. Should I do the full rebuild kit or just replace the bearings and gaskets?

 

[Skweegle89]

Honestly idk that I would order anything until you pulled that motor and found out what the problem was. You can try just dropping the pan and replacing the pump but that's just going to be a temporary fix at best.


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[GTME94]

I still don't exactly know what bearings I need to replace. I think its the crank bearings?

It will most likely be crank main bearings or connecting rod bearings. I agree that you should try to pull engine and see everything it needs. I bought my truck knowing it had a very bad lower end knock. We only ran it for less than a minute before shutting it off. It turned out one of my connecting rod bearings was bad and had ruined the journal on the crank. The piston had enough extra movement to contact the valves and head. If I had tried to run it more it would have caused more significant damage. It turns out my dad found another engine with a good crank and piston/rod we could use. As bad of news as this is for you, pulling the engine first will let you fix everything without any more significant damage and save you money in the long run.

 

[hambo]

It will most likely be crank main bearings or connecting rod bearings. I agree that you should try to pull engine and see everything it needs. I bought my truck knowing it had a very bad lower end knock. We only ran it for less than a minute before shutting it off. It turned out one of my connecting rod bearings was bad and had ruined the journal on the crank. The piston had enough extra movement to contact the valves and head. If I had tried to run it more it would have caused more significant damage. It turns out my dad found another engine with a good crank and piston/rod we could use. As bad of news as this is for you, pulling the engine first will let you fix everything without any more significant damage and save you money in the long run.

Okay. Thanks for the info. Thats what I figured but the only way to really know will be to tear it apart which I plan on doing. Im just a highschool kid who took auto class this semester where we stripped down a v6 and put it all back together so I have a little bit of idea what Im in for but not a lot. I was going to buy a manual off amazon called "How to rebuild Big-Block chevy engines." I was just wondering are all chevy 454's used throughout the decades in muscle cars, trucks, and so on pretty similar? Will the manual be specific enough to help me even though it covers all chevy big blocks? Thanks!

 

[GTME94]

Would the auto shop teacher take on your engine as a project for the class?

I glanced at the book on Amazon, looks like a good basic book about rebuilding an engine. There is a picture of a Square on the back cover.
I haven't seen the whole book but I'm guessing it should cover your engine well enough. It looks like an older book and that's good since there weren't many changes on the engine up through the square body years.

It would be good for you to read through to make sure you know what you're getting into and should look out for.

 

[hambo]

Would the auto shop teacher take on your engine as a project for the class?

I glanced at the book on Amazon, looks like a good basic book about rebuilding an engine. There is a picture of a Square on the back cover.
I haven't seen the whole book but I'm guessing it should cover your engine well enough. It looks like an older book and that's good since there weren't many changes on the engine up through the square body years.

It would be good for you to read through to make sure you know what you're getting into and should look out for.

No I wish he would, but he says he has to go through all the other units in our class, and wouldnt have time for me to bring it in and tear it down. Thanks for your opinion on the book. I think it will help too. Ill order that soon.

 

[hambo]

So I've been thinking, and I dont think I have the cash to do a full rebuild. I just want to basically tear apart the engine and check the bearings, replace them if need be, and replace any other parts that may have been damaged from the lack of oil. And Im guessing ill need to replace the oil pump as well. Would this be okay to do? Because I've been reading and people generally say while you have it torn apart to do a bunch of other stuff and machining like honing the cylinders, polishing the crank and cam, etc. I just dont think ill have the money to do that so would it be okay for me to just replace the damaged parts and then throw it back together without doing a full rebuild?