Engine knock

[chicklin]

Didn't you say in another thread that you broke a mounting "ear" on the generator when you changed the belt. There's a good chance this is somehow related.

Brett

Yep. That was just from tightening down the retaining bolt too tight. That, in itself, shouldn't be a problem, but I did pull the generator back pretty good to tighten the belt, so maybe the tension is greater than before. I'm going to try loosening the belt to see if the noise goes away.

[chicklin]

Get yourself a mechanics stethescope and start listening for the location of the noise.

Good idea.

[chicklin]

Didn't you say in another thread that you broke a mounting "ear" on the generator when you changed the belt. There's a good chance this is somehow related.

Brett

Yep. That was just from tightening down the retaining bolt too tight. That, in itself, shouldn't be a problem, but I did pull the generator back pretty good to tighten the belt, so maybe the tension is greater than before. I'm going to try loosening the belt to see if the noise goes away.

Well, that wasn'it. Loosened everything up front, no change. I tried to listen closely to each engine accessory (water pump, distributor, fuel pump, oil pump, generator) and I'm pretty convinced it's coming from inside the engine itself. I'll check the compression tomorrow and see what the story there is.

[MSeriesRebuild]

Didn't you say in another thread that you broke a mounting "ear" on the generator when you changed the belt. There's a good chance this is somehow related.

Brett

Yep. That was just from tightening down the retaining bolt too tight. That, in itself, shouldn't be a problem, but I did pull the generator back pretty good to tighten the belt, so maybe the tension is greater than before. I'm going to try loosening the belt to see if the noise goes away.

Anytime things get worn & especially broken, that means the affected components are no longer held truly in line as they are designed to operate. Getting strange noises & actions as a result aren't unusual. You seem to just dismiss this as oh well I over torqued a bolt & broke this. Don't dismiss the fact that this bolt has a purpose & now a repair needs to be made. It may not be the source of the noise you are trying to locate, but it's still an issue that now needs attention.

I think I see your theory coming clear in all this & you may disagree, but at least take a minute & give it some thought. We all like to hope when issues like this come up that it could be just a little simple something. It's certainly smart to inspect & be sure before looking on at more major issues. We look for the minor stuff first also when issues like this come into our shop. This appears to be where you are in this, you are starting to sound like you are trying to fast forward to the earth's end rather than realize this may lead to some major internal issue that must be addressed in order to save your engine. You say you are a do it yourself guy, no problem with that either. I made an earlier suggestion that you seek a professional in diagnosing this issue. This doesn't mean you have to spend big bucks with a pro. It simply means you ask for experienced help in locating what your issue is, pay the guy for an hour of his time, then go home & repair or rebuild it yourself if you desire.

I'm anxious to hear the outcome of the compression test, I suspect there will be some tell tail signs from that result.

[chicklin]

Didn't you say in another thread that you broke a mounting "ear" on the generator when you changed the belt. There's a good chance this is somehow related.

Brett

Yep. That was just from tightening down the retaining bolt too tight. That, in itself, shouldn't be a problem, but I did pull the generator back pretty good to tighten the belt, so maybe the tension is greater than before. I'm going to try loosening the belt to see if the noise goes away.

Anytime things get worn & especially broken, that means the affected components are no longer held truly in line as they are designed to operate. Getting strange noises & actions as a result aren't unusual. You seem to just dismiss this as oh well I over torqued a bolt & broke this. Don't dismiss the fact that this bolt has a purpose & now a repair needs to be made. It may not be the source of the noise you are trying to locate, but it's still an issue that now needs attention.

Of course it needs repaired, the generator won't work without it. I was only dismissing it as it pertains to the topic of this thread, i.e. the strange noise coming from the motor.

I think I see your theory coming clear in all this & you may disagree, but at least take a minute & give it some thought. We all like to hope when issues like this come up that it could be just a little simple something. It's certainly smart to inspect & be sure before looking on at more major issues. We look for the minor stuff first also when issues like this come into our shop. This appears to be where you are in this, you are starting to sound like you are trying to fast forward to the earth's end rather than realize this may lead to some major internal issue that must be addressed in order to save your engine.

Not sure what you mean there. I most definitely realize this could lead to some serious internal issues. I'm just trying to rule out something stupid before I go down that road.

You say you are a do it yourself guy, no problem with that either. I made an earlier suggestion that you seek a professional in diagnosing this issue. This doesn't mean you have to spend big bucks with a pro. It simply means you ask for experienced help in locating what your issue is, pay the guy for an hour of his time, then go home & repair or rebuild it yourself if you desire.

I'm anxious to hear the outcome of the compression test, I suspect there will be some tell tail signs from that result.

Yep, me too. I need to get my dad over to help me do this real quick.

[chicklin]

Okay, here we go. Compression, back to front:

96
100
100
90
98
100

Not going to win any races, but doesn't look too out of the ordinary. Also, I discovered a couple things about this mysterious noise. First, it does have a regular pattern. Sometimes, it's pretty faint, so it was hard to tell at first, but it's definitely consistent: tap...tap..............tap...tap.............tap...tap, you get the idea. The second thing we noticed is that it doesn't seem to change with the speed of the engine. Very odd, but makes me feel a lot better about the internals of the motor.

Now, I'm kind of leaning towards something maybe rattling around in the intake or exhaust. We stuck the old metal listening rod in a bunch of places above and below the motor and cannot seem to find anywhere the noise registers as a vibration.

So, still stumped, but I'm feeling a bit more optimistic. Again, the noise sounds like if you took a bolt and lightly tapped it on the engine block. Another thing I noticed is that in the pairs of taps indicated above, the second tap always seems to be louder. Like tap...TAP............tap...TAP.

[Lifer]

Well, if it doesn't vary in intensity or frequency as the RPM increases and decreases, I'e have to agree that it doesn't seem to be an internal problem. A "flopping" heat riser valve in the exhaust would be easy to isolate, so I'll count that out. Without being able to see it and hear it for myself, I'm stumped. The only thing I can think of at this point would be a broken motor mount or a loose mounting bracket for some accessory or another.

[chicklin]

A "flopping" heat riser valve in the exhaust would be easy to isolate, so I'll count that out.

My dad thought of that, too. Where is the heat riser on these in a stock setup? I've seen those as part of the manifold and inline in the exhaust pipes, as well.

As far as accessories, I think I ruled out the generator, fuel pump, water pump, distributor and oil pump. It sounds like it's coming from the middle to back area of the motor, moreso on the passenger's side. That would be consistent with some sort of intake/exhaust rattle.

[MSeriesRebuild]

Okay, here we go. Compression, back to front:

96
100
100
90
98
100

Not going to win any races, but doesn't look too out of the ordinary. Also, I discovered a couple things about this mysterious noise. First, it does have a regular pattern. Sometimes, it's pretty faint, so it was hard to tell at first, but it's definitely consistent: tap...tap..............tap...tap.............tap...tap, you get the idea. The second thing we noticed is that it doesn't seem to change with the speed of the engine. Very odd, but makes me feel a lot better about the internals of the motor.

Now, I'm kind of leaning towards something maybe rattling around in the intake or exhaust. We stuck the old metal listening rod in a bunch of places above and below the motor and cannot seem to find anywhere the noise registers as a vibration.

So, still stumped, but I'm feeling a bit more optimistic. Again, the noise sounds like if you took a bolt and lightly tapped it on the engine block. Another thing I noticed is that in the pairs of taps indicated above, the second tap always seems to be louder. Like tap...TAP............tap...TAP.

Well, from your statement, you fell the readings are decent, WRONG. Here are the facts. First let me say there should be no more than a 5 lbs variation between cylinder readings, you are way out of that range. A decent reading would be way above 100PSI, 115 or above has some significant life left. 100 is borderline, maybe run fair - maybe not, you are not in the good column there since you highest was 100. 90 is not at all good & in many cases an engine with low readings like that will be intermittently skipping on 1 or more cylinders with the 90 readout. Top notch readings would be in the 120-125 PSI or above range, so you can see where yours stands.

I know this isn't what you want to hear, but you need to do a major overhaul. Don't expect any decent service or performance out of this engine in its present condition, it won't happen. The noise you are puzzled over is absolutely the least of your problems. You are aware it is there, be on the look out as you disassemble, you will stumble upon whatever the issue is along the way most likely. I really see no need in you or us here trying to figure the noise out in a long distance fashion. Good luck. A NOTHING LEFT UNTURNED rebuild & balanced engine will run in the range of $3,000 - $3,500 if you do the work yourself, don't get jipped with a half done job.

[chicklin]

Well, from your statement, you fell the readings are decent, WRONG. Here are the facts. First let me say there should be no more than a 5 lbs variation between cylinder readings, you are way out of that range. A decent reading would be way above 100PSI, 115 or above has some significant life left. 100 is borderline, maybe run fair - maybe not, you are not in the good column there since you highest was 100. 90 is not at all good & in many cases an engine with low readings like that will be intermittently skipping on 1 or more cylinders with the 90 readout. Top notch readings would be in the 120-125 PSI or above range, so you can see where yours stands.

I know this isn't what you want to hear, but you need to do a major overhaul. Don't expect any decent service or performance out of this engine in its present condition, it won't happen. The noise you are puzzled over is absolutely the least of your problems. You are aware it is there, be on the look out as you disassemble, you will stumble upon whatever the issue is along the way most likely. I really see no need in you or us here trying to figure the noise out in a long distance fashion. Good luck. A NOTHING LEFT UNTURNED rebuild & balanced engine will run in the range of $3,000 - $3,500 if you do the work yourself, don't get jipped with a half done job.

Well, if that's the case, I'm just going to run it and enjoy whatever I get out of it. It would be cheaper to buy another 230 (or several) and drop in than having this one rebuilt.

I think it all depends on what you want out of your truck. For this particular project, I'm not looking for a perfect restoration, just a good farm truck (with shiny green paint and stars). There are a lot of other things I'd rather spend my money on than a 50year-old 230 ci motor in what amounts to a toy.

Thanks for the compression info.

[Lifer]

[Well, if that's the case, I'm just going to run it and enjoy whatever I get out of it. It would be cheaper to buy another 230 (or several) and drop in than having this one rebuilt.

You'd be extremely lucky to find even one good stock 230 cheaply. Buying several would cost you a big chunk of change and they'd still be questionable.

I think it all depends on what you want out of your truck.

You're absolutely correct on that point.

There are a lot of other things I'd rather spend my money on than a 50year-old 230 ci motor in what amounts to a toy.

I'm really sorry you feel that way. Still, it is your truck, and you can do with it as you like...or you can sell it to someone who is willing to do what you are not.

[chicklin]

[Well, if that's the case, I'm just going to run it and enjoy whatever I get out of it. It would be cheaper to buy another 230 (or several) and drop in than having this one rebuilt.

You'd be extremely lucky to find even one good stock 230 cheaply. Buying several would cost you a big chunk of change and they'd still be questionable.

I think it all depends on what you want out of your truck.

You're absolutely correct on that point.

There are a lot of other things I'd rather spend my money on than a 50year-old 230 ci motor in what amounts to a toy.

I'm really sorry you feel that way. Still, it is your truck, and you can do with it as you like...or you can sell it to someone who is willing to do what you are not.

I get what you're saying and I'm usually pretty stingy about keeping things stock, but how can I justify dumping $3000-$3500+time into a running truck that cost less than that to acquire in the first place? Would it be nice to have a stock, rebuilt 230? Sure. Would it be nice to have $3500+time available to make this happen? Sure, but I don't.

In the end, these trucks (for me) are just toys. I love MV's, I enjoy working on them, tracking down parts, finding out their history, but it's still just a hobby. If I was retired and/or hand plenty of spare cash laying around, maybe I'd shell out the thousands of dollars it requires to do it right, but that's just not what I'm looking for. If I ever get in that kind of bind with it, I'll just sell it. Hopefully, as you pointed out, to someone that does have the time/money to do it right.

Thanks for all the ideas and suggestions, I'll be sure to update this thread if I ever figure out what that darn noise is.

[MSeriesRebuild]

I wouldn't bother with it either unless I could do it right. Buying used engines is just not a good idea, 99 out of 100 will also need a rebuild, & many sellers also deal in the London Bridge or they just don't know what a good engine really is. No way would I buy one expecting to get a good runner unless I had accurate compression test results that showed positive.

[k8icu]

Run your truck and have fun with it. When it breaks find another motor to swap in and keep going. I understand your position this HOBBY (capitialized for emphisis and not yelling) takes two things, time and money and sometimes we don't have either so we have to make do with what we have when we have.

Have fun!