Need Help Understanding Source of Engine Noise

[JohnGunn]

B engines are internally balanced not externally. That's why we can do all these engine swaps and use the 93 B3 crank pulley without worry of swapping a harmonic balancer like you do on externally balanced engines.

I'm running a 97 Aspire motor in my 93 Festiva and have no vibration issues. And I just recently swapped a 93 bottom end into an 89 and used all 97 Aspire pulleys to retrofit it to a serpentine belt setup. Again, no vibration issues.

Also, the pulleys and/or balancers are not specific to each individual engine. Even on engines that utilize an external harmonic balancer, they can be swapped as long as the balancer is correct for that engine. I.E. early model Ford small blocks were balanced at 28oz and later models (post 79ish) were balanced at 50oz. You can swap them between engines as long as it is the correct balance for the engine(s). A 28oz balancer can be swapped between engines produced between the mid 60's up to 78 and a 50oz balancer can be swapped between engines produced between 79-95.

Thanks, Zanzer. As usual, your comments have been extremely helpful. The knowledge that all Aspire balancers are the same is particularly useful to me. Just think of all the time I could have spent collecting Aspire pulleys while looking for the one that might correct the imbalance I hear in my engine.

I am somewhat surprised, with all the members here who have spent countless hours up to their elbows in the guts of these engines, that I have yet to hear anyone say they ever heard a noise like the one I am dealing with.

In all the research I have done, I found only one report of a noise at about the same rpm. I found it on a thread at the Rover P5 Club site. For those with first hand knowledge of engine internals, maybe reading that thread would give information that would help me. He was able to lower his idle speed to a point at which the noise was not evidenced and found higher viscosity oil to have had a beneficial effect. Well, anyway, the thread is found here.

Thanks, again, Zanzer.

[JohnGunn]

As a last-ditch before you scrap a running motor I would run a few quarts of oil thinned with solvent for 30 minutes or so idling and see what comes out. Repeat until clean.

Thanks for the suggestion, georgeb. Of course, I've heard of this being done, but never done it. What solvent would you think appropriate? Higher dosages of Seafoam, ATF, diesel fuel? Have you done this yourself and gotten positive results?

[georgeb]

I would use mineral spirits, maybe 50/50 or so. There will still be lubrication enough for idling. It has roller rockers so you don't half to worry about a wiped cam. I've never done it but would not hesitate if I suspected clogged passageways due to crappy maintenance. I've heard about stuff you add to the oil before you drain it which does the same thing. The way I suggested you'd be using new oil, just enough to be picked up by the pump and circulated. Hopefully any abrasives will be picked up by the filter. If anyone sees any red flags with this suggestion, do not hesitate to comment.

[walth]

Any updates to this John?

[htchbck]

I'm running a 97 Aspire motor in my 93 Festiva and have no vibration issues. And I just recently swapped a 93 bottom end into an 89 and used all 97 Aspire pulleys to retrofit it to a serpentine belt setup. Again, no vibration issues.

Kinda makes ya wonder where he comes up with all those alternator pulleys to do that, eh? BTW those crossmember bolts you sent make the whole rest of my car look like crap lol.

John, I think you need a louder stereo But really, I've heard all kinds of crazy sounds from various engines over the years, and if its not too bad and only at a certain RPM, I take the necessary precautions and checks and if things look ok, I just don't spend much time in that RPM range . Like my Miata. between 3000-3100RPMs the exhaust heat shield rattles horribly... so I either shift right at 3k or blast past it really quick. One of these days I'll get up under it to fix it, but till then, I just avoid what I know causes the sound.

[JohnGunn]

Any updates to this John?

Yes, there are updates to be made. And I believe important ones.

In the last several days a couple of other problems have catapulted themselves above worries about this engine noise. In a few minutes I'll leave for the public parking lot I use for my workshop to start an extensive process to clean out my transmission, so I'll have to give the updates later.

But, as a tease, I'll say I think I understand completely what is going on and the proximate cause of it, if not the ultimate one.

[JohnGunn]

I've heard all kinds of crazy sounds from various engines over the years, and if its not too bad and only at a certain RPM, I take the necessary precautions and checks and if things look ok, I just don't spend much time in that RPM range . Like my Miata. between 3000-3100RPMs the exhaust heat shield rattles horribly... so I either shift right at 3k or blast past it really quick. One of these days I'll get up under it to fix it, but till then, I just avoid what I know causes the sound.

Thanks for your take on my problem, htchbck. You're not the first person to tell me to, basically, learn to live with it.

I think I could do that a lot easier if it were something like a rattling heat shield that I was having to live with. But when the noise sounds like my engine crying out for help; that, I truly believe, is not possible for me. I'd sooner just stop driving the car and allow it to sit in my parking space gathering dust. My friend Sid keeps telling me my car is not a person. But I'm not so sure.

When I'm driving the car, my ears listen only for that noise. And each time they hear it, I almost wince.


And now for my take on your problem:

If the exhaust of your Miata is like a Festiva, there is a noise suppression baffle in the pipe between the catalytic converter and the muffler that will rattle in sync with the vibration of the engine when it breaks loose. Hit it with a rubber mallet to test.

How about this? Your noise for mine earns you $100.

[JohnGunn]

That sounds very dry to me, like you're not getting enough oil pressure.

Iceracer may be onto something.

That B3 is thirsty! No oil in that valve train!

...starved for oil...

I just read back over this whole thread. The above quoted contributors would be winners of some kind of prize, if some kind of prize were being offered for the most accurate analysis concerning the cause of my engine noise.

It is starved for oil, but not because of low oil pressure. But to understand that I'll need to tell more of the story. (Note: If you're in a hurry, there is a summary at the end of this message.)

When I bought my car I, of course, changed the oil right after I cleaned the engine. In 17 years of changing the oil in my Festiva I always poured in exactly 3.6 quarts and that always brought the level on the dip stick up to "F"ull. I did the same thing with my new Aspire and didn't bother to check it carefully.

It must have been a couple weeks before I noticed that the level was considerably above the "F"ull mark. What would you do in a case like this?

I hope you would not do what I did, because, without understanding what was happening, I drained the extra oil out and brought the level down to "F"ull. The amount removed was a little over half a quart. Only then did I begin to figure out what was wrong.

I figured the problem could be caused by either of the following:

1. An incorrectly installed dip stick tube.
2. When I poured 3.6 quarts of oil in the engine, it had not completely
   drained the old oil out.
   1. The engine was not level.
   2. Oil was pooling in the head and slow to drain down.

Had the problem been a misaligned or incorrect dip stick, it would have been a mistake to drain the oil. The engine wants 3.6 quarts regardless of what the dip stick might say.

I checked the level of the engine with a round, bubble level. The bubble centered perfectly.

I then started a long and tedious process of monitoring the time it took for the level in the sump to rise after shutting off the engine. First, I had to establish how high the level in the sump could rise. I let the car sit for two or three days and measured the level on the dip stick with a digital caliper. Then I would start the engine, run it a while, turn it off, and start measuring the level on the dip stick. The results of this study are recorded in this post. (To understand what follows you need to read it.)

Though I was wrong in one important aspect. My speculation about what will happen when drain holes are blocked was correct and that is in fact what my engine is demonstrating.

The part I got wrong was in assuming that when air is mixed with oil the oil pressure will drop and the engine will be starved for oil. It is true that the amount of oil delivered through the system will be reduced by the amount of space taken up by air, but it is incorrect to think that that air is not capable of showing pressure on an oil pressure gauge. When air is mixed with oil, a good oil pressure reading does not accurately reflect the amount of oil that is flowing through the engine. This is extremely important to know.

These matters began to fall into place the last time I changed oil in my Aspire. Instead of putting 3.6 quarts of oil in at once. I followed the advice of several members who said they put in less, say 3 quarts, and topped it up by adding more oil until it reached the full mark.

When I did that and started the engine with only 3 quarts added, the engine sounded like the proverbial bucket of bolts with a few nuts thrown in for good measure. Clearly there was very little oil reaching the valves. After waiting a while, the dip stick showed slightly less than 1/2 quart low. Wanting to leave room for the 8 ounces of Seafoam I planned to add later, I added 4 ounces of oil, but the valve racket did not noticeably improve. I thought if I drove the car around a little the situation might change. (Caution! This was a mistake.) It didn't. After that trip it sounded as awful as before, but the oil pressure gauge read 14 PSI, as high as it ever got while at idle, even when the valves were not being starved.

The next day I added 8 more ounces of oil and the clatter stopped. Before adding that cup of oil I assume the level in the sump had been hovering close to the level of the oil pump pickup tube opening. After the cup was added the pump was able to get enough oil to at least quiet the valve, but very likely still sucking air, depending on the rpm of the engine.

After adding 8 ounces of Seafoam, the level on the dip stick was well above the full mark on the dip stick, but the noise that started this thread was reduced.

Summary:

I didn't hear this noise when I bought the car. Of course, at that time the level on the dip stick was above full. When I decided to remove oil to bring it down to full, I caused the level in the sump to drop down to around the oil pump intake level which allowed air to be mixed with oil which led to the wear that started the noise.

The Seafoam seems to be helping the drain down times from the head, but it is still far from sufficient. Now that I allow the level to rise considerably above full, the sound is lessened and appears to be getting better slowly. My assumption is that the Seafoam is working and that as drain down times shorten less and less air is being mixed with the oil pushed out by the pump.

I still believe the engine is being oil deprived, and am thinking I might add a quart of ATF, in place of the Seafoam, at the next oil change to see if that will speed up the cleaning process. And if that doesn't bring quicker results, it may be time to take the valve cover off and see if there are any blockages I can see and affect with it off.

As always, your comments are welcomed and desired.