Two 1998 Civics - inexpensive improvements?

[MamaBear2015]

Originally Posted by MobilOne

You mentioned a grinding noise when you accelerate the sub-optimal Honda. Could it be a very mild spark knock? Cavitation in the torque converter? Dry axle cv joint? I'm trying to think of what could cause a grinding type sound when accelerating.

Sounds like it's inside the cylinders while firing, but not a ping like I've heard in the distant past with other cars.

Transmission slipping?

Between 2nd and 3rd gears, especially when going up hills and accelerating - the harder the acceleration, the more it happens. It's independent of the grinding.

Does the tach bump up when you hear the grinding?

No.

Do you drive with one foot touching the brake?

Nope, never have.

Does anything else occur when the grinding sound happens?

No.

When one accelerates, the engine torques backward (top of engine tries to move toward the firewall). Could this action be causing something to rub, such as a pulley?

No, this sounds internal, in the firing cylinders.

It might be worthwhile to check the engine mounts. Perhaps one was left loose when the camshaft belt was changed? You can tell; the grinding noise bothers me. Especially since no one else has addressed it.

I wonder if the timing is actually retarded? Could it do that?

Well, I've ordered a timing light ( couldn't find my old one ) and it should be here in a week.

[MamaBear2015]

[QUOTE=California98Civic;477735]The sixth gen distributors also have an electronic igniter build into them... their not entirely traditional.
/QUOTE]

Yeah, we used to call that an "electronic ignition", where it was electronics that generated the higher voltage spark with a square wave, instead of just the old coil and points. Apparently the 98 Civic is one of these cars, not yet to the individual coils for each cylinder, that got rid of the distributor cap & rotor, though.

[MamaBear2015]

This may be something: I THINK you're supposed to check transmission oil when the engine is hot, and on level ground, but... the cars are in the driveway, slanted backwards downhill. But even so, the regular oil stick is fairly accurate that way.

Ok, so they're both cold now too. But I just checked the transmission oil sticks and the Teal car ( one without the slipping problem ) is all the way up at the top dot. But the Silver car ( one with the slipping ) is only 2/3 the way up between the dots. I should check it hot, on level ground, at a gas station, now. But it may need fluid. Someone was saying that the transmissions on these 98 Civics are a small compartment, so if I go uphill, it COULD push the oil to the back and cause a problem, unless the thing is full?

[MobilOne]

Yes, you want to check it on level ground.
Retarded spark would not cause spark knock. Too advanced spark could cause spark knock (i.e. the mixture in the cylinder is being ignited too early in the piston's travel and fully explodes before the piston is at top dead center. That's one cause of spark knock.

A second cause of spark knock is having spark plugs that have a heat range that is hotter than the engine needs. How this works is that the spark plug sticks a little farther down into the cylinder and thus absorbs more heat from the combustion gasses. They were used in cars, years ago, when a car suffered from fouled plugs caused by incomplete combustion.

A little more insight is needed here. Does the noise (I'm going to pursue spark knock here) happen when the engine is cold? That is, when you first start off and accelerate hard, do you hear the noise? If not, that suggests that the timing is OK (most likely), and that the Knock (pinging) is caused by a hot spot inside the engine. Such as a red hot carbon deposit on the cylinder head, piston, spark plug, or exhaust valve. More later after another coffee. lol

[MobilOne]

Hi again,
Let's try to identify more characteristics of this noise. I have been guessing that the noise is generated when the engine is under load, but I don't know that. So, lets find out. What we are going to do is to run the engine up in rpm to say 3000 or 3500 or so. We are going to do this while parked with the hood open and and brakes applied (Parking and stopping brakes, both); and with the transmission in drive. Do you hear the noise? Do this test with both a cold engine and with a fully warmed engine. If the sound is generated by the stone cold engine (having sat overnight), chances are that if it is a spark knock, it is because of too advanced ignition timing, because the engine hasn't had time to develop any hot spots from carbon deposits or too high a heat range plugs.



Also, try to describe the noise using some other adjectives, if appropriate. Spark knock is usually heard as a pinging, or mild rattle rather than a hard knock.

[MobilOne]

It would help if you had a helper to do the brake/accelerator work while you were outside, beside (not in front of) the car to better hear the sound.

Now if the sound is not generated with the car parked, and only with the car moving, that tells us that the sound is being generated by the running gear.

More later.

[MamaBear2015]

Originally Posted by MobilOne

Yes, you want to check it on level ground.
Retarded spark would not cause spark knock. Too advanced spark could cause spark knock (i.e. the mixture in the cylinder is being ignited too early in the piston's travel and fully explodes before the piston is at top dead center. That's one cause of spark knock.

A second cause of spark knock is having spark plugs that have a heat range that is hotter than the engine needs. How this works is that the spark plug sticks a little farther down into the cylinder and thus absorbs more heat from the combustion gasses. They were used in cars, years ago, when a car suffered from fouled plugs caused by incomplete combustion.

A little more insight is needed here. Does the noise (I'm going to pursue spark knock here) happen when the engine is cold? That is, when you first start off and accelerate hard, do you hear the noise? If not, that suggests that the timing is OK (most likely), and that the Knock (pinging) is caused by a hot spot inside the engine. Such as a red hot carbon deposit on the cylinder head, piston, spark plug, or exhaust valve. More later after another coffee. lol

I'm not sure about that. I did just run a can of BG44K through a tank of gas. Hard to say if that helped.

[MamaBear2015]

Originally Posted by MobilOne

Hi again,
Let's try to identify more characteristics of this noise. I have been guessing that the noise is generated when the engine is under load, but I don't know that. So, lets find out. What we are going to do is to run the engine up in rpm to say 3000 or 3500 or so. We are going to do this while parked with the hood open and and brakes applied (Parking and stopping brakes, both); and with the transmission in drive. Do you hear the noise? Do this test with both a cold engine and with a fully warmed engine. If the sound is generated by the stone cold engine (having sat overnight), chances are that if it is a spark knock, it is because of too advanced ignition timing, because the engine hasn't had time to develop any hot spots from carbon deposits or too high a heat range plugs.

Also, try to describe the noise using some other adjectives, if appropriate. Spark knock is usually heard as a pinging, or mild rattle rather than a hard knock.

It's not like the ping I recall from years ago, but it happens when pushing down harder on the gas pedal, especially uphill. I dunno, maybe it's normal for Civics. We drove Corollas for many years before this.

[MobilOne]

I went back and read the whole thread again. You described the sound as sounding as if it was in the cylinders, and under a strong load. That sure sounds like spark knock. But, the Civic should have a spark knock sensor which retards the spark just enough to prevent spark knock.
So, if your civic has a spark knock sensor, it could be bad. That's worth checking.
Also, you might try a couple of tanks of premium gas and see if the knock goes away. Premium burns slower and that may be enough to make a difference. Good luck.

[MamaBear2015]

I should have the timing light by next weekend. Thanks!