URGENT HELP! Knocking sound in engine

[John Orentas]

"we noticed the engine coolant water has gone from a nice shade of green, to a yucky shade of brown. We siphoned this off over the weekend but the brown has come back, and we think this may be oil getting into the water".

 

 

Hi Stoney.

 

Don't expect the coolant to stay a pretty green colour, it is simply picking up the bit of rust that forms in the engine.. Don't keep replacing it, all you are doing is giving the engine another dose of oxygen which will promote more rust.. Brown is good.

[Scotty]

Glad to hear that RCR gave good news.

 

And well done for taking in what he was saying, you'll be an expert soon

[BlueStringPudding]

Sorry to hijack here. I wonder if we will get your man. I am waiting on him being available to come out to us either today or tomorrow.

 

The chap who has come out to us in the past, when bits of the engine were trying to fly off was also great. Looks about 12 years old (the feller, not the engine... although it's not far off that age!), but he's a bloomin' genius and really helpful.

 

It turns out that the chap who does the services and engine inspections for RCR (and who came out to us on Saturday) trained him! And he was another patient, helpful feller.

 

I'm genuinely astounded at how helpful the peeps from RCR have been - not just doing their job (and doing it well) but keen to help out with other questions we've had, patiently talking us through what they're doing, what we can do to improve our engine and what we need to look out for. Brilliant, the lot of 'em!

 

P.S. You can probably tell by my use of words like "feller" and "chap" that I'm not very good with names.

[Radiomariner]

Glad you have things sorted out BSP.

When it comes to line up pullies, one of those laser beam spirit level gadgets with magnets (or blue tac) on can be extremely useful I imagine. Not expensive. I have not tried it, but I have such a device and would most certainly consider it.

 

 

Rgds

[John Orentas]

Hi Bluey.

 

Yes glad you have got things sorted, but what was the problem, unless I've missed something.

[bottle]

John

 

Did you read post #65

[Yoda]

It's not a good idea to leave belts hitting each other for too long as it can knock out the pulley bearings quickly.

[BlueStringPudding]

Finally, after several different mechanics-a-tinkering with the alternator/fan belt system, we are free of knocking sounds! Yay!

 

Our alternators were respaced a couple of days ago, and new fan belts put on. Problem solved. However I have noticed something else - which may or may not be related to this work being done:

 

The batteries, as far as we were aware, have always charged at a voltage of 14-point-something volts. Since the alternators were respaced they charge at 12.3V, then up to 14-point-something, then down to 12.3V again, and so on.

 

Is this normal or is something wrong? I've never noticed the charge voltage vary like this before (but perhaps I've simply never noticed it before...?)

 

I thought I'd ask you all, as I have the chap's pay cheque in my hand as I write this...

[chris w]

Finally, after several different mechanics-a-tinkering with the alternator/fan belt system, we are free of knocking sounds! Yay!

 

Our alternators were respaced a couple of days ago, and new fan belts put on. Problem solved. However I have noticed something else - which may or may not be related to this work being done:

 

The batteries, as far as we were aware, have always charged at a voltage of 14-point-something volts. Since the alternators were respaced they charge at 12.3V, then up to 14-point-something, then down to 12.3V again, and so on.

 

Is this normal or is something wrong? I've never noticed the charge voltage vary like this before (but perhaps I've simply never noticed it before...?)

 

I thought I'd ask you all, as I have the chap's pay cheque in my hand as I write this...

 

There is definitely something wrong here. One would expect the charging voltage to start out at around say 13.5v or thereabouts, with discharged batteries, and gradually rise up to the alternator regulator voltage of 14.2v or thereabouts.

 

This voltage will stay constant from there on in unless the alternator regulator gets very hot in which case the voltage would drop back to about 13.6v or so. I don't understand where the 12.3v is coming from, unless that's the voltage you are measuring with the engine OFF which would be about right for (50%) discharged batteries????

 

Chris

[BlueStringPudding]

There is definitely something wrong here. One would expect the charging voltage to start out at around say 13.5v or thereabouts, with discharged batteries, and gradually rise up to the alternator regulator voltage of 14.2v or thereabouts.

 

This voltage will stay constant from there on in unless the alternator regulator gets very hot in which case the voltage would drop back to about 13.6v or so. I don't understand where the 12.3v is coming from, unless that's the voltage you are measuring with the engine OFF which would be about right for (50%) discharged batteries????

 

Chris

 

No - 12.3v is defintely the charging voltage. The first time we turned the engine on after the alternators were respaced, it charged at 12.3v constantly.

 

The second time (yesterday) it charged at 14-point-something for a few minutes, then down to 12.3v, then when I checked on it sometime later, it was back up to 14-point-something.

 

Any ideas wassup, anyone?

Edited December 17, 2007 by BlueStringPudding

[RobinJ]

No - 12.3v is defintely the charging voltage. The first time we turned the engine on after the alternators were respaced, it charged at 12.3v constantly.

 

The second time (yesterday) it charged at 14-point-something for a few minutes, then down to 12.3v, then when I checked on it sometime later, it was back up to 14-point-something.

After a couple of long cruises I noticed that my alternator shuts down when the batteries are fully charged, so the voltage drops to about 12.5, no idea whether the alternator is ouputting anything. I put this down to the fact that the external controller was working and the alternator was waiting for the batteries to settle before going into float. Can't say that I understand an alternator cutting back in so quickly unless there is a fairly heavy load?

[BlueStringPudding]

But any idea if this could be related to the work recently done to the alternator system?

 

Or could it be anything to do with the cold weather? We've been iced in for a few days.

Edited December 17, 2007 by BlueStringPudding

[chris w]

After a couple of long cruises I noticed that my alternator shuts down when the batteries are fully charged, so the voltage drops to about 12.5, no idea whether the alternator is ouputting anything. I put this down to the fact that the external controller was working and the alternator was waiting for the batteries to settle before going into float. Can't say that I understand an alternator cutting back in so quickly unless there is a fairly heavy load?

 

Which controller do you have?? Your internal regulator must be disconnected for this to happen.

 

Chris

[bottle]

Hi Blue

 

Mention it when you pay the bill but in the mean time back to basics check all the connections, I doubt they are dirty but they may be loose.

 

Check the drive belt, if a new one then it may have stretched a little after initial set up.

[RobinJ]

Which controller do you have?? Your internal regulator must be disconnected for this to happen.

I don't think so Chris, its a new alternator with a very good internal controller, seems to detect the battery voltage, shuts down when it detects fully chrged battery voltage and waits until it drops again. Never fails to come back in?

[chris w]

I don't think so Chris, its a new alternator with a very good internal controller, seems to detect the battery voltage, shuts down when it detects fully chrged battery voltage and waits until it drops again. Never fails to come back in?

 

What model of alternator is it? I haven't ever seen one do this before?

 

Chris

[BlueStringPudding]

Erm... hello?

 

Can anyone advise why my charging voltage might be changing in this way, please?

 

Thanks.

 

[Keeping Up]

OK let's try and think logically. First some questions:

 

1. EXACTLY where were you measuring the voltage. Where was the positive meter probe applied (battery positive - if so which one, starter or domestic battery?), and where was the negative probe (battery negative , engine block, alternator body, hull, etc)?

 

2. You mention "Alternators" in the plural, and seem to imply that the same problem occurs on both of them. Is it one alternator for the starter battery and a separate one for the domestics? If so, which one is playing up, or is it both?

 

3. Do you have an ammeter? What is it doing at the time? Do you know which battery it is indicating?

 

4. Do you have an ignition warning light? Is it behaving normally (including, if you look at it at night, can you see a dim glow at any time?)

 

5. Do you have an external alternator conntroller? Split charge relay? Diode splitter? Any other unidentified little boxes? Or other secrets that you'd like to share with us?

 

Sorry to ask so many questions but without being there for a hands-on experience, it's the only way.

 

Allan

[Chris Pink]

Erm... hello?

 

Can anyone advise why my charging voltage might be changing in this way, please?

 

Thanks.

 

 

is the 12.3V the same as, or more than, the voltage when the engine is stopped?

[Sir Nibble]

OK let's try and think logically. First some questions:

 

1. EXACTLY where were you measuring the voltage. Where was the positive meter probe applied (battery positive - if so which one, starter or domestic battery?), and where was the negative probe (battery negative , engine block, alternator body, hull, etc)?

 

2. You mention "Alternators" in the plural, and seem to imply that the same problem occurs on both of them. Is it one alternator for the starter battery and a separate one for the domestics? If so, which one is playing up, or is it both?

 

3. Do you have an ammeter? What is it doing at the time? Do you know which battery it is indicating?

 

4. Do you have an ignition warning light? Is it behaving normally (including, if you look at it at night, can you see a dim glow at any time?)

 

5. Do you have an external alternator conntroller? Split charge relay? Diode splitter? Any other unidentified little boxes? Or other secrets that you'd like to share with us?

 

Sorry to ask so many questions but without being there for a hands-on experience, it's the only way.

 

Allan

Ahhhh! You speak in riddles monkey king.

[John Orentas]

I'm a bit confused too, this thread started off with a knocking engine and it has slowly metamorphosed into the usual forum charging problem.. Oh yes along the way it was somehow decided that the knocking was caused by two 'V' belts banging together, didn't believe a word of any of that either.

[bottle]

I'm a bit confused too, this thread started off with a knocking engine and it has slowly metamorphosed into the usual forum charging problem.. Oh yes along the way it was somehow decided that the knocking was caused by two 'V' belts banging together, didn't believe a word of any of that either.

 

See post #83, you may not believe it but re-spacing the alternator has stopped the banging. Must be coincidence.

[Sir Nibble]

'S gonna be a bugger now finding out what is REALLY wrong now the symptoms have gone away.

[chris w]

'S gonna be a bugger now finding out what is REALLY wrong now the symptoms have gone away.

 

[Malarky]

A virtual waterways community...?