3YM30 Yanmar + Balmar 95-60 Alternator

[rgleason]

Excuse me, it is a 1995 Balmar 90-65 alternator. 65 amps derated, so it outputs more at lower rpm.

[colemj]

Originally Posted by rgleason

Excuse me, it is a 1995 Balmar 90-65 alternator. 65 amps derated, so it outputs more at lower rpm.

Yes, that is fine and a good operating choice for ruggedness, but it doesn't effect the tach in any way. The tach is dependent on rotor speed only and not alternator output at that speed.

You have a fixed number of pulses per revolution sent from the alternator poles. The speed of the alternator changes the frequency rate of those pulses. The tach is adjustable to calibrate the frequency at a known rpm with the pointer number.

The pulley ratio also determines the pulse frequency rate. If two 12-pole alternators have different tach readings, the pulley ratios are probably different. Either in diameter, or in how deep the belt sits in them (groove width). European/Japanese alternators often have metric pulley diameters and belt grooves. The slight differences between metric and imperial can cause tach differences.

The magnitude of your differences, however, are more likely different nominal size pulleys or different stator pole numbers between the two. Most likely it is the pulley size, which is why I stressed checking the OEM pulley with the Balmar pulley.

Usual OEM pulley sizes are ~2.7", while some Balmar pulleys are 2.2". The 2.2" pulleys are usually put on those alternators designed to be derated and put out more current at lower rpms.

Which is how you describe yours.

Mark

[rgleason]

..I didn't know you were comparing alternators and tachs on different engines...

I am not really, I just want to get the Yanmar 3YM30 showing the proper Engine RPM while using my Balmar 90-65 without much more trouble!

What pulley diameter was on the stock alternator that came with your current new engine? Does this match the Balmar pulley? If the same, I would think the rpm's would be the same because I think the Hitachi alternators are 12-pole like the Balmar. Also check that the belt depth is the same in the two pulley

Yes, I need to get the new 80 amp pulley diameter. The pulleys are for 3/8" belts for this Yanmar engine and both alts. I will try to check depth when I am back to the boat, but I don't think that is the issue for some reason. Its interesting that you think the Hitachi is 12 pole!!! I will try to verify good idea.

[rgleason]

I just read you last post. I get it now.
I think maybe the Mechanic is telling me that the pulse setting is some digital thing that is not continuously variable, so that it is impossible to set it properly if we do not have the exact same pulleys (perhaps?). I have to dig into this more with Yanmar, they are IMPOSSIBLE to get information out of them.... totally uncooperative.

[colemj]

Yes, the tach adjustment settings are not continuous - they have specific steps. However, they are usually stepped close enough to get pretty close accuracy. They go in 5% steps if they are VDO tachs, I think.

Mark

[D.D.]

Originally Posted by rgleason

I just read you last post. I get it now.
I think maybe the Mechanic is telling me that the pulse setting is some digital thing that is not continuously variable, so that it is impossible to set it properly if we do not have the exact same pulleys (perhaps?). I have to dig into this more with Yanmar, they are IMPOSSIBLE to get information out of them.... totally uncooperative.

Have you tried to call Mack Boring as I suggested earlier? Who are you dealing with for Yanmar info? It's my understanding they are THE ones to deal with re: Yanmar. Good luck with your search.

[rgleason]

I have called them and am working on several alternatives, including two different types of senders, one mechanical and one is electrical.
The Balmar 90-65 (correct now) has 14 stator pulse not 12 according to Elton from Balmar.
Yanmar Mack Boring, Mike, technician, says 3gm30 has a Tach Sensor in the bell housing that is geared to the flywheel. On the 3ym30 they eliminated that and use the alternator. Their Hitachi 80 amp is a 12 but sends pulses at 10.3. He told me not to ask why so I didn't. The pulse settings are done with a Allen wrench in back of the tach. Evidently only the dealers have access to the full manual!!! This is a protection racket for mechanics. No wonder the recommend them all the time. Seriously. More later on options.


Sent from my SCH-I545 using Cruisers Sailing Forum mobile app

[Horror Hotel]

I paid just paid $50 for the Ym manual , haven't even opened it yet. I hope not to need it for many years. I'm curious so I'll give it a look when I get back to the boat. The manual supplied with the engine is pretty basic. Maybe you already have the shop manual.

[D.D.]

Oh Boy......Sounds like the usual marine monoply. Makes you feel like you really do not own your boat, you rent it from the experts who have all the secrets. Hope this gets solved as you have invested quite a bit of time and money. Good Luck.

[DotDun]

One has to assume the OEM alternator sends 10.3 pulses per engine revolution not per alternator revolution (that can't happen).

I'm not sure I understand the negativity towards Yanmar. You buy a 'system' from them, tear it apart and substitute your own parts and then are angry when the 'system' doesn't work as you think it should?

[rgleason]

Dot Dun, you misrepresent what happened. I did not do anything. I hired a mechanic and wanted information about integrating my Balmar before we even started the project of replacing the engine. That information was never forthcoming as a consequence the Tach RPM is not correct almost one year later (beyond warrantee) therefore it now requires further attention and time by me to get to the bottom of it.

Since when did cruisers and boaters not install accessory equipment on their engines to suit their needs, particularly alternators!!! That is a very very common practice. Why shouldn't Yanmar provide the settings and ability to make these changes easily rather than clamping information and not providing the settings!?

To fix the problem I have been digging into the information available. The MackBoring sales rep was not helpful during the process prior to and during the engine installation, however I have found MachBoring techniical Mike to be very helpful, and he has sent me the information needed to install a Tach Sender along with the part number, along with information about the standard Hitachi 80 amp Alternator, and how the set the Pulse setting to 97 for the sender.

The 90-65 Balmar has 14 poles to provide better performance, however it will send 14 pulses, and there is no appropriate adjustment in the Yanmar panel for this, (the selections are not continuous or sequential as one might expect for a digital panel, but discrete numbers. I hope this will be changed for others, so a tach sender is not necessary.

Also I have managed to find a download location (not Yanmar) for the operation, install and parts for 3YM30. I did not know purchase of a manual was available, thanks for that information.

That will close my responses to this thread. Thank you all for your suggestions and help. My initial reservations and opinions about Yanmar remain, but have been modified by later improvements in communication, and I will reserve room for adjustment based upon outcome and continued interaction.

I'd like to thank Eldon at Balmar for his help and advice, and Mike at MackBoring for his advice about the Tach Sender and documentation.

Thanks again all.
Rick Gleason

[DotDun]

Obviously your mechanic sold you a 'system' based on his experience. Apparently his experience did not include the 'system' you wanted. It's obviously subjective whether to blame the mechanic or Yanmar.

IMHO, to expect Yanmar tachometers to support every variation of alternator and pulley size combination that anyone can put together is asking for too much.

Caveat Emptor!

[colemj]

Warranties on new engines are less than a year now?

Mark

[rgleason]

Obviously your mechanic sold you a 'system' based on his experience. Apparently his experience did not include the 'system' you wanted. It's obviously subjective whether to blame the mechanic or Yanmar.

IMHO, to expect Yanmar tachometers to support every variation of alternator and pulley size combination that anyone can put together is asking for too much.

Caveat Emptor!

...suppositions on your part. Please Read above. As OP I am not responding any further, leaving you the last word.

[Horror Hotel]

This is a forum for cruiser to discuss issues, you don't just get to pull the plug as you see fit, even if you are the OP. Do you not think that someone a week from now might have a better grasp on your problem? You don't know that's why you asked. Regardless if you want to participate, stating your done and won't be back is pretty lame. Maybe it wasn't your intention to sound so smug, tone is hard to judge online.