3YM30 Yanmar + Balmar 95-60 Alternator

[rgleason]

Tach RPMs do not match Engine RPMs

1981 Bristol 32
2013 Yanmar 3YM30
1995 Balmar 95-60 Alternator Rebuilt 2013
2013 Balmar ARS-5-H

Balmar advises:
"This stator output provides the pulse required to drive most electric tachometers. Most current Balmar alternators feature 12-pole stator outputs (meaning 12 pulses of AC voltage during each alternator revolution). Extra-large case 98-Series and older 9-Series alternators feature 14-pole stator outputs. Most electrical tachometers feature some level of adjustment to calibrate the tachometer to your alternator’s pole settings and pulley ratios."

Our Mechanic advises:
After consulting with Yanmar about getting the Tach RPM to match the Engine RPM our mechanic advises the that closest he can get the rpm is by using a Pulse of 11.08, which results in the following:

Pulse at 11.08Eng RPM Tach RPM
3000 3300
2700 3000
2500 2250
1850 2000
1375 1500
870 950-1000

Pulse at 10.25
Eng RPM Tach RPM
2900 3500
2500 3000
2000 2500
1500 1800
870 1000

The mechanic advises that there is no way to get the RPM correct. Normally there has always been a way to choose the correct setting to get the Tach RPM's to match the Engine RPMs. Yanmar has changed their equipment.

At midpoint in the process, after being pesky about compatibility of my existing Balmar with both mechanic and Yanmar, I was advised by the mechanic:

"..in the past the tachometers come standard with an pulse adjustment built into them in order to accommodate several different types of alternators. I am not sure about the new panel yet but it has to have a way of adjusting it to fit other alternators You are certainly not the first person to want to put a Balmar on a new 3YM30 I m sure. We will figure it out."

Does anyone know how to get the Tach RPMs to match actual Engine RPMs? Has anyone else had a similar problem? Why has Yanmar changed their normal adjustments?

I have paid a significant amount for the engine, and for a C30 Panel and I would like to have the RPMs match the engine properly.

Thanks for your help.

[Horror Hotel]

Is the c30 panel the small stock panel supplied with the engine? I just installed a 3ym30 weeks ago and believe I had 4 or 5 pulse settings . I have the stock 80 amp alt and serp belt, now I wonder if I'm actually at the correct rpm. What tranny ratio and prop do you have?

[rgleason]

They offer two panels, the B20 is standard and the C30 is optional. The C30 adds gauges for oil pressure and temperature and is bigger.

Your so called "stock" Yanmar 80 amp will show the correct RPM, because they've made it work, and have screwed up use of other alternators!!!

[Horror Hotel]

I'm over propped, I know this. I bought 2 different used props because my old engine was left hand rotation. I didn't know know how much hull clearance I had and didn't want to haul and not have it fit. I got the 2.62:1 trans and put a 3 blade 15x16 on. I can only get to 3300 rpm which is pretty damn close to max. I'll have the prop changed to 14 pitch at some point. Just curious what trans/ prop combo are you running? Everyone I talk to has the 3gm30 rather than the ym, and I don't feel the comparison is equal. I was bummed when I noticed the harness wasn't tinned. I had to cut and solder to install.

[rgleason]

Yanmar 3YM 30 diesel engine with a KM2P 2.62 to 1 transmission
Last year we used the old prop which was 3 blade Federal RH 14" x 11"
The engine operated 200 rpm over required max rmp, so we need to add 1" of pitch.
Boat seems to be much slower and needs the additional pitch.

Do not understand why as we had a Westerbeke W21 with Hurth 2.1:1

The Bristol is 11,000 lbs. 22' on the waterline, and 9'-5" beam.


Any thoughts on my tach problem? Thats the reason I posted!

[pbiJim]

I'm a pretty big fan of having 2 charging circuits anyway. How about you use the stock alternator to charge the starting battery & run the tach, then have a second mount for your Balmar & use that one to feed the house bank?

Alternately, you could probably mount a pin wheel on the front of your alternator pulley, with 11 pins on it, & have a prox sensor see the pins, then send signals to your tach.

I don't know what signal type or strength your tach is looking for. If you can fill me in on those details, I can probably give you a more detailed version of option #2.

[rgleason]

I really like your first idea go mount the 80 amp Hitachi from ya near and charge the starter batt. I will check for space in front, We had to cut the mounts 3" and slide the engine forward 3" so there is less room in front now. Also can now fit my body over top of engine to work on shift under the cockpit. This is a huge benefit, I'd rather not loose due to 2nd alt. I suppose I'd need new double pulley for 3/8"?

I will pester both balmar and yanmar for more details for you. In looking over my correspondence I must note that Yama representative completely failed, the company has gotten too arrogant in my opinion, culture has changed. If I'd gotten the 3gm30 the balmar would work!! They do have a chance to redeem themselves now. Am I going to have post a card with the rpm translation on the bulkhead after spending about 16k on engine and controls and then another $250 to rebuild the Balmar + the cost of a new ARS-5, when reuse of the Balmar was on the table and in the request from the beginning? Mechanic did not know Yamar had changed its pulse filexibility between 3gm30 and 3ym30 (the replacement model), how would he know? Yanmar rep should have told him. At the very least the yanmar should should have responded to my very specific questions and email about this before the project went forward. Instead he ignored two emails about it and let the mechanic answer.
They've become balcanized. Betas advantage...

Thanks for your help! Could I put the Balmar in my 1988 Volvo w/O affecting rpm (alt is failing) then remount the cheaper Hitachi and attach the brand new ARS-5? Or would that be a poorer choice for charging my 2 AGMs (144 amps × 40% = 60 amps acceptance rate.)?
thanks
Rick

[Horror Hotel]

I was also thinking the aftermarket crank sensor route, but that wouldn't be cheap and I wouldn't think is was the best solution. Now running two alts is not a bad idea. I was interested in seeing what brackets yanmar had available I would like to add a alt and reefer compressor. I know beta has tons of bolt on options, I wanted to go beta but I also wanted it in days not weeks. I settled for yanmar because I got it 2 days after I paid for it. Going back to the stock alt and adding brackets for the balmar might be the easiest option. Do you need the extra power though? Never hurts.

[D.D.]

Did you contact Mack Boring in N.J.? No insult intended, but I did not see who helped you from Yanmar, other than the mechanic. I believe Mack Boring would be a good place to start for your solution. You can contact them directly, I have found them quite helpful.I feel your pain, Good Luck.

Mack Boring & Parts Company - Reliable Power. Everywhere.

[DotDun]

Originally Posted by rgleason

.........If I'd gotten the 3gm30 the balmar would work!! They do have a chance to redeem themselves now. Am I going to have post a card with the rpm translation on the bulkhead after spending about 16k on engine and controls and then another $250 to rebuild the Balmar + the cost of a new ARS-5, when reuse of the Balmar was on the table and in the request from the beginning? Mechanic did not know Yamar had changed its pulse filexibility between 3gm30 and 3ym30 (the replacement model), how would he know? Yanmar rep should have told him. At the very least the yanmar should should have responded to my very specific questions and email about this before the project went forward. Instead he ignored two emails about it and let the mechanic answer.

FWIW, the 3GM30 gets RPM from the flywheel, not the alternator.

[Horror Hotel]

I believe we are talking about a 3YM30, not a gm. These engines have many differences if I'm correct.

[colemj]

Check the pulley diameter for size differences between the stock alternator and the Balmar. If different, get a new pulley the same size or swap them. If the same size, then get a slightly different diameter pulley for the Balmar and try the tach adjustments again.

Mark

[DotDun]

Originally Posted by Horror Hotel

I believe we are talking about a 3YM30, not a gm. These engines have many differences if I'm correct.

No doubt, I only mentioned it as the OP did.....

[rgleason]

OP here. Engine is 3YM30. Gets RPM from Alternator not flywheel. If we had installed a 3GM30 we would not have a problem with the Balmar 95-65 Alternator (.. 9-Series alternators feature 14-pole stator outputs )

Have considered the pulleys and have determined they are identical between the old westerbeke and this new engine. Have not checked the new 80amp alt with internal regulator that came with the engine.

Pulley Sizes:
Original Westerbeke W21 Alt 2.75", Flywheel 4-5/8", H20 pump 3.5"
New Yanmar 3YM30 - Alt 2.75", Flywheel 4-5/8", H20 pump 3.5"
This is a ratio of 4.625"/2.5" = 1.68
Could reduce Alternator to 2.5" perhaps with a better set of pulleys and belt to eliminate dusting and slippage.

I don't think pulleys is the way to get this right, but I could be wrong about that. The pulley size is used to adjust the max charging vs cruise speed... It is the 14 pole stator that Yanmar 3YM30 is rejecting.

[colemj]

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

Mark