M35B Hisssss

[Sailing Amok]

As mentioned in my recent thread regarding our alternator failure, Coral Wave's engine started producing an intermittent hissing sound about two seasons ago. When our alternator recently failed, I attributed the hissing to an early warning of that issue, however, the alternator has been replaced, and the hissing remains. It's really hard to say whether it sounds more like an air/fluid hiss, or a bearing hiss. My buddy who has spent his life on tractors gave it a listen, and thought it seemed to be coming from the area of the raw water pump (Sherwood) but he wasn't really sure. He also wondered if it could be the alternator cycling, as it is intermittent, almost like somethings switching off and on. I don't think it's the thermostat, as it happens within a minute or two of startup, while the engine is still cold. It does seem to happen less frequently as the engine warms up, but does still occur at operating temperature, and at all engine speeds. Anyway, I shot a little video, it may be a bit hard to pick out the change in sound but it happens around the 5 second mark in this video. In the video it sounds more like a sizzle than a hiss, but in person I'd say a hiss is the best description.
Anyone's 35's do this? https://www.youtube.com/shorts/u8Xkf4vmrjE

[Breakin Away]

Before I looked at the video I was thinking it might be belt slip, but from the video it looks like your belt tension is plenty (no wobble at all on the right side).

If you suspect a bad bearing, I suggest pulling your raw water pump and having it checked at a good pump dealer. (I used Depco to inspect/rebuild mine.) You really don't want a water pump bearing to seize up because the greater resistance could break the end of your cam shaft, which will ruin your sailing season (at the very least).

When you pull off the pump, check the slotted end of your camshaft to make sure it has the reinforcing sleeve installed. This critical fix was described in Westerbeke Service Bulletin #235. Have a look at it so you know what you're looking for:

https://www.westerbeke.com/service%20bulletin/service%20bulletin%20235%20universal%20cam%20sleeve%20update%2006-28-13.pdf

[KWKloeber]

I would suspect the closed coolant pump/bearing if, perhaps, the belt was overtightened after replacing the Alt.  What was the cause of the Alt seizing -- bearing?  If so that points (IMO) to an overtight belt.

[Sailing Amok]

My thinking is that it could have been an overtightened belt that eventually destroyed the alt bearing. So, I preemptively purchased a replacement fresh water pump from Kubota, to have as a spare, just in case. The bearing in the fresh water pump feels smooth when I spin it by hand though. With regards to belt tension, I purchased a Krikt, and the new belt is tensioned to about 100lbs, which feels a bit too tight to me, but the gates belt tension calculator on their website is indicating I should be at 130 lbs. that seems crazy tight. What is everyone else setting their 3/8 belts to on the krikt?
I suppose now would be as good a time as any to do the Oberdorf conversion. I feel a bit of play in the raw water pump shaft, but nothing leaking from the weep holes or anything. Could an issue with the raw water pump have anything to do with causing the alternator failure? I can't imagine it could, but maybe there's something I'm missing.
The PO had the copy of the Westerbeke service bulletin on his binder, and friends of his mentioned that he had done all the service bulletin work over the years, but it has been in the back of my mind. Maybe it never got done. Seems that the bulletin was updated at one point to indicate that Westerbeke had determined poor maintenance was the cause of the issues, not the missing collar. And I've got no signs of corrosion or anything around the weep holes.

[Breakin Away]

I typically tighten to 60-70 lb on the Krikit gauge (measured at about the midpoint on the port side (between the main pulley and the alternator). The belt starts to wobble on the port side at around 40 lb.

Disclaimer: I'm not saying that 60-70 lb is the correct tension, it's just where I like to have it because I don't like seeing the belt wobble. I did have a coolant pump fail once, but it was a long time ago, before I started adjusting my belt tension.

I have a good trick for de-tensioning my belt for easy adjustment, and I took some pictures of it the other day. See this thread: https://c34.org/bbs/index.php/topic,11731.0.html

[KWKloeber]

Could an issue with the raw water pump have anything to do with causing the alternator failure? I can't imagine it could, but maybe there's something I'm missing.

Seems that the bulletin was updated at one point to indicate that Westerbeke had determined poor maintenance was the cause of the issues, not the missing collar.

In a word. No."

In Westerbeke's typical fashion, SB 235 was updated to point the finger toward the owner instead of to the faulty designed IRON pump that can seize up. 
"the sea water pump....require daily inspection" Really? REALLY?  The pump is so badly designed that it needs to be inspected EVERY DAY?

The ring on the camshaft was simply a bandaid (a very slight hedge against a seized pump.)  As you may know, Westerbekle has finally wised up and retired that G908 pump and replaced it with a proper "marine" BRONZE pump.

[Breakin Away]

Could an issue with the raw water pump have anything to do with causing the alternator failure? I can't imagine it could, but maybe there's something I'm missing.

Seems that the bulletin was updated at one point to indicate that Westerbeke had determined poor maintenance was the cause of the issues, not the missing collar.

In a word. No."

In Westerbeke's typical fashion, SB 235 was updated to point the finger toward the owner instead of to the faulty designed IRON pump that can seize up. 
"the sea water pump....require daily inspection" Really? REALLY?  The pump is so badly designed that it needs to be inspected EVERY DAY?

The ring on the camshaft was simply a bandaid (a very slight hedge against a seized pump.)  As you may know, Westerbekle has finally wised up and retired that G908 pump and replaced it with a proper "marine" BRONZE pump.

Just curious, the G908 has a bronze pump cavity. Only the part that mounts to the motor is cast iron, and Depco painted mine when they rebuilt it, and I have not seen any rust. How does changing that part to bronze reduce the likelihood of bearing failure? Have the bearing materials been improved in some way? Are you recommending the new version of the Sherwood pump as a worthwhile purchase?

[Sailing Amok]

I typically tighten to 60-70 lb on the Krikit gauge (measured at about the midpoint on the port side (between the main pulley and the alternator). The belt starts to wobble on the port side at around 40 lb.

Hmmm... Maybe I should have purchased the Krikit that goes from 50-150lbs then? I selected the 100-300lbs version based on the Marine How To article here: https://marinehowto.com/marine-alternator-installation-tips-tricks/ which is also the article that suggested using the Gates V-Belt Tension calculator. That's the calculator suggesting 85-115lbs for a 3/8 belt. Too me that feels way too tight. Has anyone been running at the calculator suggested ranges on this forum? I know the Krikit tool is popular among folks here.

As you may know, Westerbekle has finally wised up and retired that G908 pump and replaced it with a proper "marine" BRONZE pump.

I didn't realise the G908 had been superseded. Are folks still doing the Oberdorf swap then, or going with this new pump from Westerbeke? I also hadn't realised that the collar was to protect the camshaft from a seized water pump, I thought it was to protect the water pump from failing in the first place. Sounds like they were clearly aware the pump was an issue. What are the symptoms of a failing water pump(water flow is normal)? Is the sound in my video something anyone has experienced with the Sherwood? it does seem to be coming from that area...maybe. I wouldn't think a bearing would make an intermittent sound like that though; It sort of goes for 10-30 seconds, and then stops, and then cycles again. I mean, if the engine had done it for all the time I've had the boat, I would have assumed it was some sort of relief valve or something. But because the sound wasn't present for the first season of ownership, I know it's not normal.

[Breakin Away]

Hmmm... Maybe I should have purchased the Krikit that goes from 50-150lbs then?

That's the one I have

I selected the 100-300lbs version based on the Marine How To article here: https://marinehowto.com/marine-alternator-installation-tips-tricks/ which is also the article that suggested using the Gates V-Belt Tension calculator.

That sounds very tight to me too, but one thing I've learned is that if Rod says to do something, it's a good idea to do it. I'll have to read over that article and see what he said. Every time I think I've read all of Rod's advice, someone comes up with something else that I missed.

I guess one important question is what is the designed side-load limit (beyond which bearing failure is accelerated) for the water pump and alternator? If I knew those limits, I'd divide the lowest one by two (since side load = 2x tension*cos(belt angle)) and use that as the maximum allowable tension.

[Sailing Amok]

I guess one important question is what is the designed side-load limit (beyond which bearing failure is accelerated) for the water pump and alternator? If I knew those limits, I'd divide the lowest one by two (since side load = 2x tension*cos(belt angle)) and use that as the maximum allowable tension.

My thoughts exactly.  The side load limit would be the logical place to calculate belt tension from. I'm not sure why Universal/Kubota doesn't give this information, rather than "push the belt 1/2". Maybe there is some basic engineering rule based on bearing size and lever length?

[Breakin Away]

I looked at the Gates calculator. I think that calculator gives the recommended tension that the belt can withstand. How much side-load the water pump and alternator can withstand is a separate (unanswered) question. It could be higher, it could be lower.

[Sailing Amok]

I sent an email to Gates, asking what their calculator is accounting for. We'll see if I get a response from them.

As you may know, Westerbekle has finally wised up and retired that G908 pump and replaced it with a proper "marine" BRONZE pump.

Ken, in my reading through the forum, I see that you were at one time selling modified Oberdorfer pumps? Is that something you are still doing? I think I may make the swap, even if just to reduce the pain of impeller changes. The Sherwood is 25 years old with 1360 hours on it, so it's probably not a bad idea. Maybe I'll get lucky and the hiss will go away with that change. Going to try the dowel to the ear method this weekend, to see if I can pinpoint the source regardless.

[Ron Hill]

Aaron : To isolate the noise I'd use a stethoscope or a long shank screw driver . Put the screw driver tip on a an engine part and the handle to your ear.  Keep doing that until you isolate where that noise is coming from. I use a stethoscope from an old blood pressure set.  Hope you find the critter that making the noise!!

I don't think it's the Sherwood, but put the screw driver on it and listen!!

A thought

[KWKloeber]

Rodd's article has an error -- the Krikit II is 100# (not 50#) to 300#.

The recommended operating tension is 85-115 lbs, so the Krikit to use is 30-160#.

That range is after a new or used belt is installed and "set in" by running it for a while.  So regardless of the install tension, it must be checked again after the belt is run.  A new belt will stretch more so it would be wise to check it after a day run vs a half-hour run of a reused belt.

The reason that Universal already does the work and provides a simple tensioning method is that what typical owner is going to mess with calculating the max tension based on bearings in the alternator and the water pump?  Really? 

BESIDES, that's beside the point.  The proper tension will vary with pulley/belt contact length and that is not a function of the bearings.

Besides the max tension isn't what to use -- use the minimum tension that does the job.  Thumbs do work.  If there is vibration or a squeal after a belt sets in, just tension only enough to eliminate it.  No more than that.  You folks' belt is SO easy to access/install/tension compared to mine.


[quote au
thor=Sailing Amok link=topic=11728.msg94951#msg94951 date=1688644785]

I typically tighten to 60-70 lb on the Krikit gauge (measured at about the midpoint on the port side (between the main pulley and the alternator). The belt starts to wobble on the port side at around 40 lb.

Hmmm... Maybe I should have purchased the Krikit that goes from 50-150lbs then? I selected the 100-300lbs version based on the Marine How To article here: https://marinehowto.com/marine-alternator-installation-tips-tricks/ which is also the article that suggested using the Gates V-Belt Tension calculator. That's the calculator suggesting 85-115lbs for a 3/8 belt. Too me that feels way too tight. Has anyone been running at the calculator suggested ranges on this forum? I know the Krikit tool is popular among folks here.

As you may know, Westerbekle has finally wised up and retired that G908 pump and replaced it with a proper "marine" BRONZE pump.

I didn't realise the G908 had been superseded. Are folks still doing the Oberdorf swap then, or going with this new pump from Westerbeke? I also hadn't realised that the collar was to protect the camshaft from a seized water pump, I thought it was to protect the water pump from failing in the first place. Sounds like they were clearly aware the pump was an issue. What are the symptoms of a failing water pump(water flow is normal)? Is the sound in my video something anyone has experienced with the Sherwood? it does seem to be coming from that area...maybe. I wouldn't think a bearing would make an intermittent sound like that though; It sort of goes for 10-30 seconds, and then stops, and then cycles again. I mean, if the engine had done it for all the time I've had the boat, I would have assumed it was some sort of relief valve or something. But because the sound wasn't present for the first season of ownership, I know it's not normal.
[/quote]

[KWKloeber]

Aaron I haven't done a conversion in a while.  Mainly due to available time.

It's a long, sordid story but originally the first two conversions (one round clip-on base and one bolt-on base) were trials that worked great and are still on those engines.  My plan was to buy N202-16 pumps before Ob drilled the bases and modify those for the B engines.  Unfortunately, I sent a photo to Depco showing the conversions and, well, about 8 months later, as would fate have it Ob started selling its round base pump.   Very coincidental huh? 

At that time the family-owned Ob sold the company and it was about impossible to talk to anyone about the un-machined pump bodies.  When I finally did get a price from Denver Pump, the minimum order was pretty steep and the cost too high.  I dropped it.

A just sold a customer a 202M-16 that he modified for a buddy for an M-25XPB and it worked great.  He MIGHT do another conversion.

Because of the difficult impeller swap out are you dead set against a pump like the Sw but in bronze?