How hot is too hot and what’s with these alternator belts?

[KeelsonGraham]

Hi all, thanks to everyone who helped me with my cooling issues. I flushed the HX, filled the header tank to the correct mark and burped the engine. But now I'm puzzling about what should be a normal operating temperature. At 1500 RPM the indicator reads a needle's width past the central vertical mark. At 1800 RPM the indicator reads a needle's width under 180 degrees, is this about right or too hot for a Universal M35?

Second question. I've taken much time and trouble to buy a correctly sized alternator belt, make sure it's aligned on the pulleys and tensioned correctly. But the darn thing will start slipping after a few hours. I really don't get this. The belts on my car go for thousands of hours without needing any attention, so why can't the boat belt do the same?

[Jim Hardesty]

At 1800 RPM the indicator reads a needle's width under 180 degrees, is this about right or too hot for a Universal M35?

I wouldn't think that's too hot.  However Shamrock stays at a solid 160 degrees.  That's the thermostat setting.

I've taken much time and trouble to buy a correctly sized alternator belt, make sure it's aligned on the pulleys and tensioned correctly. But the darn thing will start slipping after a few hours. I really don't get this. The belts on my car go for thousands of hours without needing any attention, so why can't the boat belt do the same?

Do you have a high output alternator.  If so the stock belt may not be up to the added load.  Shamrock has the original alternator and belt.  I loosen the belt during winterizing, adjust before starting in the spring and it goes fine all season.  Last season was 200 engine hours without any additional adjustments.  Is your alternator belt still tight when it starts to slip?  If not possibly didn't get tightened enough.  The nuts and bolts under the alternator and the alternator bracket are not easy to get to.  FWIW I buy Gates belts if at all possible.

Hope that helps.
Jim

[Catalina007]

Hi all, thanks to everyone who helped me with my cooling issues. I flushed the HX, filled the header tank to the correct mark and burped the engine. But now I'm puzzling about what should be a normal operating temperature. At 1500 RPM the indicator reads a needle's width past the central vertical mark. At 1800 RPM the indicator reads a needle's width under 180 degrees, is this about right or too hot for a Universal M35?

Second question. I've taken much time and trouble to buy a correctly sized alternator belt, make sure it's aligned on the pulleys and tensioned correctly. But the darn thing will start slipping after a few hours. I really don't get this. The belts on my car go for thousands of hours without needing any attention, so why can't the boat belt do the same?

seems close enough. your gauge also may not be 100 pct accurate. what is the seawater temp you operate in?

[Ron Hill]

Keel : From what I've seen, the factory usually installed a 160F thermostat in the engine. However, a PO could have changed it to a 180F !?!  The temp is stamped on the thermostat !!

On your belt, make sure that the inside of the pulleys are free of oil/grease.  Just take a rag with some lacquer thinner and wipe the inside of the pulleys to clean them.  When you tighten the belt just make sure that you can't turn the belt (with you fingers) no more than 180 degrees.

The belt should should have notches on the top side for heat transfer; you don't want a smooth toped belt!

a few thoughts

[Breakin Away]

A few comments:

On your vintage of MkII boat, you have an M35B (also called M35BC, since Westerbeke did some special electrical things for Catalina). M35 and M35A are different models from M35B, and those differences can be significant.

I think 180F is too high, especially at only 1800 RPM. I would not assume that the gauge is wrong, since temperature gauges are usually pretty good. I'm not sure how you could check this. Maybe there is a place near the thermostat where you could point an IR gun.

Before doing too much, I'd pull the thermostat and see what temperature is stamped on it. I remember reading some "folklore" that some people prefer slightly higher temp than Westerbeke's spec of 160-165F, so maybe the PO installed a hotter thermostat.

Aside from that, there are several other possible causes for high temperature. If your belt is slipping on the freshwater pump pulley, that could cause the freshwater pump to be circulating too little coolant. It's possible that your water pump bearings are going bad, which could cause friction and slippage (and leaking of coolant). This might also be why your coolant reservoir is low. I learned that one that hard way (and replaced my coolant pump) a few years ago.

Are you tensioning the belt properly? I generally need to tighten my belt 2-3 times per season. There are several ways to tension it (I have a unique way, but it's too much detail to explain now; see this thread: https://c34.org/bbs/index.php/topic,11731.0.html). I use a Krikit tension gauge and tighten to 50-70 lb on that gauge. As the V-belt gets old it tends to wear on the sides and get narrower, thus sinking into the pulleys further, which is why you need to keep pushing the alternator out. I typically end up moving the alternator out on the bracket 1/4"-1/2" per year. I do keep my belt a little tighter than some, because I found that any "wobble" at all between the engine pulley and the alternator causes subtle engine vibrations that transmit all the way to the shaft and cause wear in my stuffing box. But that's just my boat, and the higher tension comes at the potential cost of wearing out my water pump bearings (expensive) and belts (cheap) more frequently. I just bought a replacement belt from NAPA. If you have the original alternator (not an upgrade) the part to get is NAPA #15395 (note correction), and it only cost $5.49. I haven't tested it yet, since it's a spare for the genuine Westerbeke one that I just installed. The NAPA guy told me it's made for them by Gates.

What raw water pump do you have? Many here swear by the Oberdorfer N202M pump, and they work perfectly on older boats with smaller engines. However, Depco Pumps told me that it is only rated for up to 30 HP, and the M35B puts out 35 hp. Nevertheless, many people use them successfully on MkII boats with M35B, but there are isolated cases where MkII owners have not been successful (steam in the exhaust) and those owners went back to the Sherwood G908, which has a wider impeller providing higher throughput (at the cost of greater resistance on the crankshaft coupler, which some will tell you horror stories about). However, I'm sticking with Sherwood for now.

Key takeaway: Every decision you make has tradeoffs. Changing a part spec, belt tension, thermostat, or most anything else may solve one problem but create another one.

[Breakin Away]

One other comment/question about your new belt: Does it have the ribs in it, or is it a solid belt? A ribbed belt is critically important for heat transfer area. A solid belt will overheat, and that might be why you see it start to slip after a short warmup time.

[KeelsonGraham]

Thanks for the tips. I'll action all these points next time I'm down at the boat (2 weeks from now). I'm using a ribbed belt and tensioning by eye/finger pressure as per the manual. Sea temp is 12c at the moment so that shouldn't be a factor.

[KWKloeber]

@KG

Which TStat do you have?  160F (salt) or 180F (freshwater)?

Per Teleflex troubleshooting (IN THE WIKI), temp gauges are plus/minus 15 degrees.
The temp sender may be going bad.  Check it with a laser temp thermometer
There could be many reasons if the temp is actually high (so you first need to determine the actual temp.)

[KWKloeber]

I remember reading some "folklore" that some people prefer slightly higher temp than Westerbeke's spec of 160-165F, so maybe the PO installed a hotter thermostat.

Folklore?  Diesel engines run more efficiently at higher operating temps.  This is a long-established fact about diesels -- Kubota knows this and its equipment (and others that use Kb engines) run at 180F.  The problem with using an engine on the water that was designed for a farm is mineral deposition in the exhaust train from too-hot salt water.  That's why Universal/Westerbeke replaces the 180F TStat with a 160F TStst.  If in freshwater the TStat should be 180F because the diesel will like it better.

there are isolated cases where MkII owners have not been successful (steam in the exhaust) and those owners went back to the Sherwood G908, which has a wider impeller providing higher throughput

There is ONE instance of that on here, and reading the follow-up investigation the issue was (apparently?) not the pump/seawater flow and the owner has since reinstalled the Ob pump.  Others, including a C34 w/ an M35 in the warm Gulf has no issue with the 202-16 pump.   

Depco is good but sometimes "They ain't all that."  Being located in the south they understand that phrase.  I've had instances where they are less than stellar.  Like returning a serviced pump with the pulley installed backwards.  And handing out very bad information -- like a woman who had to buy expensive (~$250) parts from Westerbeke to install their pump, which was the wrong pump.  Depco is only as good as its people and there has been a lot of turnover.

(at the cost of greater resistance on the crankshaft coupler, which some will tell you horror stories about).

What's a crankshaft coupler and where is it? Can you elaborate on the issue -- and the source of this info?  I've heard of no such problem but if there is I would like to investigate more. 

[Breakin Away]

Folklore?

I referred to it as "folklore" in emphasis quotes because I've heard it many places, but couldn't cite exactly where. I was not implying that it is inaccurate. Literally, it was lore coming from the folks.

There is ONE instance of that on here...

Maybe only one case here (I wasn't counting), but C34.org does not have a monopoly on information, and the C34MkII is not the only boat that uses the 35 horsepower M35B. I've heard of other cases from different sources and on different boats, and you can find them if you choose to look. My statement was factually correct, and I stand by it. I acknowledged that there are other pumps that work in many cases, but people should get all the facts. CatalinaDirect gives the same warning about the Oberdorfer pump. I may even purchase one sometime, but not just yet. Note that Pentair has discontinued the Sherwood G908.

Depco is good but sometimes "They ain't all that."

The same can be said of all free internet advice. And unlike some of the advice, Depco will happily sell you Oberdorfer, Sherwood, or other brands, as well as DIY rebuild kits or even do rebuilds for you (sometimes for less than buying the rebuild kit, if like my you only need a partial rebuild). So they have less incentive than some to give biased advice.

What's a crankshaft coupler and where is it?

I was referring to the issue described in Service Bulletin #235, and the failures ("horror stories") that led up to that critical fix. I could not look up the proper terminology because I was having online access issues.

[KeelsonGraham]

So, just to be clear on this, are we saying that any steam in the exhaust is unacceptable??

[Ron Hill]

Keel : Absolutely NOT!!!  There are atmospherics (low outside temp and high humidity) where you can have the exhaust form steam!!

a few thoughts

[KeelsonGraham]

Thanks Ron.

[KWKloeber]

Note that Pentair has discontinued the Sherwood G908.

The G908 was actually owned by Westerbeke -- long history starting with the G903 (aka G908), which was supposed to be sold only as a Westerbeke part.   Westerbeke 042175 (G903/G908) is supersceded by Westerbeke 057866 $1,160 (see the next comment.)

I was referring to the issue described in Service Bulletin #235, and the failures ("horror stories") that led up to that critical fix.

All instances that I have seen were due to the shaft seizing in the iron body pump (not an issue w/ Westerbeke's new 057866 all-bronze pump.)  I have not heard of any of those failures of the camshaft fork being due to the larger impeller or greater pumping rate. 

[Depco has] less incentive than some to give biased advice.

Biased isn't the issue.  Not always the expert is the issue (even if they are inadvertently/unknowingly incorrect) -- there is a feeling among some that Depco is "THE" go-to source and that they are "THE" expert about pumps on our engines.   They are one of the best, but just as you do from other sources, their info needs to be filtered -- (as I exampled) they are not always the expert that they are made out to be.

[TortolaTim]

Keel : From what I've seen, the factory usually installed a 160F thermostat in the engine. However, a PO could have changed it to a 180F !?!  The temp is stamped on the thermostat !!

On your belt, make sure that the inside of the pulleys are free of oil/grease.  Just take a rag with some lacquer thinner and wipe the inside of the pulleys to clean them.  When you tighten the belt just make sure that you can't turn the belt (with you fingers) no more than 180 degrees.

The belt should should have notches on the top side for heat transfer; you don't want a smooth toped belt!

a few thoughts

Ron, what type of belt are you using that has the notches on top? I was buying Dayco Top Cog belts, but for the last 2 years they are smooth belts. I've ordered them from O'Reilly Auto parts and Summit Racing. The pics on the websites still show the notched belt, but it isn't what arrives in the package. Do you recommend any other brands?