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E35 Sherwood Crossreference Counterpart?....and more

knuckle47

knuckle47

Advanced Contributor
Seems like the "X" years cycle may be coming around again so in being proactive, I have gone thru the entire cooling system (FWC) to clean and drop temps back to normal. Port side started to reach 170 at prolonged cruise

1.) During the cleaning (poking that brass brush into all of thos heat exchanger core holes) process, I began to wonder if there may be a different RAW water pump that can directly replace the E35 and provide a higher volume of cooling water thru the system. Does anyone have any clue?

2.) I have asked before and have read hundreds of posts about exhaust steam. I THINK the answer is that: cooling raw water in the U-cooler is reacting to the heated areas inside and THAT is how this exhaust steam is produced...IS THIS CORRECT?

3.) Would my thinking that a greater flow volume of cooling water would keep the overall heat level below a point that it steams?


To Don K...That little brush is a pleasure to use and I think of you each time I use it....works great! Thanks
 
Sounds possible. With a t-stat in place, you can't theoretically over cool a motor.

I'd visit a few marine stores and eyeball the impellers of various Sherwood pumps, comparing their size to yours. A bigger impeller pumps more. Period.

Jeff
 
knuckle47 said:
2.) I have asked before and have read hundreds of posts about exhaust steam. I THINK the answer is that: cooling raw water in the U-cooler is reacting to the heated areas inside and THAT is how this exhaust steam is produced...IS THIS CORRECT?
Click to expand...

By measurement, I have not seen any temps above 212 deg at the U cooler. At cruise, I'll measure the engine oil temp at just over 200 deg. On the other hand, the 1400 deg exhaust temp will definately cause salt water to boil, causing the steam. If the water flow is high enough, that steam condenses.
So, from any number of reasons, a reduced flow of raw water will cause steam out the pipes.

I would not pursue more than stock raw water pumping capacity. I think it's enough. The reason is that any clogging in the risers will cause higher back pressure for the heat exchanger, putting more pressure on the end caps and soldered structure. Higher system pressure will tend to pop hoses off of fittings as well. If I were to spend $ in that area, it might be to put in a raw water FLOW meter. This would tell you if either the pump is loosing capacity or if there are restrictions in the system.
 
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These are interesting . I have not seen a specific FLOW measurement device for 'marine" use so I am thinking and adaptation is necessary? Dave, do you know about how much "back pressure" is possible in a reduced flow system. I assume we are defining riser as the elbows in my configuration (1992). I think it is a great idea and will persue it. My port elbow is starting its' 4th yr and my starboard its' 3rd. (years= boating seasons)

Jeff, I think the same thing. Since the t-stats will control the heat, even running in ICE water should be acceptable...in theory. If supplying great flow will extract heat, it should emulate a radiator in a car's cooling system.

All I can say is that I statrted this boat several years back with those SAME posts I read here every week about temps climbing and climbing..then reducing rpm and it cools down...I am just hoping to stop a problem before it develops and shuts down a weekend we now get so few of, to go out and get some good fishing in. I have been maintaining, replacing and correcting "Stuff" for 4 years....so , now it starts all over again. I see your point Jeff.....Weee , Ain't boating fun ?

Dave, THANK YOU for that STEAM explanation. Simple to know heat and water make steam but the actual process seems to have eluded me for some reason or another... I think I have too much other useless "stuff" in my head.
 
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The easiest way to increase the volume is to change the pulley on the existing pump; smaller diameter = faster rotation = more volume. Like most things, it doesn't come for free. Like DD, I believe the stock system is adequately sized.

All that steam is created in the exhaust....as the flow of raw water is impeded, more steam will appear, environmetal variables discounted.

The flow meter is a viable monitor but not cheap (the newer 555 PCM systems have this as an input parameter). Your fuel flow sensor is the basic part so you can ballpark the 2x cost factor. I think Jeff's approach - using a pressure switch - is an economical alternative to monitoring raw water flow. Since the normal failure mechanism is restriction of cooling water in the elbow, it's occurence coincides with a pressure increase. a $10 pressure gauge is another alternative though you'll likely need one at each elbow for an accurate representation.
 
I did an experiment a few years ago; I put a high quality, all stainless, liquid filled, 0 to 15 psi gauge in the raw water side, at the Heat Exhanger. With newish risers, it recorded on the order of a 4 psi reading, with quite a bit of fluctuation, due to the exhaust "pulses". But, the gauge clogged and failed just a couple of years into the experiment, so it didnt' take me all the way to a semi-clogged system.
I think even with raw water strainers, there is enough zinc bits, sea water life, calcium residue and other "stuff" that will make this a non-trivial task.
In retrospect, the best way is not to leave the gauge installed, just put it on to take a reading.
 
you think the pulsing was due to the exhaust? I'd think the pump itself would be the more likely culprit. An adequately sized exhaust shouldn't see that much backpressure (4psi) until above a cruise rpm.
 
I am hoping to eliminate the water pump by measuring something...Problem is the variables are quite large and I have not reference as to what the flow should be....YET!

I was there today and now have both HX cores brushed out...Not really any blockages but certainly some brownish coating. That nmay improve things somewhat for heat transfer but I don't believe that situation would create a 10% rise in op temp above 3000 rpm. Removed the u-cooler hoses, filled the cooler with 50/50 muriatic. Did the alka-seltzer thing for only a minute so I really don't think they are causing any restriction either so ...IF none of this has made a difference in op temp, ( I will know this weekend) then it is into the elbows we go. Seems like 4 yrs is a little premature. Especially that once IN from the ocean, we run about 15 miles in bay water where the salinity is probably 1/2 of the seawater. I'll pull out my hydrometer and check
 
My 5 y/o crusader riser completely blocked on me, and that's with routine fresh water flush after every use.
MM; the gauge was in the water system, and suspect most of the pressure at that point was due to the riser water passage restrictions, not sure. The impeller frequency I figured was much higher than the exhaust valve frequency too.
 
Thanks Jeff....I'm on it tomorrow. I get the feeling Dave is right...The elbows may be starting to clog. Either way, HERE WE GO AGAIN !
 
I know this is no help to the discussion but the sooner you divest yourself of the Sherwood pump in favor of a Johnson or Jabsco the better. My 2 pennies.
 
o2batsea said:
I know this is no help to the discussion but the sooner you divest yourself of the Sherwood pump in favor of a Johnson or Jabsco the better. My 2 pennies.
Click to expand...


Why? durability, quality, ease of rebuild, capacity?? don't they have similar impellers?
 
You get what you pay for. My experiences with Sherwoods have been dismal. Gawd, they even have ones with a cast iron body!
 
Those are the JABSCO pumps we switched to years ago. They use the same impeller and the same belt pulley so the capacity is the same. (yes, cam diminsions give same deflection.)

We switched mostly because of the design - more bearings with a wider base (separation) so the shaft is more stable....no carbon bushing either. Much less maintenance.

Al- no matter which pump you use, if the elbow is restricted, things won't stay cool.
 
Funny thing Is, prior to these favorable comments, I had printed out the pdf on that pump. The first page is the picture, so while I was waiting for the other 3 pages, I went ot check the cost and that's when I just reacted before really reading all of these differences. After all from the instant view of the picture, it looked like the same rhing

I do have a set of new elbows in my truck along with gaskets and ss plates as of yesterday AM, so one day in the next 3...it may be installed if the next run proves to be an issue.

My re=power is using 4" elbows and exhaust hose. As it goes into the cylinder style mufflers and out the transom, I am using a reducer to go back to the 3" system that remains from the original 270HP 350's that were replaced. Would anyone believe that this "restriction" shortens elbow life?
 
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The reducer shouldn't have any impact on the elbows' life, only the ability of the engine to breathe at elevated RPM.

just doing a quick search, those pumps are around for $450 - If you were serious about the swap, I'd try to negotiate a package deal.
 
Right now I am hesitating in swapping the pumps. I found them for around the same price. On the other hand, I am changing the elbows (MAYBE) if my cleaning did little to reduce the slightly elevated (170) temp on the port side. Both my E35's were new within 3 yrs (seasons)and my impellers are new last summers so I am not in NEED of the pumps while it might be nice. I just spent a nice bundle on the DC panel and 1600 feet of wire along with a few new saloon lights, courtesy lights, fly bridge air conditioning and other things. If it isn't going to add something I truly need....it can wait.
 
Looking at the Jabsco 42730 parts view, certainly they are doing some things better than Sherwood. I see a SS replaceable wear plate on each side of the impeller, Sherwood butts the impellor against bronze on each side, one of which is the main body, essentially non-replaceable. I see the dual bearings, although mounted pretty close to each other, they do negate the need for the wetted graphite bearing in the Sherwood. The cover O ring should be easier to deal with than the paper flat seal on the Sherwood cover.
If I find one of my Sherwoods unrebuildable, I'd certainly look to switch. Though, no reason to before they get to that point.
 
Flow meter for your raw water.

Check out Gems sensors RFA series. Brass or stainless body with 1" ports. 0 to 10v DC output (varies directly with flow). So, you can just put a dash voltmeter up there and monitor your raw water flow. Takes 24V DC power, too bad. Next step is costing, but i'll bet just the one sensor is in the $1000 territory.
 
$1000.00 to measure the flow of my raw water? Hey, maybe its' cheap compared to the price per pound of fish we caught last year ! I just actually measured the flow of the cooling water pump for the air conditioning unit. VERY SOPHISTICATED....a 5 gallon bucket and a stop watch....then a piece of paper and pencil..! Damn good flow meter.

By the way NOT CRUSADER RELATED....anyone know the water flow requirements for a 16K btu air conditioner? Manual does not list it.
 
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This is my guess since I don't have the data either. It is likely that the heat to be removed from the condenser of a 16,000 BTU/hr airconditioner would be about 32,000 BTU/hr (50% efficiency). If you are getting a 10 degree temperature increase across the condenser it would require 6.5 gallons per minuite to remove the 32M BTUs/hour. Each pound of water will remove one BTU per pound for each degree change in temperature.

Chuck Hanson
 
Wow Chuck...I knew I should have paid more attention to those science courses. That works and means that between the head of the pump and its' volume at that height, I am well within the ball park ! At 9' she pumps about 720 gph. Because of the GREENHEAD flies, we are going to keep the enclosure UP all summer and the curtains closed. Once we get to the inlet, they disappear but near the salt marshes, they are horrific. Bought this unit on eBay for $240.00 used but working very well so there it is , and Thank you !
 
DD - no wear plate on the 'back'; they use the cover just like sherwood does. BTW, the bearings are the same as used on a Delco 10SI alternator so they are readily available if needed.

Al - the rule of thumb for the marine air units is 500 GPH for ever ton of cooling. It runs a bit short on the smaller units so nobody goes below a 250GPH pump, even on a 4500 BTU/hr unit. If you are flowing 720GPH, you should be more than adequate. Be careful when you enter the ocean when the wind has been blowing W or NW - those greenheads go for miles.

Chuck - where did you come up with the 50% factor for the heat transfer of the gas? I'd concede it in a heartbeat for an older unit's system level rating but having a hard time believing the condensor won't shed all the heat picked up from the evaporator.
 
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