5432 engine pump and cooling thread

02-11-2006, 08:56 PM
I changed the Oberdorfer pump for a Sherwood. Original one needed rebuilding and the Sherwood has higher capacity for better cooling. Mechanic friend told me the Oberdorfer is a better quality pump (bronze vs. cast iron) Also I think there is an optional taller cam that will make the Oberdorfer pump almost the same capacity as the Sherwood. My oil filter is just below the pump and points aft….

I thought your boat would have an M-40 instead of the 5432.

02-12-2006, 12:53 PM
Here’s an engine pic with the Oberdorfer. This pump seems to work fine up here, coupled with a 3-inch dia. heat exhanger. Water temps rarely get above 60 in Puget Sound, so I haven’t had any problems.

Couple other interesting differences in these pictures. The engine shop that rebuilt my exhaust system also replaced my broken engine mounts. Our mounts look like the same model, but my forward mount is oriented differently than Ben’s. Intuitively, I’d say Ben’s is correct for resistance to the thrust forces, but the well-respected shop owner says no – that’s not the best orientation. I think the fore-and-aft arrangement is the factory installation, so I’m still a little confused. We’ve had no problems since the change.

He also increased my exhaust dia. from 1-1/4″ (orig. spec.) to 2″ which matches the current M-40 spec. from Universal/Westerbeke. With the reduced back pressure, I believe I am getting maybe half a knot more at a given RPM setting than before. Pretty hard to say for sure. The engine temp stays way cooler with the exhaust changes and new HX (and stainle$$ exhaust elbow).

Your engine room insulation job looks great, Ben. I have some repairs to make to mine, since we disturbed the insulation on the ceiling when I had the cabin heater installed above it. I have been surprised to hear that the right rear area of the engine compartments were left open to the lazarette. I have an insulated 1/2″ or 3/4″ piece of plywood (removable) that forms the inner wall of my lazarette back there. One of the POs must have put it in.

mark reed
02-13-2006, 10:20 AM
We have a 5432 and did the conversion to a Sherwood raw water pump upon purchase in 2002, at the recommendation of our engine surveyor. The Oberdorfer broke siphon and had to be re-primed after heeling over on our our sea trial, even though it had just been re-built, and the engine had a history of overheating.
The only problem with the conversion was a small oil leak where one of the original Oberdorfer mounting studs had been removed. Turns out the hole for the stud had been bored all the way into the block. That was fixed by re-inserting a short length of threaded stock into the hole.
The Sherwood has been great. When I replaced the impeller after 3 years / 400 hours of running it looked like new. Engine runs very cool all day at max rpm.

02-13-2006, 01:27 PM
I have been plauged with overheating issues that I have not found a solution to. I find that if I run mine at much over 2200-2300, say 2500 or more, after about 15-20 minutes temps start to get very close to 200. I always back it off and dont let it go over 200. This is assuming I start at operating temp of 190 at 2100. 190-195 is what the manual says but it sounds a little hot to me to begin with. If I run it at 2000-2200 it will stay at 190 or below all day no matter how warm the bay gets. (80-85 in summer). I do think my tach is a little off and needs to be calibrated but its not more than 150rpm off. Heres what I have done so far:

Cleaned heat exchanger, removed it from the boat and flushed it out, blew compressed air through and did not notice any obstructions. It is the larger 3″ version. Perhaps it needs an acid dip?

Rebuilt oberdorfer raw water pump. New impeller and seals
Checked thermostat for damage.
Flushed coolant system with “radiator flush” stuff.

None of this seems to have had much of an impact.

I need to adjust the valves and I would like to do a leak down test to see if my head gasket is good, but not really sure how to on a diesel. I am also thinking I will pull the heat exchanger and have it acid dipped. I did not test the thermostat in water on the stove to see what temp it opens at. I have thought about going to the sherwood pump but its I think like 3 bill$ and I figured I would try these other things first. Anyone know details on changing the cam in oberdorfer to increase its output?

Loren Beach
02-13-2006, 01:40 PM
Hi Ted,
This topic seems to come up on all sorts of sailing venues…
One thing you did not mention is the age of the hoses. Last year a friend of mine with an early-80’s Ericson had a piece of material partly block the inside of the original black exhaust hose and the tone of the exhaust changed a lot, too. 😮
One new hose later and it was back to normal.

I know, wrong end of the problem! But still, those HD coolant hoses do have a life span. I replaced all of ours a several seasons ago when some showed a bit of swelling at the clamp points. The thing is, you can get a “bubble” inside the inner wall where a small weak spot has allowed the moving fluid to get under a layer and expand it — invisible but reduced-flow is the result.
These hoses are quite an modern industrial marvel of rubber/wire/fabric lamination, but they do age. :rolleyes:
You have covered so many of the possibilities, that there is little left to suggest…
BTW, we replaced the thermostat on our engine when we did the re-hose project.
Olson 34, Universal M25XP

02-14-2006, 05:07 PM
Thanks Craig…. I have a drop in wooden panel in my stbd side cockpit locker but behind that was open to the engine room. I made a panel for the ceiling and a panel for the aft side of the engine. It goes just in front of the exhaust muffler but aft of the transmission. I made it in an upper and lower panel to make it easy to remove. I also added a panel to the inside of the stairs so that it seals right at the engine bed in front of the fwd mount. This effectively seals the compartment and really cuts down on the noise.

Ted, the other mod to my engine (and I think its the most important one ) is to plumb the water heater into the thermostat bypass instead of the main cooling circuit. The theory is that the water heater being in the loop can impede the flow of coolant. It would get worse as the engine speed/coolant flow increases. My engine used to go up to about 210 at full rpms, then i would back off before it went higher. Now I can run at full throttle all day at
185f. I know they were hooked up improperly at the factory on boats of my vintage, not sure about your models.

Its easy to see: Right below the stbd side of the thermostat housing is a short (3″) 1/2″ rubber hose elbow. It comes up from the waterpump and goes into the thermostat housing.
The water heater circuit should go from these barbs. One out to the heater and one back from the heater. If the elbow is there then your engine has the water heater plumbed incorrectly. This bypass circuit will allow hot coolant to still flow to the water heater but the main cooling flow is not impeded by it. Actually the bypass will send warm coolant to the heater first before the thermostat opens.
Its a very easy change to plumb it correctly You will just need to adapt the 1/2 hoses to your water heater fittings (probably 5/8″ barbs)
This change made the most difference in my engine temp.

I also got rid of the bronze check valve(not needed) in the exhaust and carried the 2″ hose all the way to the transom. (new muffler)

I’m still looking for the oberdorfer tall cam part number.

02-14-2006, 08:01 PM
Thanks Ben. I will have to check and see how the heater is plumbed. This is the most sensible thing I have heard yet. I have a hard time believing it is a head gasket as the engine starts very easily and runs great with no evidence of moisture in the oil. Still plan to set the valves and check compression. I will probably send out the heat exchanger to a local radiator shop for the acid dip too. Although I do have some muriatic acid, maybe I’ll just dip it myself in a solution.

02-14-2006, 10:49 PM
As a 5432 owner, I have done many of the things commented on in this thread including replumbing the heater, removing the backflow valve in the exhaust, replacing the exhaust hoses (inner wall had failed), upgrading to the 3″ heat exchanger, and rebuilding the muffler. Two other things to look at are (1) potential blockage at the fitting where the hose goes from the heat exchanger to the exhaust manifold as this will rust shut; and (2) carefully check the exhaust port of the Oberdorfer pump to see if a blade of the impeller might have come off and lodged at the point were the nipple screws into the pump or in the elbow. Item 2 was the case on my 5432. The blade blocked the flow. It was almost impossible to detect the lodged blade. With the improvements, my 5432 never goes above 180 where it once went to 210+ under load (we sail in Lake Huron). If all systems are working properly, the Oberdorfer has plenty of capacity to cool the engine. One other test to consider is measuring the pumping capacity of the Oberdorfer with a bucket at the exhaust. With a bucket and a stop watch, you can determine the flow rate at a specific RPM. If the flow rate meets spec, you have a problem unrelated to coolant flow and Oberdorfer performance.

02-14-2006, 11:52 PM
Ted, are you loosing any coolant? If not,I wouldn’t expect you have a head gasket issue. I am thinking more on the lines of Craig, and think it might be a restriction in the outflow of raw water through the exhaust. Check and see if you have that notorious Bronze Flapper valve in your exhaust. If you have the correct size Vernalift muffler, you really dont need it, unless you do stuff where you might get pooped by a large following wave. Even if that is the case, with the engine running, it won’t be a problem. Most of the valves I have checked were deteriorated bad enough that they were ineffective anyway. Also check where the raw water enters the exhaust riser. they tend to plug up ther with rust and scale. the new riser is made or aluminum, and has bigger fittings than the original. I run an Oberdorfer, and after I took my own advice, the temp dropped from 200 f. at 2300 to 185 f. at 2500, running continuous. Good Hunting, use an infra red gun, Harold

02-15-2006, 01:03 AM
The “white smoke of death” thread mentions that some raw water intake fittings at the hull have a grate that can build up coats of bottom paint. Last April I had the boat out for bottom paint and I noticed that condition on mine and cleared the old paint off before putting on the new coat. That is an insidious situation – hard to fix from the dock, too.

The engine guy I mentioned (that’s Pat, at Pat’s Marine Engines in Seattle) also increased the raw water hose diameter from 1/2″ to 5/8″ I believe.

Looks like the obvious possibilities have been covered by the other replies. I wonder about the Oberdorfer capacity. I get good temp control – it creeps up to 160-165 F after several hours at 2100 rpm. I seldom run higher RPM than that. I see about 5 deg increase when I kick in that 195 amp house bank alternator. I also see a little bit of light steam at the exhaust after the engine reaches operating temperature. Sometimes it is more evident than others.

The incident that caused me to get the exhaust system work was fun. Not funny – it cost me $3700 :esad: – but the exhaust hose between the elbow and the muffler delaminated, the inner silicone liner separated and temporarily blocked the exhaust. Then the pressure built up, released, and the muffler end of the hose blew off. Overpressured the muffler, but didn’t hurt it. Smoky, smelly, but no fire of course. Sailed to the dock (at Dockton, luckily) for the first time. It seems like single piece silicone hose would be better for this short length, as long as there are no bends required. We used such a hose for the jury repair that got us home. The $200 I spent on the stainless elbow will, I hope, be a good investment.

Great thread as usual!

Oh, and the water heater bypass plumbing tip – I have to check on that. Thanks.

02-15-2006, 01:41 AM
Craig, thats a terrific looking mixing elbow. Much improved over the cast iron one. Also admiring your alternator setup, where did you get the double groove sheave for the motor?

Ted, soak the HE in diluted muratic acid yourself, mine just fit in a plastic dishpan. Really easy to do , just rinse it well between soaks, try to slosh it around while its soaking. Let it soak in fresh water for awhile when done and somebody mentioned adding baking soda to the final rinse to neutralize any acid left.

wear something old as youre garanteed to get some on you:cool:

e38 owner
02-15-2006, 09:40 AM
I had overheating problems for years.
Last year I took the grate of the bottom of the boat when I installed new thru hulls and installed a forespar raw water filter. I also increased the size of the hose from the thru hull to the raw water filter. (3/4 to 1 inch)

This has made all the difference in the world. The old grate had a little bottom paint etc on it and the filter is great easy to clean and winterize.

Also the torreson marine site has great pictures on redoing the hotwater heater by pass as well other 5432 heating issues

02-15-2006, 02:44 PM
Here is the info I had found before. Wish i had found it before I bought the Sherwood pump.

I’m not 100% sure its the same pump. Does anyone know the Model No of the Oberdorfer? Anyway the guys at Moyer should be able to help…..

Seems like a no-brainer upgrade with the $12 cam….. Even the whole pump is only $165??

02-18-2006, 08:09 PM

Thanks – I really was impressed with the elbow, too. We’ll see if it works forever.

The double pulley was added by the PO, so I am not sure where it came from. Maybe a tractor engine place? One of the Westerbeke or Universal outfits can probably help if you’re thinking about adding another alternator.

One description of my electrical system is at at thread called Alternators for M-40


02-19-2006, 03:23 PM
On the torrenson link for the hot water heater bypass install they show the return line from the water heater hooked to the pipe coming up from the water pump. Is that right? Mine is reverse of that. I was thinking water was flowing from that pipe up to the t-stat housing. Is it going the other way? I am going to try the pump upgrade, acid dip my heat exchanger, and replace the t-stat. Still want to do a compression/leak down test but my compression tester does not have the correct size fitting for the glow plug hole. Its a regular automotive tipe meant to go in spark plug holes. Also I am noticing some differences on my 5432 from craigs pix. My raw water pump is mounted upside down from his. Ie the inlet and outlets are on the bottom. My oil filter also runs laterally as opposed to fore aft. I would like to rotate the water pump 180 like craigs so my hoses are not as close to the oil filter as they are. They are not touching th efilter but are close. Just curious if any of you guys have tried moving this motor out of the compartment? Would make replacing the insulation a lot easier.

02-19-2006, 11:14 PM
Craig ,
who made your exhaust elbow? I think thats a terrific upgrade. I’ll try a Kubota dealer for the double groove crankshaft sheave.

02-21-2006, 08:08 PM
Anyone ever hear of heat exchangers made by these guys? A guy on Ebay is selling “New” 3″ heat exchangers for the for $234. I am rather sceptical but perhaps someone else has heard of these?

02-22-2006, 12:19 AM

Wish I could add an idea to help with the overheat. The upside down Oberdorfer orientation doesn’t seem to me to be a big deal. If the pump is right on the waterline (thinking of Mark Reed’s comment about breaking suction) then the inlet being a few inches lower may help it prime quicker after startup. I’ve never really run the engine while sailing. If a pump and/or the plumbing is on the “edge” it might break suction on a starboard tack, which would elevate that side of the engine and the pump. The raw water inlet is real close to the hull centerline on my plain 38 (you and Mark have the 38-200?), but I wouldn’t think they moved the through-hull that far.

I have never heard of Seakamp.

Oil filter orientation – The older, heavier 5432 block has a casting that bolts to the side of the engine. That casting is what the oil filter spins on to. You’d have to ask an expert if you could re-arrange your newer engine to point your oil filter that way. I zoomed in to the picture and you can see the casting and gasket. Then I had an inspiration and went to the Universal Atomic Diesel 5444/5432 Service Manual and found the detail of the oil pump and it shows a casting. Just a little additional confirmation. No part numbers though. It’s called a “filter cover assembly” and consists of the cover casting and a safety valve assembly.

The Universal Atomic Diesel 5444/5432 Service Manual – I discovered I have a fairly good copy of the 9/80 version (Sept 1980?, price $10.00). I forgot to secure a few items when we sailed last time and while re-arranging the mess from my document tub, I found it. 25 pages. Filled with important facts like nozzle cracking pressures and running clearances for crankshaft bearings. I will try to scan, PDF and post it to the Specs/Docs page sometime later this year. If anyone is desperate for a copy, let me know, I can copy and mail paper easily.

Ben, I will find out who made the elbow. I’ll have to call Pat’s to find out. Checked the bill and it was $225 – he probably added the $25 as his design/markup charge. They apparently pack the pipe with sand and then make an “S”. Must be some kind of bending machine. It’s a company up here in Seattle (Ballard), WA.

Loren Beach
02-22-2006, 12:31 AM
Seakamp Engineering
3985 Hammer Drive, Bellingham, WA 98226
(360) 734-2788

I have heard of them (selling heat exchangers) , but know nothing about their product line or reputation.

02-22-2006, 01:25 PM
Thanks guys. My raw water pump also does not have a grease cup like Craigs. That looks a lot like the Atomic 4 pump I wonder if the Moyer Marine cam will fit my pump?
Took off my heat exchanger for cleaning the other day. When I pulled the caps off it looked rather dirty. The zinc was completely gone and bits of it were plugging part of the exchanger. So I suspect the acid bath will help. I am a little concerned about the zinc though. I just replaced it last spring. I would think the pencil sized xincs would last at least a full year? Last summer I used a galvanic meter and did not see anything abnormal. This meter you hook to your DC ground and then there is another lead you drop over the side into the water. I have been running a small oil filled heater all winter though. I should try the test with the heater on and see whats up then. When I dove the boat over the summer my shaft zincs looked good. On dipping the heat exchanger any thoughts on the solution? 50% muriatic acid? 20%, 10%?

Chris Miller
02-22-2006, 05:15 PM
I just had our exhaust riser elbow replaced with a silicone bronze elbow that an annapolis company had cast due (they had about 10000 of them done, I’m guessing that was a minimum) to the number of corroded out riser elbows they see. My failed one is pictured below- I’ll get pics of the new one later this week. Part price is $198. There’s always one more option— one of the things I love/hate about boat maintenance…

02-23-2006, 01:59 PM
I mixed the acid about 50/50 with water. Not sure of the strength of the acid in the jug. Its what they had at Ace Hdwr.

I also found the pencil zincs from West marine are a little too long. Had to cut off about 1/4 inch with a hacksaw.(I have the 3 inch heatexchanger)

Good news is they are cheap. I should have measured what fit and written it down:rolleyes:

02-24-2006, 05:21 PM
50/50 sounds good. I was a little concerned about the zinc not lasting a year. My shaft zincs seem to be holding up well though. I have been leaving the boat plugged in to AC all the time with the battery charger on autopilot. This winter I have been running a small oil filled radiator heater as well. Probably not a good practice since I don’t have a galvanic isolator. Hopefully will be cureing this over heating problem with the clean heat exchanger and a new t-stat. Still want to check compression and do a leak down test. Anyone out there ever pull the glowplugs on this motor? I need to make an adaptor for my compression tester too.

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