repowering cd 28

[Wayne Grenier]

Greetings:

I have a 1974/75 CD 28 with a Volvo MD11 that is freshwater cooled but overheating. I have removed the thermostat, flushed out the heat exchanger and checked both the fresh and raw water impellers and replaced the surge tank cap.

I have not solved the problem.The raw water side is fine.

I am at loss.

Am thinking of repowering with a Beta 20 HP diesel. I am told this is a good fit. it is 1/2 the weight of the volvo and parts and service are avaialble.

The MD11 has not been made since 1981. I put it in myself in 1990. So it has had a good run.

Does anyone have any thoughts or suggestions or aware of any issues?

On the plus side, if anyone needs parts for a Volvo MD11 let me know. I am told the MS1 gear box is unavailable. Mine is working and was replaced about 10 years ago. I think I got the last one in existence.

Thank You'

Wayne Grenier

[simplehand]

I wonder if the 20HP might be overkill? I repowered my 1977 28 with a Nanni 2.14, which I think is pretty much the same as the Beta 14, and it doesn't feel underpowered to me.

[Jim Walsh]

Fred Mueller, our esteemed potentate extraordinaire, has an immaculate CD27 “Jerezana” which he has repowered with a Beta 14. You can do a search to see what he has posted here or PM Fred for further details. The 1,500 pound difference in displacement between the CD27 and CD28 may be a deciding factor but Fred’s experience may help you make an informed decision.

[Carl Thunberg]

I have to ask. Are you considering re-powering because of an overheating issue or are there other factors driving the decision? You didn't say whether water is making its way through the cooling system to the exhaust. If so, then the water pump is fine. The next thing to look for is the exhaust elbow. Finally, are you positive the engine is actually overheating? Do you have an infra-red temperature probe that can measure the temperature of the water as it exits the exhaust? They are surprisingly inexpensive and they give a lot of good information. I have labeled several places along the cooling system on my boat and have recorded base-line temperatures, so I know what "normal" looks like at various points. It also can be used to isolate where along the path of water the temperature increases. Good luck whichever way you go.

For what it's worth, be thankful for a small engine. I have a 165 HP Volvo TAMD40B diesel and am dreading the day I need to re-power.

[Wayne Grenier]

Thank You

I have the usual copious amounts of water coming out the exhaust. In neutral at idle the temp gauge goes to 250 in 20 minutes. The manifold gets very hot. The coolant does not. I am thinking I have a blockage in the manifold. I ran it without a thermostat.

A volvo MD 11 is an obsolete engine last made in 1981.

I do not see much downside to a new motor.

But if its something simple that is a different story.
Per Beta the 20 hp will fit
I would like to put the largest motor that will easily fit.


Wayne Grenier

[Frenchy]

Hi Wayne - have you checked the heat exchanger? They sometimes accumulate zinc anode remnants. A radiator shop can
clean it out if it's plugged.
On another note, I replaced my old engine with a Beta 25 and have been very satisfied.

[Wayne Grenier]

You are in Padanaram?

So am I.

Who did the work? I cannot fine anyone to do this. I am interested in any details you can provide.

I did check the heat exchanger. It is clean.

Wayne Grenier

[Frenchy]

Hi Wayne - sent you a PM. - Jean

[John Stone]

I can't help you with the Volvo overheating as others have more time sorting that issue out than I do. But I'll share my perspective on engine size. But first, what is your rational for wanting the biggest engine you can fit into your boat? You don't have to answer that but I recommend you are really clear in your head about the why of it. I also recommend you make a list of the pros/cons of going with a 15 vs 20 hp. Maybe you have already done that.

I am a big believer in your boat, your money, your way. So do what you want but a 20hp is a lot of engine for a 9000 lb sailboat. While some, or even many, will disagree with me, IMO an engine is not a safety device. It's a convenience. Safety is what's between your ears.

A bigger engine will use more fuel because you have to run it harder to get it into your best RPM range. There will be a challenge getting the prop diameter (you are limited by the aperture opening) and pitch correct for that size engine. For the engine to have a long life you need it be able to operate at wide open throttle within 50 RPM of max under load specification. That came to me right from Beta as we discussed my engine install. If the prop is over or under pitched it's not good for the engine. It will also be harder to work on because space with be tighter than a smaller engine. I have never heard anyone say they have too much room to work on their engine.

I have not looked at the specs for a 28 but you won't be able to use all that horse power because you'll be at hull speed long before you get there. The difference in fuel economy operating at 80-85 percent of hull speed vs 100 percent of hull speed is stunning.

My CD 36 came with a Perkins 4-107 50 hp. I installed a Beta 25hp. It has worked very well. I originally planed for a 16HP. Got talked into a three cylinder ("it's so much smoother"). Ended up with a 25 due to the argument it was essentially the same size and future owners would want a bigger engine. The cost was only $300 more than the 20 hp. So I went with the 25. I can cruise at 2200 making 5.5 kts and burn about 1.3 liters per hour. 2500 RPM will get me 6 knots. WOT will get me hull speed on smooth water. A small 20 gallon fuel tank will give me almost 300 miles.

I sailed the boat from NC to the Virgin Islands two years ago with the 25. It all worked out but my view is I would have been just as happy with the 16 or 20 and had more space to work on/maintain and I could have run it at at 2300-2500 RPM (better for it) and got the same range as I get now at 2000 RPM.

The Beta is a great engine. It's not difficult to install, especially as a repower. I personally think you'd be thrilled with the performance and reliability of a Beta 15. But probably some of that is mindset. Be true to yourself. If you are determined to have the biggest engine you can shoehorn into your boat then go for it but accept that it's not going to do more for you than the 15 hp.

Here is a thread on my engine install. Maybe there are some ideas there.
https://farreachvoyages.net/2020/01/08/ ... #more-2593

A YouTube video on the install: https://youtu.be/JcwbQ2jAyNM?si=km85CYKoZvY-zTGr

[keneasley]

Regarding:

"I have the usual copious amounts of water coming out the exhaust. In neutral at idle the temp gauge goes to 250 in 20 minutes. The manifold gets very hot. The coolant does not. I am thinking I have a blockage in the manifold. I ran it without a thermostat."

As a coincidence I have been helping a friend get his old Volvo diesel engine running on his 1978 Sabre 28. That engine is original and may be similar to yours. He had an overheating issue for years and lived with it because he is on a mooring with a short run out of the harbor to sail but this year he decided to fix it.

Anyway...the problem was in fact the manifold which was very clogged with a thick black hardened gunk. We removed the manifold bolts (which surprisingly were not seized on) and he took it home. He soaked it in vinegar and spent some time digging into the many small water channels and removing the black gunk. The channels in the engine were also blocked and were cleaned out as best we could. Then we reassembled with new gaskets. It was fairly difficult to reassemble because the manifold also held some metal water lines in place, and they had o-ring seals. We just got it started last week and that seems to have corrected the overheating. As you said - the water was running through it and out the exhaust. The problem was the manifold was blocked such that the cooling water never got through to cool the engine but rather it bypassed the engine. It looked to be designed to allow water to bypass if blocked

If you like I can post some of the pictures of the manifold. But maybe you've decided to replace the engine. Let me know.

It was not rocket-science to fix but it was very tedious to reassemble and tricky to bend and seal the metal pipe so that it didn't leak. He was lucky to find a new old stock replacement pipe. The old one got cracked during disassembly.

[RichardM]

I repowered with a BETA 20 three years ago and have been happy with the conversion. CD 28 original Volvo MD7A died after 42 years. BETA 16 would also have worked but decided on BETA 20 due to availability and additional HP to push thru wind and waves on Buzzards Bay if necessary to get home. Parkers Boatyard did the conversion and were excellent for the work that was done. Give me a PM if you want to talk.

[Dave Sherman]

We repowered with a Westerbeke 12. It's been very reliable, and very loud. We will get up to hull speed between 2500-3000 RPM. It will punch us through the waves fairly well. I sometimes covet the 16, but realistically don't need the extra power. I'm sure the Beta 14 would be adequate, but get the 20 if it helps you sleep better (assuming the prop and pitch are comparable)

[pschwa]

From October 2023 to August 2024, I repowered our new-to-us 1975 Cape Dory (#57) with a Beta 20. The length of time it took was a function of the fact that the boat, then located in Camden, ME, was over 500 miles from my home in DC. I completed the repower over the course of three trips north, a total of about three weeks of work. As part of the repower, I also replaced or renewed everything attached to the engine - fuel lines, fuel tanks, exhaust system (all the way to and including the vent), engine controls, raw water through-hull, prop shaft, prop, cutless bearing, stuffing box, etc.

The boat’s original Volvo Penta MD2B was dead with lost rod bearings at the time of our purchase. We considered rebuilding it, but several conversations with knowledgeable people (including vintage Volvo expert Dick Vosbury of Vosbury Marine in Annapolis), along with our desire for the highest degree of engine reliability, led us to decide on a repower. A major factor for us was the limited availability and high cost of parts for the MD2B, which is a significant issue with engines that have been so long out of production, and which were not based (as most current small marine diesels are) on “commodity” non-marine diesel engines.

We looked at the Beta 16, but went with a Beta 20, and we are very happy with the decision. It will power the boat up to hull speed on calm seas, and the added power was welcome when my friend and I had the wind directly on our nose, with occasionally moderate seas, during almost the entirety of our seven-day passage to bring the boat down to its new home on the Chesapeake. The three-cylinder 20 is theoretically a smoother-running engine than the two-cylinder 16, and even being slightly larger than the 16 (but still small compared to the monster MD2B…), there is still relatively clear and easy access for maintenance. We had no issues with propeller matching - I procured a used, low-hour 13” Max-Prop Classic feathering prop, and set at the recommended equivalent of 9” pitch, it hit max RPM at full throttle on the first sea trial. That propeller does have a bit of interference with the rudder when it is not feathered and the tiller is VERY (~80 degrees) far over, but it has not been a concern, and I understand is not uncommon even with a more compact fixed prop given the modest aperture size on Cape Dorys.

Happy to answer any other questions you may have about the repower. Apart from help lifting the old engine out and the new Beta in, I did all of the work myself, and learned a lot along the way.

All the best,

Peter
1975 CD28 #57 “Spondee”

[Wayne Grenier]

Peter:

I would love to talk to you.

I have the old vovlo mD 11 out and my first impression is that the propeller shaft flange on the volvo is much lower than the Beta 20 in relation to the motor beds.

I have an angle iron engine bed that is not adjustable.

were you able to get the Beta 20 output shaft to line up with the propeller shaft flange? without changing the engine bed?

in that you have done this before I would greatly appreciate your input. Either by this board, a call or a private message. I would love to pivk your brain.

Thank You

Wayne Grenier