L-36 topics

Repower your L-36?

A series of emails regarding repowering
(Click HERE for service manuals on many engines)

I'm considering repowering Eagle Borne. I wonder which newer diesels have been successfully fit into the L-36 engine compartment. Would any of her sister's owners have suggestions?

Her existing is a 30-year-old Volvo Md11C. I found 22 HP somewhat underpowered recently while trying to power through a passage in a gale. Making 3 kts through water we only made 1 kt over ground. In flat water that same engine can make about 6.5 kts. Age is wearing on her reliability though, and the noise is rowdy.

Repowering is something I have undertaken twice with JOLIE (#68).

The first time was in 1980, swapping an Atomic 4 for a badly deteriorated Grey. It essentially was a simple change-out requiring only minor modifications. The second, in 1989, was a shift to diesel and the installation of a Perkins M35.

The 35 HP diesel somewhat overpowers the boat but does provide a reserve sufficient to maintain a reasonable SOA in heavy weather, plus cruising at hull speed at about 75% power.

The downside is that the engine is a tight fit, with minimum clearance along the port side of the engine box. Its also taller than the Grey and Atomic 4, requiring raising the cockpit sole about 4.5 inches. Some modifications were also required to the mounting base to accommodate a somewhat wider pan, and replacement of the original arrangement for throttle and shift control with a Morse system.

Incident to modifying the cockpit sole I also replaced the original - and most unsatisfactory - hatch with a watertight aluminum one that, although somewhat out of character for the boat, provides improved topside access and doesn't leak.

Some photos are available should anyone be interested.

On Leda we replaced the original Greymarine 4 cylinder twice (with Greys). The Greys gave us no end of electrical trouble, probably because the cockpit access hatch leaked salt water right onto the distributor cap, and eventually the light dawned when we threw a rod through the engine block right motoring home from a refit at List Marine in Sausalito. So in 1994 we installed a 3 cylinder Yanmar diesel. It has been rock solid reliable ever since and provides ample power (even with our folding prop) to motor into a big headwind/headsea combination. No major structural modifications were required. List Marine in Sausalito did the work; they were pricey but did a great job (and gave us a credit for the Grey they had destroyed). If you want to know any specs on the Yanmar (model number, displacement or whatever) let me know, and I can likely dig it out of the archives.

Cheers, David James Leda, L36 #71 Belvedere, California

I thought I would document my experience for the list for completeness even though it isn't what you were looking for directly.

I have a Greymarine 4 like David did on Leda. Unlike David, I have had very little trouble with it once I got new fuel lines installed and bypassed the old fuel pump. Previous to that, crud would get into the carb and cause no end of problems. Other than that I have had only two other problems with it over the 19 years I have had it. One was that the water pump froze up. I was able to get a rebuilt one, which solved that problem. The next problem was a blown head gasket. There are 15 very hard bolts holding the head down. 5 of them broke when I removed the head. If anyone wants to know how to drill out head bolts, let me know. I put a new gasket in and all is well.

The interesting part of the head gasket episode is that it allowed me to inspect the cylinder walls for wear. I have rebuilt many engines over the years and I have never taken one apart with no noticeable wear as was the case with this engine. I found that to be a good sign.

If I do need a new engine or throw a rod like David did (didn't the boatyard close the water inlet seacock or something?), I would replace it with another one just like it. This is only possible because of Vanness Engineering. In fact, my ability to fix the water pump and the head gasket were only possible because of Vanness Engineering. His business is these old engines and he knows them well.

So, if you decide repower with a replacement gas engine, contact Dave at Vanness Engineering. The contact information in on the L-36.com web site.

As for power, it is fine except when it is blowing a gale. The only time I had trouble was with 30-45 knott winds in which case I couldn't move. I have only been out in those kind of winds once in 19 years. I have a very old 2 blade folding prop.

By the way, this is a great thread and I will post it on the L-36.com web site for future reference should anyone else have the same question.

Dear Mr.Walter Heins.

Allen Edwards of l-36.com has sent me your request about repowering your L 36.

The original motor inserted in my L36 "Paniolo' in 1960 was a 2 cyl Lister diesel which was air cooled. It had very little power and was very noisy but always reliable and would always get us in and out of our berth. So we put up with it for years, though under power in flat seas we could only power at about 3-4 knots. Because of this we sailed nearly all the time while others were under power.

In 1976 we finally decided to repower. We installed a 2 Cyl. Yanmar diesel model 2 QH20. This is rated as a 22 HP motor but with the 2.2 /1 reduction gear there is much more power given to the propeller. We also changed to a 3 blade 16" X14 R hand propeller. The weight of the engine was about 500 lbs.

It made a huge difference to cruising for then we could keep up with, if not pass, all similar sized boats when under power. It is also very economical, using about 3/4 Gal of fuel per hour at 1800 revs and at that rate we can go at about 5 - 6 knts.

It is salt water cooled so no need for a heat exchanger.

During the past 32 years that we have had the Yanmar we have had very little problems with the engine. The only expense we have had was that we had to have the gaskets changed a few years ago but otherwise the upkeep is only the change of oil every year.

Since we installed our new engine, Yanmar has developed newer and better models, in that they are lighter and more powerful. I know of other sailboat owners who have installed Yanmar motors and have been similarly impressed with their products. They are the largest producer of motors for sailboats.

I hope that our experience will help you in your quest for a new motor.

Sincerely, G.Westgate. of Paniolo.

My l-36 is about the same vintage as yours. I bought it very cheap from a non-profit. It has a Westerbeke 30b, rated at 27 HP, which was apparently put there in 1998. The engine doesn't run (the injector pump, for example, was full of gummy diesel) but it fits in the engine compartment. The top of the head cylinder head is pretty close to the cockpit sole so I don't know if i will be able to pull the head in place or not. The boats motor mounting beams had "shimms" bolted on to them to accomodate the motor mounts for the westerbeke Access is good except for the starter.

David Custodio

My L-36 is powered by a Yanmar 3GM30F. I find it to be very appropriate for the boat.

I have spent the past couple of years as an apprentice marine mechanic, so I am developing some opinions, and sometimes a little knowledge to back it up.

I don't have the MD11C specs available to me, but I don't think their hp is as high as you think. I typically see them installed in older glass boats of the 27' to 30' range. I expect their output is around 17hp. They are a nice and simple design. They tend to be smoky and not fuel efficient for their power output. Parts are getting hard to obtain and have become very expensive.

For our customers with this type of engine, we suggest they be ready to repower the next time something significant goes wrong.

All of the contemporary diesels are smaller and lighter than the MD11C for the power range appropriate for your boat. Volvo and Yanmar are the industry leaders. The important thing about that is that both have good parts distribution and because they are so common, marine mechanics are familiar with them.

You can save up to $1500 on the purchase price of another manufacturer's engine, but you may end up spending more to maintain the engine in the long run. We are just a lot faster at fixing what we are familiar with.

If you are going to learn to do all of your own maintenance, then an alternate manufacturer's engine becomes a viable option.

My Yanmar 3GM30 is theoretically a 30hp engine, but with the load losses of things like the alternator and the transmission, it is rated at 24hp. Our hull speed is around 7.25knots and I find we can cruise at 7knots over the water without taxing the engine.

Both the new Volvo and Yanmar "30hp" engines are rated for 29hp, or 20% more than the older model I have in my boat. Our shop is just finishing the install of a new Volvo D1-30 into a 1989 35' Beneteau. We will sea-trial tomorrow, but based on the performance we saw while tied to the dock, it will have no difficulty getting the boat up to it's 7.7knot hull speed.

My engine installation required some custom engine brackets to be manufactured. My engine beds (and yours too, I presume) are on 19 1/2" centers. Contemporary diesels want something like 15" centers. Plates were welded on to the stock engine brackets to bridge the extra distance.

This is a little simpler for the Yanmar Y3M30 than the Volvo D1-30. The Volvo port forward engine bracket is also the pivot mount for the alternator. Customizing is a little more complex, but shouldn't be considered a deal breaker.

The Yanmar 3YM30 comes with a 60A alternator standard or an optional 80A alternator. The Volvo D1-30 comes with a 115A alternator standard. Depending on your electrical system, this may be a consideration.

Generally, I prefer Yanmar, but that is probably because I am more familliar with them. Here on the west coast, Yanmar dominates the market. I do really like the alternator set up with the multi-groove belt on the new Volvos. Both products are a good choice. I would suggest looking around the area you plan to sail in to see which manufacturer is best supported.

As for cost, you are looking at something in the neighborhood of $10000.00 for one of these engines. With the world market as it is, prices are fluctuating quickly. It takes about a week for a professional shop to do a basic engine install, including pulling the old engine. Depending on customization of exhaust, controls, instrument panel, engine mounts, etc., the labour and additional materials will vary. For this D1-30 install, which is pretty simple, requiring a custom mixing elbow and a simple instrument panel was estimated at around $16 000.00 all in.

I hope this is helpful. I'd be happy to answer any questions.

Rick "Nyon", Hull 34, Victoria, BC

You can try opening the bleed screw and pumping the lift pump to see if you are getting the fuel flow you are used to. If it seems normal, the filters might not be the problem.

Pop both decompression levers on the valve covers and turn the engine over a couple of times by hand, just turning the fly-wheel. Is the rotation smooth and free? Any sticky spots? Noises? Irregularities could mean bearing damage or other internal problems.

I haven't pulled the injectors on a MD11C yet. They would need to come out to do a compression test. The injectors are mounted in a copper sleeve in the head. It can be challenging to remove them without damaging the sleeve. If the sleeve is damaged, the head will need to come off.

Here is a link to a shop manual, if you don't already have one:


To pull the injectors, remove the fuel lines and the bracket that holds the injector in the head. Try to pull the injector without damaging the sleeve. Sometimes, gentle tapping and rocking will work. You might try some penetrating oil, but don't force it unless you are prepared to remove the head and deal with the complications that go along with that.

Any diesel shop should be able to test the injectors for you. Print off the spec from the manual and take it and the injectors with you to the diesel shop (if only one comes out, take it in anyway). I don't know what the process is for servicing those injectors, but if they are out of spec, the shop should be able to tell you.

You will probably want to do a compression test next. A dummy injector and a compression gauge will be required. If compression is good, get the injectors serviced. If compression is bad, look at replacing your engine. The cost of a partial rebuild would be better spent on a new engine.

It looks like the MD11c is rated for 22hp after all.

If you can find a rebuilt diesel that is less than 15 years old, that is an option too. Make sure whoever rebuilt it has a good reputation and will still be around in a few years.

Good luck,

Rick "Nyon", Hull 34 Victoria, BC
Man, this is a terrific reply. Thanks for your input.

I had engine tropuble last time out. It acted like fuel starvation, as if a clogged fuel filter, but I have other reasons to suspect that it may have suffered lubrication failure. (It smokes and is harder to start). Maybe both?

While I'm winterized and not running, I'll have the oil analyzed. If the oil analysis comes back OK, i.e. no sign of overheated bearings or rings, then I'll replace all of the fuel filters (pre & final in the fuel line, and the OEM on the engine) and try to get her back up and running smooth.

Can you suggest any other approach? Can a compression test be done on the MD11C?

It's good to know that the Yanmar 3GM30 is a good fit for the L-36. I think we have a better service network here for them. I like the idea of a little more HP.

Again, Rick, thanks for your reply.

Walter Heins, "Eagle Borne" Hull 49, Anchorage, AK

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