A27 99hp Repower - Yanmar or Beta

[DonGuy]

Hello,

I'm setting out to replace the Nissan in my 1986 A27 SC. Currently looking at
the Beta 105 or Yanmar 4JH4-HTE, both 99hp. I'm looking for an easy slow cruise
at 7kts, and fast cruise a little above the magic 11 kts. Plus a little
headroom. New engine, gearbox, prop. Same 1 1/4in shaft.

I'd be greatful for any opinions/comments/advice. I'm in particular wondering
how the two engines are on the "smooth and quiet" front. Thinking the Beta
might be smoother/quieter since it is heavier and runs at lower rpm - but I hear
the new Yanmars are pretty good too.....?

Other alternatives that are nice and smooth/quiet?

Thanks,
Don Guy
1986 A27 SC, NoName III
McGraths Cove, NS

[denchen]

Do you need as much as 99hp to get to 11 knts

[DonGuy]

From what I've been reading, mainly on the Yahoo AlbinCruisers forum, 99hp seems to be about right for a sustained fast cruise at a little above 11kts. I'm looking for an easy 11kts, with some reserve.

90hp looks like enough for sustained cruise at 11kts, but with no reserve.

My 78hp Nissan will just barely do 11kts, sometimes, but at 4000rpm and wide open throttle - can't cruise like that.

As a rule of thumb, it looks like 80-85% of max rpm is a typical max sustained cruise rpm, but I'm not sure if this is universal. Engines generally have ratings for max continuous rpm.

The prop needs to be sized correctly. I'm headed for a 19in 4-blade prop, not yet sure what pitch.

There is an interesting table on Yahoo group AlbinCruisers, in the database section.

[CayoHueso]

What do you intend to do with your Nissan 78?

[DonGuy]

I haven't yet made a decision on path ahead - the cost to repower is giving me pause....
Might have the Nissan injector pump and injectors refurbished and just stay with it. If I repower, the Nissan will be for sale.

[jleonard]

Let's crank up that Nissan and add some ponies!

[DougSea]

Let's crank up that Nissan and add some ponies!

Is there an easy way he could do that? Different injector set or some such?

[jleonard]

You can likely crank up the pump for starters.

[DonGuy]

I'm intrigued, but don't know how to proceed. Haven't heard of anyone working up the Nissan.

I've some experience with gas engines, but none with building up diesel engines. Will ask the pump/injector overhaul people. Another consideration - presumably there is some limit to what the engine block, pistons etc etc can take.

I appreciate the idea - thank you.

[DougSea]

I started doing some looking around to see if I could find any additional info for you but there are a bunch of models out there. Can I ask the specific model? Turbo charged?

I'll post if I find anything. Best of luck!

[jleonard]

Sounds like you don't need much, maybe an additional 10% or so. You don't want to go too much or you will compromise longevity.
I've cranked up several Cummins 6Bs, they are easy, and I know how to tweak a Perkins T6, and VWs, but never did a Nissan.

[hetek]

My 27 FC has the Lehman 4D61 (4 cylinder, diesel, 61 hp) which is the same engine as the Lehman 4D50 except the 4D50 has the injector pump "detuned".

Bob Smith, of Lehman fame, told me the 4D50 was offered for a client that only wanted a 50 hp powerplant. They just took a 4D61 and tuned it down to 50 hp.

I looked into a repower once and came to the same conclusion as you. It's a very expensive proposition for only a few more knots.

[Russell]

How do you crank up a Cummins 6B? If I could get 10 percent more out of my 250 hp it would be fantastic.

[jleonard]

Unfortunately the 6BTA 250 is not a good candidate for bumping up as it's already marginally cooled.
Does it have a Bosch injection pump? Those are pretty easy to tweak. A lot of the truck guys turn theirs up, you can buy fuel plates at many performance shops online for around $200 and 330 or 370 hp injector sets for $300.

If it's a Mitsubishi pump I have never worked on one of those.

[DonGuy]

Doug, jleonard - it's a Nissan LD28M. In-line 6 cyl. Diesel Kiki pump (much like Bosch) and injectors. LD28M is the marine version of the LD28, which was used in the mid 80's in Nissan Maxima cars, various industrial rigs, and boats. No turbo. Rated at 78hp at 4000rpm. Getting it to 90hp would be enough, 100hp would be perfect. I appreciate your interest and assistance. Thanks, Don