Engine repower

[Carol Calvert]

Hi all

 

I would appreciate some help please.  Repowering p40, removing the nanni and replacing it with a Yanmar 4jh5e 54hp at 3000rpm. I have noted a few comments from people that have gone down this path and all seem to be positive.

Some questions:

·         The shaft size is 32mm/1 ¼”, prop dia = 16in. Did you need to go to a different prop size or shaft size?

·         Any suggestions on what should be factored into the engine project at the same time?

 

Regards

Daryl

[Anthem]

Do it - you won't regret it.

We repowered Anthem with the 4jh4e a few years ago - we love it.

The old Nanni was working, but getting weaker by the year and the
sound drove me nuts- It sounded (to me) like it was going to blow
apart any minute.

The new engine is quiet, smooth and powerful. That, plus new sails
really added enjoyment to our adventures. Motoring or sailing in the
7's, with potential for more is quite a treat. Our only regret was
not doing the engine swap sooner.

We changed shafts just to be prudent (my new word for the year) - same
size, and reinstalled/repitched our 17" Maxprop. It's a great set up.

The boat has amazing power - we towed a Hans Christian 43 across the
Chesapeake (had no choice, they were our boat neighbors) in
conditions that would have had the Nanni in a hissy fit, even without
the tag along.

The only thing we've changed is the alternator. We had it rewired for
an external regulator, which we added - it makes a huge difference in
charging.

Bob Peahl
Anthem P40/70

[Michael Moradzadeh]

I am still holding out for electric power.� Problem is, to do distance work, I need a diesel generator, and then it's just... stupid.

Michael
Cayenne (home of the Nanni) Passport 40

Anthem wrote:

Do it - you won't regret it.

We repowered Anthem with the 4jh4e a few years ago - we love it.

The old Nanni was working, but getting weaker by the year and the
sound drove me nuts- It sounded (to me) like it was going to blow
apart any minute.

The new engine is quiet, smooth and powerful.  That, plus new sails
really added enjoyment to our adventures.  Motoring or sailing in the
7's, with potential for more is quite a treat.  Our only regret was
not doing the engine swap sooner.

We changed shafts just to be prudent (my new word for the year) - same
size, and reinstalled/repitched our 17" Maxprop.  It's a great set up.

The boat has amazing power - we towed a Hans Christian 43 across the
Chesapeake (had no choice, they were our boat neighbors)  in
conditions that would have had the Nanni in a hissy fit, even without
the tag along.

The only thing we've changed is the alternator.  We had it rewired for
an external regulator, which we added - it makes a huge difference in
charging.



Bob Peahl
Anthem P40/70

On Jan 29, 4:09�pm, "Carol Calvert" <calve...@bigpond.net.au> wrote:
  

Hi all

I would appreciate some help please. �Repowering p40, removing the nanni and
replacing it with a Yanmar 4jh5e 54hp at 3000rpm. I have noted a few
comments from people that have gone down this path and all seem to be
positive.

Some questions:

� � � � � The shaft size is 32mm/1 ��, prop dia = 16in. Did you need to go
to a different prop size or shaft size?

� � � � � Any suggestions on what should be factored into the engine project
at the same time?

Regards

Daryl
    

[Bill Schmidt]

Hi, Daryl. Sorry to take so long to reply. I was at the Seattle Boat Show (terrific).

    We repowered Wind Witch with the same series Yanmar several years ago. I wrote then about the experience and the results, but have lost those letters when my hard drive crashed. Perhaps Michael Moradzadeh has them.

    Anyway, in summary: we did not replace the prop shaft nor the prop. But we found that the 16" MaxProp, pitched at 11 degrees for the Nanni ,was WAY underpitched for the Yanmar. We increased the pitch to 26 degrees and have had enormous power reserves. We can still run @ 3800 rpms w/o overheating, no problem. Given unlimited funds and discretion, I probably would like to have an 18" MaxProp, pitched lower, but we have lots of power to cruise up the West Coast from SF Bay To British Columbia in all kinds of foul weather. No stalling out on square waves as we had experienced with the Nanni. Our fuel consumption has gone up about 1/4 gph, running 2800 rpm and typically moving 6 1/2 knots.

    We had the engine bed refabricated so that we could mount the engine flat, using the angled transmission option for the Yanmar. In retrospect, this was a lot of work and cost which I don't think was worth it.

    One of the alarming things we found while removing the exhaust hoses was that there was a severe stricture of the exhaust outlet causing high back pressure  for the Nanni all it's entire lifespan. Consulting with Yanmar engineers impressed me with the admonition that diesel engines HATE exhaust back  pressure. As a result, we completely replaced the exhaust system such that the entire system is 3" I.D. I am certain that we have, as a result, gotten a lot more power out of the Yanmar with a lot less stress on the engine.

    With the new hoses going into and out of the water lift muffler in the keel (the old pipes were cut out and new, bigger pipes were inserted and fiberglassed into the same keel cavity unit), getting to the old keel cavity mounted bilge pump and switch - never a delight anyway- would have become an impossibility. So we mounted a new bilge pump up over and behind the new engine with just the pickup strainer in the bilge and just a diving bell sensor for the bilge switch (also mounted up out of the bilge area) mounted on a platform in the bilge, but removable to clean/clear them. I recommend this system even if you don't replace the exhaust system. Incidentally, the Yanmar engineers said "OK" to the old system hoses (2" diameter), but were not happy about them - too small a diameter. We even removed the fiberglass outlet from the side of the hull and put in a 3" bronze outlet. No regrets there.

    We left the Yanmar alternator in place and mounted a high output alternator forward of the engine underneath in the bilge cavity such that the drive pulley was in line with the Yanmar drive pulley. That has worked well. We found out that we could wire the field wire of the high output alternator in parallel with the field wire of the Yanmar alternator so that the Ample Power Smart regulator can drive both alternators simultaneously, but have never gotten around to doing such. We have left the Yanmar alternator in place disconnected as a backup if ever needed.

      This is a good time to pull the prop shaft and replace the cutlass bearing in the strut, incidentally. Also, if you have a folding prop that is getting worn and "loose", this is a good time to send the folding prop in for rebuilding. We did that later and could have saved time and money by doing it while out for the engine....incidentally, I forgot to mention that we did not haul the boat to replace/rebuild the engine.

    If you have been following this website long, I am sure you already know how delighted I think you will be with your new engine. Let us all know how it goes.                       Regards,     Billy Manana

[Anthem]

Daryl,,

As noted, we replaced the Nanni with the Yanmar. With respect to the
exhaust, after discussing this with our mechanic and with Yanmar, both
advised that the current exhaust components be used. We use 3" hose
and muffler with reducers for the thru hull and the thingy dingy in
the hull. Exhaust pressure was tested after installation and was well
within Yanmar tolerances. We were aware of other installs like this
and no one has related problems.

I have the impression (from the Yanmar guy) that the 3" sizing is
simply a current norm and appears to be more critical if you get the
turbo version of this engine. FYI, a friend has the turbo - the boat
stands on end when he guns it - he'd prefer the aspirated version ,
noting that the turbo is handy if you forget to untie and decide to
take part of the dock with you - but that's another story.

Bob Peahl
Anthem P40/70