New Question - Lehman 4D61 Engine Opinions

[allante]

Does anyone have experience with the Lehman 4D61 Engine? Im looking at a 27SC that has one with less than 1000 hours. Wondering if at only 61HP the boat would be under powered?
Thoughts Please????

[hetek]

A few quick points:

At 1,000 hours, Bob Smith (formerly of Lehman, rip Bob) would say it's a baby. Mine had just shy of 4,000 and I've heard of one hitting 8,000.

My 1984 27FC had the 4D61 as did almost all the early 27FC's. I'd say the FC (family cruiser) is heavier than the SC (sport cruiser). My FC cruised at 6 knots all day long but would hit 8.4 when pressed hard. Hull speed is its friend.

To be honest, I've never heard of an SC with a 4D61 before. Many came with much higher horsepower engines.

From what I'm hearing now, parts availability is a topic of concern. I always found what I needed (or had repaired or rebuilt) but that was quite a few years ago.

Hope this helps.

[DCatSea]

I agree with Jon B, the 4D61 is a tough engine and gives about 6-8.5 knots in the FC, with a 1 - 1.5 galls/hour fuel rate. Ours has 1520 hours on it and purrs like a somewhat noisy kitten.
Parts are a little tricky, but not unobtainable. You could also have parts rebuilt. I've had the alternator and water pump rebuilt, put in a new oil cooler, installed new engine mounts, v-belt, and most hoses which I found fairly easily at Autozone. Oil filters are also fairly common. Maintenance is quite straightforward (and I'm no expert), and there are still mechanics around who know this engine. I also had the Hurth transmission rebuilt and a new damper plate installed. Touching wood I've had no major issues (meaning I can handle them).
From what I have read, most SCs have larger engines, but if you are not into racing around at more than 10-12 knots, the 4D61 should push you along at a comfortable speed for ever.
Like the proverbial cockroach, the 4D61 should still be running after the Apocalypse or Armageddon

[allante]

Thanx guys. Ill probably go look at it this week

[motthediesel]

We have the same engine in our 27FC. While we don't have much experience with it yet (we bought it last October) I've never heard anything but good reports about these engines. In regard to parts, yes, it's a bit of a challenge, but so far I have been able to find everything I need. All the injection equipment is Roto Diesel, which is the same as CAV, and so any US diesel service shop can service the injectors and pump.

Would I prefer a new Yanmar? Sure, they're smoother and quieter, but the old French rattler will serve us just fine for now.

Tom

[DCatSea]

The Mighty Lehman/Peugeot will outlive us all. These things were build to push French delivery trucks along at Euro-speeds for hours on end, year in year out. A few thousand hours in a marine environment shouldn't faze them one little bit as long as you give them a minimal amount of "Tendre soin affectueux" (change the oil occasionally).

I'll be interested to see your comments on the 4D61-powered SC.

[allante]

Any thoughts as if the boat would be under powered?
There is another 27 I want to see that has a Yanmar 170hp. Big difference I would think in performance no?

[motthediesel]

Something I learned just recently. Peugeot is actually the very first company to sell diesel powered cars. They offered there first one to the public in 1928! That was a number of years before Mercedes Benz (who I thought was the pioneer) followed suite. Vive la France!

[DCatSea]

27 is a displacement hull, so I would think that sticking it with a 170hp engine would be like putting an F1 engine into an '84 Ford Escort; it'll go a little faster, but why bother?
Max economical hull speed of the 27 is SqRt of 27 = 5.2 x1.5 (ca. 8 knots) so all you'd be doing is using a lot more diesel to not go much faster. I've heard of them achieving 12 - 15 knots, but the consumption goes way up, and handling can become exciting (just like an overpowered Escort).
This is not a fast hull.

[hetek]

To answer the "underpowered" question...

I always wished I could go faster than what my 4D61 could deliver, but was it underpowered? To go hull speed (about 6 kts) it was just fine.

I've looked into an Isuzu 157 hp powered 27FC but never pursued it, let alone went for a test ride. Obviously faster but with a higher fuel burn. At best, these are semi-displacement hulls that will push a lot of water when at speed. I've heard this power combo would deliver low to mid teens in speed.

In the end, I determined that 6 kts was a very relaxing pace for me.

[Lockerman]

I just closed on a 90 A27. It has a perkins m80t and a ZF Hurth 250 transmission. I have the serial number but cannot find a ZF site that tells me the reduction for this unit.
Any advice?
Thanks,
Doug

[Ambler27FC]

I used to have an M80T in my 1989 27FC. I could not find a readable label or stamping giving the gear ratio on the Hurth. I convinced myself it was 2.74 - from an old brochure I think. It is a higher rpm engine, so 2.74 makes some sense. My re-engine performance calcs worked out well, so I suspect I was about right.

[REO]

I have a 4D61 in an Albin 27 and it seems to be about the right power for the displacement hull. The boat is most comfortable at about 6.5 knots. That is what the hull was designed for. More power does get you more speed, but it will never be on a comfortable plane like a planing hull. To us the more important issue is noise and vibration. Our engine runs fine and has few issues, but we are looking at replacing it because my wife does not like the tractor noise and vibration. I think other engines are quieter, but maybe someone who has experience with the 4D61 compared to other Albin engines could comment on the difference.

[Mainer]

REO,
My A27 sport has the Isuzu 157 hp engine and I have 4 layers of sound deadening on the pilothouse floor to reduce the noise. I couldn't install Sounddown on the under side of the hatches because the engine is so tall it touches the hatch in several places. My friend had a Yanmar repower in his A27 FC that was superb. Great fuel economy, very responsive, and most importantly very quiet.

The older diesels all seem to be pretty noisy. The Isuzu was meant to give fishermen more speed, and I knew a guy in New York who regularly did 12 knots with his. I cruise between 7 and 8, which is all the noise I can handle.

My wife finds it much more comfortable to sit in the aft cockpit when we are under way rather than with me in the pilot house, so she would identify with your wife.

Repowering an old boat is an expensive decision that is tough to justify when the original engine is still working well.

[Ambler27FC]

Concur with Mainer.

You might reduce noise by one or two decimals with a good sound-deadening solution. If there are significant vibrations above idle, then engine mounts and shaft coupling/transmission alignment want inspection. For the coupling, a couple hours with calipers, a wrench, and hammer could cut vibration a good bit.

I think a ~60Hp is right-sized, and 6.5-7 knots is the sweet spot.