Re-power Perkins 4.108 with Beta 38 or Beta 43?

[BozSail]

Considering replacing my wornout Perkins 4.108 with a Beta. I don't know whether to go with a Beta 38 or a Beta 43. My boat is a 1981 Endeavor 37 that displaces 21,000 pounds. Has anyone done a similar re-power and what was your satisfaction level?

[Marathon1150]

We recently re-powered our Benteau Idylle 1150 with a Sole Mini 44. The Beta 43 was also suggested as an option by the yard doing the work. We chose the Sole because there was a promotional price available. The total cost was nonetheless eye watering.

The Sole easily has enough power to drive the boat but is noisier than the Perkins, which, was a remarkably quite engine. The Sole is based on a Mitsubishi engine but finding non-Sole parts like filters etc is challenging.

[ohdrinkboy]

The general rule of thumb i've always heard is 2hp per thousand pounds of displacement. If the 43 fits, I would go for that.

[donradcliffe]

I repowered a Beneteau 456 which had a design displacement of 26,000. Beta recommended the 37, and I went with the 50. Never regretted that choice. The install was pretty simple, because I could use the 4108 exhaust system, and the Beta was on the same side. The Beta 50 was smoother and quieter than the 4108.

[stormalong]

I replaced a 4.108 with a Beta 50. Beta marine recommended a 43 but the 4.108 was underpowered for my 12.5 ton (design) and actually 15 ton in the slings boat.

The Beta is narrower and a little longer than the 4.108. It fit my engine space just fine. Measure the length of your engine space carefully. One more thing. Beta will do custom engine brackets for you. Here again measure very carefully. The custom brackets will save you a huge amount of time doing the swap - well worth the cost. With careful planning I did the swap in less than a week.

[Katapult Mike]

Originally Posted by BozSail

Considering replacing my wornout Perkins 4.108 with a Beta. I don't know whether to go with a Beta 38 or a Beta 43. My boat is a 1981 Endeavor 37 that displaces 21,000 pounds. Has anyone done a similar re-power and what was your satisfaction level?

A Perkins 4.108 is never really worn out. They can be rebuilt endlessly with new pistons, liners etc. Parts are amazingly cheap - you cna get a full rebuild kit on eBay for $500. If you get the old perkins going, you won't have to change the skids, shaft, exhaust, prop,engine compartment or anything. Repowering is incredibly expenive. Look into rebuidling instead.

[Tia Bu]

I replaced a 4108 with a Beta 38 seven years ago. Never regretted it. The 38 has a lot more power than the Perkins in real life.

[stormalong]

Another bit of info you should know.

The Beta 43 and 50 are the same block with a different cylinders bore. The overall dimensions are the same for both.

[Searles]

Forget horsepower torque and desired shaft rpm is all you need to consider, remember a larger engine will in mast cases require a larger exhaust system,back pressure must be considered as well as available free air for cooling and combustion,it’s probably cheaper and easier to fully rebuild the 4108 as everything already fits .⚓️⛵️

[W32PAMELA]

I replaced a perkins M50 with a beta 38 in my 20,000 lb Westsail 32 a few years ago and find that it is smoother, uses a bit less fuel and I don't notice any power loss.

[FPNC]

When it comes to replacing a 4.108, it really depends on the vessel.

The continuous HP rating for a 4.108 is 37 hp @3000 RPM. However, due to price and availability, the 4.108 found its way into anything from a 30', 10,000 lb boat to >40' >25,000 lb boats.

It is a good idea to base your new engine power on the vessel displacement and water line length and the largest diameter propeller (blade area) that you wish to turn.

[NorthCoastJoe]

I replaced a Perkins 4108 with a Beta 50 in a 44 foot 30,000 pounds loaded boat. The only thing that really was close was that the Beta was a little longer but made it in the existing space. I had to make a custom exhaust elbow and motor mounts. Otherwise it was an easy job for me working alone not at my home port.

" There aint no replacement for displacement " Old street racing saying.

So if your gonna do it go with the 43 or 50 it is always nice to know you have more juice if you need it.

I also have a Pearson 30 running a Yanmar 3GM30F again a bit over powered but with a matched prop I have punch when I need it.

And I am not a motor head, Plenty of sails to chose from too!