Help with Repower Question

Hi All! I find comparing diesel engines very very confusing! Specifically, in planning a Repower of an existing perkins 4-236 would I be better off getting a new warranty 4-236 or going with perkins new replacement for the 4-236 which is the M92B? Help pls.

Thanks in advance.
P.S. . I Have no clue how to choose old vs new.

Take a look at the Beta Marine 85 hp which is a big displacement, slow reving- 2,800 rpm at max hp engine. I think it is based on an Isuzu block and Beta's marinization is first rate.


Another smaller displacement, turbo charged possibility is the 2 liter Yanmar 4JH-TE (I think I got that model right). No after cooler to worry about but I would only go with this engine if I were going to cruise on 30-40 hp. Otherwise the Beta would be a better choice with its big cubes.


Beta is very helpful with installation and provides engine mounts to match your existing stringers. It comes with a serpentine belt system that Beta will fit with a Balmar high output alternator.



David

I second the Beta Marine 85

The Perkins should be a relatively easy swap, like for like. You can reuse transmission, mufflers and such.
Check out www.TADiesels.com


What happened to the old engine?

A friend of mine is in the same boat .. basically.

His Perkins 6 cyl lost it’s harmonic balancer and destroyed the splines on the crankshaft. The engine is in the shop awaiting the new crank. I didn’t ask him how much it cost.

But before he got to where he is he had the choice of buying a new and different engine. A comment he made indicated he didn’t like modern engines. When I repowered and got my Mitsu engine from Yukon Engines (then Klassen) and would almost no doubt go the same route again.

When I think of old engine v/s new I think of a fellow Willard owner that had his crankshaft break while running northbound in Chatham Strait brobably near Angoon on Admiralty Is. That was the 4-107/8 Perkins engine in a 30’ Willard boat. Never heard an explaination why the crankshaft broke at cruising rpm but one can only wonder if it was problem w British steel at the time of manufacture. Don’t know.
I’ve always been a fan of rebuilding old cars but a broke down car can almost always coast to a stop on the road quite safely. I thought about that after our engine dropped to an idle and wouldn’t do more for several minutes. That was 150 yards off the rocks at Cape Caution BC. On-flow breeze for additional pucker.
For those that are curious it was an air in the fuel lines problem. Not the engine.

Rebuilt old engines aren’t usually tested for metal fatigue or other defects. New engines are no doubt much more and more often QC checked for many elements of quality. But they may vary considerably brand to brand or even year to year of manufacture.

I bought a new converted industrial engine and consider it the way to go generally speaking. But one could have a special boat whereas the engine is part of it’s specialness. For example if I was dealing w this posts question and I had an old Forest Service boat I’d prolly keep the original engine that would probably be a DD. Or if I had a 46’ Monk soft chine wood boat from the 50’s w a Chrysler Royal flat head straitght 8 .... I’d rebuild if I could.
Otherwise it’s a personal thing. But IMO it should be a question of what is the smartest and wisest course to take. In my case if we wern't going to Alaska to live the old Perkins would probably have served us well here in Puget Sound. So it’s very dependant on individual situations. But if one can afford it a new engine is most likely the best route .... depending on the many variables.

David and Pack Mule- thank you for the response! If I'm reading spec sheets correctly the Beta 85 is of the new breed of diesels appearing to be at least 200 lbs lighter than the perkins m90 and the new m92. I subscribe to the rationale that the slow rpm big pounds per hp blocks are the best longevity engines in slow heavy trawlers, like the m90 series.
High Wire- I plan on replacing all exhaust and periferal equip with new at swap time, including tranny, shaft, prop etc. Existing eng still ok, just want to start out new life with all new equip.
Nomad Willy- Very comprehensive reply. Based on your ideas, which were new thoughts for me and I agree with what you wrote,, think you're saying I should go with the new m92. Thanks!! P.S. being a Willard guy you maybe will appreciate that my boat selection has finalized on the Willard 36 aft raised pilot house. Love that layout beyond all other trawlers!

The Beta 85 is an excellent engine!
Not Isuzu...it is a Kubota diesel. Wonderful products.
It is NOT electronic (bonus)
Very low pressure turbo
NO after cooler
Not super high pressure common rail injection (yet meets tier 3)
As mentioned, low rpm at 2800 max
And much simpler than many new engines

What’s not to love?

Durant F wrote;
“What’s not to love?”

Probably the price.
As a British product parts and service may be questionable.
And ya gotta like red.

2800 RPM slow reving?

How about 325? That's slow reving....

Portage_Bay said:

2800 RPM slow reving?

How about 325? That's slow reving....

Click to expand...

Not slow reving but slow rpm. Graphs/spec sheets suggest cruise normally at 960-1200 rpm, that's slow rpm to me.