Marinized Engine With Which Transmission ?????

[svquintana]

where do some people get this information?
All diesels have governors.
An engine that maintains it's rpm regardless of load has what's called a variable speed governor.
Most engines, car AND MARINE have limiting speed governors, they simply stop the engine from overreving.
A big, old, 2 stroke 71 series or 53 series is only good for sitting in the back yard and making your neighbors angry. Unless you're using it in the back woods, stay away from them for boats. They're very heavy and don't put out much power.
More cylinders = smoother running, simple.
Transmission for boats, zf is the most common. Twindisk is experiencing a bit of a resurgence, but zf is the most common and about the same price.
For 20-30 hp, zf 10m-15m or the older hbw 100- hbw 150.
Engine recommendations for budget minded builder. ASSUMING A USED ENGINE:
Yanmar, Kubota. I'd lean towards Kubota for rebuilding parts prices.
I'm building a 49 foot Cat and we're marinizing vw tdi engines (without turbo, so technically SDI). 40 hp at 2600 rpm, 60 hp at 3600 rpm, 450 lbs with tranny. We've rebuilt the engines to "new spec".
We're using the zf 25a transmission, it's hydraulic whereas I'd recommend a mechanical tranny for ease of repair if you're watching your budget long term. The zf 25a is the same price as the zf 15m, due to it's popularity and availability, but it'll handle up to 150 hp as "light duty" or up to 60 hp as "commercial duty".
There you go. An older yanmar or Kubota (even from a lawn mower) and if it doesn't have a transmission, zf marine.
Be very careful buying an engine and trying to get an SAE bellhousing to fit, it's not quite as easy as has been suggested. Supply is slim.
If you want more hp, try a vw from 1974-1995, they all use the same bellhousing and are mechanical engines. The TDI also shares a bellhousing but the engine is electronic and more difficult to marinize.
Pathfinder marine used to marinize the vw, look for parts on e-bay.
Someone recommended a popular UK supplier of marinizing parts, that's a great place to start.
Cheers.
Paul.

[svquintana]

Oh, if you're marinizing a new engine, don't bother. It'll cost you more than an off the shelf marine engine. If you're marinizing an older tractor engine, ok. But buying a used marine engine will save you money.
Paul.

[svquintana]

Sorry, the previous post should have read "old engine" tractor, car or otherwise.

[wolfenzee]

Aa far as which transmission I have, would recommend and have been recommended a Hurth transmission, they are said to be "bullet proof" and easy to repair...not to mention have a long relatively trouble free life.

[svquintana]

Agreed, but Hurth is now known as ZF marine.
Paul.

[wolfenzee]

Originally Posted by svquintana

Agreed, but Hurth is now known as ZF marine.
Paul.

I was just told I have a Hurth and the mechanic that told me talks about the Hurth in his boat...how long has Hurth been known as ZE...

[svquintana]

ZF bought Hurth in the 1990's.

[oldcal46skipper]

There seems to be many ex-perts (ex=has been, perts=drips under pressure) following this thread. I would like to see your resume of formal training, experience and the name of your current employer.

The OP asked about marinizing an automotive or industrial engine and which gearbox to use.

I agree with many of you that, unless you have extensive training, experience and a fully equipped machine shop, you will be much better off buying a good used marine engine and gear. Defining "GOOD" is the issue. The designer of an engine should first determine what it is to be used for and loads, fuel consumption, longevity, reliability, etc.

The applications for an automotive engine are very different than those of a boat engine. Without major modifications trying to use a car/truck/genset engine for a boat engine is a recipe for failure - IMHO. However, I have only been a "wrench" for 50+ years, have completed formal training and been certified for diesel engine, transmission,(gears), outdrives, outboards, etc. plus had my own business repairing the same since 1972.

My lists of good/bad are a bit different from some of you honorable cruisers who have posted. As a shop owner, Yanmars, Volvos, ZF, etc. bring me a lot of business, however, I have refused to work on those for several years. Details on request at my place on Bayou Chico over a cool beverage since I have been threatened with lawsuits by the "Green Grief" for telling the truth.

My "GOOD" lists include Detroit Diesels, Perkins, Borg Warner, Lister, older slow turning Yanmars and other slow turners. Please feel free to contact me off the forum to discuss, PM, email or come and visit.

Tom

[wolfenzee]

My transmission is the one recommended by the engine manufacturer...an engine designed for marine use....that is usually the best way to go.

[forsailbyowner]

Originally Posted by wolfenzee

Aa far as which transmission I have, would recommend and have been recommended a Hurth transmission, they are said to be "bullet proof" and easy to repair...not to mention have a long relatively trouble free life.

google hurth/zf and you will find pages upon pages of people complaining of their woes and failures. Im rebuilding one now and as typical am aghast at the gouging when it comes to the prices for parts. They fail often and zf makes a fortune from this fact by charging $85 for paper gasket sets. $45 for a thrust washer etc.... I saw one rebuild kit that was just friction clutches and gaskets that was $650 Borg warner on the other hand last and last through the decades.