Auto engine marinization

It's a Mercruiser "factory replacement block". Sorry, I would have elaborated more yesterday but my computer is giving me fits.

 

Is it a "true" photo or just something posted on the web? So is mercruiser now using the weaker two bolt main blocks?

 

I'm not sure if it's an actual photo (no way of knowing), but i've rebuilt a few Mercruisers with 2 bolt blocks. I've also seen 2 bolt blocks from PCM, Indmar, Crusader.....

 

It seems like marinizing engines deserves a forum of its own. Perhaps with a boxing ring It brings forth more debate than anything else. I am going to start a thread suggesting a separate forum.

 

I can see where a two bolt small block may be OK in say a 19 FT bowrider, relatively light load, never seeing blue water kinda thing. I had one in a 26 FT trojan in semi-protected waters. I don't think I would trust one in my current 50 FT where my small blocks seem under powered. I have to run in excess of 3400 RPM to get in the mid teens.

 

It seems to me like most of differences in the long block assembly relate to the use of raw water cooling. SS head gaskets and brass freeze plugs being the most obvious. So if you run a heat exchanger where all the engine sees is antifreeze mix, why would you need that stuff. I'm trying to decide which route to go with the 350 in my 19' Renken. I'm strictly a small lake guy where having a breakdown is not the biggest deal in the world. It seems like buying a heat exchanger and setting up fresh water cooling would be a lot cheaper than building and trying to maintain the full marine version. From the number of people in this discussion, I would say that the "marine" motors don't hold up all that well either. It's just a tough environment for any engine.

 

"Hold up" is very subjective. A car engine would work fine for the usual 100 hour a year 1000 hour service life usually designed into most outboards.

Car engines suck in big boats where they drink 25gph each and don't last very long running 12 hour days.Used at 5 to 10 gph would make all the difference.

A second water pump will be required to use a heat exchanger cooled car engine .

The heat exchanger should be figgured on cooling the exhaust manifolds too, and after the exchangers (engine & tranny) the sea water is dumped into the exhaust .

The usual seawater pump is a Jabsco , so needs to have impellers renewed every season , 300 hours , or sooner if you run in dirty shallow water.

Marine kits are avilable to do this to a large number of engines.

455 Olds Rocket power?

FAST FRED

 

Hi back into fight LOL

A part of a post that I did in the beginning, some superflu calculation

The endurance: I mostly drive my cars (2nd hand BMW) 160.000miles avg speed 50 Mph this means 3200 operating hours. A big deal of that time (if not all the time) on the highway I drive 107 Mph 4500RPM.

Even I would say avg RPM during Holliday trip
4000-4500 during 12 hours, making only a stop to fuel up, avg consumption 8L/100Km
DIESEL

Daniel

 

So the pump in the stern drive leg isn't up to the job of supplying the heat exchanger? As far as use, in my case, if I managed to get 20 hours of run time in a year it would be a miracle. That's another reason I like the idea of running antifreeze, no plain water sitting in the block between runs.

 

A little info: My last boat was a 1976 Marinete with a 360 Chrysler marine, raw water cooled running in Brackish water, the Chesapeake Bay. It had the original engine. My current boat, a 1976 Burnscraft 350 Chevys raw water cooled, one engine is the original. I don't know what happened to the original. Replacement is from Jasper, I found the reciept. Turns 350 RPM less then the original engine. Probably one of those pesky two bolt main engines Anyway with proper flushing and winterization as well as corrosion protection raw water engines can last a long, long time. Oh one more my 1965 owens had raw water, lived in the chesapeake it's whole life. The engine was still good in the year 2000 when I sold her. So there is a 35 year old raw water engine. If you are running in a Lake I would not bother fooling with fresh water cooling.

 

Antifreez is a very poor coolant, it has only 5/8 the heat caring cap of plain water.

Yes it is good at not freezing , raising the boiling point and has great anticorosive abilities.

If overheating is a problem only 1/3 of the coolant needs to be antifreez to obtain the anticorosive ability.

Diesels need special antifreez and should never use "car" goop.

FAST FRED

 

Hi everyone!

marization of a auto engine is possible and in Europe people are doing it.

Try Seenergie.fr, they have a kit for DiY marinization of the PSA diesel motors Peugeot-Citroen).

All depends in what boat do you have, what for, regular use and so on.

I'm not a rich person but I manage to convert an old cargo ship lifeboat to a 7,50 meters gaffrig for 4 persons, did all the wor, sew the sails and now is marinizing a PSA motor...

greetings

ndias

 

What is the cost of marinizing an old automotive engine versus buying a used marine engine? In my experience a used marine engine is cheaper. If money is a problem, a custom job makes no sense.

 

Hi

In europe boats run with inboard diesel and outboards with gasoline.
Problem that second hand marine diesel motor are veryhard to find, so or you buy a new one or you marinize.
In Portugal, the new Yanmar of 25 hp cost 7300 euros, a Bukh of 25 hp costs 9000 euros. Buying a PSA or Opel 1500 diesel costs you 400 euros and a PSA motor from France with the marinizationdone from factory costs you 4700 euros.
I bought an Opel for 400 euros and the kit (tachometer, hourmeter, voltmeter, raw water pump and heatexchager) for 300 euros, if you put some gaskets and joints, I can for 800-900 euros have the motor marinized.

 

I think Gonzo is totally right on this if the engine is a brand that has never been marinized. I want to use a Infinity V8 or a Nissan Titan V8 - same basic engine. I trust the engine more than any other. The amount of time and money is proving to be a lot more than expected. Plus I and a bunch of experienced guys are going to have to buy- layout- fit- mount- take off- refit- the brackets for a lot of parts to mount on the engine. It is not a project to start unless you have people who like to help others. AND have the talent not to take short cuts when it bogs down. We thrive on bringing back to life any " dead boat ". Money- just have 3X more than you would think you honestly estimated. Do it with others, safety AND more ways to solve a toughy. Rich -------------------Here is a surprise I just heard, Cadillac is now ordering dealers to toss any new blocks that need a rebore of any amount, as they are casting wall thickness only to meet warrenty life expectations. Big volume is going to close a lot of good independant marine rebuilders. We have all been lucky to live in the age before real cost cutters take control of all we love to do with our boats and engines. If I were 25 I would buy a couple (6) GM marine long blocks- correctly prepare them for long storage and use them as a pension fund which will definatly go up faster than money. Anybody have any perfect Deusenberg engines? Rich