Alternative engines mated to sterndrives

[HorizonblueDK]

Is there anyone here who has mated another engine to a sterndrive(Mercruiser, Volvo, OMC), other than the ordinary 3.0/4.3/5.0/5.7/5.8/7.4 etc?

Here in Europe we like diesel engines alot There are actually companies in Germany who converts Mercedes (diesel)car engines into marine use. They supply most of the parts needed for mating the engine to Volvo sterndrives.

I have also seen Rover V8, Jaguar V12 and BMW V12 mated to Volvo Penta sterndrives, those were probably home made.

But how about boaters in the US, have you made any "Frankenstein engine/sterndrive" ?

 

[Silvertip]

Re: Alternative engines mated to sterndrives

For the average boater here in the U.S. there is no need to engineer a custom engine/drive setup because there is such an abundance of GM and Ford engines which have used fairly standard bellhousing patterns for decades. Has it been done here? Certainly -- but it is not what one might consider a "common" occurance. You folks have a much different marine environment in that fuel costs, replacement engine supply, and other factors play a big part.

 

[coastalcruiser]

Re: Alternative engines mated to sterndrives

http://forums.iboats.com/showthread.php?t=422225

There is a diesel conversion thread on here,



I think the poster did an amazing job converting a diesel, but now looking at a gas engine.

Just like you I always wondered about that too but like silvertip pointed out it's just not economical.

 

[HorizonblueDK]

Re: Alternative engines mated to sterndrives

Intertesting thread with that diesel rebuild. A shame that he wants to go gasoline again, but he writes that the boat is underpowered and noisy, so I understand that he wants to do something. Actually I'm restoring a 25 fot Flybridge boat from A-Z and planning to convert a pair of Mercedes OM603 Turbodiesel from the old E-class(late 1980's) to marine use. 6 cylinder straight, approx 4600 rpm, 147 hp. This engine is pretty quiet for an old school diesel. The boat had 2x OMC 120 hp stringer engines and drives(removed now), so with the Mercedes engines, there will be a power increase. These engines will be mated to Volvo SX drives, I have made an adaptor(laser-cut steel) so it is fairly easy to bolt the two things together.

Anyway, I had a feeling that it was not that common to build special sterndrive/engine set-up's in the US, since parts for the GM/Ford engines are found everywhere and diesel are not that popular. Overhere it's a bit different.

 

[Bondo]

Re: Alternative engines mated to sterndrives

Anyway, I had a feeling that it was not that common to build special sterndrive/engine set-up's in the US, since parts for the GM/Ford engines are found everywhere and diesel are not that popular. Overhere it's a bit different.

Ayuh,.... What are ya doin' for the water coolin' of the exhaust on these oddball motors,..??

That's the biggest issue I see in freelance swaps...

 

[greg82255]

Re: Alternative engines mated to sterndrives

He basically had to fab up everything for mounts, exhaust, etc.

I suppose if you have enough time and resources to do it yourself, or enough money to pay someone else to do it, anything is possible..

I'd like to see some pics of this along the way - it would be really interesting to see how you are able to fit a mercedes engine to a volvo drive. I hope all the parts you are using are marine grade/ignition protected.

 

[HorizonblueDK]

Re: Alternative engines mated to sterndrives

I suppose if you have enough time and resources to do it yourself, or enough money to pay someone else to do it, anything is possible..

I'd like to see some pics of this along the way - it would be really interesting to see how you are able to fit a mercedes engine to a volvo drive. I hope all the parts you are using are marine grade/ignition protected.

I have a website with the complete story, so far. It is written in danish, so you probably don't understand much of the text, but there are pictures also.

On this page http://horizonblue.dk/22kvartal.htm there are some pictures of how the Mercedes engine is bolted on to the Volvo SX bellhousing.

The story from the beginning:
http://horizonblue.dk/Draco projekt.htm

 

[HorizonblueDK]

Re: Alternative engines mated to sterndrives

Ayuh,.... What are ya doin' for the water coolin' of the exhaust on these oddball motors,..??

That's the biggest issue I see in freelance swaps...

There are two German companies who makes watercooled manifolds, one is welded steel, the other cast aluminium. They are a bit expensive, so I plan to weld them myself. The exhaust holes in the Mercedes cylinder head are circular, that makes the job a bit easier.
Actually the proffesionally built manifolds are not more expensive than an original Volvo Penta Diesel manifold, but I also think that's expensive....

 

[Luhrs28]

Re: Alternative engines mated to sterndrives

Horizonblue: I don't know how to send you the link, but go on Youtube and do a search for "GM 6.2 L diesel marine". The guy who posted the video is "Villym". I think he's in Croatia as I recall. Anyway he did a really nice job fabricating his own exhaust manifolds.

Bert

 

[coastalcruiser]

Re: Alternative engines mated to sterndrives

I switched over from mercruiser 302 to volvo 350 much lighter.
the volvo drive fit in the same hole as the old alpha, I bought a complete package from someone that upgraded to a larger engine.
sold the old mercruiser to a guy that was converting from an older volvo 302 to mercruiser.
got the remote controls and guages too, so did the buyer of my old stuff.
i'm happy with the results very reliable and good economy, highly recomend the duoprop.

 

[wca_tim]

Re: Alternative engines mated to sterndrives

Here's one...

http://www.turbokart.com/turbineboat.htm

 

[HT32BSX115]

Re: Alternative engines mated to sterndrives

Here's one...

http://www.turbokart.com/turbineboat.htm

Yeah.......I love boating with ear protection!!

 

[williampagano]

Hi, to our Danish friend, God love your enthusiasm and courage. That is a great amount of work you have accomplished and undertaken. Good luck to you. By the way the original engines in your Flyfish pictures are OMC "stringers." I have a 1969 210 HP version on my Thunderbird 233. I have been thinking of re-powering also with diesels and would like your thoughts on the replacement size, and also whether Yanmar or Volvo preferences.

 

[GA_Boater]

Welcome William. This thread is over three years old and we prefer that you start a new thread instead tagging on to an old one. You will have better results because old threads are ignored by many members. Thanks.

 

[HorizonblueDK]

Yeah, I know that we are breaking the rules a bit here, but I (the OP) still read the thread :joyous:. Even though this is an old thread, the project I'm referring to in post # 7, is still in progress. There has been a lot of delays, but I have finally the design of the exhaust manifolds ready for fabrication. In a few days, a bunch of stainless steel pipes arives and the christmas holiday will be used for cutting/welding.
Williampagano: regarding re-powering to diesel, I would say that an engine with around 200 HP is fine for your boat. Diesels have a good amount torque. Find a secondhand, but well maintained/low hours Volvo Penta AQAD41/DP. It has 200 HP and I believe its the best diesel engine/sterndrive package around. It's a simple, reliable, old school diesel engine, without electronics, but can still spin close to 4000 rpm. It will pull much better than the old V8. They are fresh water cooled (including exhaust manifold) so they never rust inside.

 

[aerobat]

i first hand know a guy who adapted a mercedes OM603 3 litre 6 cyl 113hp ( non turbo ) diesel to an old baja 220 which previously had a 5.7 with an alpha gen I .

after some custom work for engine mounts , exhaust ect. he finally got it indeed running - that all with a very tight budget he has. the fear was if the alpha will shift in reverse since normally there is an ignition interrupt for reverse what is not an option here - but wih the low idling speeds of this engine it works fine.

beyond that it was what i have feared - a fail. you can do whatever you want, the engine has not enough power to bring it on glide. he tried the lowest possible prop ( 13 pitch) with no result. next year he will try a lower gearing for the alpha but i believe it will not help also.

the overall problem is in my opinion : when you try it for a budget old car diesels simply lack in power compared to the GM gassers. convert to a modern direct injected turbodiesel is far beyond any budget solution for the engine alone, and even when you can afford it there might be no economical sense since you will never save costs in fuel vs the investements for a high power modern turbodiesel as an average recreational boater.

 

[HorizonblueDK]

One Mercedes OM603 N/A with 113 Hp is for sure not enough to push a 22 footer on the plane. If the owner was boating in a place where there is a speed limit of 8 knots, it would be a fine setup and cheap to run. He should have opted for a Turbocharged 606 (177 hp standard). They can make some serious power. There is a driftcar (team black smoke racing) on youtube with such an engine, approx 600 hp. Less can off course do and lasts longer.

But you are right, some people find an old diesel from a car, drop it in the boat and find that it doesn't have any power. Has happened before and will probably happen again.

On my project, I have purchased 2 x OM 603 Turbodiesels (6 cyl, 147 HP, 4600 rpm). I believe they should be fine for a 25 footer. Not a rocket but ok.

 

[aerobat]

well, yes - at least a OM603 turbo would be nice. but like said he has financial problems , bought a donor baja as a "dream" with a 5.7 which you could only use as an anchor. the 603 naturally aspirated is to get for close to nothing, a 603 turbo or a 606 turbo not anymore... and the 603 is simple and purely mechanical.

i drove this engine in a 300D W124 mercedes and it was not that weak - we learned now a boat is a different story. so the GM blocks are not that bad in power and midrange torque. i had a 21 footer with a VP 3.0 GS /SX drive and it planed out even with several adults.

 

[K-2]

If you ever go shopping for a AQAD41 Volvo Penta, look for a AQAD41B or newer. The AQAD41A smokes more than the "B"s or newer. Or if you have a 41A and are rebuilding it , convert it to a 41B . Pistons and injectors are 2 of the main differences.
I have seen a 210HP 3208 CAT adapted to an old Mercruiser III , it was not fast , they babied it like crazy and the sterndrive could not hold up.

 

[HorizonblueDK]

That is correct, avoid the A series 41 engine. They are heavy smokers. Not so much when running, but on a cold start they can cover the marina in black smoke.