idle afternoon musings: diesel repower?

[barato]

so my buddy Brett----my partner on the sailboat and the evil soul who got me started on the BMW-powered Westy project----tosses out the idea: if your engine and outdrive are obsolete with NLA parts and you'll be repowering anyway, what about using a small diesel? if frugal is the point, can't beat the gph of a diesel for cheap offshore trolling.

no TDIs, as those are too computer controlled and non salt-environment friendly, but maybe an earlier VW diesel, an Isuzu P'up motor, a 190D/240D motor, or a forklift/industrial engine from Isuzu/Nissan/Toy/quien sabe. looked at Perkins etc marine diesels but most are either too small in terms of power or too big in terms of weight. mating it to an outdrive seems the least of the issues, and not really a big deal.

issues that jump out at me: 1. none of these are marine-ized (and no marine manifolds that i'm aware of) so fresh water cooling would be essential. 2. gearing....most diesels have "happy" range in the low 2000s rather than the 4-5000 rpm of marine gas motors, so some major re-propping would be needed 3. towing weight.....the basic ChevII engine is quite light for a cast iron block/head (320 lbs acc to one reliable source); most diesels would add 200 lbs just in block/heads.

i'll freely admit this is idle mental massabation for now, but curious to get some input. have i been wallowing in too much teak oil fumes and Dos Equis? are there Major Issues other than the ones i foresee? no, i realize it will not be cost effective but this boat is not about cost effective for me.

flame away..........

 

[Mntom]

Re: idle afternoon musings: diesel repower?

That sounds like it would be a fun project!! You could always put in a Cummins 5.9. If you get one with the p-7100 pump I can tell you lots of ways to get more power and RPMs out of it!!

 

[Daltonxj]

Re: idle afternoon musings: diesel repower?

might try a 4cyl jeep diesel engine they where real lite but scares....

I had one in a cherokee i had and it was liter then my I6 i got now... had good range of rpm's also....

 

[paparoof]

Re: idle afternoon musings: diesel repower?

mmm... Dos Equis...

 

[Huron Angler]

Re: idle afternoon musings: diesel repower?

I'd love to see this happen...I've spent some time pondering it myself(not that I know much about it) but I'd say a 26' Starcraft Islander tin can would be best suited for an ocean-going diesel rig considering the weight.

You'd save some serious coin as far as MPG, so by all means do it, please.

 

[fshngho]

Re: idle afternoon musings: diesel repower?

I'll have to concede I know nothing of deisels, but

"i'll freely admit this is idle mental massabation for now"

Can you say that on this forum?:redface: Lolllllll

 

[ezmobee]

Re: idle afternoon musings: diesel repower?

Check out this thread http://forums.iboats.com/showthread.php?t=369819 it's about a member in Australia putting a Buick 3800 (my favorite motor) in a boat. Obviously this isn't a diesel, but I think this thread will give you some interesting insight into the kind of fabrication required to install an engine into a boat that doesn't have marine-ready parts available for it. He's doing a real nice job of it also.

 

[barato]

the plot thickens

the plot thickens

this came up on local CL:

http://lascruces.en.craigslist.org/pts/1802082503.html

hope link works.... jap import 2.8 Nissan diesel six, 94 hp @4800 and 130 ft lb at 2400. ironic that this motor came avail about now....it gets around lots of the issues i've found with other possible engines (it's about right power, about right rpm range (so less extreme re-propping required)(and with low rpm torque of 176 nm/130 ft lb, i could run one seriously tall prop!), complete, looks in at least usable shape). 6 cyl is slightly problematic since it will add likely 200 lbs and eat up more of already-limited-due-to-length-of-boat cockpit space.
we might be able to keep length increase down by ditching current front engine mt arrangement (adds 3" to front of engine beyond the pulleys) in favor of side mounts resting on a stub crossmember connected to stringer on each side.

EZMobee, thanks for posting that link...he mentions some stuff i hadn't considered, like the oil pump pickup issue. might be easiest to just add an accusump. i'll take my chances on non-marinized alt and starter since this is diesel and there's no USCG in Old Mexico.

but what happens if i run non-water-cooled exh manifold? between my plasma cutter and Brett's expert TIG skills,we can fab one if needed but i don't even understand the concept. can anyone suggest a resource where i can self educate on water cooling of exhaust?

this has gone from being "idle personal self gratification that's fun but not likely going anywhere"* to getting fairly serious. Brett is between consulting jobs right now and offered to install this for me for $500. i'd insist on paying him more but having him as "project mgr" would accelerate the job about 763%

protocol Q: should i have started this thread in I/Os section?


* family friendly-ized just for fishingho but you gotta change your moniker to something like fishingpersonofillrepute to do your part to keep the site Clean

 

[ezmobee]

Re: the plot thickens

Re: the plot thickens

I'm going to move it to I/O.....(not cuz of protocol but for best responses)

 

[45Auto]

Re: idle afternoon musings: diesel repower?

What kind of boat are you talking about putting it in? Lots of people consider a 140 HP 3.0L to be underpowered, you're going to be running about 33% less power than the 3.0L.

94 hp @4800 and 130 ft lb at 2400 .....

and with low rpm torque of 176 nm/130 ft lb, i could run one seriously tall prop!

The typical gas 3.0L puts out about 130 ft-lb of torque at 1000 RPM, and climbs to a peak torque of about 175 ft-lb at 3500 RPM. It has about 150 ft-lb at 2400 RPM. Do you consider the prop on a typical gas 3.0L to be a "super seriously tall" prop? You're going to have to run less prop with the diesel.

 

[barato]

Re: idle afternoon musings: diesel repower?

another related Q: if i'm fabricating connection to outdrive, i should probably also update to newer outdrive than current Mercruiser 1, not least for prop & parts availability. which one would y'all use? would any of em be compatible with existing steering and/or trim/tilt bits?

THANK YOU FOR ALL INPUT!!!!!!

 

[HT32BSX115]

Re: idle afternoon musings: diesel repower?

no TDIs, as those are too computer controlled and non salt-environment friendly

http://www.youtube.com/watch?v=bx7pGsn2Eno&feature=related

http://www.youtube.com/watch?v=rXexRcYDKPw&feature=related

I think the VW TDI engine would be a great in a boat!!

 

[barato]

Re: idle afternoon musings: diesel repower?

45auto, thanks for input....i'd rather learn all potential deal-killer problems now! i'm an old hot rodder who would rather do an engine swap than watch TV, but so much i don't know about marine engines.

boat is a 1964 Starcraft "Starchief" light 18' cuddy cruiser, hull weight w/o engine is probably <900 lbs, currently powered by 120hp 4 cyl Mercruiser. prev owner claims he saw 41 mph indicated. not sure how torque on the 2.5 compares to the 3.0, but 130 ft lb should be in the ballpark for 2.5. have no interest in skiiing etc, just want to troll for large toothy things in the Sea of Cortez and make it home safely.

 

[Silvertip]

Re: idle afternoon musings: diesel repower?

You touched on two issues in your search of engines and then seemed to gloss over them with the idea that there are other more pressing issues. Truth is, short on power and long on weight are two of the biggest reasons diesels aren't used in smaller recreational boats. And then swapping props will not get the job done either. Lets assume that the gas powered outdrive spins a 21 - 23 pitch prop at 4800 engine rpm. Since the diesel will be rpm limited (lets assume for simplicity that it is 2400 rpm) you would need a prop with twice the pitch (42 - 46 inches of pitch) to obtain the same speed. Good luck finding one of those. So you would need some drastic re-gearing in the outdrive. Diesel-to-V drive might be a better conversion since there should be an abundance of transmissions available for all sorts of diesels. But then you end up with this big hole in the transom. Now here is an idea! There are still plenty of GM 5.7 liter Olds/Buick/Pontiacs in the bone yards with 5.7 liter diesels based on the Olds 350 gasser. Rebuild one of those. At least some of the parts would be available since Olds gassers were used in Berkley Jets and elsewhere.

 

[windsors03cobra]

Re: idle afternoon musings: diesel repower?

Yea it has to be the 350 diesel, I do wonder are the exhaust ports axactly the same as a gasser and the gasser marines manifolds would fit ? I doubt it, but ya never know with GM.
I know the bell housing is the standard GM.

350 diesel baby, now an obscure collectors item.
Oh and lest us not forget GM's 4.3L V6 diesel, ah the ghosts of diesel past.

 

[HT32BSX115]

Re: idle afternoon musings: diesel repower?

Well, if you want a GM diesel, use one of these:

Peninsular Diesel 6.5L 340HP

 

[barato]

Re: idle afternoon musings: diesel repower?

nice motor, but i fear that dropping a 1020lb engine into a 900 lb hull will result in my boat looking like it's on viagra.... or looking like it's on the bottom.

and not sure why anyone would want to go anywhere near an older GM diesel...

Silvertip, you raise valid points. since the motor i'm looking at has power peak at 4800 rather than the 2400-redline you postulate, tho, it shouldn't require such drastic regearing....maybe a couple of inches. i am concerned about the 200ish lb weight increase, although i could substantially offset that by leaving one of my tackle boxes home.

i'm also still pretty concerned about the water cooled exh manifold issue, if it is an issue. any input from anyone on that?