Truck diesels

Discussion in 'DIY Marinizing' started by parkland, Nov 7, 2012.

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    FAST FRED Senior Member

    Look in Boats and Harbors , any good tranny rebuild shop should have a USED bell housing ar modest cost.
  2. whitepointer23

    whitepointer23 Previous Member

    Yes . Plenty of marinised auto diesels in Australia. Diecon do kits for nissan and isuzu. Bowman sell kits for European diesels.
  3. sdowney717
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    sdowney717 Senior Member

    I found out some typical designs of these adapter plates.
    1/2 inch thick steel .
    For attachment at engine bell housing, a shoulder is machine cut into the plate, so it is an insert of plate into bell housing for the alignment.
    Engine crankshaft is concentric with the bell housing.

    I am pretty sure a machine shop can easily do this, and for a lot less than $1100.
    Used is of course good idea, if such a thing exists for a velvet drive.
  4. sdowney717
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    sdowney717 Senior Member

  5. black_sails
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    black_sails Junior Member

    To original poster and beyond despite years ago keeping alive a convo I think deserves to continue, I dont know why it isn't more common either - I think they are incredibly well suited to this. Here's my brain dump hoping it's useful for someone.

    I too would like to use one in a sail assisted powered multihull i'm slowly designing. (like a motorsailer but more like the sail is the auxillary/simple and downwind only to take advantage of wind when available) The transmissions that bolt on would be SAE of course - which as far as I know is standardized between medium/big truck use, industrial, marine and similar - and totally unlike car engines with all their variations. The main issue I could think of is needing to fab up the marinizing parts.

    I'm torn between the Cummins 6bt and the International DT360 - the latter is substantially stronger and with other advantages (wet sleeve like you mentioned) however the Cummins 6bt is ubiquitous and already has marinizing parts widely available.

    The International is definately the stronger engine without question - ask guys in the diesel sled pulling world - the Cummins start to spray rods out of the blocks no matter what you do in the four digits certainly by 1800hp, yet I too have heard of 3000hp DT engines or even more. The DT's basically take 1000hp without any internals upgrades or block changes at all. It's also a few hundred lbs heavier (around 1400-1450 I believe) especially vs the 12v 6bt (which is closer to 900) and seems more suited to the heavier side of medium duty loads.

    The DT408 and DT466 I believe are a taller deck version of the DT360, the DT530 and DT/HT570 are even higher deck versions. I think they share the same bore but vary stroke in each. Being able to go up to 570cid basically as a bolt in in the future is one thing in favor of starting with a DT360. Though turbo boost makes the displacement more irrelevant. Some later ones are designed for electronic injection (530/570, some 466) but you can apparently backconvert to mechanical with DT466 parts and bigger injectors if that's needed. The newest versions were named MaxxForce and are all electronic, they may not be able to convert back to mechanical injection which might make power boosting more difficult. I think increasing incompatibilities occur with the MaxxForce sourced parts.

    One common way to pick up a cheaper Cummins 6bt is to buy a schoolbus with one, the Internationals also turn up there very often especially the DT360's which nobody wants. (vs the bolt in place DT466 and such)

    One model i'd considered if I scaled up my boat design and went really big were the Cummins N855 based class 8 semi truck engines specifically the Big Cam III (as the IV had cooling issues and backconverting is an annoyance). If nearly 3000lbs of engine block isn't a problem, big rig hot rodders would put down 800-900hp with absolutely no problem or affect on the million mile reliability seemingly, indeed it was one of the earlier million mile engines, whose reliability and power was seemingly not as readily attainable in other semi engines i'm aware of, let alone at the price in the early 80's. They were mechanical injection. Since they are considered "utterly obsolete" by now in terms of truckers need to run EFI for max fuel efficiency (often using Detroit Series 60's with mpg figures often not matched by newer models from any maker including Detroit) they can apparently be picked up from wrecking yards for as cheap as the medium duty engines though rebuilds not nearly as cheap.

    There are other big semi engines but none i'd look at. Kitty Cats are always way too expensive for what they are, needing specialized tools and rebuild kits costing 3x as much think 20 grand. Detroit 2 strokes were known and loved back in the day but they've had their day - even I admit that finally and I was a huge fan of them. They don't match reliability or power potential of something like an N855, they uniquely want to run away, they always leak oil - the N855 Big Cams are honestly the engine series that finally put my Detroit love to rest. Used to be cheapest to rebuild Detroit 2 strokes, parts costs are finally notably up, whereas N855's are still low - maybe 6k last I heard? Low for a semi engine. Less interested in newer or other Cummins too - not convinced anything newer is any better in terms of "keeping it simple stupid" and lasting a million miles and big power, dont like the electronics on any of them. Mack V8's super powerful and loved by some but i've heard not the cheapest to build up and i'd think parts notably rarer than an N855. Other brands I don't know about Volvo and such but Cat/Cummins/Detroit are the biggies in the USA.

    Going the other way there are a bunch of other smaller and medium sized japanese diesels from their class 3-5 cabover box trucks in the 105-130hp range like Nissan SD33 6cyl, Isuzu 4BD1/4BD2 4cyls which are great at lower power (harder to hop up), Cummins 4bt which i'm less of a fan of due to its noise/vibration/harness, and others I forget the model numbers of. For someone building on the cheap they would likely work well too - for someone concerned about global availability of parts i'm wondering if Cummins might be better - simply being in so many dodge ram pickups counts for alot. Though the japanese cabovers are also often sold worldwide moreso than the american mediums in many cases.

    =====responses to others postings

    FWIW the mildest Detroit 2 strokes could match the John Deere - the 2-71's used for train reefer cars would sometimes have like 44,000 hours on them, i've seen pics. The big 12-71's in low hp marine use like big lobster boats would go 3 decades endless daily duty too with tens of thousands of hours. Life really goes up as HP demand goes down on them - but the inverse really true with those 2 strokes. Jack a 6v-71 to 320hp and it might last 700-1000 hours by what others have told me.

    The John Deere sounds great for ultimate life but i'd wonder if I could get parts easily in some small island marina somewhere in the south pacific... I mean that's always a concern but some engines are more common than others. Where I went would matter alot. There's probably still Detroit 2 cycle people on every island though - some old codger who can't quite see straight but can work on them blindfold so it doesn't matter anymore.

    Those KTA19 Cummins are capable of both incredible power and incredible longevity in part because not very stressed but $$$!!

    I can second the DT360 boost handling - I talked to a place that builds up alot of the DT's for the sled pulling guys while I was considering a crazy tow buildup once, and 1000hp from one is basically just compound turbo for 100psi, injectors, fuel pump. For a cummins you also need head studs, maybe fire rings, then driveability goes to hell with fire rings, internals upgrades worth considering like upgraded rods... at around 600hp it's a wash and the Cummins might be cheaper. At around 1600hp Cummins breaks the bank and will die very quickly maybe even your first few dyno runs. I'm not sure how long any of them would last under extended marine use - even the 600hp Cummins might be a 700 hour engine by then if that. These numbers are all dragracing/sled builds which is not always the same kind of toughness. I'm told the DT360 will make 500hp all day long though for comparison and is a common figure among hotshotters towing 30k through the rockies and such uphill. No problems ever reported.

    In pickup sourced i'd stay away from all GM 6.2/6.5 UNLESS it is one of the 2001up AM General Hummer engines which fixed all the problems with brand new castings and redesign at stock power. The P400 ones are even better. Ford's various diesels after the 6.9 IDI have all had various problems starting with cavitation in the 7.3 without the right coolant. I've never owned one but heard of alot of problems with 6.0's and 6.4's, always different things for each new model, which may or may not be permanently fixable. I'd just prefer to stay away from engines that I "hear bad things about" and probably tells you something if theyre completely redesigning their engine every few years, hmm... Duramaxes make big drag power - how well they stand up to sustained marine power I don't know. But they get over 600hp on fuel alone surprisingly easily. They need electronics though which i'm never a fan of - any engine that just needs "fuel, air, lubrication oil" is far better than something for which some random sensor can die leaving you up a crick without a paddle.

    The above is from my own 'research files' where i've read up on or talked to others all over at different levels for a number of different projects over the years, if anyone else has differing opinions or wants to add new engine models or commentary to the list please contribute even if it's years later. I just hope my post is useful to someone. :)
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