sprink58

GREAT POST !!! What are your thoughts on using a crank mounted Sea Water pump as Volvo uses on their conversions as opposed to a belt driven pump ? Just curious..

kidturbo

I don't see why it couldn't work if your running an aftermarket dampener. But the OEM unit doesn't have a flat mounting surface, or any bolt holes to connect the pump. Since the belt track is built into the dampener ring, GM never expected extra pulley's or hardware.

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I've found no major disadvantage to the belt driven pumps on this platform. Mine has logged 300+ hours on the same belt, and about 4 impellers. However changing those impellers was always a pain in the ....

Hoodoo is using a nice multi-stage setup on his build. Dave uses a double in/out design on his Sonic. So it's really up to your rigging requirements. Just remember, as I'll get into later, these engine do require substantial water volume..

The OEM pump is gear driven, but not positive displacement. So it's good enough for a closed loop system, or as secondary in raw water cooling setups.



Pretty reliable pump, and that's good. Cause changing that pump requires removing the dampener with 270ftlb of torque on the bolt, plus a special puller and new front seal. Not something your gonna enjoy doing in the boat. So I'd suggest changing it during your marinisation process. You can also easily delete and block it off if your cooling setup is fully belt driven.

sprink58

Thanks...understood. I think the volume would be satisfactory but the mounting logistics might make it more trouble than it's worth. The crank driven pumps do work well...I used them on my twin SBC Vortec/Bravo I conversion from Pre Vortec/Pre Alpha. When I'm running on the hose thru the drive the suction will implode/collapse most garden hoses. I started with 140* thermostats and ended up with 160*s because even in 85* water the engines ran too cool !!

I had a Sea Ray 39EC a few years ago with twin 502 gas motors and often thought about dropping a pair of Dura Max Diesels in it. Those boats as well as 34EC's are plentiful and cheap and would make great boats for this conversion...it's really got me thinking...running thru a pair of ZF Transmissions would be sweet.

What's a fair average price I could expect to pay for a decent conversion candidate Dura Max in a salvage yard?

Thanks again for the thread.

kidturbo

Great question !! Depends on year, mileage, and how much you expect to invest after the purchase...

Since all model years share the same same basic block, head, and turbo configuration, it comes down to picking the best internals, fuel system, and electronics for marinisation. This is where it gets a little tricky, as hoodoo can attest.

Newer is not always better when it comes to Duramax engine swap models. The internals keep getting better, while the rest keeps getting more complicated. They all weigh in at about 850lbs, but some years are definitely better than others for several reasons.

So hear is a specs breakdown I borrowed from:
http://www.duramaxhub.com/duramax-timeline.html

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The early years like [LB7] are most abundant, but the fuel system had some serious issues. Injectors are mounted under the valve covers and prone to leaking fuel into the oil system. It also used a wastegated turbo rather than the VNT model introduced in mid 2004. On a good note, it didn't have an EGR cooler.. I'd personally avoid them for marine swaps.

2004.5-2006 LLY, this is what I owned, and the first Duramax on record to be marinized. That said, I'd skip it too. LOL... Seriously it's a great engine platform if you dump a little cash in them. Better fueling than the LB7, but still shared pistons, rods, and a 17.5CR. Which produced some bent rods and crack pistons. The LLY also used an ECM / FICM combo like the LB7. More electronics to fail.

Next you have the LBZ in 2006-2007.5. Isuzu/GM made some great internal and external improvements on this model. Better rods, pistons, and lowered the CR to 16.8. New stand alone ECM and improved injectors also. This is the year most Duramax swap projects start looking for. There was no DPF systems yet, so nothing to delete that requires special ECM tuning.. On this year, just add some head studs and run that thing at 500hp all day long..

The LMM came along in 2007.5 and ran thru 2010. This is my favorite model year, because it's abundant and basically identical to the LBZ inside. ECM operating system was changed and the exhaust DPF crap was added. But if your dropping one into a boat, it's gonna be running custom ECM tuning anyways. From 2007 to present all models share a common HS GMLAN CANbus network that allows simple translation to your modern gauges or chart plotters.. More on this later too.

Last is the 2011 and newer LML models. The most powerful 6.6l model to date includes improvements to the block, rods, oiling, turbo, fueling [debatable], along with GM's feeble attempt to lock the ECM down so no one can peal off the exhaust and crank em up to 800hp like previous models. This is where things can get expensive.
Yes it's a great bottom end, but a bit tricky to yank out of a truck and drop in a boat without a few techie buddies... Plus while not heavily advertised, the newly upgraded CP4 fuel pumps have been known to randomly grenade and gut the whole fuel system.. But they can be still marinized.

Hoodoo has 2 "beautiful" LML/LBZ/LMM models setting on stands just waiting to hit the water. Maybe he will share some more pictures.

So the short answer for sprink58, $5,000...

A completely non-bias model year comparison is available at: http://www.trucktrend.com/cool-truck...diesel-engine/

kidturbo

Ok let say you've found a good deal on a average mileage Duramax donor. What should you keep off the truck? Or if you purchase an engine only, what will you get?

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Here is an average engine as removed from the truck. The engine harness disconnects with 2 large weather tight plugs, and one master 12v power breaker lug. The majority of our required sensors is on this harness. However the ECM and accelerator pedal sensor are part of a second harness typically not included with an engine only.

The fuel system feed and return line are quick disconnects, and belt accessories and starter all remain intact. About everything required should be on there. Exhaust manifolds up pipes and turbo also typically come with a complete engine. While we might not use all of it, is good to have for reference.

Next is what to remove, and what to upgrade.

TruxtonFox

Keep it coming, this is great info, I am a duramax nut and have thought about doing this for several years knowing the type of power these motors are capable of. I'm glad you are sharing this info with all of us here. Hats off to you

kidturbo

Thanks much.

My first Duramax experience was the one in my boat...So I learned about this the hard way, breaking stuff then asking guys who drag race or truck pull them why it wouldn't hold up.. LOL.

It took a few attempts to get all the bugs worked out, but once I did, no more problems. And these things will run with a 800hp blown BBC till their tanks run dry. Then you can boat another day or two on your own..

90profx

Just asking out of curiosity, what kind of drive holds up to all that torque ?

kidturbo

Another great question. Which I plan to discuss in much more detail later.

For now let me say, smaller than than a ASD8, it's gonna require some upgrades. Gearing is a huge unresolved issue I feel needs addressed. And a big reason I wanted to share how to get most bang for the buck on initial rigging investment.

Below is the XR that came with my 21' Warlock, handling about 675hp / 1300ft lbs. Drive was installed new in 2006, upgraded by IMCO a month later, and currently around 350 [flat water] hours on it. I also know of a similar weight boat running a pretty much stock Bravo1 behind a 500hp Duramax.

One nice advantage to this platform, you can power slope or torque limit the RPM curves with a laptop. Along with option to add 5 switchable on the fly power levels. So you could setup a 400hp tune with 700ft lb torque limits above 2600rpm for offshore running, then flip a switch to a 600hp/1200ft lb tune that spins 4000R's on flat water.

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hogie roll

Cool