alh m-Tdi marinisation to match Mercruiser Gen1 drive

To go up to 200, in a boat, I think would require a larger engine than the ALH. Boat's have a higher demand for
hp, than cars. For a car, once you're up to speed, the hp requirement lowers. For a boat, keeping the speed up,
requires a lot of hp, for a long time. You'll want an engine that can produce 200hp on a continual basis, which
I doubt you could do with an ALH.

Paul,
Thanks, you've summarized my conundrum. By the looks of the Mercruiser diesels they're using the V6 found in the Audis. I'd love
to have the economy & durability of one, but it'll take some deep pockets.
Cheers!

Marinizing a v6 would be a better prospect, or perhaps a Touareg v10? . Though more money too.

Good luck.
Paul.

A 17 ft searay shouldn't need 200 hp to get up on plane. Im willing to bet a 140ish hp 4 cyl was also an option in that same boat. Many 5.0 v8 motors were very generously rated in the 200 to 225 hp range, my 23ft cabin boat included.

To get 200hp out of a 1.9tdi îs a tricky stuff. I have a friend Here that put on a 1.9tdi ARL on a bayliner. He first tuned The engine AT 220hp and managed to melt The turbine and The water pump impeller [emoji16]. He then detuned The engine AT about 180 i guess.
I put a 2.0tdi 140hp on a Sea Ray 185sport and I intend to make IT AT 150hp. Maybe will try 190hp next year if IT will work ok AT 150 but will need a GTB1756VK turbo or a GTB2260VLKR. Be aware that EGT over 750 degrees celsius means no turbo în 150-200 hours.

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The V6 would be the way to go, then you could run the motor well
below max. In my experience with boats, better to overpower than
underpower, lot easier on the powertrain.

There îs a bunch of clips on YouTube made by a Guy from Europe. He installed a 2.5tdi V6 from a 1997-2005 Audi C5 on a Searay 170.
There îs also The 3.0tdi ASB engine, edc16 but bear în mind that Alpha One ca not whitstand more than 350 Newton-Meter torque. The 3.0tdi yelds about 500NM
. Idk if IT can be found în The US.

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dukku said:

There îs a bunch of clips on YouTube made by a Guy from Europe. He installed a 2.5tdi V6 from a 1997-2005 Audi C5 on a Searay 170.
There îs also The 3.0tdi ASB engine, edc16 but bear în mind that Alpha One ca not whitstand more than 350 Newton-Meter torque. The 3.0tdi yelds about 500NM
. Idk if IT can be found în The US.

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Click to expand...

We didn't get the big Audi diesel V6s.

We did get plenty of bravos and volvo pentas that would hold up.

Searay shipped many cabin boats with the 7.4 and alpha1, these were not considered durable. Some of the old pre alpha 1st gens that were matched to big blocks were stronge than any gen alpha 1 and were coveted by people building high permanence v8s for marine puroposes.

A duo prop would be ideal as it allows you to get on plane quicker and a higher top speed. This will help the narrow torque band of the diesel compared to that of the gasser v8

Thanks gents! Appreciate the input. The boat needs some serious work on the engine beds, and more than likely the transom as well.
Whether or not it's worth it I'll have to evaluate this summer when
I get to the cottage. Lots of projects this year, and both of the utility
outboards are running, so it'll be a while before I seriously tackle
the SeaRay.

Cheers all!

Rrusse11 said:

To go up to 200, in a boat, I think would require a larger engine than the ALH. Boat's have a higher demand for
hp, than cars. For a car, once you're up to speed, the hp requirement lowers. For a boat, keeping the speed up,
requires a lot of hp, for a long time. You'll want an engine that can produce 200hp on a continual basis, which
I doubt you could do with an ALH.

Paul,
Thanks, you've summarized my conundrum. By the looks of the Mercruiser diesels they're using the V6 found in the Audis. I'd love
to have the economy & durability of one, but it'll take some deep pockets.
Cheers!

Click to expand...

Ding, Ding, Ding,....we have a winner....LOL....

In my many years of experience working marine engines to successfully use an auto engine under the marine demanded constant power (no off max power time like you get while coasting down a hill or while driving over rolling terrain at speed) mdoifications are required....

The constant power requirements kill the an auto engine without the designed in extra lubrication, extra cooling and hardened materials in crucial areas that lead directly to the reliably that is part of marine use....

Also, you must detune the engine significantly below what you can get away with in auto use if you want a transplant to last without eating itself from the inside out....

I saw first hand from people I knew who were very smart engine builders back in the 80s trying to install mazda, nissan & toyota engines in boats with very little long term success. In what seemed like short order under normal use these engines would melt friction bearings leading to thrown rods most of the time without or with very little warning it was about to happen.....

what I was told which makes perfect sense if you have ever been on the water for any length of time is the constant power requirements, no hills to coast down to reduce the time under full load to reduce oil & coolant load temps is not something auto engines are designed to survive for any period of time unless they are extremely detuned.....

in marine designed engines you have rollor or needle bearings or very specialized lubrication systems which increase friction bearing lubrication & cooling to many times that of an auto used application of the same engine......

I commend anyone who makes something like this work and be durable for a reasonable amount of time that makes one of these conversion a successful project....good luck,,,....


If I was going to try to do this I would start by getting a passat 140hp pd block converted to use an alh head & 11 mm shaft injection pump. I would then drill out main bearing & crank oil passages to allow for better higher volume flow to all of the friction bearings. Then I would install a higher volume oil pump with a water cooled oil heat exchanger capable of holding oil temps within safe range all the way up to full throttle sustained(detuned to a point your heat exchanger can handle the heat build under marine constant load. A dry sump setup with a large oil tank could help.....

I would closely monitor wear with an easily installable magnet in oil system to catch issues before they become catrostrophic failures that kill the purse paying for this project....

I would make and install a for purpose heat exchanger just for the oil coming out of the turbo.....

I didn't do a search but there are decades of data out there showing what has been learned from people trying to build something like this, I would read everything I could get my hands on, talk to anyone you could find who had tried to do this at some point with an auto engine transplant...

do your homework and it is possible to successfully do this in a durable way....good luck to all that decide to try,....

Rotary,
Thanks for the detail as to why the standard auto engine just won't
cut it in a marine environment. The smart move would be just to
bite the bullet and buy the mercruiser 3 litre motor based on the
Audi V6 TDI.

But ouch!, major expense of probably on the order of $30k when all is said and done.

Rrusse11 said:

Rotary,
Thanks for the detail as to why the standard auto engine just won't
cut it in a marine environment. The smart move would be just to
bite the bullet and buy the mercruiser 3 litre motor based on the
Audi V6 TDI.

But ouch!, major expense of probably on the order of $30k when all is said and done.

Click to expand...

Marine engines are what seem to be rediculous in cost for a reason, the reasons I described....but for that investment if you buy or build all the parts that are listed as being required to do this you will have something that could run without issue for decades under normal use with normal required maintenance.....

the other option is to find a how to and parts list to do as I suggested using that overbuilt block used in 140 passat tdi-pd, drill out the block oil holes to feed those being overworked bearings on the crank...

and most importantly detune the thing to a reliable ~100 brake HP/ 170 lb-ft, check and monitor temps as I described ...

Installed in the system in several places to monitor the temps before they go into an unsafe for service life zone with the extra required cooling held in a three liquid heat exchanger (lake to lake safe coolant) to isolate poisoness coolant from the lake to hot oil. ....

....you could install a fan equipped radiator for the engine coolant to keep heat spikes from throttle use to plain off before you back off to a more efficient lower load setting to hold plain....

....If you get what I am describing this system could be used to cool oil & coolant safely without risk of pollution being released.....

Not enough hp, if I was going to re-engine the boat, originally 170hp,
I'd go for more. Here's some specs:

https://www.mercurymarine.com/en/us/engines/diesel/mercury-diesel/30l-150-270hp/#specifications

Looks like they'll supply in various power levels, 200/220hp would be ideal.
Should be able to cruise at 40mph ~3000 rpm. I'm in the 1000
Islands area of the St. Lawrence, a hop and a skip from Lake Ontario.
You could be in Toronto in a coupla' hours on a tank of fuel.

Im not sure about that detune theory. A 383 is one of the most popular rebuilds/reman/crate small block v8 motors there are and that's doing the exact opposite with a 350. Then there is the cummins marine 4bt that pumps out 250hp compared to the 140ish we find in the delivery trucks.

PickleRick said:

Im not sure about that detune theory. A 383 is one of the most popular rebuilds/reman/crate small block v8 motors there are and that's doing the exact opposite with a 350. Then there is the cummins marine 4bt that pumps out 250hp compared to the 140ish we find in the delivery trucks.

Click to expand...

If they have gone up on power for the marine application I guarantee the internals are re-enforced and oil flow in volume is different(much higher flow(larger oil passageways) oil sprayers under the pistons & likely higher pressure). that is why the price of a marine designed engine is so much more expensive than a on road replacement...

I know first hand that the 454 they use in marine application has these upgrades when installed in a marine application...

Rotarykid, thank you for The very pertinent respone.
AT my Project i use a 140hp Passat engine, colant to water heat exchanger.
Do you think, by runing river fresh water în The stock PD-tdi oil cooler would solve The oil cooling?
My most important gauge will be The EGT hence I intend to drive The engine by The EGT value.

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dukku said:

Rotarykid, thank you for The very pertinent respone.
AT my Project i use a 140hp Passat engine, colant to water heat exchanger.
Do you think, by runing river fresh water în The stock PD-tdi oil cooler would solve The oil cooling?
My most important gauge will be The EGT hence I intend to drive The engine by The EGT value.

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Click to expand...

It couldn't hurt, but keep in mind you need a buffer system to prevent the thermal shock of introducing "cold" lake water that is too cold below what ever you are trying keep cool to prevent cracking of a pipe or radiator system. that is why it is important to use an isolation system between the engine parts and the lake water. I have seen metal turned to what acted like glass when temp changes are too rapid....

You need use the closed system to cool the oil that sends that heated up coolant into a heat exchanger that is filled with cold lake water and you will prevent thermal shock related parts failures...

A dry sump system with a big oil tank along with a oil to water heat exchanger like Porsche & VW have used for years on high load/output engines is also something I would consider, that could give you a better handle on keeping EGT's under control by increasing the oil volume used in the cooling of the turbo...

I've done a good bit of I/O work over the years. The GM and Ford marine engines are very different internally than automotive engines. When I was an auto tech in the 90's people would bring their boat engines in and asked for everything to be swapped over to an automotive equivalent engine. I knew there were differences and talked to a friend that sold marine rebuilds. After that, I started rebuilding marine engines or swapping in marine remans. It was very difficult to get customers to understand that marine engines are different than auto engines even though they look nearly identical. In the end, we quite dealing with marine engines completely.

ben2go said:

I've done a good bit of I/O work over the years. The GM and Ford marine engines are very different internally than automotive engines. When I was an auto tech in the 90's people would bring their boat engines in and asked for everything to be swapped over to an automotive equivalent engine. I knew there were differences and talked to a friend that sold marine rebuilds. After that, I started rebuilding marine engines or swapping in marine remans. It was very difficult to get customers to understand that marine engines are different than auto engines even though they look nearly identical. In the end, we quite dealing with marine engines completely.

Click to expand...

What exactly were all these changes?

Having been through some Chevy powered Mercruiser engines, the rumors I had heard about internal differences seemed to be a myth. With them apart on stands next to each other, the "Marine" block, heads etc shared casting numbers with their automotive counterparts. Inside, aside from special head gaskets to resist corrosion from raw water cooling, it was just a Chevy smallblock.

The biggest differences were in the engine dressing. Flywheel, water cooled manifolds, a modified version of the automotive carb to not overflow fuel, unique fuel lines, distributor etc to comply with USCG safety regulations.

I think the simple truth is, that these blocks and components were designed to produce a certain amount of power safely. If temperatures etc are kept in check, which is easy with the near unlimited cooling available to a boat, there is no problem running these at their car equivalent power ratings. I find it common to actually see the Marine version rated higher than the automotive version. 350 Chevy's are a good example. The Marine 2.0 TDI was rated at 170 HP. I'm sure there are special cases where more demanding applications required more modification, but I believe the 'specialness' of Marine engines is vastly overstated.

On another note, as mentioned, I definitely would not run raw water through the oil cooler passages. It will clog in short order I'm afraid. To protect the engine and all cooling system components, I would only use a closed cooling system. It'll let the engine actually get up to temperature to where it can run more efficiently.

They dont close down the gm engine assembly line for a run of special 5.7 motors. They use stock everything, asside from a marine spec cam, bronze freeze plugs and stainless gaskets the intenals are the same. Cast iron inakes and heads only in raw water cooling systems. Now "building" your block requires a different technique than building a hot rod motor, too much valve overlap =water intrusion and too aggressive of timing means melted pistons.


The distributor, fuel pump and other elections are all obviously marine specific because things can go boom and the marine dizzy cant use vacuum advance.

What PickleRick said plus... GM Marine pistons are different and have a thicker casting. Some have dished pistons to help prevent detonation problems. Some engines depending on years had thicker main and rod bearings. Similar or same as regrinds or rebuilt rods. In some engines, the connecting rods are more like forged units. A marine block has thicker material around the cooling jackets and cylinders. I've found the crankshafts to be thicker in the area where it's weighted and not ground with a taper as some auto cranks are. The heads are built different but use auto castings. Usually the valve guides are a little different as is the valves. Usually thicker like the old pre unleaded days. It's a lot of little things that usually go unnoticed. Cam grinds are different. Some of the HO engines come with roller valvetrain and roller timing sets. Also, some marine engines can be reverse rotation. All of this can be universal across engine manufactures. No, they don't stop production to build marine engines, they are added in. Each engine has it's own line of parts that are sequenced on the engine assembly line to ensure the engine is built to marine specs. I've also worked for auto manufacturers. The last marine engine I worked on was around '96 or '97. Things may have changed and they may all be spruced up auto engines since then. Not many boats from that time still have to OE marine engine.



It's not uncommon to find auto engines in boats from dealers, not manufacturers. That is usually because they have swapped them out after allowing the original engine to sit with water in them and freeze after running the engine for a customer or giving demo rides. One dealer in my area went out of business after doing this a few times. An auto engine will last for a while in a boat. Dealers that use auto engines as replacements know that most of their customers will only take the boat out a few times a year unless they live on a lake. Then they may use a true marine engine.

Rotarykid, how about water jacketing The oilpan?
I mean runing The water that exits from The heat exchanger în The oilpan cooling jacket and sending IT to The exhaust elbow.

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I can assure you that gm had no special blocks for marine purposes other than on the 5.7 they used a 4 bolt main that was not available in a 305. Many of the 327 motors were from the corvette line!!!

The roller cams only appared as that was what gm went to in the late 80s, same as the 1pc rear main in 1986 iirc.

I've heard rumor of hardened valve seats but have yet to find any proof of such. My parents 7.4 rv runs on lp and or gas so i expected the same im it. One of the most popular mods to a 5.7 Chevy pre vortec is a vortec head swap, right out of the jegs catalog with a new cast iron carb intake. 30 to 40 hp out of the box. Since boat motors maintain up to 4800 rpms i suspect some motors had better valve springs and retainers but the heads themselves are the same.

Same with oil squirters on a marine 454, even bored and stroked out to 600 hp this isnt needed until you toss in a blower or turbo. Raw water cooling does lead to uneven cooling so i do see it's upside in a stock application.

As for pistons they are just dished pistons for low compression to prevent detonation. Try finding q/e reverse dished pistons, not too many options.

As for thiicker main and rod bearings, the factory motors will not be balanced or blue printed but when rebuilding any engine properly the crank is checked, turned if needed and possibly linear bored which if both is done will result in any rebuilt motor having thicker bebs.

For the short version of my reply: I agree with PickleRick, and others; there's nothing much special about a marine engine. For the long version, read below.

I've been a diesel mechanic since Pontius Pilate was just an air cadet. And, I've been doing serious boating for just about 30 years now.

Here are a few facts I'd like to share, from what I've seen by repairing, using, and building marine engines.

Marine (diesel) engines are no different than industrial engines, or automotive engines; in block, pistons, and internals. Some are derated, some not. Some have different timing in their cams, or extra lubrication, some not. They run the gamut, just like cars.
Everyone (factories) has their recipe, and things that they think will make their engine special, but, generally, an engine's an engine. The factory will rate it at max hp, and at continuous hp. If you use an engine within it's continuous hp rating, it will last for it's design lifetime. Whether you're trucking, racing, boating, or using it on a lunar lander (I'd like to see that!).

Continuous rated hp is just what it sounds like. So whatever engine you have, be sure you can remove the heat from the coolant, and use it below it's continuous rating. Don't worry about the oil, or cooling the oil, the engine's already equipped with what it needs to do those things, at the continuous hp rating; read the fine print on the rating.

So get a heat exchanger that'll transfer that heat to the ocean/lake, and get a transmission/prop combination that'll absorb all that hp, and go out there and have some fun.

Cheers all.
Paul.

First post here so hi to all.
Couple of questions - OP - did you ever overcome the over heating problem with the turbo?
Also, did you complete the kit for a conversion like this? If you did, i’d Be very interested in discussing it further. I’m toying with a similar ideas long time except hopefully go down the ecu route. And the more I use my current set up(Mercruiser 4.3 in a heavy boat) the closer this project becomes more like materializing.
Finally, is there anyone currently undertaking on a project like this?
If so , I would be really interested in discussing where you sourced parts etc.
The worrying thing for me looking at a project like this is that there appears to be very few people who have successfully made a conversion like this that has stood the test of time. A lot of projects are very well documented in forums at the beginning and then seem to stop as if the work is incomplete or gave up.
Over heating turbo appears to be the biggest hurdle to overcome. Has anyone successfully overcome this?
Thanks in advance.

A couple of hurdles im currently working with.

A: i want to be able to water cool my manifold and turbo

B: gearing. My current set gets on plane at approx 3700 rpms. Shes most comfortable cruising on plane at 4200 rpms. This is with a 260hp 5.7 v8.

With the tdi id like to be on plane at 2400 to 2800 with the tdi. With a volvo penta and bravo 3 there are many prop options. I just need to research gearing options.

PickleRick said:

A couple of hurdles im currently working with.

A: i want to be able to water cool my manifold and turbo

B: gearing. My current set gets on plane at approx 3700 rpms. Shes most comfortable cruising on plane at 4200 rpms. This is with a 260hp 5.7 v8.

With the tdi id like to be on plane at 2400 to 2800 with the tdi. With a volvo penta and bravo 3 there are many prop options. I just need to research gearing options.

Click to expand...

why not size the turbo to breathe at the same RPM as the V8?
with an he341 off a dodge and a chinese t3 manifold you'd be good to go
you will want some bigger injector nozzles though

Correct me if im wrong but that turbo would not spool untui 4000+ rpms making getting on plane a chore?
Also the goal of sub 3000 rpm cruising if for economic cruising.

Probably wouldn't be quite as bad as that. The he341 and 351's have an extremely small turbine housing. Holset has some magic voodoo going on with those turbines, they spool like lightning and flow decent enough as well. P0wer has a boost log of a 1.9 with a 9cm hx35 in his thread some where. Makes like 10lbs of boost at 2800 or something like that?

Any valve train mods needed to run at 4800 rpms for hours on end?