BMW D190 Diesel Riser/Exhaust Elbow Design

[friz freleng]

First post. Just acquired the engine but minus the riser after turbo. Looked at replacements and at having one fabricated. Something about the design just doesn’t make sense to this “closed loop cooling” noobie. As in the picture the outgoing raw water inlet to the pipe is just after the turbo on the uphill side of the pipe. What prevents raw water form flowing back into the turbo when the engine is shut down? There is a “nub” directly underneath the raw water inlet. Possibly it is a pressure valve which opens and drains when exhaust pressure is lost at engine shutdown? The OEM part from Germany appears to have the same design.

Topic

[friz freleng]

1) Regardless of what the seller told you, when propping, think of it as 200-250HP ( max) diesel at 4000 RPM.. Exceed that loads at that RPM, and even if the engine is in good condition and you will get very little life out of it

Tony – The D190 is rated 165HP. Currently the boat has a Chrysler LM318 rated at 225HP. The Volvo
outdrive has a 17 pitch prop. Do you think that is too much pitch for the D190? It will be pushing a 6K lb
(max) boat mostly at trawler speeds around 10 knots.

2) Regardless of the low hours, saltwater was left in the complex mixed metal cooling system when the engine was put in storage, you may be in for some very expensive surprises.

Tony – I will open the heat exchanger covers and inspect.

3) The base engines roots come from a very high production automotive unit from mid-90’s in Europe.Various companies tried to Marinize it and pump the HP up to 300-ish.. None did well as to any longevity. The individual aluminum heads gave nothing but issues as soon as the HP went above 200-ish on the engines or were even slightly over propped… I believe this “base design” had 4, 5 and the 6 cylinders versions in the automotive world. It possible Chrysler used this “base engine” in some of their diesel vans in the late 90’s, early 2000’s.

Conclusion——————-Prop the engine very light, and assume the seawater system needs a complete “go-thru” ….Be sure the exhaust design is safe and you have 12″ minimum to the spill over point……….IMO, you need to be totally hands-on to deal with this engine… BTW, Google has tons of stuff on this engine–both automotive and marine ones.. Both mechanical and quasi- electronic versions.

Tony – Great advice. Just what I was looking for. Understand the 12″ minimum. Still have questions about
the riser I am looking at fabricating. Looks like 316\L SS is best suited for the job. Plan to put the raw
water inlet on the downhill side of the dry riser.

Looking for advice on lagging/insulating a dry riser. Will it
keep the heat down enough in the engine space/room?

[Tony Athens]

VM Motori

Just some thoughts about this “VM Diesel” based on “actual field experience from about 15-20 years ago..

1) Regardless of what the seller told you, when propping, think of it as 200-250HP ( max) diesel at 4000 RPM.. Exceed that loads at that RPM, and even if the engine is in good condition and you will get very little life out of it

2) Regardless of the low hours, if saltwater was left in the complex mixed metal cooling system when the engine was put in storage, you may be in for some very expensive surprises.

3) The base engines roots come from a very high production automotive unit from mid-90’s in Europe.Various companies tried to Marinize it and pump the HP up to 300-ish.. None did well as to any longevity. The individual aluminum heads gave nothing but issues as soon as the HP went above 200-ish on the engines or were even slightly over propped… I believe this “base design” had 4, 5 and the 6 cylinders versions in the automotive world. It possible Chrysler used this “base engine” in some of their diesel vans in the late 90’s, early 2000’s.

Conclusion——————-Prop the engine very light, and assume the seawater system needs a complete “go-thru” ….Be sure the exhaust design is safe and you have 12″ minimum to the spill over point……….IMO, you need to be totally hands-on to deal with this engine… BTW, Google has tons of stuff on this engine–both automotive and marine ones.. Both mechanical and quasi- electronic versions.

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friz freleng

[friz freleng]

So I took Tony’s advice and read several of what I guess are his “Tony’s Tips” on marine exhaust systems. Beginning to understand the basics. So, I believe I understand that the original riser and the SS fabrication are “wet”, pipe within pipe and will eventually fail dumping seawater into the turbo. So what I am leaning towards is a single walled dry pipe where the raw water from the heat exchanger is injected at the lower end of the downhill side of the pipe. Depending on where the pipe might fail, it would either exhaust gas into the engine space or flood raw water into the bilge. Both scenarios look preferable to destroying the turbo.

Is insulating or lagging the dry pipe feasible and or recommended.? I see it a lot in photos. I suspect the pipe will get pretty hot and needs some type of heat mitigation?

The engine is a mid 80’s, very, very low hours. The following info comes from V12 Engineering in Canada – Blocks were cast in Italy and then completed by BMW and sold by BMW Marine. Mercruiser bought BMW’s marine operation continuing to produce the line and eventually merging it into it’s own diesels. I understand that Mercruiser is now owned by Brunswick/AMF. The BMW diesels remain in use mostly in Europe. Hence the warehouse for OEM parts for my engine is located in Belgium. I bought my engine from a private seller in Houston and no, the engine is not a “one of custom”. I believe the D190 (mine) went out of production sometime after Mercruiser bought BMW Marine.

[Tony Athens]

Doomed to Failure Exhaust Riser

This “riser” is “doomed to failure”..

It’s not if it will, it’s when it will, and when it does, your turbo will be dinning on at least 1 pint of salt water by my estimate..

Better do some research on the exhaust articles on this web site.

~~~~~~~~~~~~~~~~~~~~~~~~~~~

May I ask what you know about this particular engine and the history of the base engine? Who is selling them these days? Is this a “one-off” custom marinization or or ??..

Tony

[friz freleng]

donald roth wrote:

As long as the water jacket remains intact, the design will work, as the water injection is on the downslope side.

Foolproof design would be with a dry riser, no water introduced until it cannot backfeed.

You’ll still want to determine where the waterline figures into this scenario, and if the riser height is sufficient.

Mea Culpa! I don’t think I explained myself clearly. The picture is looking at the riser from the engine side. The cooling water inlet is maybe a inch after the turbo on the “uphill” side of the riser. Talked to the man who made these but no longer available through him. Secret is it is a double walled pipe, a pipe within a pipe. The exhaust gas in the inner pipe is completely surrounded by cooling water contained in the outer pipe. That is why it is welded in sections to facilitate an inner pipe. I agree with your “dry riser” idea. I may have a single pipe one made and move the cooling water inlet to the downhill side of the riser. Now that pipe is going to get hot. I would guess that insulation/lagging would mitigate the heat? I probably could find a fabricator who could build the “pipe in pipe” one but somewhat more expensive than a “dry pipe” one. Already have a quote of $200 for a “dry pipe” riser. Or, I can order the original, from Germany for $1450. I will probably try the “dry pipe” first.

[donald roth]

As long as the water jacket remains intact, the design will work, as the water injection is on the downslope side.
Foolproof design would be with a dry riser, no water introduced until it cannot backfeed.
You’ll still want to determine where the waterline figures into this scenario, and if the riser height is sufficient.

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friz freleng

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