Coolant Conundrum/Exhaust Riser Replacement [Master Thread]

[bsangs]

If I've gleaned nothing else from this informative thread Jeff, you've really made me happy my engine is a Yanmar. Great work.

 

[Prairie Schooner]

EXHAUST RISER / MIXER INSTALLATION - pt 1
The riser assembly is installed and working, though I'm going to revise the brace.


There were a couple ways the different fittings could have been arranged, but this worked well with the way I was going to add the auxiliary support/brace. The mixing head was cleaned with Barnacle Buster, primed with engine primer, and painted with engine paint. The manifold flange was abrasive cleaned and sprayed with engine grade primer and paint. (I don't like the Universal gold color so anything I take off has been getting a new paint job. But to be honest, the gold is a pretty good color because it shows oil and other stains well, making it easier to trace problems.)


It was Doug's @bigd14 suggestion in post #125, page 7, that got me here. Thanks Doug! Because of the height of our riser, it couldn't go direct from U-bolt to manifold as in his sketch. Once I got the idea of using turnbuckles, I was enamored of the way it would look and couldn't break away from it. A number of prototypes for the manifold attachment were made, during which I re-imagined the U-bolt orientation. I used aluminum flashing, then .060" aluminum for the prototypes.


The final piece would have been a perfect candidate for water jet cutting, but I needed to turn it around fast. The .125" stainless steel was drilled then cut out with a jewelers saw. From layout to finished piece took about four and a half hours. It still bothers me that I didn't line the jaws of my vise when I bent the 'wings'.

 

[Prairie Schooner]

EXHAUST RISER / MIXER INSTALLATION - pt 2


The manifold flange studs weren't long enough to accommodate the additional stainless plate so I ordered longer ones. A high temperature anti-seize product was used for assembling all this, including the stainless & iron riser. Almost everything I put back together on the boat gets some kind of anti-seize product.



Those were the shortest stainless turnbuckles I could find that had clevis pin ends and still looked strong enough. To get them past the riser to the eye nuts I went with a bigger diameter U-bolt and added silicone padding. There are a couple problems with this. 1) It is all too squishy. 2) I angled the mixer about 20º toward boat center to be more in-line with the muffler. The inboard turnbuckle is tightened about as much as it can be. This will eventually be replaced with a smaller U-bolt and a fabricated piece something like this in place of the U-bolt plate.


This is certainly more complex and maybe more robust than anybody needs. But I spent my career in product design and development (prototypes and tooling models) and this is kind of my default setting. Change is hard.

- - - - -
Seaboard Marine had some great examples of exhaust installations. None of their specific examples made it to our final configuration, but they helped expand my approach.
- https://www.sbmar.com/articles/proper-exhaust-bracing/
- https://www.sbmar.com/articles/custom-marine-wrap-around-exhaust-supports/
- https://www.sbmar.com/articles/custom-marine-exhaust-supports/

 

[bsangs]

Big deal, Jeff. I installed a new VHF radio this weekend. That’s some fine work man. Quite a detailed project. Well done.

 

[Prairie Schooner]

Big deal, Jeff. I installed a new VHF radio this weekend. That’s some fine work man. Quite a detailed project. Well done.

Bravo! A good radio is a beautiful thing.
Thanks, Brian. And it hasn't fallen off yet.

 

[Kenneth K]

View attachment 53174

Jeff, in reference to the picture above (post#183), any chance you can change the position of the u-bolt around the pipe to what is shown in post #182?

In post 182, tension on the turnbuckles opposes the torque created by the weight of the riser.

In post 183, tension on the turnbuckles ADDS to the torque created by the weight of the riser. I think this is opposite of your original intention.

 

[Prairie Schooner]

Jeff, in reference to the picture above (post#183), any chance you can change the position of the u-bolt around the pipe to what is shown in post #182?

In post 182, tension on the turnbuckles opposes the torque created by the weight of the riser.

In post 183, tension on the turnbuckles ADDS to the torque created by the weight of the riser. I think this is opposite of your original intention.

That's a good question, Ken. I like to call myself an intuitive engineer, which is probably a face-saving way of saying I'm an untrained hack.


Looking at the forces involved, I felt like the longer reach of the upward facing U-bolt would have much more leverage than what I ended up with. And it would be at such an angle that it created greater pinch points. But, you're right, it does lift more. The arrangement I used pulls much more forward than down, but it does indeed introduce a down force.


The strap you used in post #41 of your thread is probably better because it offers support without introducing new forces. I veered away from that for something adjustable because the geometry changes when all the riser pieces are screwed together. But that could have been achieved by putting slotted holes in the strap(s). Once I landed on the turnbuckle scheme it appealed to me aesthetically and I stopped thinking about it critically. The strap to the block does depend on that bolt being really tight to keep it from vibrating down. But that can be checked routinely. Plus, I didn't take the manifold off so I would have needed to connect to the lift tab. Still quite doable.

When I revisit this, I may go to something with straps instead of turnbuckles. Perhaps still connecting to the mount I put on the flange.

Thanks Ken. I always appreciate your perspective.

 

[Kenneth K]

Jeff, these photos are better. While having the attachment rings below the pipe DOES induce a counter-clockwise (CCW) torque in the pipe itself (acting in the same direction as the weight of the elbow), it looks like its effect on the flange-joint is still a CW torque (as was your original goal). In other words, I think you lowered the torque stresses on the flange-joint at the expense of increasing stresses elsewhere in the pipe assembly. This is probably okay because the flange-joint is the critical one you are trying to protect.

It‘s tough to say if placing the rings above the pipe would be better or worse. While a higher placement creates a longer moment-arm for the turnbuckle tension to act from, the horizontal (CW) component of that tension becomes less and less as the turnbuckle gets closer to vertical. At the same time, the vertical component of the tension gets larger and larger, which would add more (downward) shear stress to the nipple-joint you are trying to protect.

You’d have to run calculations with the actual distances and angles to figure out which placement is best.

 

[bigd14]

Jeff, why not put a long pin through both turnbuckle clevis’ to bear against the upright portion of the pipe and eliminate the u-bolt entirely? The forces would then be directly in line with the turnbuckles. The goal is to reduce stress on the nipple between the exhaust flange and the elbow, right? Wouldn’t that accomplish it?

 

[Prairie Schooner]

@Kenneth K
"You’d have to run calculations with the actual distances and angles to figure out which placement is best."
Ken, I don't have the engineering chops to do that, but if someone does, I'd be interested in seeing the results.

@bigd14
Doug, Is this what you mean?


I grew up in Iowa, with quite a few farmers in the extended family. I'm not infrequently tempted to just use bailing wire to solve a problem.

 

[bigd14]

@bigd14
Doug, Is this what you mean?

Exactly!

 

[Prairie Schooner]

As I've reviewed how others here have worked these spaces I realize a good deal of it is how to arrange things. The following threads have been helpful.

Engine Compartment Clean up

We’re scheduling a haul out later this month to get the bottom painted, cutlass bearing replaced, speed transducer replaced, and install a dripless shaft seal. The previous owner left the stuffing box unattended while they had to deal with some health issues which damaged the engine mounts...

ericsonyachts.org

Also, Bilge Hose Replacement Battle by @Nick J

New hot water heater in 32-3

I recently replaced my original 6 gallon Atkins hot water heater with a new 5.3 gallon Isotemp Spa unit. So these last two seasons, we have avoided using any hot water because it was always foul, even though I had done everything I could to make it useable. The heater itself was inconveniently...

ericsonyachts.org

Loren speaks of relocating the oil filter outside the engine compartment.
There are a number of options once one breaks out of the framework we're given.

A few shots of what I did:

 

[peaman]

Looks good, Jeff. You've made the most from what Bruce King has given you.

I'd be a little nervous about your raw water strainer placement which I guess is several inches above the water line and therefore subject to air leaks at the hose connections or cap when the engine is not operating. But it should be easy to manually prime before starting after a haul out or impeller change. Also, that's a lot of water to drain out before checking the impeller. Just another example of everything is a compromise.

Any difficulty with oil dip stick access under the overflow tank?

 

[Prairie Schooner]

. . .
Loren speaks of relocating the oil filter outside the engine compartment.
. . .

Correction: Loren has spoken of relocating the FUEL filter.

 

[Prairie Schooner]

Looks good, Jeff. You've made the most from what Bruce King has given you.

I'd be a little nervous about your raw water strainer placement which I guess is several inches above the water line and therefore subject to air leaks at the hose connections or cap when the engine is not operating. But it should be easy to manually prime before starting after a haul out or impeller change. Also, that's a lot of water to drain out before checking the impeller. Just another example of everything is a compromise.

Any difficulty with oil dip stick access under the overflow tank?

Hi Seven,

Regarding the strainer height, yes to what you say. On the other hand, a leak there is less likely to drain the boat. A bonus was that during winterizing it was really easy to close the thru-hull and just pour anti-freeze in the strainer while the engine is running.

Dip stick: No, but it is a pain to get past that cable. (I can't remember if it's throttle or cut-off.) At any rate, I'm trying to be Zen about it.

 

[Kenneth K]

A bonus was that during winterizing it was really easy to close the thru-hull and just pour anti-freeze in the strainer while the engine is running.

Best idea ever! I had to build a fancy 2-way inlet pump valve to be able to do an antifreeze flush without disconnecting hoses.

Also, just an open-minded comment on double hose-clamps: I know that's the general rule for through-hull fittings, but I don't typically don't do it on engine hoses (probably just from my old habits from working on cars years ago). Maybe it's a good idea to double-clamp, at least as long as the hose barbs are long enough to support 2 clamps (they usually are on through-hull fittings). But, you wouldn't want a clamp around a hose if there's not a solid barb completely inside it to clamp against.

 

[peaman]

A bonus was that during winterizing it was really easy to close the thru-hull and just pour anti-freeze in the strainer while the engine is running.

THAT is a nice bonus. I'm still working on a way to make my winterizing procedure easier.

 

[Prairie Schooner]

Hi Seven,

Regarding the strainer height, yes to what you say. On the other hand, a leak there is less likely to drain the boat. A bonus was that during winterizing it was really easy to close the thru-hull and just pour anti-freeze in the strainer while the engine is running.

Dip stick: No, but it is a pain to get past that cable. (I can't remember if it's throttle or cut-off.) At any rate, I'm trying to be Zen about it.

@peaman
Boy, I was flying too low and too fast.

Steven!

And I meant to attach this image.

 

[Angel D.]

@peaman
Boy, I was flying too low and too fast.

Steven!

And I meant to attach this image.
View attachment 54034

If there is not something on the way or need to be a contortionist in order to work on it, then it would not be a sailboat .
Nice pictures Jeff.

 

[Kenneth K]

Ken, I don't have the engineering chops to do that, but if someone does, I'd be interested in seeing the results.

Yeah I scratched my head on this at first but then after not looking at it for a couple days I realized it wasn't so hard.

You just need to measure:
- the angle between the turnbuckle and the lower pipe, and
- the horizontal and vertical distances from the outer turnbuckle attachment point (C) to the center of where the lower pipe attaches to the flange (B).

Then:

(You subtract the second product from the first because the torques act in different directions and, thus, offset each other to some degree).

Since the engine doesn't sit level in the boat, the terms horizontal and vertical aren't really correct. What you're really concerned with is that the "horizontal" measurement is taken parallel to the long axis of the pipe, and the "vertical" measurement is taken perpendicular to it.

If you're really bored, you could repeat all the calculations with the measurements taken at the upper attachment point (D) and see which case gives the pipe the more support (or, whether it's worth changing). You could also take a wag at estimating Doug's solid-bar-through-the-turnbuckle-shackle option.