Exhaust Batching

[lat 64]

1968 Columbia 36 with a water-jacket exhaust.
Essentially a dry exhaust. Not sure I should have even voted. Mine gushes water—lots. I could fill up a dingy if I was not careful

Russ

[Crash]

The video shows exactly what my exhaust sounds and does at all speeds and loads.

[dvd]

Don,

Yes I took the survey.

dvd

[dvd]

However, after viewing the video I'm now unsure whether my response to the survey is correct. Although on long trips I do tend to look back at the exhaust from time to time to make sure water is coming out, I'm starting to think mine batches as indicated in the video. I guess I'm not sure now. I will check it and respond as soon as possible.

dvd

[sastanley]

I've got some video to post up too. My faithful companion hung over the transom for me on Saturday while we were out.

Boat & engine performed flawlessly with the in-laws aboard & we had a great sail and got to see the Blue Angels.

edit - OK here it is...
2,000 RPM - this is I think at 30 FPS...the ferocity of the exhaust is a little bit higher in 'real life' or maybe at a higher frame rate..

This is a RWC Catalina 30 with a Vetus plastic water lift muffler installed & 1.5" exhaust hose. I also have a bypass valve installed and positioned somewhere in the 50% closed range to achieve a relatively steady 145-165F temp range.

[YOUTUBE]ycKNxSgsiMc[/YOUTUBE]

[Mo]

Poor weather this morning so I went down and took some pics and video just for this thread.

Photos include:
- plugs NGK XR4.. hotter running plugs. 1 thru 4 from the left.
- ball valve and position that I keep it in.
- hot exhaust that I rebuilt Sept 2010
- muffler ... on the boat when I bought it.
- hose from muffler that exits the transom.

http://www.youtube.com/watch?v=EhYc6t5WmaI

C&C 30 MKI - The engine starts immediately and I haven't had problems with water incursion or overheating. RWC with by-valve and no T-Stat. I trust my engine. Motored home 6 1/2 hours on Sept 4th, no wind but a bit of swell and that engine ran perfect. I ran hard; held 6 kts because one of the kids was queezy and wanted to get back quick.

[Kelly]

I'll have to look at my plugs to post a complete reply but here is a video of the exhaust on my Cheoy Lee B30. No batching here with my standpipe exhaust and downhill (or level) run to the transom for the water/exhaust mixture...

[YOUTUBE]o_kr96hwtCo[/YOUTUBE]

[Don Moyer]

Kelly, thank you so much for the great video. Your nice even discharge is a perfect sequel to the one Bill posted a few days ago to clarify what we meant by a "batching" exhaust.

[Michael Edwards]

I thought that the flow was related to the pump output and the volume of the water lift mffler. My Ericson 32 batches , but it is very quiet. At W.O.T. there is an almost a steady stream(spray).
Are we looking for a problem? A lot of variables here. I recently upgraded to fresh water cooling and the Moyer pump for raw water, which does seem to push a little more water flow.
BTW, I installed the no-longer-available Indigo Temperature Control Valve.
Over a week long cruise, I came to love the higher operating temperature that I dialed in. There is no fluctuation in temperature. The A-4 really likes 180* setting. The guage says 180; but I can't say what the actual temp. is throughout the engine. But it is running better than ever before, and I'm not troubled by the needle swinging up and down the scale.
Don, how about fuel injection?

[sastanley]

hey Mo, I just posted up my video from YouTube of my exhaust batching & added it to this discussion (back in post #20) & it "suggested" I see yours...mine is very similar except I think I have a slightly larger transom thru-hull fitting so the effect may be slightly less dramatic on my boat...but other than that, our engine behavior seems about the same!

[Mo]

Shawn,
Looks about the same to me. I heard your temp was 150 and that was good too ...so she's moving lots of water. I need to put a tach in mine. I have another set of gauges in the garage but no desire to mess with it. It won't be long now and the gig will be up and I'll be on the hard. I only have 799 nm so far this year...it rained hard on me today, lost my sense of humor, and turned around before she hit 800. Terrible spring and just lost 13 perfect sailing days due to steering failure...all good now....had a great labor day weekend. If you are on facebook there are a load of pics..

[domenic]

My system batched from day one. Thought it was normal. Does it hurt anything?

[Don Moyer]

Shawn, do you recall what the condition of your plugs were prior to adjusting your water flow (sooty/not sooty), and will you be willing to operate for a while at the new more even flow long enough to see if the plug condition improves (assuming they were a bit sooty to start with)?

[sastanley]

Prior to water flow adjustment, I've always had what I'd call, slightly sooty plugs. They also vary across the cylinders, #1 being the most "ashy" and normal looking (similar to Maurice's in post #21), and sometimes #4 being a bit oily, the latter I believe due to a frequently sticking valve, which since has been remedied. On occasion, I rotate the plugs around as well.

I need a little clarification...when we say sooty, do we mean a grey ash color, or do we mean sooty type deposits on the plugs/electrode? I picked the 2nd option in the poll.. - Bill, maybe a couple of pictures of what you and Don consider sooty & light grey would help??

When I am not having coil problems, the engine is now running better than ever. This video was taken on Saturday, Sept 3, on the way in from a great day of sailing. The condition of the plugs should still be in the running condition they were in at the time of the video. I can pull them and take some pictures of their present condition to compare to my report above. I don't think I've pulled the plugs at all this year, except when I'd yank one to check for spark during coil failure.

As for the adjustments in flow from a "standard cooling configuration"....I've had the bypass valve installed almost since I've owned the boat...so I really have limited experience with the plug condition/water flow prior to the bypass. Additionally, this summer, I pulled the side plate and enlarged the tee fitting to 1/2" NPT (the "Dutton modification"), and also added cast fittings where I could and reversed my manifold flow, (the "Thatcher modification"), I think a combination of adding the 1/2" NPT to the sideplate and the cast fittings seems to allow an additional volume of water flow and a slightly lower overall operating temperature on the gauge. (The ultimate plan is to introduce my motor to FWC, but I am being a bit lazy about installation..) - Prior to these modifications, I was running 165-170 pretty consistently, and now it seems to swing a little more again, as low as 150 to maybe as high as 180 if I am watching the gauges closely enough. I have not moved the bypass valve from its 'somewhere in the middle' setting.

As you can see, I am a tinkerer & like to experiment, so I might throw off the results a little bit...but I'll be happy to test some things and report what I can! - I'll review some of my earlier posts here on the forum and see if I have any pictures from way back with plug condition prior to all this tinkering.

Mo, My wife is on the FB, so I'll have her check out your pics. The motor is definitely moving more water this summer, I think mainly due to the side plate fitting enlargement. I have 5/8" hose everywhere except a short run of 1/2" hose from the new sideplate tee fitting to the thermostat housing.

[Don Moyer]

Shawn, evaluating plug condition is somewhat subjective, but by "sooty" I've always been referring to black/dry sootiness (sometimes referred to as "velvety". This condition is not all that unusual and can be caused by a slightly rich fuel mixture, very infrequent running, quite low compression, and even a slightly elevated exhaust back pressure. In more exaggerated conditions, the black soot can have a damp/wet look caused by burning a bit of oil, or even gas if a particular cylinder is beginning to misfire which will of course cause the engine to miss and loose power.

In our experience, the light grey surface on the plugs in post #21 (particularly the two on the right) are great examples of a well running normal engine on all counts. I can't be 100% certain, but it appears to me that the plugs in post #21 may have a slightly higher heat range rating then Champion RJ12C plugs judging from the rather long porcelain post and center electrode. If this observation is correct, the higher heat range would account in part for the cleaner burning.

I have one question for you, Shawn, which relates to your reference to reducing the water flow from your exhaust by controlling the valve in your bypass loop. In a normal configuration, the bypass valve only controls the amount of water that's passing through the block and head, and unless there is a significant restriction within the block or head, the flow out the back of the boat should be approximately the same. So the question is, are you sure the flow out of the back of your boat is decreasing as you close the bypass valve?