Fresh Water Cooling - Indigo?

[Smuggli]

Does anyone have any first hand experience with Indigo's fresh water cooling conversion kit? I will be sailing from Lake Superior to the Atlantic and I obviously can't rely on the clear waters of Lake Superior to do the work. I do not have the required room to run the MM conversion off the fly wheel.

Specifically, I am wondering about the ability to run a high amp alternator along with this unit since it appears to be driven off the alternator belt (or a modified version thereof).

Has anyone gone down this road? Thanks!

Scott Muggli
s/v Anna Rita

[ndutton]

Yep, been down the same road. My space constraints were the same as yours. My concern over the the accessory drive mounted pump that Indigo offers didn't have anything to do with the ability of the drive to do the job (it's pretty robust) but rather the reduced belt contact with the alternator (mine is a 105A Delco), same reduced belt contact with the FW pedestal pump.

I decided to go electric with the Johnson CM30P7-1 pump. It does not pump the same as an impeller pump but I traded off the lesser performance for the advantages of FWC. It was worth it to me. I even bought a spare pump just in case but decided later it was so much work to swap out that I made my get home plan B scheme in the event of a pump failure to revert back to raw water cooling as a temporary measure, takes one short length of hose. Not needing a spare pump any more I installed it in series with the other electric pump, running two now.

In my opinion an important part of electric FWC is to open up the passages to reduce restrictions as much as possible. For me it meant replacing the square elbows at both ends of the manifold with regular round plumbing elbows (they flow much better) and enlarging the water jacket sideplate Tee from 3/8" NPT to 1/2" NPT including the diverter cap on the inside. While the side plate was off I physically cleaned out the block followed up with an acid flush after reassembly. I ran for years with no thermostat, bypass fully blocked for maximum cooling with a marginal capacity ebay heat exchanger. That exchanger has been retired in favor of one with 34% greater volume and twice the passes (4 pass vs. the earlier 2 pass).

I just completed some field testing of Moyer Marine's new thermostat product with this cooling system. A partial report can be found here, post #6.

[romantic comedy]

I made my own FWC. I used an Oberdoefer 201 pump mounted in place of the alternator and a Balmer 100 amp alternator mounted at the flywheel with a half inch belt. Has run for 20 years this way.

fresh water pump is the stock pump.

(hope I got the pump number right)

[sdemore]

I bought a used version of the Indigo system, but had problems mounting the pump. I bought the electric pump and I like it a lot better, less maintenance and I can have it running without the engine running.

[thatch]

Hi Scott, My FWC system is very similar to Indigo's mechanical system. The belt driven pump is an Oberdorfer "thin shoe" pedestal mount model that is circulating the coolant rather than the seawater, which is the norm. I am also running a 105 amp. alternator and am quite pleased with this system's performance. If there was a down-side with this system, I feel that, as Neil mentioned, the reduced belt contact on the alternator pulley might cause some "slipping squeal" if the batteries become severely discharged.
Tom

[ndutton]

I am also running a 105 amp. alternator . . . . the reduced belt contact on the alternator pulley might cause some "slipping squeal" if the batteries become severely discharged

Tom makes a good point - if the batteries become severely discharged. It's not that we have 105 amp alternators by themselves but more like what we may need from them. I have a digital charge amperage monitor to keep a casual eye on how hard the alternator is working. Even at the dock with the batteries kept up by a shore power charger my alternator is called on for a little under 50 amps right after start up, drops down to more like 13 amps pretty quickly. Over a Catalina weekend I'm running refrigeration around the clock and if the moorings are full I'll be counting on an electric windlass to manage the anchor. Even with the contribution of a 100W solar panel I can expect the alternator to be called on to earn its keep. It's at those times belt contact really matters.

[joe_db]

My experience with FWC and electrical pumps is that you *absolutely have to* get the block cleaned out and you have to make SURE the engine is bled of all air.
I had two pumps and had one rigged to run from a separate switch and used that one to bleed the engine.
If you even slightly suspect that there is ANYTHING in the block that will come loose, you need to rig a filter. The heat exchanger has very narrow passages and any loose junk ends up in there.
I found that with two pumps, the engine ran 5-10 degrees cooler with both on.

[sastanley]

I am running a home built system with a johnson electrical pump for the antifreeze side too. I am not having any problems, but as others have said, CLEAN out the block thoroughly before you introduce the HX, so nothing gets lodged in there..the passages are the size of drinking straws in many cases.

[MLW]

Currently FWC with Indigo using their newer Bosch pump. So far so good. Engine was FWC when I got it but HX was cracked, sheaves misaligned and pump needed new impeller so I just bought the kit.

[Grant]

I am new here, so this has probably been asked many times, but here goes. I just bought a used A4 that came from a Great Lakes boat and was raw water cooled. It looks great, but I am going to pull the side plate and clean as much of the inside as I can and then do an acid clean. I will be in salt water so I am going to add a heat exchanger and have fresh water cooling. Looking at both Moyer and Indigo, I seem to see that they both convert the original raw water pump to run the antifreeze side (most of the drawings) and add another pump (mechanical or electric) to run the raw water side. I believe the Moyer kit runs the same mechanical pump for both raw and antifreeze, so why re-plumb the raw water pump (original) to anti freeze. It just seems to be more work and plumbing and the original plumbing has an intake filter on it.? What am I missing? The Indigo system makes even less sense to me, in that they mount another mechanical pump from the alternator drive and then use an electric for the raw water. I understand the electric switching with an oil pressure switch, but it seems to be just more complication, and what happened to the original raw water pump? I am sure that someone can give me logical explanations to this, but I sure cant see it at this point. I look forward to learning a lot from this forum. _____Grant.

[indigo]

Indigo FWC Systems

All Fresh Water Cooling Systems (antifreeze) require two separate pumps to circulate the raw water and the antifreeze.

Indigo offers two distinctly different FWC systems for those applications where it is not feasible to add an additional mechanical pump on the flywheel end of the A4 as Universal offered originally and MMI currently offers.

Mechanical FWC - This system adds a second mechanical pump which is driven from the same, albeit longer, belt that drives the alternator. This new pump becomes the raw water pump and the existing pump becomes the antifreeze pump. Experience has shown that the small 3/8" wide belt that is used is capable of carrying the load of the pump as well as a high output alternator.

Electric FWC - This system adds a second pump which is driven by an electric motor. This new pump becomes the antifreeze pump (for a host of reasons) and the existing pump remains the raw water pump. Mounting of the electric pump is at the owners discretion as long as it is at about the lowest point in the system, as the pump is not self priming.

I hope this helps to clarify the configuration of the two systems.

Tom Stevens

[Grant]

Thank you Tom. That clears up my misunderstanding. I will go electric for the antifreeze. Grant.