#1
IP: 24.152.131.220
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Another thought on coolant flow
As relayed to me by Tom Thatcher (Thatch), he's best to describe the details but I'll start the ball rolling.
Tom reasoned that with the backward tilt virtually all of us have, coolant entering the high point of the manifold would immediately and naturally move in a downhill direction, that is, away from the UHS (Ubiquitous Hot Spot). He did not suggest this was the reason for the hot spot, I mentioned the UHS as a position reference (although . . . . hmmm, I wonder, given our informal poll a while back that showed more tilt almost guaranteed the hot spot, by like 90%). He explained that if coolant was introduced at the lower end, the manifold would have to fill completely without voids before it could exit at the higher end, the opposite of how our engines are normally plumbed. It made a Helluva lot of sense to me. Check out his pics. I should also mention that after bench testing for flow, he found cast plumbing elbows performed dramatically better than those pretty machined ones.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 12-04-2010 at 07:17 AM. |
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TimBSmith (09-28-2021) |
#2
IP: 24.224.206.117
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Pretty sharp.
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#3
IP: 173.166.26.241
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Interestingly the manifold failure I experienced was at exactly that spot. I wonder how many such failures might be related to this UHS. This could be a breakthru. Nice job, Tom!
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IP: 75.197.137.46
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Quote:
Bill |
#5
IP: 75.197.137.46
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Typically, the cold stuff and the hot stuff in a heat exchanger flow in opposite directions ("countercurrent flow"). Does this idea violate that principle?
Is the heat exchanger fill cap above the manifold? Bill Last edited by Administrator; 12-03-2010 at 10:50 PM. |
#6
IP: 24.152.131.220
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We'll need Tom to provide the details but as I understand it, his test setup measured flow using the same pump with the two different styles of elbows.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#7
IP: 24.152.131.220
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If you're referring to the jacketed manifold, I can see where Tom's plumbing scheme supports the countercurrent principle whereas the standard plumbing does not (exhaust and coolant outlet at the same end).
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#8
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Quote:
Bill |
#9
IP: 173.9.105.253
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But Bill, this IS a design review meeting/forum. Tom's idea needs to tested some more and I intend to do just that on my engine. Hanley
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IP: 24.152.131.220
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Anybody see any problems with the reversed waterjacket flow?
I'll go first. I don't. The whole concept intrigued me and I don't think the manifold casting cares where the coolant enters and exits. Add the tilt factor and gravity (and the UHS) and it looks like it could be a real improvement. I'm starting to amass the parts for FWC now that electric coolant pumps are surfacing and I'm really thinking of doing the described replumb as part of the project. I'd like to hear of any, ANY reason not to. I'll throw it in here rather than another thread, Tom also has an excellent pic of his electric coolant pump installation.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
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TimBSmith (09-28-2021) |
#11
IP: 173.9.105.253
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going to antifreeze cooling
Neil - Because you will be reversing the flow in a manifold used for raw water cooling there could be an issue with dislodging metal flakes and chips. May I suggest that you remove the freeze/casting plugs and thread the holes for 3/4"NPT brass plugs. I did this and was able to accomplish a very thorough cleaning. In addition, the threaded holes give future access and can be used for temp monitoring. Hanley
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TimBSmith (09-28-2021) |
#12
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Agreed. After 33 years of RWC, the move to FWC will certainly include a thorough descaling throughout.
Here are a couple low-res pics of the HX I bought this week. The journey begins . . .
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 12-04-2010 at 11:22 AM. |
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IP: 173.166.26.241
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That is one rugged looking unit - stainless and copper?. It will be interesting to see how you design the fill and header tank. Keep us posted.
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IP: 24.136.77.31
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2 cents and 2 cents.
I like the idea (Tom's) about the filling of the manifold from the low end it makes sence. I'm not sure that it will eliminate the hot spot as the manifold is a symetric casting. Some are drilled for the exhaust to exit the front of the engine so there is no water jacket around the area that is exposed to the exhaust. I believe the hot spot is normal and nothing to worry about. However the water filling from the bottom will elimanate the air pocket that could form and not go away.
I have a lot of experience in low preassure hudraulics and the cast fitting do flow much better. I always "port them a bit if there is a bit of a casting lump on the mael ends. They flow better because they turn the flow in a radiused orfice. The machined fitting have the flow crash into a wall where it bounces around and finds relief and begins to head in the new direction. They many times appear more open but don't flow as well. I have also been involved in testing oil cooler performance on offshore racers wit some awsome "thunder motors" well in excess of a 1000 HP. One interesting point is that the coolers performance was affected by the direction it was facing and the angle it was mounted. If we moved the water aft and the oil forward with the water coming in at the low end worked best. I don't remember how mch cooler they ran but we changed many instalations after finding that out with a heat gun and guages. I have a raw water motor that is 40 years old and does not lend itself to an extra pump. I am seriously thinking of going the the electric and going to a HX. How much current does the pump draw? Dave Neptune |
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TimBSmith (09-28-2021) |
#15
IP: 24.152.131.220
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Quote:
edit: Oops, my mistake. It's fused at 1.6 amps reference: http://www.johnsonmarinepumps.com/sp...s/cm10p7_1.jpg
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 12-04-2010 at 11:17 AM. |
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TimBSmith (09-28-2021) |
#16
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??
Wow Niel, I would have expected 8~10 amps. Thats less than a small bilge pump and far less than the ventilation blower. At 2 amps that would equate to around 1/30th of a HP which is the same as many of the coolant pumps I use at work. It should be plenty of circulation and BTW that is the same "Teel" pump I use for my acid flushing every 4~5 years. I spoke to Tom about it when we met at the races and he seemed to think the reliability of the pump was good. It was rated for a thousand hours I think.
Is the pump portion replaceable or does it require a complete replacement of the assembly if the pump fails? Dave Neptune |
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TimBSmith (09-28-2021) |
#17
IP: 71.129.176.117
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"Better late than never?"
Sorry I'm so late getting on board with this discussion. I have made a few notes on the questions raised and will try to address all of them, but I'm sure I'll miss some so please ask again. The conversion process began with a long conversation with Tom Stevens at Indigo who felt that the secret to success using the "Johnson" circulation pump was to enlarge the hoses and fittings as much as possible and to clean the block and manifold as well as reasonably possible. The inlet and outlet ports on the electric pump are 3/4" so those hose runs are that size. The rest of the hoses are 5/8" except for the block bypass hose which remains at 1/2". Several months ago I did some "driveway" pump flow tests on 3 Oberdofer pumps and found that by simply changing from the stock machined fittings to plumbing style fittings, flow increased considerably. The I.D. of the machined fittings is about 3/8" compared to the plumbing style which measured at over 7/16" in all of the fittings I checked. The "sweep" of the elbows also probably improved coolant flow.
Hose routing on my A4 comes from my education of converting several automotive engines to marine use. The principal was always to run the cooling water into the lowest point and out at the higest place possible. In the case of the A4 manifold and the ability to run it at an angle of up to 15 degrees, filling it from the low end meant reversing the factory setup. As Neil pointed out, this should insure keeping it full. There may be a side benefit of this approach in that the coolant is attacking the hottest part of the manifold where the exhaust from all 4 cylinders is flowing rather than the exhaust of cylinder #1. The coolant cap is as high as I could mount it and in the case of a Cat 30 puts it slightly above the coolant level in the block. I actually replaced the pressure spring in the cap with one that holds only about 1 pound of pressure, my thinking on this being that I wanted to reduce the pressure on the coolant passages as much as possibly. I seems to be working well so far. I hope this answers some of the questions, and as I said before please ask again. Tom P.S. Neil, thanks again |
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TimBSmith (09-28-2021) |
#18
IP: 75.197.101.225
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Quote:
I track somewhere around twenty different forums, many of them associated with amateur (ham) radio, which is a "hobby" fiercely dedicated to experimentation and innovation. This one is by far the most intellectually stimulating and filled with fresh thinking. Witness this week alone, where the timing mark device and this idea bubbled up within days of each other. Separately, there was a picture of the Tom Stevens belt tensioning attachment, an all but free add-on which is living proof that the Universal folks certainly didn't think of everything. Bill |
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TimBSmith (09-28-2021) |
#19
IP: 71.129.176.117
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Pump Info
Dave N,
The Johnson pump is just a circulation pump which probably explains the low current draw and long life expectancy since there are no actual rubbing parts internally, except for the motor brushes. The pump is a "non serviceable" unit so it would have to be replaced upon failure. At $175.00 I will not be carrying a spare, just hoses to route around the problem temporarilly. Tom |
#20
IP: 24.152.131.220
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Re: forums
Quote:
The timing device and coolant flow discussions popped up close to each other only because I had the good fortune of a stimulating visit with Thatch two days ago. No doubt these things have been in development for some time but when he dropped over 100 pictures on me seeking assistance in editing/sizing/posting, I couldn't get them posted fast enough. No reason to hold back with ideas like his. Look at the people around here (and Tom's only one of several), this is a good place to be.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
The Following User Says Thank You to ndutton For This Useful Post: | ||
TimBSmith (09-28-2021) |
#21
IP: 75.197.101.225
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Some of the plumbing details escape me. Actually, I have never really grasped all the variations on the theme.
Do the v-drive installs have countercurrent flow, but the direct drives do not? Bill |
#22
IP: 71.130.87.183
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"V-drive hose routing"
Bill,
A technical drawing at the back of an old A4 parts catalog seems to indicate that the V-drive models are plumbed the same as the direct models, which means that the exiting water is going out at the closed end of the manifold or similar to what I've done. It is my assumption that Universal ran the hoses the way they did to keep runs as short as possible and that they assummed that an anti-siphon riser would serve to keep the manifold passages full. Tom |
#23
IP: 74.103.39.3
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Plumbing the heat exchanger?
Can anyone explain why my heat exchanger says the seawater inlet is the one closest to the resevoir cap? I didn't notice this note in the installation instructions until after I routed the hoses the opposite way (nearest to cap=sea water exit to exhaust elbow).
The unit is from Indigo and appears similar to the blue one Thatch has. I can't see how the water flow direction could affect performance here. I switched it to the recommended way and saw no performance difference. I'd like to switch it back, since my hose runs are better the other way... Anyone got a theory? |
#24
IP: 71.168.64.77
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Quote:
but only recently advertised it as a separate product. Regards |
#25
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Quote:
Roadnsky posted a pic of the original Indigo on his alternator, the Indigo site has the current one. Here's Roadnsky's original Indigo tensioner http://www.moyermarine.com/forums/at...1&d=1291425758 And the modified Indigo on their website http://www.atomic4.com/ADJ.html Note the credit below the price box. The "Anonymous Customer" came from here!
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 12-05-2010 at 03:36 PM. |
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