#26
IP: 24.152.132.65
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Sure, as long as it works. A few considerations though:
Regarding a question in your first post, I'd avoid Muriatic acid for the thermostat. Vinegar works fine and is far less aggressive. The Holley three spring thermostat is much sought after and no longer available so treat it like a fine gem.
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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 |
#27
IP: 24.56.243.202
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Hey folks, my thermostat is kaput (engine runs waaay too cool always, probably stuck open) and I want to install a new one. I've read all about the original double acting Vs single acting with bypass valve, but I'm not sure what's currently installed on my A4. See the pictures below. It sort of looks like I've got that 1/4" spacer, and those fancy nuts look like what are in the Moyer kit. If so, all I need is to order the CSTH_01_510 and OI should be good, right? So, can someone tell from these pics whether this is the case? Thanks
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"A ship in the harbor is safe ... but that's not what ships are built for. |
#28
IP: 68.111.10.118
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Are You RWC Or FWC?
Why not take the thermostat out and see what is going on? They you can test the thermostat in a pan of heated water to see if it is closing and opening correctly.
If the thermostat is cruded up maybe all you need is to soak the thermostat in vinegar. If the cooling system is full of crud it would be a good time to do an acid flush. TRUE GRIT |
#29
IP: 137.200.32.6
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Take the elbow off too!
Mine was totally plugged with goo and pretty much disabled the thermostat. |
#30
IP: 184.0.21.175
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One a side note, can you tell us what that ducting in front of the manifold is for?
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-Jerry 'Lone Ranger' 1978 RANGER 30 |
#31
IP: 24.152.132.65
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Quote:
Wristwister, my RWC engine ran between 100° and 120° with a functioning 140° Holley 3 spring thermostat. I did the vinegar soak and stove top test but still the same result. Low temp is not necessarily conclusive that the T-stat is dead.
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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; 12-12-2016 at 10:48 AM. |
#32
IP: 76.7.99.222
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Makes sense with the exit hose from the manifold heading in the same direction.
Dan S/V Marian Claire Edit: I believe wristwister has a Tartan. It may be one with the A-4 mid-ship and off to port with the standpipe exhaust so having the exhaust exit the flywheel end would make sense. Slow day here in the mtns. Last edited by Marian Claire; 12-12-2016 at 11:13 AM. |
#33
IP: 70.199.155.181
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Thanks for the quick advice folks. Yes, that's a heat shield. Like Marian said, it's a Tartan 30 with the engine up front just behind the mast. The exhaust runs forward and out.
ndutton, I'm curious how you'd be running at ~100 with a known good $140 thermostat. Bad temp sender? I my case, I've been running consistently ~180 for years, then one day started registering no higher than ~120. Yes, I agree I should pop out the thermostat, test it, do the acid soak etc. I plan to do that. It's just that I've learned the hard way that anything can happen on even the simplest of tasks on a 44 year old marine engine. Busted screws, bad fittings, other weird anomalies. I just want to be fully prepared before I crack that first nut to prevent the boat being out of commission for too long once I get started.
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"A ship in the harbor is safe ... but that's not what ships are built for. |
#34
IP: 161.213.49.150
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Remember the lower the resistance in the sending unit, as the engine heats up, the higher will be the gauge reading.*
So if there is resistance in the circuit temp sending unit -> gauge the gauge will read abnormally low. Edit: Corrosion on the wire end fastener will have the same effect. To test for resistance in the boat's wiring let the wire loose at the sending unit and loose at the gauge then connect a jumper wire at one end and measure the resistance at the other two ends. S\B zero ohms. *By way of illustration, as best I can recall at the moment, the spec for my temp sending unit is something like 550 ohms at 70 degrees and 30 ohms at 212 degrees. TRUE GRIT Last edited by JOHN COOKSON; 12-12-2016 at 03:12 PM. |
#35
IP: 24.152.132.65
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Quote:
I'm not so sure the front of the head right next to the thermostat housing (late model) is the best place to sense temperature.
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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 |
#36
IP: 24.56.243.202
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OK folks, the next chapter of the Tartan's running-too-cool saga:
I popped out the thermostat, it's definitely the single-acting with the bypass, but the bypass has no restrictor valve. The thermostat was pretty gunky, and closed. I did the vinegar soak, cleaned it up, and tested, opening at 160 just as it should. It definitely wasn't stuck open and likely was working fine. So ... any ideas why the engine is running so cool? Could it be because there's no restrictor in the bypass loop? This would be weird, because it's been running at ~180 for the last few years, and then one day last summer it just started running cool, going no higher than 120. Ideas?
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"A ship in the harbor is safe ... but that's not what ships are built for. |
#37
IP: 72.194.218.226
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Quote:
Did you check the wiring for resistance? Post #34. TRUE GRIT |
#38
IP: 96.76.48.110
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Soot in thermostat
Hello guys,
Joined the forum to learn how to maintain properly my Atomic 4 which I have on Coronado 30. I'm new to the engines so please don't throw stones in my direction I have few issues with my A4 among others is milky oil/moisture in first two cylinders. I'm trying to understand how would the soot/grime get into the thermostat per pics attached. Could it be the manifold has a crack sipping water in mixed with exhaust gas when operating? The engine is raw sea water cooled. Any thoughts or ideas? |
#39
IP: 69.251.78.78
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Quote:
I recommend you start a new thread on this issue. |
The Following User Says Thank You to scratchee For This Useful Post: | ||
sastanley (02-12-2022) |
#40
IP: 69.250.111.245
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Jr.
Plus One...start a new thread on your particular issue so we can keep it all isolated to you! And, welcome aboard.
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#41
IP: 96.76.48.110
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Quote:
The moisture in 1,2 cyl is an ongoing issue that was fixed temporarily couple years ago by a local mechanic and now looks like it's back and I have some ideas on what is causing this which I will share in relevant Discussion Topics threads |
#43
IP: 199.119.235.167
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installing MMI Thermostat, 150 degree (late model double-acting)
a hint for the community on installing a MMI Thermostat, 150 degree (late model double-acting). What appears to be a simple job becomes more complicated when having to remove the alternator to get at the hoses for the bypass valve and remove them to take the thermostat housing off. It took me 3 tries to get the new thermostat centered in the head so that the housing wouldn't leak. What worked for me on the third try was glueing the thermostat to the flange inside the housing with a tiny amount of Permatex seal-a-gasket, and clamping it overnight. On this attempt when I turned the housing with the thermostat attached, I was able to center it in the head so that it no longer leaks. I can think of no other way to center it without trial and error, because the 'hole in the head' (no pun intended) is larger than the diameter of the thermostat. The flange of the thermostat just fits in the lip of the housing, so glueing it in there just makes sense. It would be great if Ken could supply a tiny amount of Permatex seal a gasket for just this purpose.
I used the aviation Permatex for the gasket itself and even put a thin layer on top of the gasket (just to be sure) even though it's not recommended. With having to take the alternator and short hoses apart the whole process is very time consuming and frustrating if the housing leaks after putting it all back together again which is the only way to test the seal. You simply can't tell if the thermostat is centered until you start the motor. Ken doesn't like the idea of using Permatex on the top of the gasket and the housing lip because of difficult cleaning at maintenance time. Personally I'd rather apply a little elbow grease to cleaning than having to re-install the thermostat and housing. Just my thoughts in case anyone else comes up against this issue. |
The Following User Says Thank You to Captain Kirk For This Useful Post: | ||
TimBSmith (04-23-2023) |
#44
IP: 24.184.45.46
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Does MMI Thermostat eliminate need for bypass back pressure?
I am installing the MMI thermostat and Moyer's comments make me think it eliminates the need for any restriction in the by-pass loop. "This design also eliminates the need for any additional restriction in the by-pass loop." Which makes sense as the thermostat when fully open will close off the bypass. (My thermostat housing is in good shape.)
I assume that means I can remove the "Check Valve" with the 2-3 PSI back pressure installed in the bypass loop. I don't see that it does any harm to leave it in place, but it does make removing the thermostat when winterizing or doing an acid flush a bit of a PITA. Or does it mean any restriction in addition to the Check Valve? |
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