#1
IP: 38.118.55.125
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By way of background, the original late model factory solution was to use double-action thermostats which start to open and allow some coolant through the block and head as engine temperature moves past 140 degrees, and they then close off the bypass port in the thermostat housing when the engine temperature reaches 180 degrees. In standard late model bypass systems, engine temperature is free to vary between 140 and 180 degrees, depending primarily on the condition of the cooling jackets, temperature of raw water, and the load imposed on the engine.
Double-action O.E.M. thermostats have become very expensive, and (although still listed in our online catalog) are becoming problematic to keep in stock. We eventually joined others several years ago in offering an aftermarket thermostat that functioned like the O.E.M unit until the source of those thermostats disappeared in the past several months as well. At that time we concluded that the most cost effective and reliable solution was to incorporate a single-action thermostat into our kits, using a separate method of regulating the bypass loop. The separate method of providing a bypass restriction for single-action thermostats (to finally answer your question) is because they have no ability to regulate the bypass loop as temperature increases past 180 degrees. On our test stand, a spring loaded check valve providing 2 to 3 psi backpressure maintained normal temperature in a raw water cooled configuration using the single-action thermostat provided in our kits (CSTH_01_510). In freshwater cooled engines it’s frequently necessary to fully close the bypass loop when operating at high power settings in warm climates so a manual ball valve is recommended in those cases as well. In an effort to cover both applications, we currently provide a spring loaded check valve and a small manual ball valve in our by-pass restriction kits (product number CSOT_01_61). It should be noted that the need to provide a restriction of some kind in the bypass loop is not limited to the single-action concept. Universal themselves realized that unless their bypass type system had a restriction in the bypass loop, many engines would operate hotter than desired. In a technical bulletin from the mid-seventies, they recommended that the 90 degree elbow in the inlet to the thermostat housing be filled with lead and then re-opened by drilling an 1/8” hole in the lead. That technical bulletin was largely ignored in favor of more practical solutions and many Atomic 4s today are already equipped with either a manual ball valve or a spring loaded check valve in the bypass loop. Don |
#2
IP: 24.61.3.16
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Bypass retriction
I switched over to FWC about 3 seasons ago. I have removed the thermostat from the engine thinking it would run cooler. After getting and reading my new maint. manual I bought from Don, I have come to realize my actions are what caused my higher operating temps, especially at higher throttle.I will be reinstalling the themo as well as a restriction for the bypass(which I also removed).
OK here is my question. How much hose can I add the the system without adverse affects on the pump? I would like to mount the valve to restrict the bypass so that I can regulate it from the cockpit.Prob.about 5 feet of hose total. Thanks, Mike |
#3
IP: 173.166.26.245
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The problem is not in the length of the hose but in the vertical rise. It will be difficult to keep such a line purged (or burped). Why not look into a valve you can mount low near the engine but operate from the cockpit? http://www.stcvalve.com/Process_Valves.htm#43
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#4
IP: 76.217.56.241
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Thermostat, Holley Mfg. Co., 9A6 140
This is really confusing. I see several thermostats. Which one would replace the one with the above identifaction numbers and letters? My current one worked, but it's really corroded and I'd like to replace, update, or whatever it takes to have good operation.
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#5
IP: 24.152.131.155
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Assuming you have the original Holley 3 spring thermostat in a late model head MMI's replacements are this one or this one. The second link has a new housing if yours needs replacement.
Back to your original thermostat. The Holley 3 spring has been referred to as the Holy grail of thermostats. Why not remove it, give it an overnight vinegar soak, perform a stove top test with a meat thermometer and reinstall it? If the metal is still intact and it's functioning properly your stat is as good as it gets.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#6
IP: 174.94.25.188
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So, I take it there are no problems with the supply of early model A-4 thermostats?
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#7
IP: 24.152.131.155
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Quote:
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#8
IP: 76.217.56.241
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Quote:
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#9
IP: 69.70.12.123
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Moyer thermostat question
In 2005 I purchased CSTH_03.3_412. It has worked fine. I see now you are selling only CSTH_01_512.
My questions: What is the difference? What part number should the replacement thermostat be? Should I install (CSOT_01_61) Cooling system bypass kit ? Engine has run well with your new thermostat and housing. |
#10
IP: 76.180.1.249
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just finishing up a4 r, r, and r....machine shop reinstalled my late model double acting thermostat for me....may have put it in upside down....
anyhoo -- removed it last nite because water temp never rises on gauge....thermo was on its side....the flange which holds the spring which is held on with a circlip [or eclip?] was gone.... so.... 1. is it likely stuck somewhere in the cooling system, blocking something?....not that i'm gonna r, r, and r the a4 again....but i do wonder... [water flow out the exhaust seems normal] 2. any ideas on a fix? can i just replace it with a washer and another circlip / eclip? k
__________________
keithems [1976 c&c 30 mk 1] |
#11
IP: 76.221.67.25
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Hello, all,
This past summer I had noticed a bit of white steam in the exhaust so decided to take a closer look. It appears that there are a couple of hot spots on the exhaust manifold; one at the forward end (pic 1) and one at the aft end (pic 2). I removed the thermostat (pic 3) and put it into a pot of water on the stove. It worked, but I did not think to check the temperature that it opened at. Pics 4 and 5 show the thermostat housing full of crud/mud/gunk. Since the thermostat worked, should I just put it back in or replace with a new one? I can clean the crud/mud/gunk from the housing area, but is that just the tip of the iceberg? Any and all thoughts are appreciated. Thanks in advance. Raymond |
#12
IP: 24.152.131.155
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Sadly, those hot spots are normal although you might be the first one to report a spot at the rear end. We haven't determined it to be a remedy but consider replumbing the manifold following the Thatch modification, it can't hurt. Details found here.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#13
IP: 206.125.176.5
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Raymond,
In addition to Neil's suggestions, I think I might also go for a full water jacket clean out..at least a muratic acid flush followed by a few vinegar flushes..The rest of the water jacket will look exactly like your t-stat housing/head, and there will likely be lots of muck inside the block near cylinder #4. Your motor looks to be in pretty good shape! I am going to make a guess that it is in a Catalina 30, based on the intake location, the type of access I see in the pictures, and the battery tray directly adjacent.
__________________
-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!!) Last edited by sastanley; 11-07-2012 at 10:25 PM. Reason: fix up some bad gammar & sphellign errors :) |
#14
IP: 128.183.140.38
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Pay particular attention to the ring-shaped boss inside the thermostat housing. The two-stage thermostat has to seal against this to control the flow through the bypass. Is the surface is deeply eroded, you might want to consider replacing it with one of Don's bronze castings.
Soak the thermostat in vinegar overnight and scrub it with an old toothbrush. It'll clean right up.
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#15
IP: 76.221.67.25
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Thanks
You guys are great! Thanks for the advice.
Shawn, very astute observation. She is a Catalina 30, hull number 120. I bought her new in 1975. She has spent most of her life on Saginaw Bay, Lake Huron. In 1977 I took her down the Mississippi and as far as the Bahamas; brought her back to Saginaw Bay in 1981. Four years ago, I started to treat her to heated winter storage. That has been terrific for various projects. Thanks again. |
#16
IP: 71.252.8.11
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Raymond, Always good to see another C-30 still floating. I am the 2nd owner, but I was 6 years old when my Dad bought #511 new in 1977.
Compared to the condition of your boat in the pictures, it does not appear my father kept my boat in as good condition as you have.., but my wife and I are continually working to put new life back into the old girl! We really enjoy her, and a successful trip to the Bahamas without flying there (I've done neither) would be a real treat someday.
__________________
-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!!) Last edited by sastanley; 11-07-2012 at 10:23 PM. |
#17
IP: 76.221.67.25
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I agree with you about our good old boats still floating. Thanks for the compliment on the upkeep. I just wish that I had kept better records. For instance, I can't remember when that thermostat was last replaced and I wasn't keeping a maintenance log back then.
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#18
IP: 132.246.194.14
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When did single action thermostat kits start being sold?
I'm having overheating problems with my FWC engine. They are drastically reduced when I clamp off the bypass, which makes me suspect the thermostat. Since the original double-action thermostats are expensive, I was contemplating the use of Don's Thermostat conversion kit: CSTH_01_512.
However it looks like the 1/4" spacer has already been installed on my engine, but by adding longer studs rather than modifiying the thermostat housing. I bought my boat in 2003. When did the did the single action thermostat kits start being sold? Did anybody else sell something like it? Last edited by StephenGwyn; 08-20-2014 at 02:30 PM. |
08-20-2014, 03:47 PM |
BunnyPlanet169 |
This message has been deleted by BunnyPlanet169.
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#19
IP: 161.213.49.150
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Quote:
MMI sells a handy dandy "kit" that consists of a restrictor and a ball valve for the bypass hose. Betcha this would solve your overheating problem in a flash. BTW #1: How long has it been since the last acid flush? BTW #2: The hose clamps are way too tight. The clamps should leave only a slight impression on the hose. If it doesn't seal with this amount of pressure there is something wrong with the hose and\or the barb. TRUE GRIT Last edited by JOHN COOKSON; 08-21-2014 at 05:45 PM. |
#20
IP: 132.246.194.14
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Install manual valve, replace hoses, install check valve, do acid flush, I plan to do all of those things.
However I'm also planning to take the thermostat apart, but before I do I'd like to know how long it's going to take to put put it back together. If it's the original style thermostat, it's 150$ for a replacement, or slightly cheaper to add 1/4" spacer and a new style thermostat. And while I don't mind giving money to MMI, I live in Canada and UPS charges a hefty customs brokerage fee, even though marine engine parts made in the US are duty free under NAFTA. Love MMI, hate UPS. Also, it means the engine is out of action for at least a week while I wait for parts. But if it already has the 1/4" spacer, it might already have a single action thermstat available locally. |
#21
IP: 24.152.131.153
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I think what John is saying is many of us opt to run without a thermostat using the bypass valve to control the temp instead. It's a personal choice.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#22
IP: 198.11.8.218
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Guessing (only) from your picture, there is no good reason for that extra part to be there except to accommodate the aftermarket thermostat. MMI offers a kit which also replaces the studs. Looks like that's what you have.
http://www.moyermarine.com/cgi-bin/s...=CSTH_03.4_241 It's only minutes to remove. A few more to scrape old gaskets. A few more to replace old hoses that won't come cleanly off fittings.... You'll want two new gaskets to replace.
__________________
Jeff S/V Bunny Planet 1971 Bristol 29 #169 |
#23
IP: 50.72.246.102
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Holley Tstat etc
I'm back. I want to acknowledge all the excellent advice I received last fall when I asked for help in winterizing my Atomic 4 for the brutally cold Manitoba winters. The detailed advice from “Ed” “edwardc” and from some of the other Afourians was much appreciated.
I am now back with some more questions. My thermostat and housing look very much like pictures shown by Raymond of his thermostat and housing, except that my thermostat is a Holley 3 spring. I soaked the Tstat in vinegar overnight and scrubbed it with a toothbrush, as advised by Ed . I read the suggestions by nnstanley and my questions are as follows: 1.Do I soak the Tstat housing in full strength muriatic acid?; 2.In order to flush the water jacket with muriatic acid, do I by just pour it into the head of the engine and then start the engine?; 3.Do I follow the same procedure with the vinegar flushes. I can't find a thermostat locally. Is it okay to use the “Water Pump & Thermostat Housing RTV” Gasket Maker by Permatex instead of a regular thermostat? I would appreciate hearing responses to my questions. I appreciated all the advice I received last fall when I posted for assistance. I am impressed not just with the knowledge of the many persons who provide detailed advice but also with the amount of time that is obviously being taken to read the posts, analyze the problem, critique and evaluate the answers given by other Afourians and then provide advice that responds to the questions asked. |
#24
IP: 65.160.210.134
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Quote:
As you may already know, you have the holy grail of A4 Thermostats. See the attached procedure for acid flush. (you can substitute vinegar if you'd like) The pic is an example of the "T-Fitting" mentioned in the procedure. Gaskets, new studs, a new housing, etc are all available here from this site. Just give Ken a call and he'll walk you thru exactly what you need as well as invaluable advice.
__________________
-Jerry 'Lone Ranger' 1978 RANGER 30 Last edited by roadnsky; 05-11-2015 at 10:37 AM. |
#25
IP: 50.72.246.102
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Thermostat etc questions
In my previous post, I said:
I can't find a thermostat locally. Is it okay to use the “Water Pump & Thermostat Housing RTV” Gasket Maker by Permatex instead of a regular thermostat? I should have read that sentence more carefully. What I meant to say is: I can't find a thermostat gasket locally. Is it okay to use the “Water Pump & Thermostat Housing RTV” Gasket Maker by Permatex instead of a regular thermostat gasket? Sorry for any confusion. |
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