I need to replace the thermostat on my 1981 Atomic 4 engine. The replacements are $250.00 +. Is there a standard replacement available at a reasonable price??
Atomic 4 thermostst
- Thread starter Mike Kane
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You need to call Ken at Moyer Marine. 1 610 421-4436. He can hook you up.
Might also want to check out the excellent Moyer Marine Forum.
Might also want to check out the excellent Moyer Marine Forum.
So $250 for a marine thermostat seems a it rich? What kind of yachty are you anyway?
As I recall the thermostat was a 'special' construction. The thermostat cap has two hoses- one from the cooling pump and the side plate on the block and the other went to the exhaust manifold. When cold the thermostat would close off the passage directly down to the block forcing all water to pass directly over the thermostat to the exhaust manifold. When hot, the thermostat would close off the direct-to-manifold passage and direct the pump water into the side plate the block and out of the bottom of the thermostat back to the exhaust manifold. Thus the thermostat acted like a Y-valve. This is much different than a normal thermostat that simply opens to allow water to pass through it.
I wish I could help you with an affordable replacement. Have you checked the large A4 dealers and eBay? I wonder if there is another non-marine engine that uses this diverting type of thermostat?
As I recall the thermostat was a 'special' construction. The thermostat cap has two hoses- one from the cooling pump and the side plate on the block and the other went to the exhaust manifold. When cold the thermostat would close off the passage directly down to the block forcing all water to pass directly over the thermostat to the exhaust manifold. When hot, the thermostat would close off the direct-to-manifold passage and direct the pump water into the side plate the block and out of the bottom of the thermostat back to the exhaust manifold. Thus the thermostat acted like a Y-valve. This is much different than a normal thermostat that simply opens to allow water to pass through it.
I wish I could help you with an affordable replacement. Have you checked the large A4 dealers and eBay? I wonder if there is another non-marine engine that uses this diverting type of thermostat?
Here's a couple of options
$150 RWC or 135 for FWC, see pic below.
http://www.atomic4.com/thermostat.htm
An adjustable thermostat bypass valve makes the Atomic Four have that "vintage" engine look, but is completely unnecessary if a functioning thermostat of the correct temperature rating to suit the engine is fitted to a properly tuned engine that has reasonably clean water jackets, a properly functioning water pump, and (in the case of a post 1968 Atomic Four) a thermostat housing with a bypass port boss which is in good condition. If there is a need to restrict the bypass hose with an adjustable valve to prevent overheating, the engine and/or the thermostat or thermostat housing should be repaired/replaced. source:http://www.cncphotoalbum.com/atomic4/faq/atomic4faq.htm
Westerbeek 140 Degree Thermostat
$163 -- http://www.marinepartssource.com/newdetails.asp?mfg=Universal&pnumber=uJHW262278
OK?
I am not using this but maybe I will someday:
$150 RWC or 135 for FWC, see pic below.
http://www.atomic4.com/thermostat.htm
An adjustable thermostat bypass valve makes the Atomic Four have that "vintage" engine look, but is completely unnecessary if a functioning thermostat of the correct temperature rating to suit the engine is fitted to a properly tuned engine that has reasonably clean water jackets, a properly functioning water pump, and (in the case of a post 1968 Atomic Four) a thermostat housing with a bypass port boss which is in good condition. If there is a need to restrict the bypass hose with an adjustable valve to prevent overheating, the engine and/or the thermostat or thermostat housing should be repaired/replaced. source:http://www.cncphotoalbum.com/atomic4/faq/atomic4faq.htm
Westerbeek 140 Degree Thermostat
$163 -- http://www.marinepartssource.com/newdetails.asp?mfg=Universal&pnumber=uJHW262278
OK?
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A4 Cooling
Pretty Good Rich. Here's how it works:
The bypass loop transfers coolant from the pump via the sideplate Tee to the top of the thermostat housing. If the thermostat is closed (cold, prevents coolant from leaving the head/block) the coolant passes through the top of the T stat housing from the bypass directly to the exhaust manifold through the short hose. Nothing or very little flows through the block or head. When the stock Holley T stat opens it closes off the bypass to the manifold forcing coolant into the sideplate, circulating coolant through the block and head to the bottom of the thermostat recess, through the open thermostat and to the manifold. Said another way, the head gets it coolant from the block. The thermostat housing is a coolant exit from the head, not an entrance.
As already stated: Moyer Marine has everything needed to keep the A4 running sweet. Yeah, $250.00 is too much. http://www.moyermarine.com
Mike... Have you tried soaking that T-stat in vinegar overnight? Try that and then set it in a pot of water and heat it up. If it's functional you should see it open.
One other item for you to consider is the housing itself. If it's severly corroded in the inside it might prevent your T-stat from operating properly.
Pretty Good Rich. Here's how it works:
The bypass loop transfers coolant from the pump via the sideplate Tee to the top of the thermostat housing. If the thermostat is closed (cold, prevents coolant from leaving the head/block) the coolant passes through the top of the T stat housing from the bypass directly to the exhaust manifold through the short hose. Nothing or very little flows through the block or head. When the stock Holley T stat opens it closes off the bypass to the manifold forcing coolant into the sideplate, circulating coolant through the block and head to the bottom of the thermostat recess, through the open thermostat and to the manifold. Said another way, the head gets it coolant from the block. The thermostat housing is a coolant exit from the head, not an entrance.
As already stated: Moyer Marine has everything needed to keep the A4 running sweet. Yeah, $250.00 is too much. http://www.moyermarine.com
Mike... Have you tried soaking that T-stat in vinegar overnight? Try that and then set it in a pot of water and heat it up. If it's functional you should see it open.
One other item for you to consider is the housing itself. If it's severly corroded in the inside it might prevent your T-stat from operating properly.
Re: A4 Cooling
Mike,
I took my old cruddy thermostat and soaked it in vinegar and it cleaned right up; also popped at the right temp in a water bath on the stove (160 for mine I believe). Salvation!
Incidentally, you haven't mentioned it, but have you ruled out issues that might be causing overheating instead of a faulty t-stat?--assuming that's why you are considering replacing the t-stat.
My t-stat turned out not to be my overheating problem: my rwc exchange manifold was completely filled with silt and crud--zero flow. I filled it with vinegar for 24 hrs and then back flushed it too. The old A-bomb now never overheats.
Mike,
I took my old cruddy thermostat and soaked it in vinegar and it cleaned right up; also popped at the right temp in a water bath on the stove (160 for mine I believe). Salvation!
Incidentally, you haven't mentioned it, but have you ruled out issues that might be causing overheating instead of a faulty t-stat?--assuming that's why you are considering replacing the t-stat.
My t-stat turned out not to be my overheating problem: my rwc exchange manifold was completely filled with silt and crud--zero flow. I filled it with vinegar for 24 hrs and then back flushed it too. The old A-bomb now never overheats.
Re: A4 Cooling
Hi Mike,
Indigo eletronics has them cheaper.
http://www.atomic4.com/thermostat.htm
All U Get
Some one beat me to it.
Hi Mike,
Indigo eletronics has them cheaper.
http://www.atomic4.com/thermostat.htm
All U Get
Some one beat me to it.
At that price them thermostats are no throwaway parts. I like JohnyQ's approach. I would clean it out and thoroughly test it again required specs before deciding on replacement.
I have a atomic 4 for sale ran a few years ago I pulled it out of my 67 cal 30' and re powered with a westerbeke 4-107 I'll take 1200 for it core alone is worth 700. I'm in Juneau ak so shipping is pricey but im willing to crate it up if anyone wants it.
My email is mikemaass@ymail.com I can sent a few pics but I'm having trouble putting them on here.
My email is mikemaass@ymail.com I can sent a few pics but I'm having trouble putting them on here.
I think I have one. I replaced the thermostat for my A-4 years ago and kept the old one. The problem, as I remember wasn't the thermostat, but I continued to use the new one. I was digging through some old hardware and I think I found it. I also have a couple of water temperature sending units. The thermostat is rusty but I learned later that they clean up well can go on. PM me I would be happy to send it. I can send a picture if you like. You pay postage.
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