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1984 70 hp thermostat

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scalhoun506

Regular Contributor
just got a 84 70hp and changed thermostat, yah OEM and sierra are very different, also new OEM bypass spring different then what came out and 2 springs really!. so as it stands now, plastic stat and 2 different springs( only ordered 1 before) and relief valves. ran one day no alarms, pee stream really strong, got new impeller but avoiding that job
ordering more stuff soon, new springs seem stronger, use old springs or get another new one? and need opinions on plastic stat vs old style metal, thanks
 
I believe that 1984 set up with the 2 springs / poppit valves is very good.----Less trouble than the newer 56 cube blocks.------Do NOT make any changes.----Order the correct parts !!
 
Right.....here is the masterful engineering that I throw in the woods.....as far as I can.....behind my shop. Think they showed up around 1986.
 

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Exactly WHAT is the problem with the plastic thermostats? Thousands of them out there that seem to work okay. Racer HOW would you improve the 56 cid set-up?
 
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There were overheat problems with the #2 cylinder on the 56 cube blocks.----Never saw problems like that on the 49 cube blocks.
 
racerone said:
There were overheat problems with the #2 cylinder on the 56 cube blocks.----Never saw problems like that on the 49 cube blocks.
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That was a simple problem to fix I do agree all 56 cid blocks should have the mod. And no I did not see problems like that on the 49 cid block. The 49 cid block would let water into the cylinders from the exhaust covers and that was much more prevalent than the #2 cylinder overheat.
 
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