Hey all, this is kind of a strange one. I've got a chevy 355 with what is clearly a great cooling system, since I cannot get it to warm up past 160 degrees. I had a 180 degreee stat in there, and thought maybe moving to a 195 would get it warmed up, but no such luck- In fact, it ran a bit cooler! Do I have a couple of defective stats or what? I guess I should test em huh... Oh and its not my sending unit. I have two of them hooked up (one electric and one mechanical) and they both read the same. I even physically checked under the hood using a pyrometer and it was accurate.
too cold is just as bad as too hot. Thermal expansion isnt correct on parts, fuel doesnt atomize, oil doesnt get hot enough to burn out contaminants, ect.
yup. plus carbon build up on valves and pistons and sludge in the oil because moisture never burns off. a cold engine is not efficient.
I had exactly that same problem on my 23. It had a 350 with a PRC aluminum radiator and I couldn't get it above 150 going down the road. I thought that was great because I have never had a rod that ran cool, especially in Florida. But after a while I lost compression in one cylinder and when I tore it down I found all the cylinders were becoming crusted up with carbon. The engine was not burning off excess gas and was loading it up badly. The valves were so carboned up they were not seating at all, especially in that one cylinder at the back of the block. I switched out the 160 thermostat for a 195 and the car started running at 170, which still was not optimum, 180-190 would have been better. Never did find a fix for it before I sold the car. Some cooling systems are just too efficient, I could put my hand on the bottom hose after running and it was just warm, not hot. It also depends on where you take your readings too. With my sender in the back of the block it read 120 on the dash gauge, and moving it to the thermostat housing area it started reading 150. If they make a thermostat over 195 I would buy that and see what it does..........I didn't know they made those or I would have tried one myself. Don
if you have 195 thermostat it shouldnt open til approx 195 are you circulating water elsewhere.should atleast get hotter til stat opens up???a guy i work with puts cardboard over his radiator during winter that helps
Could it be the chevy motor doesn't produce enough power to heat a gallon and a half of water, put in a Ford motor.
...I don't think he wants it to run hot, small block Chevies run more efficiently between 180 and 200 degrees. I believe he just wants it to run in that range.
Bwahahaha My 355 has always run on the outer edge of being too cool. I ended up going to a 195 stat. A good one not an off the rack stat. I still have problems with winter driving, when I was still working I had a 10 mile drive to work and in 10 miles anything in the lower 30s or below it would not get up to 160 on the way to work, even if I let it sit and idle for 10 or 15 minutes prior to leaving. Blocking the radiator doesn't make any difference in that situation because the stat never comes open. I wish I had an answer for you. I think my problem has always been a combo of good water pump ( flow cooler) and aluminum heads but I cannot answer for you in your situation. Definately go to a hot stat but keep an eye on it in traffic on a hot day because that coud also cause you a problem. Correct they do produce more power in that range at least mine does. 160 is just too cool.
My coupe has a PRC. Radiator in it....it would do what you mentioned...I finally put a 185 thermostat in....added a small moon temp gauge in the intake. And now all is good.....I will still get a variance of degrees between front of motor and back...usually. about 30 degrees. Beats the 60 degree difference the SW. Gauge showed.....I remember one year before putting the 185 in , the car would start off @ 160 in traffic and would cool of to 130. Or so after 20 minutes...
The newer GM vehicles run 210 most of the time. They have a warmer themostat. You need to be checking your temperature close to the thermostat housing. I like to use a Robert Shaw thermostat. They do cost a little more but they are a lot better quality than the ones you normally get at the discount parts house. Here is a 195 ... ideal for most SBCs. Summit Racing sells them ( $20 ) http://www.summitracing.com/parts/BRA-330-195/?rtype=10
The car is an OT Chevelle, but I figure the information is still useful here. It has a new Alumitech alum. radiator, new GMB h/d water pump from Advance Auto, and I've been using the Stant superstats. Its got a 7-blade fan clutch on it too. No shroud. Edelbrock 600 on top an air-gap intake. Runs good otherwise! I'm sure my gauges are correct because they both read the same, and the pyrometer confirms the temps both at the rad. inlet and right beside the water neck are spot on. One sender is in the driver's side head while the other is in the intake right next to the neck. I think I need to check the stats. Because I just don't see how the temps could settle at 160 if the stat (theoretically) doesn't open till 195! I drilled a little hole in both stats, but I doubt that tiny hole could provide enough flow to never let it get warmed up?! Thanks guys!
That is deff something to think about for starters, and #2 your could be bypassing enough water that it will never warm up. Most people have the other problem and here you are too cool. haha
One other thing that seems counter-intuitive... take the t-stat out completely. Theory is the coolant isn't in the rad long enough to cool off... worth a shot.
I just tested the stats. Dropped em in a pot of water with a thermometer and cranked up the heat. Both opened when they were supposed to, so now I'm not sure what that leaves me..
And the pulley size is 5-1/4" I don't know the exact timing, but I have it advanced as far as it'll go without pinging or hard starting.
I've never fully understood that deal about a 195 thermostat keeping the water in the block until it gets to that temp either. For example, I have a 160 in my 27 Ford (331 Ford Stroker) and at about 120 I can feel the top hose starting to get warmer, like hot water is starting to come through the thermostat. I had the same situation on the 23 with the 350 Chevy, with a 195 thermostat the top hose would start getting hot water at about 140 degrees. As a side note, I added one of those Mr Gasket radiator caps that have a thermometer built in the top to my 27. (yeah, I know they are ugly, but I wanted a second opinion) I find it reads very accurately, in fact just the same as my infared heat gun. In my 27 it reads 180 when my dash gauge reads 210. I've changed senders twice and gauges twice, dash gauge still reads goofy. Don
Interesting thread I have a similiar 355 in my Avanti. Patriot Aluminum heads, Summit Alum water pump and Aluminum radiator. 195 thermostat. It also ran on the cool side when I first installed it. As I got the timing and Air/fuel mixture under control, it finally warmed up to run 195 as it should. My guess would be you still need to optimize the carb and see if the cooling is by passing through the heater not allowing the engine to heat up. If you have the heater hooked up, I'd by pass it as an experiment. The first pump I had on my 355 had so much volume, I had trouble with coolant leaks and to high a flow. The Summit pump cured that. You may want to also put a smaller pulley on the crank shaft to slow the pump down. Lastly, be sure you are running the best coolant type and mixture for Aluminum as corrosion can be an issue with our combination. Hope these ideas help as your motor in stout running trim should not run that cool. If it becomes important, I'll measure the pulleys on my engine.
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