Made my first road trip with my sedan since I installed the fresh 355 Chevy engine and was not happy with the temp results, and it wasn't even that hot out! Here is the background..when I bought the car it had a 355 Chevy with 70K miles that leaked oil badly. It had a PRC aluminum radiator (new in 2009)with Spal electric fan on engine side in an aluminum shroud that was pulling air full-time. It never ran hot but had a motor with 70k. My dislike was hearing the electric fan run all the time, I felt like I was driving a hover-craft. So when I built the new engine this winter, I removed the Spal and shroud and installed a 12" flex fan in the aluminum shroud that was already there. I put the Spal on the front of the radiator (with wires reversed so it blows the right direction)and wired it to a dash switch for use as a back-up if I got in traffic and the temp went up. I was sure it would work. Duh! Here is what happened yesterday. Engine ran at 190-195 going down the road at 65 MPH. Slow down for a traffic light and it approaches 210, get in a traffic jam as we did and it goes over 210, more like 240. My engine is not a real high performance piece just a nice 355 Chevy with flat-tops and edelbrock aluminum heads. It currently has 280 miles and I run 92 octane. My hood is louvered a bunch. I am ready to do whatever it takes to get it to cool at 180 consistently, even if that means buying a new radiator! I am thinking about removing the thermostat entirely and maybe even taking off the fan shroud to maximize the air flow thru the radiator. Both just test-run ideas. Who has a similar engine combo and has no cooling issues? I am needing cooling suggestions! Thanks in advance, C-dog
are you sure you can turn that Spal fan around? i always thought that Spals were pushers or pullers and not both
Drill a 1/8" hole in thermostat. The flex fan is an accident waiting to happen - notorious for cracking at the hub and destroying radiators - get rid of it. I learned the hard way - three times. Buy a Cooling Components Inc 16" fan/shroud combo - it's whisper quiet and could suck the chrome off the bumper of a Mack truck. I got rid of my freight train SPAL as it was way too noisy and my hearing is shit! The fan in front of the radiator may also restrict airflow. Make sure that the air cannot get around the front of the radiator - all air should channel through the radiator. I run this setup in my '40 and I am OCD about proper cooling....
I have a 383 Edelbrock 460/460 in my 40 sedan delivery and it runs 165 with a 16 inch motor driven fan and shroud. No cooling problems even in traffic.
A flex fan is a poorly designed piece,,install a steel bladed fan and you will see a big improvement. A 12 inch fan is pretty small,,can you use a larger fan?HRP
pitch the flex fan, like everyone says, , I had one come apart and had a porkupine hood from 2 blades , and pull the spal fan off ,get a factory style steel fan with a thermostatic fan clutch , this way its quiet when driving , and only makes noise when it gets hot and saves on fuel too . remember to put the steel fan 1/2 way into the shroud for the best efficency and it also allows air to bypass at speed so the fan is not impeeding the flow of air .
Corndog, If your fan was designed to be a puller and you want it to push from the front of radiator . The blade of the fan need to be flipped over as well as reversing the wires. Tex1935
Well it looks like the flex fan has to go! I dont have room for a 16" fan w/o hitting the top hose, the 12" just barely makes it. I know the Spal on the front is blocking some air flow because I tried an experiment yesterday by turning it on while going down the road. The temp went up! I think I will check out the Cooling Components fan...
Speedway offers them in these sizes. Available in 15", 17", 18" or 19" diameters. is your water pump pulley smaller than your crank pulley?,HRP
I have a lot bigger fan then 12". I think it''s like 16 or 17. and I put a flex hose on the top with a 90 deg. bend. and I have a walker rad. best thing I ever bought.
Why do you want to run at 185? I've had a couple cars with small blocks that seem to feel right at home around 200. That doesn't always mean somethings wrong. If you're boiling over you obviously have a problem, but running around 200 is probably fine. Also, I think ditching your thermostat may have the reverse effect? Correct me if I'm wrong here (it's happened plenty), but a closed thermostat holds the water in the radiator longer allowing it to cool more. A constantly open thermostat (or no thermostat) could prevent cooling to some degree as the coolant doesn't stay in the radiator long enough. No idea where I heard that, but it's probably worth considering. Do you have a "cap" on the opening between the grill and radiator? Without capping those 40's the air likes to run straight up into the engine bay. Good luck! Great looking sedan! I love 40 sedans. I sure miss mine....
Well I think I fixed it, and I am embarrassed to say I think it was all just a faulty thermostat. I had read quite a bit on Google about running no thermostat and decided to just clip the center out of mine and re-install it. I also took off the Spal fan shroud that I had on the front and moved the fan closer to the radiator. I put it all back together and took it on a 40 minute cruise. The hottest it ever got was 180 when I let it purposely idle for about ten minutes. Most of the time it ran consistently at 165. A couple times going down the highway it dropped back to 150. I think the thermostat was the culprit all the time. I think I am good. Thanks for all the advice. Oh, and I am going to can the flex fan!!!
Read this: http://www.jalopyjournal.com/forum/showthread.php?t=54221 If you are heating up in traffic, this is probably the answer to the problem.
Swapped out my thermostat on my engine when I flushed it out and dropped the temperature by 20 degrees. I think my thermostat was sticking also. Saw your car Saturday Corndog. Nice looking ride. If I had seen you around I would have stopped and chatted with you.
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