The Stovebolt Site Forums The Shop Area The HiPo Shop 46 Chev 350 crate engine overheating

I have a brand new Chev 350 crate engine installed and the previous 350 had the same problem of overheating up to 280F. I put a brand new downflow aluminum rad in it with an electric fan and it has a 180F thermostat. Everything is brand new including the water pump. Can anyone who is familiar with the 41 to 46 Chev tell me what I've done wrong. Most of the rodshops that I've looked at online say the minimum CFM airflow for the fan should be 2500CFM with a 70 amp relay. That sounds powerful. I don't know what the CFM of the 16" fan I put in is. I'm getting desperate to find out the solution. Can anyone help. Bob.T

First Try another therm. Half of the ones we get are defective.
I hope you didn't do what I did. I recently put a new alum. radiator in my 56 & the temp went right up. After pulling hair out that I had very little left of, I found I had left the cap that came with the new rad. on the upper hose connection.

A radiator is simply a liquid-to-air heat exchanger. Overheating is the result of not enough radiator, and/or not enough airflow. Does the engine overheat at idle, or does it only happen out on the road? Try using a laser heat sensor gun to see what the temperature at the bottom of the radiator is as the coolant goes back to the water pump. If you're not getting at least 40-50 degrees of temperature drop from top to bottom, you're going to need a more efficient radiator.
Jerry

will it boil over when you turn it off? turn the fan on and put a shop rag in front of the grill if the air will keep the rag held to the grill you are pulling enough air. check the lower rad hose to make sure it is not sucking flat.. when it is cold take the cap off put a cheap candy thermomter in the radiator crank it up to see if the thermostate is opening at the right temp.and that the gauge is reading the same temp. if all this checks good it could be timming or carb to lean.. mine was temp gauge was 40 degrees off

To get the coolant to 280 degrees without having a massive boil-over would require a 23 pound radiator cap. I have a sneaky suspicion your temp gauge is lying to you.
Jerry

Never had mine that hot but it would get hot. I had PRC out of IN build me a shroud and used a Spal fan on it. That took care of most of it but it would still heat up going down the interstate 70 mph. I could slow down to 50-55 or idle and the temp would drop. Problem was the shroud was so thin the air became stagnet at the lower part of the radiator where the air couldn't move up and out. I cut some holes down at the dead space at the bottom and never had another problem. I also have a friend with a 41 that would heat up and he was missing the upper air dam. Once he installed it the air was forced to go through the radiator instead of up and around it. All things considered I doubt it is getting that hot as mentioned above but I would verify it.

Found out it was a brand new electric temp gauge, what made me suspicius was when I turned on the ignition in the morning with a temp of 33F the gauge would jump to 120F. Warmed it up to 240F and let it sit for 6 hours. Outside temp was 63F, engine gauge read 130F. Just to make sure I got a lazer temp gun and will try it. I think I'll go back to the old mechanical gauge. Thanks all.