The Stovebolt Site Forums The Shop Area Engine Shop engine overheating 235 swap for 216

I have a 46 pup. I swapped a54 235 for the 216. The temp guage remains in the mid range a long as I am moving. When I stop the guage goes all the was to the righthand stop. It will not start until it cools off the engine will turn over very slowly. I don't lose any coolant and the system is the non-pressurized in the 216. Will an aux. fan cure the problem?


b51r

Probably not. Start with a thorough cleaning and rod-out of the radiator by a professional shop, if you can manage to find one that still does that kind of work. A recore might be needed if the old one can't be cleaned up. It sounds like you've got a dirty, inefficient radiator that has to have a lot of airflow just to maintain a minimum level of cooling. An electric fan would be just a band-aid fix, not a good solution to the problem, on a long term basis. If the coolant isn't boiling, it's not getting as hot as the gauge is indicating. Use a laser-type temp gauge to get some actual readings- - - -places like top to bottom of the radiator core, water pump inlet, thermostat housing, etc.
Jerry

How much run time after the swap?

We also don't know what thermostat you have (temp rating) or when it was changed, what your timing is set at, where your fan is situated (high, low, right in the middle), if your water pump is new/old/shot or what and what if anything was done to the 235 before you installed it. If the 216 was running with no overheating problems then maybe an electric fan might help. If you're going to use a puller fan, you will need to remove your current fan and pump and buy a short shaft water pump for better clearance. If the amp draw isn't too high for you and the noise doesn't bother you, some of the electric fans do a really good job. You would need to make a shroud, however to ensure your fan does its best. I have the one sold by Old Air Products (uses a Spal 16 inch fan and comes with a temp adjustable switch) and that is a very good product. I don't know if they have them for the 46 year, but the one for the 52 model cools it extremely well.

The radiator has been serviced by a radiator shop and has a 20 qt./ min.flow. The 216 had the same problems. The 235 had a complete overhaul. I have a 165 degree thermostat.It was changed with the overhaul. The water pump is the original one from the 235. The fan is in the middle of the radiator.



b51r

I thought the stock thermostat was about 190. Am I way off?

B51r,
When warm, if you were to look at fluid at the top of radiator inlet, is it moving? What level does it sit at when cold? Should be just above the fins. Do you have the correct coolant to water ratio?

If you 216 had the same problems, wouldn’t that point to your radiator unless of course you used the 216 parts on the 235.

Just a few thoughts,

Chris

PS just don’t stop moving when you go for a ride! You’ll be fine! 😁

A couple more thoughts...

Fan distance to radiator? 1 inch away is ok but the further away you go the less effective your fan is.

Timing? Retarded timing will make an engine run hot and in my observation it will do it in a hurry. Timing too advanced will also cause an engine to run hot but it takes longer.

If your carb is running really lean at idle/low speeds, this can add to overheating, also. But I don't know if you have Rochester carb or what.

Also, the brand of thermostat matters. I would avoid a "Fail-Safe" brand of stat. If your engine overheats even once, this type has brass levers which lock the thermostat in the full open position...disabling it completely and forever (unless you remove it and disable those little locks). So then you don't have a thermostat, and thinking you do have one when you don't can cause all sorts of needless confusion. And the one I bought did not have an air bleed hole.

Sounds like from what you've written that you need more air flow at low speeds/idle. Try the electric fan idea. Just keep in mind the amount of amps it needs and the cfm rating. 2000 cfm or so will let you do away with the water pump mounted fan, but it takes 20 amps for one of those. Spal fans are good. Beware of anything boasting 3000 cfm with 6 or 7 amp draw (like this one): https://www.amazon.com/dp/B01MTLGP1Q/ref=sspa_dk_detail_9?psc=1&pd_rd_i=B01MTLGP1Q