VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 36 Engine running hot

There are two other threads in this report of mine. Just to update everyone who provided lots of good suggestions:
I put everything back together, ran the engine for about 30 minutes, re-torques the head, ran for about an hour and torqued again then adjusted the valves. Engine runs like a dream and HOT. At 55 degrees ambient, it hits 180 on the gauge within 20 minutes. Checked with infra-red thermometer and find the water coming to the top of the radiator (I shot this on the metal of the top tank and it is even from side to side) to be 159 degrees, so perhaps the gauge is reading a bit high. The temp of the head at the rear run a little warmer than the front which is to be expected. However; the really big surprise to me is that the bottom of the radiator (again reading constant from side to side) shows that only 6 degrees of temperature was removed form the coolant. I.E. the temperature of the bottom tank was 153 degrees. It seems to me that at 55 degrees ambient that there should be a bigger temperature differential. I haven't checked my other cars to see what temp drop I get and will do that next.

Does anyone have any input as to the amount of temperature drop I should expect?
Thanks,

Ron

You should get a much larger drop across the radiator than 6 degrees. I would expect less than 100 degrees at bottom of the radiator particularly in the center particularly with a 55 deg ambient. When the vehicle is not moving the area with air pulled through by the fan will be cooler than the outside edges. When traveling down the road the difference is much less. Looks like you have a radiator or coolant flow problem or both.

Perhaps the stat is not open and the coolant is stagnant in the radiator. I would carefully remove the cap and check the coolant itself rather than the temp on the outside of the rad. I'm thinking that with a 180 stat and 159 temp the coolant is not flowing thru the radiator thus top and bottom will be about the same. If the engine is getting hot then it should be a lot higher than 159. It would also help to know what temp the stat is.

I don't have a thermostat in the engine.

The flow through the radiator is good, no restrictions in the radiator and the pump has been rebuilt by FS. Same problem with two other pumps. What I do observe is that the fins don't appear to be attached to the tubes, they readily move with almost no pressure. Wonder if the core missed a step in the assembly procedure that assures intimate contact with the cooling tubes thus not transferring heat to the fins to be radiated to the air?

Ron

I used to have a '58 Chevy panel truck whose coolant ran nicely through the radiator, but very little heat was removed.

Turns out the fins separated from the tubes over time. Good flow, but no heat transfer.

Replaced the radiator and all was well again.

For the back story of one time my panel truck overheated, see
http://www.stovebolt.com/features/sagas/meltz/meltz_desert.htm

All my best, Dean

If the tubes are not connected to the fins the heat transfer will be reduced. Heat will not be conducted to the larger surface so air flow can remove it.

Ron,

I fought high temps and boil-overs in my 207 for months and months. After:

Replacing the water pump;
Removing the side and 2 rear freeze plugs and flushing, cleaning and clearing out lots of rust and scale in the block;
Installing a "Gano" filter in the return hose to the radiator; Gano Filter
Removing the radiator and having it cleaned by a local shop and;
Installing a new thermostat.

Some of this certainly helped, but it still tended to run quite hot and boil over on warm days.

I finally solved it by installing a 6-volt "pusher" electric fan on the front of the radiator, which on my truck is virtually invisible. No more overheating! I imagine that a new radiator would have also done the job, but the fan was inexpensive, quiet, and relatively easy to add. You can also control its operation with a thermo switch if you like.

Too bad you can not run those better later model 6 and 7 blade steel fans with the big pitches.

They will draw air as low as 500 rpm that you can feel at the grill mesh area on a 34- 35 chevy.

You would have to TIG weld a filler into the 1--1 1/2" center opening , then drill it for the hub center and the bolt pattern. And make sure the fan runs perfectly straight.

mike

actually I think what I said for the fan on early chevys will not work

mike

All Fins should be FIRMLY attached. Improper radiator may well be your problem.

A Derale 6 blade high performance reverse rotation fan can be installed. Providing a 36 is the same as the 35. Drilling the center hole and installing the fan tight to the radiator with a spacer behind will provide enough clearance so the fan blades don't hit the generator. The blades are behind the hub as opposed to the original being forward.
Most here don't approve of such modifications. This is a better option than blowing up your 1936 motor. (My opinion)