The Stovebolt Site Forums The Shop Area Engine Shop 261 still overheating!!!!

hey, ive been having problems with keeping my 58-62 261 cool.ive drilled holes in the thermostat,ive put a 6 in water pump pulley on because i thought the 4.5 in pulley might have been getting spun too fast.I have a new radiator.Im not sure what to do now.Any suggestions? Thanks
Danny

Danny,

Is this installed in a '48 6400? Have you considered putting an original-style water pump on a relocation plate?

Do you know the condition of block's internal coolant passages? Crud often accumulates in the lower rear of the block. It is a bit of work, but with the water pump off (to install the relocation plate), you could try to loosen-up and spray-out crud by working through the drain-hole in the lower, rear, manifold side of the block. The crud and rinse-water would easily exit the block at the front of the block.

Tim

I think if you explain how it overheats we might better guess at what the problem may be. More info please.
Dan

I would start by removing the thermostat and work from there. Does it overheat on initial warmup or when driving?

I had a similar problem with a 350cu chevy motor. I checked everything that was coolant related. Nothing worked. Come to find out it was the vacuum advance on the dist. It was fused with rust and would not work. Changed that and all is well. Check your timing. Hope this helps.

I second old bag. Run through the basics: adjust the valve clearances, then re-set the timing. I bought a MityVac vacuum tester kit. Easy to use, just hook up to the dizzy advance and pump it a little, see if the dizzy rotates or not. (OR, I guess you could unhook the vac. line at the carb and SUCK on it REAL HARD! ;-)
If no rotation, you need a new vacuum advance module, though this might not be the only cause of your overheating.

Also, a lean condition can lead to overheating. Does it cool down if you give it a little choke?

How is it running? How do the plugs look? Is it too hot all the time, or only sometimes? Did this just start happening?

-Michael

I have a 54 261 in my 46 and have a boiling over problem. The radiator is not pressurized since I used the original radiator (rebuilt) from the 46. On a hot day (in New Mexico that means 95 and up) when I drive up hill about an average of 20 degrees for about 2 miles and stop to turn on the road to my house the motor boils over. I can drive around town, idle, get on the Interstate and run about 60 MPH, all day. It only boils over when I make the last 2 miles on the up hill incline to my house. Haven't figured this one out yet. The temoperaturesare starting cool down so the boiling over will quite until next summer. Let me know what you findto be the solution?

do you have a fan shroud? regardless of what the original engineers had to work with, without a fan shroud, the fan is only 20% effective.

I put an electric fan on my 261 in my 46 and had to make it a pusher due to room problems but it still boils over. I think I could solve the problem by makingit a pressurized system with an overflow tank.

I put a pointless HEI ignition system that I bought from Jim Carters that really changed my 261. It is probably one of the most significant improvements I've made to the old stovebolt, rally idles allot better! The distributer and coil were from "Langly Stovebolts" (or something like that).