The Stovebolt Site Forums The Shop Area Engine Shop 261 cooling system hookup and moving radiator forward

OK, I did my homework and searched the site for this but no luck so here goes with a real DUH for a question about hooking up heater and by pass hoses on my 1962 261 engine which is in my 53 half ton. None of the heater or bypass lines were on the engine when I got it.

Heater hose and bypass mounting:
There are four outlets for water on the pass side of the water pump and water outlet. Two in the outlet and two in the water pump. In both cases they are arranged one on top and one lower.

For the heater hookup it looks like you would use one of the connections at the water outlet/ thermostat housing to go to the top water inlet on the heater. Then the hose on the water outlet on the heater would go back to one of the outlets on the water pump as that is where the cooler water goes to the engine from the bottom of the radiator. If I am wrong please correct me.

Now there is a by-pass hose that appears to go from water pump to water outlet but I don't know for sure which holes in the pump and outlet to use for the bypass and which to use for the heater connection.

Anyone got a pic of a 261 under the hood that shows these connections or can describe which is which would be most appreciated. I've been trying to get this running after swapping out the worn out 235 the PO had put in it. I think I have solved the ignition wiring and charging system wiring thanks to a good friend who spent two days helping and I think he solved wiring the OD with the help of information on the Stovebolt site, but neither of us can decide for sure on the bypass and heater hose issue. We are leaning toward using the upper hole on the water pump and the upper hole on the T-stat housing for the by-pass but sure don't want to screw the heating system up after all the work of swapping this thing into the 53.

Moving Radiator:
I haven't fully solved the radiator clearance issue but did follow the path of getting a shallow water pump pulley from the local wrecking yard (its off a 318 Chrysler product from the late 70s and fits the WP shaft perfect but had to drill new mounting holes. I cut the shaft shorter after pressing the pulley mounting flange down on the shaft. Since all the sheet metal is off the front I'm not sure about radiator clearance but think it won't be enough for a pulley-mounted fan unless I move the radiator forward a bit. Has anyone moved the radiator forward in the AD pickup and how?

Can you use one of the pump adapters that let you the old style water pump this lets you keep the rad in the original mounting holes and keeps the fan at the right height.

On my 261, the two outlets closest to each other is for the by pass hose. The lowest outlet is for one heater hose, the upper most outlet is for the other. Used to be a preformed hose availabe for the 261 by pass, but I had to make do with a longer piece of hose made into a loop.

You can have the mounting straps on your rad removed and relocated but as ttodd is saying if you use this:

http://cgi.ebay.com/ebaymotors/1955...201QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

with a 216 waterpump you don't need any other modifications. Easiest/cheapest method I think.

Curt B.

jbinwa,
I did what I.B. mentioned on moving the straps.
It gets you two things; clearence and the abilty to lower the radiator 2-3 inches getting it more centered on the fan.
If you decide to go this route you'll take a Mapp gas torch and heat the straps that are rap-attached to the radiator to melt the solder and allow the assembly to fall away. Mark top and bottom left and right for reassembly. Next drill out all the spot welds with a large enough diameter bit. This will free the L-shaped brackets from the rediator straps.
At this point you can clamp the L-brackets as much as an inch towards the motor on the straps and 2-3 inches hiher on the straps. There should be a paint line on the brackets to use as a guide to maintain the proper angle of the radiator.(Drill new holes for mounting into the radiator mounting bracket to offset the raising of the brackets). A welding shop can then re-spot weld the L-brackets. This will move your radiator foward and lower. The dimensions above are only a guide. Trial fit and measure before clamping.
Once re-spot welded you can re-attach the straps to the radiator by tinting the metal with solder both sides. Clamp to radiator and torch to te-attach.
Hope this helps.
-jeff

It doesn't matter which hose fitting you use on the water pump, they come out of the same passage.

On the bypass thermostat the lower one goes to the water pump. You can see it easily if you open the water neck- its the passage that is uncovered when the thermostat is closed and plugged when it opens.

You guys have got me second guessing how I hooked up my water heat to the intake. It seems to work. The lines get hot to the touch fairly quickly. And my heater still works. Here are pics. http://rides.webshots.com/photo/1360112016071636143VuNhEt

Thanks for all the input. A follow up question for 4onthefloor, I will look when I get down to my shop this weekend but how could that lower opening on the water outlet be plugged when the thermostat opens? its a ways below the thermostat housing. I can understand the upper outlet doesn't move any coolant until the thermostat opens because it appears to be above the base of the thermostat. Am I misunderstanding what you wrote? Darn I have being thickheaded.
Jerry

OK. I took my query in a different direction and did a search on bypass hoses and it led me to a bunch of responses I hadn't run across before dating back to about 2002. I think I am smarter and can hook the 261 engine coolant bypass correctly now but certainly this isn't the last word on this subject.

I am posting what I found so that if someone else does the search for this same subject (its bound to happen)they can get a summary here of what I believe to be accurate information.

There is a certain amount of other information out there including that the extra holes in the thermostat and water pump housings are for a second heater on things like a school bus. I didn't find that credible in light of the other explanations below.

What I do find credible is that the 261 went into really hard working bigger trucks generally and they need extra protection against heavy duty use and the coolant bypass is one of those protections. (Darn I hope I'm right).

I was looking in particular for information on how the original setup looked and while I never found a picture of the setup I did find a witness to an original setup: 4onthefloor had a previous post to another inquiry where he states:
"Well, I got my engine (261)out of an unmolested 62 burb, and the burb had the smaller fittings for the heater from the waterpump and the lower part of the thermostat housing, AND THERE WAS A BYPASS HOSE THAT WENT FROM THE UPPER PART OF THE HOUSING (THE PART THAT HAS THE BYPASS HOLES IN THE STAT) BACK TO THE WATER PUMP... (my capitalization for emphasis)

Someone else posted this information re. the 261
"...The 261 Stat has a nice bypass setup hooked to it so there can be circulation between the head and the block through the water pump without the heater hose being open."

Finally this nugget of information:
..."This is from an article in the tech tips section of inliners international: 'In its pure big truck form the 261 had a larger thermostat housing holding a double acting thermostat: This is designed to circulate water through the block and head before the thermostat opens to allow hot water into the radiator. Thus, no internal steam hot spots during warm ups, expecially in winter. This is particularly important with the very cold coolant. Vital engine spots can become very hot before the total coolant becomes hot enough to open a normal thermostat on the front of the block.' You can tell its a thermo housing from a 261 if it has two holes drilled for the smaller hose fittings in addition to the large one that feeds from the radiator. It is slightly larger than the 235 housing and it contains a hard-to-find by-pass thermostat."

I'm a much happier guy and will hook up my 261 coolant bypass as 4onthefloor indicates it should be.(top part of bypass hose to top fitting in thermostat housing and lower part of bypass hose to either fitting on water pump).

Thanks to all who contributed.
Jerry

Thanks for the confirmation. I've read all that before, but just couldn't remember. There is even more explanation in the 1960 service manual. This means my by-pass is hooked up correctly - it just goes thru the intake 1st!

look at it this way all openings in water pump side are return all openings before the thermostat in the cyl head are hot water supply or preasure so hook anyway you want as long as you pipe from head to water pump...doc

doc41, you're right for the most part, except the question here is concerning the holes in the thermo-housing. They must be hooked up in the correct order for the "bypass" feature to work properly. I think :confused:

same hookups bypass water from ther housing to water pump return,,on chevy 6 hot water or preasure is in the head for piped outlets before the thermostat,,the bypass hose is before the thermostat bypass is to keep engine at a constant temp so you could run bypass hose to any pump opening with same results but why would you...On most V8's water outlets or preasure outlets are in the intake as is the therm and bypass but some have it in the head at rear or front of intake but all are same water pump is return and head or intake is preasure or hot water supply...doc

I'd run out and take a pic of mine but I've been running it with a 235 thermostat housing instead because I couldn't get a new 261 thermostat at the local store. I'm about to yank it out and put a 302 GMC in anyway.

I'd just been making sure I warmed up the motor before I drove it hard and it seems fine.