460 Smog Delete and Oil Cooler Delete for a 78 Bronco Swap

[viven44]

I went and checked my spare bin I have the 2 below, both Motorad. Stant is Motorad since 2021?

This one has a Jiggler under the dome
https://www.rockauto.com/en/moreinfo.php?pk=4484550&cc=1124031&pt=2200&jsn=500

This one doesn't have a Jiggler
https://www.rockauto.com/en/moreinfo.php?pk=3952905&cc=1124031&pt=2200&jsn=496

I suppose i'll use the one with a Jiggler. Thanks!

[ArdWrknTrk]

Certainly makes it easier to fill.

I don't think a tiny hole compromises the thermostat effectiveness either.

[viven44]

The jiggler works as a bleeder right ? I have heard on the 351W/302s the jigger has to be pointed up to be effective (??), on the 460/351m/400, there is no Feng Shui correct ?

[ArdWrknTrk]

No matter what, the wax pellet has to go on the engine side or the thermostat will never open!  

[viven44]

Noted!

My favorite thermostat story is when I bought a truck with the 351m. The previous owner sold it cheap since it had a "headgasket" leak, he tried a new thermostat etc. I bought the truck and a whole bunch of stuff to fix the "headgasket" issue and maybe get a new cam, etc.

When I brought it home the temps were in the 230 range, but water did not flow in the radiator !!

I took out the thermostat since I suspected the thermostat and that cured the problem completely. Turned out they had installed a thermostat that belonged to a 351W which kept the coolant in the block. It was installed correctly but just the wrong design for the 335 series blocks.

[ArdWrknTrk]

335's have a piston on the back of the thermostat that covers a water passage and causes coolant to flow the whole length of the heads, instead of just circulating at the front.

Gary has a thread about his Dad's truck using the White-Rodgers design. (Maybe he used a Stay-Kool?)

[viven44]

Interesting, I knew the cooling system was like none other, but that's all I knew. I like that design a lot... the intake job is easier as there are no water ports to worry about.

The 351m I had, the intake was so tight I swear I was pulling 25" vacuum, it was so good that I think the distributor vacuum advance would have seen constant vac flow

[viven44]

Almost forgot but here is a video of the coolant pressure testing. The thermostat housing leaked because I didn't use a paper gasket, just permatex #2 and probably not enough. With a paper gasket there is an automatic control how how much should be used (or is there another mechanism such as permatex 2 only being a gasket dressing and not a standalone gasket maker?). I'm going to repeat with a paper gasket with permatex 2.

https://youtu.be/g0MjlbPXxE0

[Gary Lewis]

I like it!  My only suggestion would be to pump it up w/o water in it the first round.  Since air will leak easier than water it'll be a tougher test than with water.  If you have any leaks you may be able to find them with your soapy water spray, but if not you might find them by using a tube in your ear and listening closely.

But I really do like it.  

[viven44]

Thanks! Thats a good idea. I have done just that to stand-alone test of a radiator. I think an air based test is more thorough.

I tried to drain the coolant last week but the block drain plugs are hard stuck and I don't want to mess with them  I'll need to turn it upside down to flush it.

[Gary Lewis]

And you'll be able to hear the air hissing out in the cylinders if, perish the thought, there's a leak there.

[viven44]

Yes agreed. On an unknown engine that would most certainly be warranted. Since this was a running engine and the compression test was excellent and didn't overheat, I think it will be fine. The coolant was absolutely full when I got the donor truck and green as can be. They botched the water pump job but otherwise no concerns. My main goal was (Still is as I need to repeat) to establish a good intake manifold seal and also good water pump seal.

[Gary Lewis]

And I think you did that.  

[viven44]

Do you think what that thermostat housing leaking, if there were other issues it would have shown up in the preliminary test?

[Gary Lewis]

If I understand the question correctly, yes I think any other problems would have shown up.  But you can test by sealing that leak and going again - unless you are in a hurry.

[viven44]

OK good. At the beginning, the leak was very slow. My bad also because I did not fill the coolant all the way up. So the housing itself saw more air pressure, and caused the leak to grow more over time and it got pretty leaky fast. Second time around I'm going to use water all the way up and then re-test.

Now that i'm saying it out aloud, I'm a bit worried about running an air test as it might be analogous to a "burn-in" test of water gaskets

[Gary Lewis]

Air doesn't give more pressure than water.  It is just that I THINK water molecules are bigger than air molecules, but I don't know that for sure.  Jim will know.

[viven44]

Yes thats absolutely correct. The molecules are smaller, so they are able to find smaller passages, and once the flow gets going, it will eat through the passageway due to the momentum of airflow.

Since I like analogies now  In current carrying capability testing of materials, this is analogous to electromigration where the momentum of electron flow can knock atoms enough to cause voids in metals and an eventual "open".

Edit: its a hypothesis, i don't want to make it sound like a fact

[Gary Lewis]

How much pressure are you using?  At 15 psi like in a cooling system I don't think you'll have any damage save for a gasket that might leak.

[viven44]

Yes I agree, a gasket leak is all that i'm talking about. Just thinking an air test will be ideal in an experimental setting if you are comparing different RTVs (like Project Farm below) but in this setting I am a little worried it may potentially weaken a gasket and set it up for a coolant leak. I don't have any empirical data except the coolant housing leaking from air-only... but just paranoid. I know 15 PSI is low and probably be fine

https://youtu.be/ACIzlSanS60?si=zsywPQRigT061Y1h