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

[ArdWrknTrk]

"Air" is mostly molecules of nitrogen, with about 20% oxygen, 2% argon and the rest mixed gases like CO²... 💡

[Gary Lewis]

Ok, but how do the sizes of those molecules compare to water?  Will some of the components in air leak more through the same orifice than water?

[viven44]

Ok now I’ve got pressure stable but still a pesky nano leak at the thermostat housing. I’m impatient and didn’t allow the gasket maker to set the full 24 hours. It’s the one time I wish I had “the right stuff lol”. The PSI is still mostly steady after about 15 mins though. May have dropped 0.2 PSI. No leaks under the block or in the cylinders.

Think I’m ok to proceed ? Not in a rush but just don’t have the time during the week. I don’t think it will pass the air test as the thermostat housing would leak down a lot faster.

[ArdWrknTrk]

Well, there's trace amounts of everything, right down to hydrogen, so definitely will migrate through seals far more easily than water.

But all this is a fools errand because the engine hasn't been heat cycled, and everything is going to move, and need retorquing.  💡

When it comes down to it, the only thing that matters is how it performs in service. 🧐

[Gary Lewis]

You are probably ok.  But if you don't have time during the week to do much more then why not pull the thermostat housing, RTV it, and let it sit for 24 hours?

To RTV it I would tighten the housing down finger tight, let it sit, and then torque it down to spec.  That will get you an RTV gasket and not squeeze it all out.

[viven44]

That’s the micro leak



In about 30 mins that’s what I saw. It started right before the 1 in 15. It seems to have stabilized there for now.


Pics under the block. No coolant leaks. Also scope showed nothing in the cylinders. My take is that if it’s a leak that’s smaller than even this, it probably wouldn’t hurt the engine ? Is that a fair thing to say ? Plus as I said before it’s only a gross test to make sure I didn’t screw up anything

[viven44]

Yes I’ll do a better job with the RTV next time. As you suggested

[viven44]

Yes agreed. The thermostat housing  may not leak when warm and that is would be jelly side up…  

Update: the thermostat housing doesn't leak anymore. Just needed a bit extra time and the moisture from the coolant helped it get to a 100% maybe?

[ArdWrknTrk]

Possibly.?!.?!

I tend to use anerobics, except where indicated like my diff cover or the china walls.

I like RTV, it's great all around, but a lot of times id rather something more specific.

[viven44]

I gave permatex 2 only 2 hours to set on either side of a felpro gasket, so I wasn't being fair to it. But i'm still impressed it set well after the customary 4 hours. I like permatex 2 overall the best because it has resistance to just about everything including fuel since its solvent based. Has better working time than RTV. I avoid RTVs for anything vertical like timing cover, water pump in proximity to fuel as they are not very fuel resistant per the datasheet. A couple of fuel leaks on the intake may possibly weaken RTV as it flows down the engine.. those are at least my thoughts/beliefs. I have no data to prove/disprove any of this. I do use RTV for oil seals like oil pan, differential covers.

[ArdWrknTrk]

I like Three Bond for joints that are rigid.

It will hold engine cases together, full of oil or 2-cycle fuel

[viven44]

Interesting. Seems equivalent to "Permatex MotoSeal"..

Pre-Loctite PST, I used Permatex High Temp Thread sealant, but I think I like PST better. More consistent mix in the tube.

[ArdWrknTrk]

It is if you want protection from galling stainless steel.
Plus the fact it's intended for use in refineries and chemical plants.
Teflon is one of the most inert materials humans have ever made, and it's operating temperature window is pretty large (far beyond anything we'll see in a pickup truck)

[Gary Lewis]

Jim introduced me to PST and I now use it on a lot of things.  I always use it on stainless/stainless fittings after I had a brand new nut gall on a brand new bolt.  Just turning it on with my fingers and it got hard to turn.  Then it stopped turning and wouldn't come off with wrenches.

And it works well on things like seat bolts, the ones that go through the floor.  I've had to repair threads on two trucks recently, so use it to prevent more of that.

And hydraulic fittings, for sure.

[ArdWrknTrk]

I once had a cracked head, that would only leak after hammering on the engine and then backing off quickly.

I went through a dozen heater cores, but never popped a radiator cap!?!?

Sometimes you only find problems while in service.

[viven44]

I've followed all the best practices here hopefully. Cast iron manifold with valley pan, torqued all bolts in sequence to spec for the intake, water pump, timing cover.

[ArdWrknTrk]

You're good!
99.9% better than average.  👍

[viven44]

I've had excellent luck removing just about any type of fastener with impact wrenches, including exhaust manifold bolts, and use it at the highest torque setting for reverse. I'll maybe nudge it for a few seconds at a lower torque setting before shocking it at the high torque setting... I've found that it helps avoid galling as the rate of movement is too fast to develop any heat that softens metals. I have seen people recommending no impact on fasteners like that, but this is just my way and it "Works for Me!"

I have never used Stainless steel nuts and bolts before, so if its so easy to gall them, I might one day try a series of controlled experiments to see if its easy to prove why my impact method works.

[viven44]

Much thanks to you guys' wisdom

[ArdWrknTrk]

Regular steel, especially in iron, won't ever weld itself in place.

That's the chrome and nickel...