Deleting coolant neck for a re-route. Will a 30mm brass plug be enough or should I make an aluminum block off plate also? Not that big of a deal if I have to but I'd rather not. Thoughts?

 

SHOULD suffice. Would suck to be wrong over 4 cents' worth of aluminum though.

 

I did the same but my 949 kit included the plate, so stuck it over the top of teh brass plug to retain it for safeties.

 

I just got a pc of flat aluminum 3/4” bar from Home Depot and drilled it for the 2 bolts just for pc of mind. Don’t overthink it...

 

Will work. Works great as a safety when you run a motor hot and ruin a head.

 

Went ahead & made a block off plate. Turned into a 3 hr project but I can now move on to the next thing. Thanks!

 

I personally would have skipped the plug, bought a gasket, and put it under the plate you made. But you're good.

 

I installed a gasket under the plate also - should be good.

 

I tried that once and it eventually developed a small leak. I added a plug and then did a belt-and-suspenders method and sealed the plate on top of it.

You don't have to make a shaped plate, you can just make a "strap" over the plug to hold it in if you're concerned.

 

I did mine with a plate with RTV, but no plug. Is holding up well.

 

Ok, just for next time it goes like this:

Freeze plug, rtv, gasket, rtv, block off plate, two 6mm screws.

We running uranium through this ****? This is insane.

 

That junction is meant to have an o-ring seal, which everyone seems to have overlooked.

 

Ok so: Freeze plug, RTV, o-ring, gasket, rtv, block off plate, two grade 8 m6x1.0 bolts?

This sort of thing is a new mystery for the community and i want to make sure i got it right. This solution isn't available off the shelf to take cues from, so we're all flying blind.

 

Hmmm, might wanna go 12.9. Ya just never know...

 

Wait! What flavor loctite? I think the green tastes pretty good.

 

I thought the whole idea of freeze plugs was that if the coolant freezes and expands, the plug will pop to relieve pressure in the casting which should stop the casting itself popping.

If you're going to the lengths of fabricating and sealing a blanking plate, why bother with the plug?

 

Because. Just because. Dont be stupid.

You have vape juice on your chin.

 

The main reason the hole exists is for the removal of the core material after casting. Core plug would be a more correct term. They will not save an engine from the freezing of straight water. FWIW zinc plated steel is a much better choice then brass.

 

They will pop out if you overheat the engine, but they will not save the head.

 

That's more just a bonus feature.

As mentioned, the holes are actually just leftovers from the sand casting process, where the core needs to have some parts leading out so that it remains centred when the molten metal is poured in.

The brass plugs are pretty much just a cheap and reliable way to block off the holes left afterwards. (which btw only seem to be called freeze plugs in the US, outside of the US they seem to be more commonly called core plugs, or welsh/welch plugs)