Hot Rods screw in freeze plugs

Salty
I hope we don't suffer the wrath of the HAMB mods (traditional) with our alloy blocks.

 

Interesting I asked a Ford Engineer back in the '70s and he didn't know. LOL

 

i do recall hearing the thin wall casting reason

 

Denny..... it is a 409 if that helps.

 

Not mine but this one is 540 inches.

 

Jeesh! 'HAMB' & eggs.

 

I'm feeling a bit inadequate!

 

The one I am putting in my car is only 460 inch.

 

I've often wondered why manufacturers didn't thread the holes when they bored them out while trying to replace some that were difficult to access.

 

Think about it, with the volumes that they use in a year a mere penny saved capping each core hole adds up. And no doubt the savings per hole are much more than a penny. Consider boring the hole, then tapping and screwing in a much more expensive pipe plug. Then there is also the cost of the taps and resharpening them periodically.
No return on investment to the manufacturer, and they don’t care about a rusted, leaky plug long out of warranty.

 

Money. A dummy with a dremel can clean up a core plug hole but a machinist is required to cut threads.

 

Just curious, since I have been told those were freeze plugs for over 50 years, has anyone ever seen one of these save a block from cracking when the coolant freezes? I never have, always made me wonder. Seen plenty with rot holes in them. Maybe they are functional as sacrificial corrosion sites?

 

NOPE..

 

Yes I have, but the block was cracked all over too.

 

I've seen them pushed mostly out of the hole on a frozen block in the dead of winter. Never a running engine, always a "core" block. They all had cracks someplace else, either a head or cylinder wall. Never seen one save a frozen engine.

Not sure why the name was changed from "core plug" to "freeze plug".

SPark

 

Water expands at a rate of 1700 to one when it makes steam . If for some strange reason you encountered an overheating issue the plugs can be tossed same as freeze . These are truly not an expansion plug for freeze up issue . They are core plugs to clean sand out of the casting .

 

Ford literature I read years ago said that the screw in plugs were because regular type plugs had a chance of coming out in long distance, high rpm racing.

 

They bore the core plug holes to make them round enough to hold the plugs. The sand casting doesn't leave a clean hole. They bore and thread all of the bolt holes in the blocks as well as boring the cylinders, cam bores, lifter bores, crank bores, oil passages etc. There is a lot of machining of the engine blocks.

 

Chevy used them in the aluminum block back then, too.

 

Engine builder friend cuts hemi and stude to fit a cup. I guess you could bore out anything that used a disc instead of a cup.

 

The core plug holes are reamed.

Before all is said and done the entire block is cleaned up with a dremmel and or a chipper. The company is trying to minimize the machine process because of cost not to make it easier for the machinist. They could care less about the laborers skilled or otherwise. The bean counters care about the bottom line not the mules that pull the load.

 

Many years ago my partner, who was a Ford nut, bought several unfinished GT40 blocks and five 427 LeMans blocks plus other pieces from Holman and Moody when they sold out. I know NOTHING about Ford history but it seems there were some screw in freeze plugs in the mix. I tried ton get even with him when Smokey Yunick had his auction be he halted it when he thought parts weren't bringing what he wanted.

 

I'd trade my pony for a ZL-1 block.....

 

I think I'm going to pull all the core plugs on my engine and cut threads for screw in plugs.......right after I clip all the 'teats' off my brand new tires..... WTF?

 

the most effective way to remove tire tits is burnouts, curbs and rolling the tires in hard turns

 

If you do thread a cylinder block for screw in plugs, be careful not to over tighten the plugs if using Teflon sealer. This stuff is so slippery that it is possible to split castings by over tightening.

 

And distort the block even if you don't crack it.... Don't think it's possible???? Think about it first!!!

 

I would think you would want them in place when the machine work is performed.