Well I've read about people tapping the freeze plug holes on these blocks for a threaded plug so you don't have to worry about them popping out on you. Most everything I read made it out to be a very time consuming tough process and a lot of the engine builders I talked to said it just isn't worth the hassle. They all recommended other means of securing a brass plug, including drilling tiny holes in the sides of the plug into the block and using allen head screws, epoxy, etc. I asked the maching shop working my block if they could do it and they looked at me like I was high on crack, saying it's a BIG hassle and they don't do it, blah blah blah. So I figured I'd give it a shot on my spare block because if I screwed up the block it was no big loss. I bought my 1.25" pipe tap off ebay for $10 and had at it tonight. The tap is HUGE so I didn't have a proper tap wrench to turn it with. I ended up using a 1 1/8" open wrench which I feared would lead me to drive the tap in crooked. Nope. Much to my surprise and delight the tap took EASILY into the cast block. I used a lot of oil and cranked away. I stopped with about 1/4" of the threads still out of the hole. I didn't want the tap to get into the cylinder walls so I was cautious with it. What I've often read about is people using 2 taps, one regular tap to start and then a second tap with the end cut off so they can go in deeper without touching cylinders. I'm going to wait until I can pick up plugs tomorrow to decide if I need to do this or not, but either way it's still easy. All 6 plugs took me less than 20 minutes to do.

So now that I have it figured out I'll definitely be doing this on the 557. I'll snap some pics tomorrow when it's light out and when I can test fit the plugs. Just wanted to share the info for anyone else interested in doing this.

 

The thing is, where you live and the temps you have in the winter, you better hope your anti-freeze never goes bad and the block freezes, because with the plugs unable to pop out you will break the block for sure. Then again, if you have a heated garage always available for your baby, then no problem.

 

Sweet, good info This is the only way to go with a mill thats going to be putting out serious numbers. Provided you know how to check your antifreeze that is...

 

Well I don't, but we've got a really good shop here in town that I'll take it to so they can check it for me.

 

There is a little misunderstanding as to what "freeze plugs" are actually for and what they are not for. First, although they might be able to save your block if it actually does freeze solid, you will probably have damage elsewhere. The real reason that they are there is to get the sand out when a block is cast at the foundry. Most engine molds are sand molds and the only way to get the sand out after the casting has cooled is to have openings in various areas to wash out the fine sand. At least that is how it was explained to me. If I'm wrong, somebody fire away.

 

This is not news to me, but they do act as pressure relief for the coolant freezing is most cases, I have seen them work that way. The new lost foam casting doesn't need the holes, but the blocks are usually aluminum and you don't want to freeze them at all.

 

Well not to say it could never happen but I haven't ever had a block freeze, even at -40º. A little antifreeze and all is good to go. I'm more worried about a plug spitting out while I'm standing on the throttle and loosing all my coolant. Besides the inconvenience of having to replace a plug and being stranded because I dumped coolant I have over $40 into water wetter I'd hate to lose.

I got a 1 1/4" plug today and it fit perfect. I was gonna snap a picture but it's dark again.

 

I don't know about you guys but I think this is all pretty ridiculous, slather them brass plugs with aviation goop and slap em in and I dont really see any problems unless you have no clue what your doing or you have the wrong plugs there not going to come out, unless there doing there job. I have had freeze out plugs save the motor in my car, two popped out never did any damage and I popped them back in and put in more antifreeze all is well.

 

I would have to agree. I have several million miles under my belt and have never lost a freeze plug while just running, or even racing (probably 100,000 miles racing) a motor, so I don't think any freeze plug, properly install will come out under a pressure of 13 to 17 psi. This also assume you make sure your radiator cap is good.

 

Look at Ivans truck. . .his is not to question WHY, but WHY NOT?

 

I posted this thread for informational purposes for those who are interested in doing this to their own blocks. I'm certainly not saying this is something everyone needs to or should do. If you don't understand why a person would need to do it then I'd venture a guess you're not running an engine that might require it so it's not really of concern to you in the first place. However, if you run a stock block with no hard block in the jackets at over 1100hp with brass plugs slathered with aviation goop and you've never had a problem then let me know because I'm all ears. These blocks torque under that kind of power. Threaded plugs add stiffness to the block in addition to keeping the plugs from blowing out (which is particularly a threat if you run a mechanical water pump and you're spinning 7,000rpm). Something else to consider is the fact that several drag racers have been put into the wall by the spew of coolant from a blown plug under their tires. A sudden gush of coolant at high speeds is not a good idea. And while I don't plan to race at the track frequently I DO take the truck on some long, remote drives and I'd hate to be suck in the mountains waist deep in mud because I lost a plug and dumped 12 gallons of coolant.

Btw, the aftermarket racing blocks such as IDT's blocks are being shipped with threaded freeze plugs. Do you think just maybe they might be onto something?? Same with those silly guys in Ford Racing . . . not only selling threaded blocks but plugs to go with them!

 

Hello and welcome to the new millenium. "Slathering plugs with goop" might have worked fine with the motors you ran in the 40's, but for the levels of horsepower and torque we are getting out of our strokers these days, threaded plugs are fairly standard practice.


You live your life a quarter mile at a time, don't you?

 

Nope, I ran roundy rounders before I 1/4 miled, then I raced boats.

 

I was thinking of doing the same to a block I'm working on now. Does anyone have a source for the shallow 1.5" threaded plugs. I found 1.25" Plugs from ford for some of their racing parts, but didn't see 1.5".

Thanks

Sandy

 

Holy old resurrected posts, Batman!
Sandy, have you tried a plumbing shop or a hardware supplier store, like a Home Depot or Lowes?