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Screw in Freeze plugs. 351 Cleveland
#1
Screw in freeze plugs for 351 Cleveland.
Surely someone has attempted this when rebuilding a motor.  Looking for any tips.
Charrlie
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#2
Never tapped a freeze plug.

However I have tapped a lot of other things...

CASTROL VARIOCUT C MOLY-DEE TAPPING FLUID

The stuff is magic. Also buy a decent tap / taps. McMaster-Carr is a good source, but not always the cheapest.

I'd be tempted to use a tapered reamer to cut the hole before tapping it. http://www.victornet.com/category/NPT-Pi...s/802.html

Looks like you could wrap 100-200 dollars in a couple npt taps and a reamer, along with plugs.
[+] 1 user Likes Bentworker's post
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#3
(04-05-2018, 10:48 PM)Bentworker Wrote: Never tapped a freeze plug.

However I have tapped a lot of other things...  

CASTROL VARIOCUT C MOLY-DEE TAPPING FLUID

The stuff is magic.  Also buy a decent tap / taps.  McMaster-Carr is a good source, but not always the cheapest.  

I'd be tempted to use a tapered reamer to cut the hole before tapping it.   http://www.victornet.com/category/NPT-Pi...s/802.html

Looks like you could wrap 100-200 dollars in a couple npt taps and a reamer, along with plugs.
I have had a machine shop tap a 4 bolt main for screw in freeze plugs. Worked perfectly. I have an extra set if you need. 
Robert

movie stars with addictions go to the Betty Ford clinic,
I take my addiction to the Henry Ford clinic.Haha
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#4
With our classic Cleveland blocks, what is the benefit of screw in plugs?  I would rather use the factory protection method and let thos suckers blow out to save my engine!

But then I don't know the real driver behind screw in freeze plugs, so feel free to educate me.

kcmash
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#5
Pretty sure the benefits of the screw plugs are two things.

1) They look cool.

2) You never ever loose a freeze plug. Think of it like a safety thing. If you are at the drag strip or at a track event and your engine was to spew all of it's coolant out you would loose traction as soon as your rear wheels went over it. Best case you could recover safely, worst case you could wreck your car. Not saying pushing out a freeze plug is common, but I could see how it would be a bad day.
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#6
(04-06-2018, 11:11 AM)Bentworker Wrote: Pretty sure the benefits of the screw plugs are two things.

1) They look cool.

2) You never ever loose a freeze plug.  Think of it like a safety thing.  If you are at the drag strip or at a track event and your engine was to spew all of it's coolant out you would loose traction as soon as your rear wheels went over it.  Best case you could recover safely, worst case you could wreck your car.  Not saying pushing out a freeze plug is common, but I could see how it would be a bad day.
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#7
Thanks for the replies on the threaded freeze plugs. Most of us agree it seems that if you blew a push in you may lose a motor
before you figured out the cause. Charrlie
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#8
Freeze plug is a misnomer. It is not their purpose to push out in case of a freeze except in some marine applications . . . perhaps.


They are core plugs.

In the casting process there is a sand form for the water passages and the hole is for the removal of that sand, post casting.

Screw in plugs look cool, that is the best reason to use them. They are more substantial and less prone to corrosion eating through them-but the ease of unscrewing and reseating it in a confined space might be the biggest advantage.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#9
Totally agree with Jeff. Freeze or frost plugs as I know them, is totally a wrong description. There purpose is to allow for the removal of the core sand and that's it. My guess is that at times when blocks have frozen, the plugs being the weakest point, would probably pop out.......... or not! I recently scrapped a block I bought that had been frost cracked and welded and was not worth salvaging. Wish I'd seen that before I bought it!
So if you never have to worry about freezing up a block, well go for it.
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#10
If you stay with the normal casting plugs make sure they are good quality steel or better yet brass. Don't use cheap Chinese crap like the PO did on my engine. I’ve had to replace 2 of them and what a pain! At least so far the ones that were bad I was able to do in the car, but I’m sure sooner or later I’ll have to lift or pull motor to replace the rest.

run_horse Run Horse Run!
John 72 Q Code
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