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Hemi core (freeze) plugs

Discussion in 'The Hokey Ass Message Board' started by TDWZ28, Mar 21, 2011.

  1. TDWZ28
    Joined: Sep 18, 2007
    Posts: 152

    TDWZ28
    Member
    from Michigan

  2. For as much as you're going to run the engine, go to NAPA and get the regular steel ones.
     
  3. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    Or a set of brass ones intended for marine applications.

    They aren't that hard to install correctly and I've never had problems with stock style freeze plugs in any engine I have worked on. Put a bit of #2 Permatex in the hole or around the edge of the plug and drive it in using a driver or something the correct size for a driver.
     
  4. deuce354
    Joined: Feb 9, 2005
    Posts: 304

    deuce354
    Member

    I used brass ones from NAPA, a slight coating of JB weld on the plug. Hold the round end of a ball peen hammer on the center of the plug, Hit the flat end of the hammer with another hammer to make a dimple in the plug. This expands the plug. Did mine 12 years ago Successfully
     
    Rich B. and hinklejd like this.

  5. deuce354
    Joined: Feb 9, 2005
    Posts: 304

    deuce354
    Member

    I forgot to mention these are disk type plugs , NOT cup type plugs
     
  6. George
    Joined: Jan 1, 2005
    Posts: 7,723

    George
    Member

    What he said!
     
    Baron likes this.
  7. bangngears
    Joined: Aug 30, 2007
    Posts: 1,145

    bangngears
    Member
    from ofallon mo

    Stock Hemi freeze plugs suck,they were not designed very well,especially when you have a Chevy water pump on the Hemi.I would put mechanical freeze plugs in and feel comfortable they will not fail out on the road. Been there and was not fun,luckily i was close to home.
     
  8. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member


    WTF? Do you actually believe that the water pump is responsible for the system pressure?

    The disc style 'sucks' only if you don't know how to install them.

    .
     
    302GMC, deucemac and Andy like this.
  9. Dreddybear
    Joined: Mar 31, 2007
    Posts: 6,084

    Dreddybear
    Member

    I've had success with indian head around the plug.
     
  10. speedyb
    Joined: May 12, 2010
    Posts: 484

    speedyb
    Member
    from socal

    Funny, I just pulled a 392 out of a 57 imperial and It had all of the original soft plugs still in place and leak free, Install the new ones correctly w/a little dab of leak lock around the edge.
     
    stillrunners likes this.
  11. scootermcrad
    Joined: Sep 20, 2005
    Posts: 12,382

    scootermcrad
    ALLIANCE MEMBER

    Standard disc type... Nothing fancy. Installed correctly and they should last forever.

    [​IMG]

    Clean up the ID of the plug bore with a fine grit flap wheel or sanding drum. Don't take too much off or the disc won't over seat.

    [​IMG]

    Apply sealer or JB Weld around the bore.

    [​IMG]

    I use a piece of 1" diameter solid round stock and a big ass hammer to set it. The way mentioned above will work just as well. Needs a couple good solid whacks! Then wipe off any extra sealer after the install. If you use something silicone based, know that paint will not stick to it. JB Weld is a good way to go.

    [​IMG]

    [​IMG]
     
    deucemac likes this.
  12. TDWZ28
    Joined: Sep 18, 2007
    Posts: 152

    TDWZ28
    Member
    from Michigan

    Thanks for the replies everyone. I put a stock steel one back in it. I used the aviation perma-tex sealer and a piece of 1" round stock with a rounded end on it for a punch. Warmed the engine up and it is holding.


    Nice pictures scootermcrad! I appreciate it.
     
  13. tig master
    Joined: Apr 9, 2009
    Posts: 416

    tig master
    Member
    from up north

    Perma tex is the answer

    Tig
     
  14. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    There are actually two sources of cooling system pressure in a running engine. The one we all are familiar with is the pressure from heated coolant expanding, and trying to turn into steam. The second source of pressure (in the engine not the radiator) is the spinning water pump. It is pushing coolant through a system that has restrictions, ie, the thermostat, and when the thermostat is closed the water pump does create some pressure. If it didn't, the coolant wouldn't circulate.

    Proof? I witnessed it on a friends car last summer. Freshly rebuilt 327 Chevrolet, with plenty of power-enhancing internals and bolt-ons. He had about 500 miles on the engine, and decided to give it a little extra hard push to see what it would do. He wound it up tight leaving a stoplight, and the impeller cover gasket on the back of the water pump blew out. Where did that pressure come from?
     
    30dodgeboy likes this.
  15. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member


    The pressure he saw was localized, the same kind of 'pressure' that builds when a pump cavitates. If he/you were to measure the 'pressure' increase downstream of the impeller you could also measure a similar 'pressure' decrease upstream. This is how pumps create 'lift', by producing a low pressure zone that the available fluid wants to fill. It is a closed system, you cannot just 'make' 17lbs of system pressure without an external force (heat). Yes, if you spin the pump long enough and hard enough you will create some heat but the impeller will be dead long before you build 17lbs pressure.

    .
     
  16. Probably his leaking head gaskets.
     
  17. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    If you read your response carefully, you will see that we are saying the same thing. There is system pressure from the heated coolant, and there is localized pressure between the water pump and the thermostat. Compared to atmospheric pressure, there can be higher pressures at the "high" side of the pump than the pressure in the radiator.

    Pretty good head gasket trick, in that they resealed themselves. We thought it might have been a head gasket failure that did it, but a compression test showed otherwise.
     
    Last edited: Mar 23, 2011
    30dodgeboy likes this.
  18. bangngears
    Joined: Aug 30, 2007
    Posts: 1,145

    bangngears
    Member
    from ofallon mo

    In response to 77RR,as a matter of fact i do blame the Chevy water pump.Both times when i blew out a stock Hemi freeze plug it was because of a WOT blast down the boulevard.Now you will never convince me a freeze plug installed by exspanding it with a blow from a hammer on a dowel pin is as good as a mechanical freeze plug.Most of the racers back in the day had mechanical freeze plugs because stockers could not be trusted.The same freeze plug on 2 differant engines came out,middle plug on passenger side.If it works for you thats fine.Hope you dont have to learn the hard way.I have peace of mind with my mechanical freeze plugs.
     
    Last edited: Jul 4, 2011
  19. I drove my Willys for the first time in about a year this morning and blew the middle plug on the dirver's side for the third time in my 331 block. The Hemi hammer-in plugs are not a very good design, ast least for a block that has 60 years on it. Will hammer in another one but use epoxy this time. And believe me the water pump can add signficant pressure in the block behind even an open thermostat. First time I blew the plug was when I was cruising at temp and hit the throttle; BOOM steam everywhere!!
     
  20. for a stock application if installed correctly the stockers should be fine. problems can arise when more power is built in the engine. the hot heads plugs are far superior to stockers. i had my car on the chassis dyno and blew out three stockers. if i was on the track and that happened i would have totaled the car. since i have installed the hot heads plugs i have had no more problems. the block only needs to flex a little bit to release the tension on the plug. mopar circle track racers used to drill and tap the block then bolt a metal strap across the plugs to hold them in. core shift,rust and flex all can release a stock plug. they are cheap insurance as far as im conserned. its just not worth the risk. why go cheap now on your build? how much money do you have in your car right now where you cant aford the best parts? if there was never a problem with the stock plugs no one would have spent the time to invent a better plug.
     
  21. drumyn29
    Joined: Feb 16, 2006
    Posts: 2,190

    drumyn29
    Member

    what he said! I heard about boring the inner lip off and supposedly ford or sbc plugs work but I used the expensive yet crappy hot heads with lots of j-b weld AND silicone. Terrible design.
     
  22. TDWZ28
    Joined: Sep 18, 2007
    Posts: 152

    TDWZ28
    Member
    from Michigan

    A few days after I installed the factory ones, a couple of them started to drip. I bought a set of the HH ones and installed them. No leaks at all, and I've hammered this old Hemi pretty good a few times.
     
  23. stegto
    Joined: Jun 1, 2008
    Posts: 44

    stegto
    Member
    from Italy

    After months I am still here with problems with my 270 Red Ram leaking from freeze plugs. I was not able to find the stock ones (Dorman, Rockauto, Kanter who sold me wrong ones), so I decided to buy copper plugs from Hot Hemi Heads: bad idea, they not stay in place and leaks more then before... Anyone knows a place where I can find the original ones?
    Thanks in advance.
     
  24. TDWZ28
    Joined: Sep 18, 2007
    Posts: 152

    TDWZ28
    Member
    from Michigan

    See the link to the HH ones in my first post. They work. No leaks at all after I installed them. Not cheap, but worth the money in no aggrevation.
     
  25. bangngears
    Joined: Aug 30, 2007
    Posts: 1,145

    bangngears
    Member
    from ofallon mo

    Thank you Willys 36 for some support on this issue.Both hemis i referred to in my 2 experieces,one was supercharged and luckily happened in the garage when i winged it up,the second was from a wot launch on a back road 20 miles from home.I will say again stock hemi freeze plugs suck and or not to be trusted,go with mechanical and any worries are over.
     
  26. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,213

    sunbeam
    Member

    When was the last time you saw a recall for blown out core plugs? Must have been the installation I use little KD block sealer on them.
     
  27. ago
    Joined: Oct 12, 2005
    Posts: 2,199

    ago
    Member
    from pgh. pa.

    On my Hemi I used the bypass on top of the BB water pump and plumbed it into the crossover to equalize the pressure.



    Ago
     
  28. George
    Joined: Jan 1, 2005
    Posts: 7,723

    George
    Member

    or J B Weld...
     
  29. TR Waters
    Joined: Nov 18, 2006
    Posts: 1,439

    TR Waters
    Member
    from Vermont
    1. Early Hemi Tech

    I sell alot of the stock type, and dont hear of any problems. I do have written instructions that say to use a good sealer, and NOT silicone.
    On the other side of that, I have seen some blocks where the inner lip of the hole was very rusted. In that case I would clean the hole spotless, apply some JB around the hole, install and expand the plug, them use a narrow bead of JB around the outer edge where the plug meets the block. Of course, the above is useless if you dont take the time to clean the area.
     
  30. Hot Rod Willys
    Joined: Nov 10, 2006
    Posts: 1,700

    Hot Rod Willys
    Member
    from Ohio

    I found and read this thread after I had installed my blown 392 Hemi in my 1941 steel Willys, my motor has the factory type freeze plugs in it. I went to a Chrysler engine guy to build my motor and dyno it because I wanted to be sure he did everything right. He has built early Hemis for 40 years. I got the car running last week and today I took it for its first drive. Before today it had 4 pulls on the dyno and about 45 mins. of garage tuning, I went down the road easy as the whole car was a frame up build and everything was new. I went into an industrial park and pushed the car about 1/4 to 1/2 throttle and about 2 sec. after launch I blew the drivers side center freeze plug, what a mess! I had to call a friend and tow the car home. I am going to call Hot Heads tomorrow and ask whats best to solve this issue. My motor has 650 hp and runs a chevy electric water pump with a 5/8 restrictor plate instead of a thermostat. Im sure the builder installed the plugs correct so there is something going on with blown 392's and stock plugs and chevy water pumps. I will post what Bob Walker tells me. Here is a link to me warming the car up in the garage before driving.
    Mr. Gassers 1941 Willys - YouTube
     

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