Cylinder Block Expansion Plugs

[Peter Gidlow]

Hi Folks,

I have a '66 Eldorado with a 429 motor which I am just on the point of reassembling after a complete strip.  I have new Expansion Plugs to fit, (you might know them as Freeze Plugs?) What's the right way to fit them in the cylinder block so they are secured to the right tension?  The last thing I want to find out is a leaky block, especially from the two plugs up against the fire wall.  Conversely I do n't want to end up with a cracked block at some point in the future due to having hammered them in too tight
I seem to recall the originals were flat, but can't be sure

Regards

Peter

[Wayne Womble 12210]

If that is the old standard cup type freeze plug, you cant hammer them in too tight. They will knock right through the hole if you keep hammering them.  I will seat them until the edge is just past the edge of the hole.

[Peter Gidlow]

The new plugs I have are slightly domed, which, having now found a photo I took before taking the engine apart, can confirm that the original plugs were also.
The holes themselves have a shoulder, in the bore, to prevent the plugs going straight through.  I can just get the plugs in with a light tap with a drift making them a snug fit.  So it's just a matter of establishing how much of a 'wallop' to give them to hold them in place under normal operating pressures.

[The Tassie Devil(le)]

Ah ha...... the case of "that is why Mechanics get paid so much".......

But, seriously, all you need to do is place the Plug into the hole, after wiping a tiny amount of Loctite Sealer (can't remember the number) around the edge of the plug, with the convex surface outwards, and with a ball-pien hammer hit the centre of the plug to create a dent.

If you cannot actually get a straight "hit" with the hammer, use a large diameter drift, with a rounded end, and strike that.

The denting of the centre creates an outward expansion of the circumfrence to bind to the wall, and the sealer gust assists in sealing.

End of story.

Bruce.

[markl]

Bruce,
Your description of the procedure is spot on.  Two things I would add;  if you do have to resort to a punch w/ a rounded end, find the bluntest one you can even if you have to make one.  The idea being to get a radius that is close to the ball-peen hammer that you would have used if you could.

The sealant that should be used is Permatex No. 3.  Now one caveat, Locktite may have purchased Permatex or visa versa, but I think they kept the numbering system the same.  Another product that can be used if still in production is Fel-Pro GS 3 gasket sealer.  The whole idea being that it should be a non-hardening sealer that is happy in anti-freeze and/or water at elevated temperatures.

Mark Lowery, CLC#25216

[Wayne Womble 12210]

I am surprised that they use that type in that late model.  That type is common to earlier stuff like my `31 and `33.  You still cant hammer it too much as to crack the block though.  If you hammer the center on in it releases the disk and that is the way you remove it.   

[Peter Gidlow]

Hi Guys,

Thanks for the responses, pretty much as I thought.  But, as we all know when you do something for the first time there's nearly always someone who says "you did what ?".  It's then you find out you've just undone 12 months of blood sweat and tears 

I've got a couple of off cuts of aluminium bar I can turn down do suit as there's no problems with access, the engines still in the build stand.

Regards

Peter
(CLC 23189)

[The Tassie Devil(le)]

The idea of creating a punch the same radius as the Ball on the Ball-peen Hammer is a good idea as one can place the "Punch" in the correct position, then deliver the "Blow" correctly.   In most cases, until one is satisfied that the "dent" is correct, it may take a couple of hits, but that isn't a problem.

Trying to deliver the blow directly to the Welsh Plug leaves a very small area to hit, and getting it dead centre is hard, especially when swinging the hammer, knowing in your mind that a simple "off-target" swing won't end up well.

Plus, one should never place a hammer on the target, then strike the head with another hammer, as the fine print on hammers don't recommend this practice.

Bruce.

[Peter Gidlow]

Job done!

It'll be a while before the engine is out of the stand and in a run'able state, but I'll keep you posted.

Regards

Peter

[The Tassie Devil(le)]

Congratulations.

By the way, did you use Brass or Steel plugs?

If Steel, remove them immediately and replace them with either Brass or Stainless Steel ones.   Better than having to do it in years to come.

For some unknown reason, the aftermarket plugs just don't seem to last as long as the factory-installed ones.

Bruce.

[markl]

Peter & Bruce,
An update and correction;  Yes it is Loctite Corporation that acquired Permatex, but I believe they still sell the product under the Permatex name.
Just had an occasion to use some Permatex Form-A Gasket Part No. 1B.  On the back of the card affixed to the blister pack it came in it clearly states above an illustration that it is to be used to "Seal Freeze Plugs".  So Permatex is recommending No 1 which is a Hard Setting sealant rather than the #3 which is a Non-Hardening Sealant.  It also says "...is designed for sealing rigid materials and flanges...".  Sounds like I was wrong, and it also sounds like my revelation is too late for you, Peter, unless you are about to redo everything to install brass freeze plugs as per Bruce's recommendation.

I concur w/ Bruce's observation that whenever possible, use brass freeze plugs if they are available.

Mark Lowery, CLC#25216