Freeze plug problems

[fishman]

Took the 69 cuda (408 stroker) to the track this weekend. I put 7 runns on it friday in test & tune. First run on sat. I blew a freeze plug out of the back of the engine, I hope thats all it did. I will be pulling the trans tonight to be sure. Has anyone had this problem if so what did you do to keep this from happning again. I'm lucky that I didn't get loose and hit the wall. Any input would be great. Thanks Tom

 

[chasduster]

make sure they are in the engine far enough......what size rad cap are you using......7 lbs is plenty.....abviously replace the other ones while you are there and use blk RTV....Check the one at the back of the cam aswell...

 

[rumblefish360]

What Chasduster said. Clean the seat area well where the freeze out plug sits and RTV it. Theres several formulas of the stuff and use of a oil resistant RTV would be good.
(I once heard a guy say he used his MIG to hold one in place.....yikes!)

 

[camd64]

thats an odd one. sometimes if you bought individual plugs at a parts store and they where not paying attention you could have gotten one that was one size too small. we had a someone helping us with our inventory once put metric freeze plugs in with the standard ones. a couple things you could try is the form-a-gasket that dries hard and also stake the plugs like you do with press in oil galley plugs.

 

[PFogel]

The LA engines suck when it comes to having enough head bolts! As soon as you start to increase static compression or dynamic compression (due to cam coming into its sweet spot), the head gaskets don't want to hold. My hot 340 in my candy red '72 Demon is fully studded and I use the Felpro blues and it still wants to push the gaskets out. Use studs on the heads because you can tighten the snot out of them without failing the treads in the block like the bolts will. Mine blew out the one behind the motor mount on the passenger side and boy was that a joy to get to. Cylinder pressure leaks past the gasket and pressurizes the water jackets enough to push out the freeze plugs. Now when I build a small block with some squeeze, I install brass plugs with JB Quik. I learned this from Bob Glidden when he raced the Arrow in Pro Stock. He also drilled holes in the plug bosses and drove brads into them on each side that overlapped the edge of the freese plug thereby retaining it. I hope this helps you my friend. PS, this phenomenon occurs without totally failing the gasket!! Be sure your heads are dead flat - there is not room to give on that.
Pat