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Core plugs

Core Plugs

Hi everyone, I have to replace the core plugs on the cylinder block. The
mounted ones, was convex side out, but  I think they have been replaced. It
seems to me that concave side out is more logic. Can someone tell, how the
original core plugs are mounted ? 55 140 FHC - Jean-Louis

Jean-Louis, The convex side goes out and you dimple the center causing the
rim to expand and therefore seating in the core plug hole. - George Badger

The concave side is out when you insert it, then it is hit in the center to
make it expand it the opening.  However, I didn't use that type, though it
isn't original, there are aftermarket plugs that can be inserted and
tightened to seal the opening...I've never had a bit of leakage....of
course for those that demand original specs, this is unacceptable. -
Regards, Barry Goldman

The convex, or high spot should be towards the outside.  I put a thin film
of permatex around the inner edge and then insert the plug.  Use a steel
drift and dent in the centet.  That will expand the plug and seal the hole.
It's relatively simple if you can get at the holes. - Ken Beck

Hi Jlly, I am in the process of replacing core plugs. I am choosing to go
with a non original core plug for now. They are copper looking on the
outside with a brass acorn nut. I thing they look great. I learned about
them from our friends here on line. I bought them from NAPA here in the
States, Balkamp part number 600-4029 6 pc 1- 3/4" I heard that they can be
replaced without taking the manifolds off because of the nut etc. Thanks to
all my friends out there.. - Edgar W. Blake

Jean- Louis: Convex side out is correct. Remove the old plug by puncturing
it with a drift or screwdriver blade and pry out. Clean the seating area
well and place the BRASS replacement plug convex side out. No sealant is
required. By striking the high point of the plug with a ball pean hammer or
similar bludgeon, push the center in about 1/4". This expands the diameter
and that is all. While the plugs are out use the opportunity to back flush
the engine and poke around with a wire to free up any crud in the accessible
water passages. Good luck. - Regards: Bruce Baysinger

Core plugs are installed convex side out. After they are well seated, you
strike the center which expands the sides agauinst the block. - William

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