Be Careful With Bar's Leaks

[mike837go]

Firstly, I have sucsessfully used their product several times in the past.

My 1965 Minneapolis Moline Big Mo 500 needed a bottle of it back in 2003 and I can still jump on it for a day's use without cooling system problems.

Now to the difficulties of not following the manufacturer's instructions:

I finally got all 6 pistons out the block of my 1969 4.2. It took way more force than I was comfortable with (I expected to break one).

I found a hard substance filling the gap between the pistons and the cylinder walls. It was not as brittle as epoxy but almost as hard. With some fiberous material mixed in.

It was also clear that my engine had head sealing issues before the last mechanic openend it up. There is lots of copper color staining (non-sticky head gasket sealant) on the top of the block, at least 5 heil-coils (3 backed out during my disassemby) and an oversized-base replacement head stud (9/16").

So, somebody threw a bottle of Bar's Leaks into the radiator, ran the engine just enough to circulate and shut it down. Quite a bit of non-cured product seeped from the water passeges into several cylinders, the hot coolant and sealant leaked in and around the rings (somthing brown dripped from the cylinder walls onto the crankshaft) then cured there. It also cured at the base of the studs, which was why getting the head off was such a chore-and-a-half!

Bar's Products clearly states running the engine enough to thoroughly distribute and cure the product. A good 1/2 hour's ride at a minimum.

DO NOT SHORTCHANGE that step!

As for the future of my engine, all the studs and acorn nuts are getting replaced. All the threaded holes in the block will be inspected and repaired as required. I may send it out to get the deck and/or head planed a few thousanths. I've heard there is a thicker replacement head gasket available. Plus, I own a torque wrench and I love following the pattern in 3 steps!

[christopher storey]

By The oversize head stud do you mean the shouldered the guide stud which fits on the left hand side in the second hole back ?

[PeterCrespin]

I thought he meant a 'special' with a wider base thread to cope with stripped/re-tapped block hole?

[mike837go]

I thought he meant a 'special' with a wider base thread to cope with stripped/re-tapped block hole?

Yup, christopher storey, I found the "dowel stud" exactly where it belongs. Between cyls 5 & 6 on the exhaust side. The hole for it has one of the backed-out heli-coils.

The wider-base replacement stud was more towards the back. Between cyls 1 & 2 on the exhaust side. The 9/16-18 hole is in good shape. The replacement stud is also made of sterner stuff than the originals. However, the top threads are badly worn and will be replaced with all the others.