Cracked Cylinder?

[Mike Peters]

It all started out with water in the cylinder of a rebuilt engine. So we pulled the head and had the head resurfaced and put it back together. Still leaks water, so pulled head once again and looked closely at the cylinder. Does that look like a crack (1st photo)? Second photo shows condition of cylinder walls. Not great. Aso, I can stick an .011: feeler gauge between the cylinder and piston. Too much clearance? Opinions needed. mike

[Joe K]

Some wear? Or overbore? You say rebuilt? Might want to find another rebuilder.

Looks like a candidate for sleeving? Prolly do all four cylinders and start over?

080 pistons? Probably the 2nd rebuild? Now maybe headed to a third?

Joe K

[johnneilson]

Looks to me like first pic shows water stain, not a crack.
Hard to tell but the water stain looks like there is an imperfection on the top edge of the bore. I would look there first.


Typically a crack will start in the valve chamber then propagate across the deck and then down into the bore.


I wouldn't worry about 0.011 feeler gauge on the top of the piston, clearance is checked on the skirt of the piston (bottom side) and the top lands should be larger clearance to bore.


John

[katy]

Polish that "crack" w/scotchbrite to determine whether is is truly a crack or just a stain.

[40 Deluxe]

Originally Posted by Joe K

Some wear? Or overbore? You say rebuilt? Might want to find another rebuilder.

Looks like a candidate for sleeving? Prolly do all four cylinders and start over?

080 pistons? Probably the 2nd rebuild? Now maybe headed to a third?

Joe K

"Prolly"? Who's Prolly? Dolly's sister? I assume you meant "probably".

[Greg Jones]

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You can also liquid penetrant test it. Some weld supply shops sell the LP test kits. It’s easy to do. Clean the suspect area then spray the penetrant dye and let it sit for a few minutes. Clean off excess penetrant then spray developer on the area. If a crack you will see a red line.

[Joe K]

Originally Posted by 40 Deluxe

"Prolly"? Who's Prolly? Dolly's sister? I assume you meant "probably".

Astute.

Sorry - too much texting in my life.

BTW and ICYDHI, It is not a word - but it is used.

Joe K

[Jim Brierley]

Could be a crack? Check it thoroughly, magnaflux or other means, before proceeding. A pressure test may be enough? A and B engines can be safely bored to .125" oversize, I've seen them at .185" (3/16")

[Mike Peters]

Two new photos of same area from this morning. I cleaned the area up with scotch brite and now it's looking more like a stain than a crack. I thought I might have had something this morning, but maybe I didn't. You guys are right about not jumping to conclusions. Thanks for the replies. mike

[Joe K]

When I was at the same point, I used a head gasket as a cutting guide and cut a piece of plywood to fit over the top: the studs stuck up through the holes and I could see nicely down each cylinder bore.

I had a red rubber gasket I cut to the same outline.

I stacked up washers and pieces of pipe and used the head studs and clamped the gasket/plywood to the block.

Then an appropriate rubber plug in the water inlet hose and pressure from the air compressor (less than 15psi as the sections are thin and non-reinforced) and I proved out no leak.

I even had the soap bubbles handy - what a disappointment.

Doesn't every kid like to blow bubbles?

Joe K