Mack AC Cylinder Removal

[Great White]

Good afternoon all:

  We are working on a very well used Mack AC attempting to pull the cylinders cast in pairs retained by six  5/8-18 crankcase studs . The service manual describes only removing the six nuts to remove the cylinders.  The cylinders do not move even with the engine hoist wanting to lift the truck .  We are trying hard not to break anything along the way.   Any wisdom from someone who has been there done that would be greatly appreciated!

[T-Mack1]

Have you tried to apply heat to the engine block to expand the metal?    And, heat cycling where you use a penetrating oil to cool it back down may help.  DO NOT hammer on it.  The metal could be brittle with age. 

[Great White]

Thank you T-Mack1:  

That will be the next step .  The plan is to use a soft flame like from a propane weed burner and try to heat the aluminum crankcase evenly .  We are hoping It will  grow in size at a greater rate than the cast iron cylinder assembly and let go. We are being very careful to not break anything long the way . This old dog is 100+ years old.

[Great White]

Many thanks to T-mack1:  With some heat from the handy flamethrower and some PB Blaster we have liftoff .  The crankcase studs were seized in mounting holes in the cylinder base . A few strokes with the cherry picker started to lift the front axle then the cylinder came up . Next need to mike the bores and see if they are serviceable .  The ring grooves have excessive wear but can be squared up on the lathe easy enough. The bores look good and there is not a pronounced ridge at the top of ring travel . This old dog has fared well despite being 100 years old. Cheers!

[Latrobe Construction B-61]

That sounds like a win.  That old dog will be running again before you know it. Sounds like a very interesting project.    Keep up the good work.   

[skydawg]

Hi,just wondering how the bores can get worn when there`s a liner...isn`t the liner there to take all the wear and preserve the bore?

[Great White]

There is no liner in this 100 year old dog . The head is integral with the cylinder .   If the bores are worn beyond a ring job we may be looking at boring and sleeving or bore oversize and have pistons custom made.  It will be a challenging setup to rebore.   What we have done boring antique stationary engines is to get a large used brake  rotor and machine both sides flat and parallel then bolt it to the top of the cylinder and bolt the boring bar to it .  There may be a better way .