59 flatheads
- Thread starter Sid
- Start date
Bored&Stroked
Well-known member
If the machine shop knows what they're doing (with special lock-n-stitch iron plugs) and are experienced with flatheads, usually it is not a problem.
The 59 series blocks come with hard seat inserts, so the crack is in the cast iron below/around the seat. The hard seat has to be removed to properly inspect the crack (mag it), then one can determine how far down the bowl it goes and can you repair it with a cast-iron threaded plug. Most can be fixed - though some cannot as they can go into the valve guide area (rare). The cracks usually go all the way across the transfer area and into the cylinder. To repair the crack a set of iron-tite plugs are installed in an overlapping series to "stitch" the whole crack back together. The cylinder will need to be bored and sleeved (in most cases).
Once all this is done, then the block should be pressure tested once again - to see if the crack repair is working. Upon initial start-up, I would use a 'water glass' type of product in the coolant to help prevent any weeping from the crack repairs (into the combustion chamber). I use Moroso Ceramic Seal on all my initial startups with flatheads. The Ceramic Seal also helps seal any head stud/bolt threads that might be prone to weeping as well.
Here is one of the more common products used to "stitch" a crack:
http://www.locknstitch.com/index.html
Best of luck!
B&S
The 59 series blocks come with hard seat inserts, so the crack is in the cast iron below/around the seat. The hard seat has to be removed to properly inspect the crack (mag it), then one can determine how far down the bowl it goes and can you repair it with a cast-iron threaded plug. Most can be fixed - though some cannot as they can go into the valve guide area (rare). The cracks usually go all the way across the transfer area and into the cylinder. To repair the crack a set of iron-tite plugs are installed in an overlapping series to "stitch" the whole crack back together. The cylinder will need to be bored and sleeved (in most cases).
Once all this is done, then the block should be pressure tested once again - to see if the crack repair is working. Upon initial start-up, I would use a 'water glass' type of product in the coolant to help prevent any weeping from the crack repairs (into the combustion chamber). I use Moroso Ceramic Seal on all my initial startups with flatheads. The Ceramic Seal also helps seal any head stud/bolt threads that might be prone to weeping as well.
Here is one of the more common products used to "stitch" a crack:
http://www.locknstitch.com/index.html
Best of luck!
B&S
Sid
Well-known member
Thanks B&S. I have a couple 59 blocks someone gave me. One has two cracks. The other not sure but it is a relieved block .060 over. Not crazy about lower compression as not racing. I have two later blocks which I may just make one resemble the 59 block by changing heads cam water pumps etc. Not sure how my existing 59 is at this point but there is definitely moisture in the oil. I plan on taking it out in a couple weeks.