Cracked blocks

Bobber · Post by **Bobber** » Thu Mar 29, 2018 8:29 pm

Long story short, My block was sent to the shop. They magnafluxed it and found a crack. I had a second block in the corner and sent that one in. It too was cracked in the same place. The shop said they all crack in the same place, that's why they swapped out the motors. If I buy a new L134 block, how long till that one cracks? I'm thinking about a V6. It's hard cause I've been running a 24 volt L134. That's a lot of good parts to shelve or sell for pennies on the Dollar
Thoughts and opinoins welcome.

Post by **wesk** » Thu Mar 29, 2018 8:44 pm

Bob, You need to tell us more about the cracks. There are two common crack areas: 1-the distributor mounting area of the block. 2-the thin piece between the paired cylinders on top.

Bobber · Post by **Bobber** » Thu Mar 29, 2018 9:09 pm

Cracks were on top between 2&3 cyinders. Both blocks.

Post by **wesk** » Thu Mar 29, 2018 10:14 pm

Now you know why you always pull the head when buying any used blocks. I don't think I would pop for the off shore new repop blocks. I'd shop for another used block but this time clean up the distributor hump and remove the head.

Xamon · Post by **Xamon** » Fri Mar 30, 2018 7:24 am

Okay just curious here but could not a good pro welder grind and weld the crack and then you could sleeve the cylinders?

Post by **wesk** » Fri Mar 30, 2018 7:28 am

Yes, sometimes. Usually welding is not a successful long term solution to between the cylinder cracks. Stitching usually works on the external cracks near the distributor hump.

Xamon · Post by **Xamon** » Fri Mar 30, 2018 7:34 am

Is it because it is cast material? Does the weld separate or does it just crack beside it? Thinking strange thought but what if the area was machined down and a plate was welded over the entire area, still sleeveing the cylinders of course. Probably lots of reasons against this just my brain getting the better of me.

Post by **wesk** » Fri Mar 30, 2018 8:04 am

Cast iron has it's own set of problems including poor weldability.

Welding a plate across the top of the block gives us many problems: IE fitting the valves, loss of compression etc.

Smart folks get rid of the cracked blocks and move forward with un-cracked examples. We all want some level of reasonable assurance we won't have to keep re-visiting a cracked block during our period of jeep ownership.

Xamon · Post by **Xamon** » Fri Mar 30, 2018 9:16 am

True enough, but sometime we are going to run out of good old blocks and be forced to consider alternatives. Would be nice to have a not made in china alternative, although I would be interested in seeing someone build one of those new ones.

dpcd67 · Post by **dpcd67** » Thu Apr 05, 2018 11:54 am

Abrahams had a good one a while back that they had machined and wanted to sell;I forgot how they ended up with it; I can check on it if you want.

w30bob · Post by **w30bob** » Thu Apr 05, 2018 9:28 pm

Xamon,

Welding cast iron engine blocks isn't impossible, but is difficult to do correctly. The issue is how cast iron behaves when heated and cooled. There is tons of info on the subject online, but the bottom line is the person doing the repair has to understand cast iron and have the ability to preheat the whole block to the very high temperature required, and then be able to control the long cool down process necessary to reduce stress that develops as the cast iron cools.

There are very few folks who can weld cast iron properly......but if you can find one your block can be fixed. Letting anyone else attemp to do a weld repair on your block will not end well. If you do find an expert it will be costly......which is why most folks just toss the part and replace with another. If you decide your block needs to be saved at all costs read up on the process so you can discuss it with those who claim to be able to do it. Once you understand how cast iron behaves and what needs to be done to properly weld it you will quickly be able to determine which welders know what they're talking about and which you need to be quickly walking away from. This is one of those few things in life that can only be done properly one way.......and any attempt to cut corners, no matter how small, will end in failure. Good luck.

Regards,
Bob

WillysMotors · Post by **WillysMotors** » Sun Apr 08, 2018 11:30 am

For those that may be interested, the Willys reunion in Aurora Ohio in May will feature an engine build on site using one of the new blocks from CHina, and it will be auctioned during the event when it it's done.

http://willysreunion.com/swr18.htm