Cracked Block Options
 

I'm a total novice I've had an A all of 4 days now so I'm looking for some advice.


I looked this car over 4 years ago, I don’t remember the crack then but perhaps the paint was hiding it. The car was driven very little in the last 4 years and always had antifreeze so I highly doubt freezing caused the crack recently. I just acquired the car and hauled it home so it’s my problem now. I let it sit 3 days and collected the first cup of oil during an oil change. I don’t see any coolant in the oil but it smells like gas, I suppose that’s normalish?

As I understand it I have 5 options now and lots of questions.

• Have the block welded. I’ve read this requires all machined surfaces being redone and then the motor rebuilt. Probably costs more than a new motor or block.
• Get a new motor of some kind. This one supposedly has upgrades like; balanced crank, insert bearings, oil filter, high compression head. Replacement cost will probably exceed the cars value.
• Braze the crack. I have a feeling the block was possibly brazed in the past and the crack has reemerged. I need to grind off the paint to confirm that though.
• Lock-N-Stitch the block. This looks real neat, does anyone know if it can be done on curved surfaces or only flat? My crack seems to go down through a curve. Can this be done in the car? Then flush the coolant after or add a screen before the water pump.
• Grind and fill with JB weld. Has anyone had success on such a long crack?
• Keep driving it as is. Do these cracks generally grow until they are fatal or stay about the same size?

I am tempted to just drive it until something fatal happens then find a new motor? If the damage is already done and a new motor is in my future why not drive it into the ground first. Maybe this is a bad idea for some reason unknown to me. Which is why I’m asking your experts.

Thanks for any input.

Re: Cracked Block Options
 

I would" a 1/8 hole at each end of the crack, then grind it out about 1/4" wide and fill it with JB weld. My guess is it will seal the crack and it won't leak any more

Re: Cracked Block Options
 

By the looks of it this one has none of the ‘upgrades’ you referenced. Would have been better taken care of. If you only have a cup of oil in 3 days you need to drop the oil pan and clean out the sludge and oil pump. Clean valve galley. Nasty crack but you could do as you like and drive it till it quits

Re: Cracked Block Options
 

Hey Steve,
Welcome !
I'd do as fordwife suggests. Just make sure that the crack and area are CLEAN so that the JB weld has a firm grip !
Silver lining here is that this is in an easy access area and only affecting water jacket areas.

Re: Cracked Block Options
 

I would go with the fordwife fix. You probably should drop the pan do Steve's preventive maintenance.

Re: Cracked Block Options
 

+1 for JB weld. And if it doesn't work the first time just grind it out and try again.

Re: Cracked Block Options
 

I just collected the first cup of oil to check for water that settled to the bottom. It had plenty of oil, dropping the pan wouldn't be a bad idea though.

Re: Cracked Block Options
 

I've never had a JB weld repair fail on an outer water jacket . If one ever failed I would do what ryanheacox said above . I would also first do what fordwife said in post number 12 . Outside water jacket crack repairs are really not that big of a deal . If you are always going to worry about it , then have it pinned . I wouldn't recommend welding or brazing .

Re: Cracked Block Options
 

I would also try the J B Weld fix. Make sure the area is really clean after grinding a V groove along the crack before applying the JB Weld. A rotating wire brush in an electric drill does a good job of cleaning metal surfaces. A little sanding and a new paint job and you could probably hardly see where the cracked area was.


There are products like Irontite block sealer that will seal small cracks. You might try a pint of it after you JB Weld up the crack to make sure it is 100% sealed.

Rusty Nelson

Re: Cracked Block Options
 

Getting the oil pan off will also tell you if that balanced crank is in there, and you could better decide what kind of money to spend on the engine.

Re: Cracked Block Options
 

I would do it a little different I would drill and tap the end cracks and the one on the 45 degree. For cast tapered plugs that way the crack will not grow. Then try the V grove on the rest of the crack. then try your JD weld.

Re: Cracked Block Options
 

There are other brands of epoxy that are better than JB Weld but more expensive. So you might do a little checking.

Re: Cracked Block Options
 

40 Deluxe,
What epoxies are better than JB Weld? I suspect there might be some, but I never heard of any of them.
Rusty Nelson

Re: Cracked Block Options
 

I've sealed much worse than that crack. Drain the coolant, then as others have said, drill the ends, V it out just a bit, then put a thin layer of the standard JB weld. After that is cured, add more layers to build it up. The JB Quick isn't as strong in my opinion however if you are getting too much sag on the second coat, the JB Quick sags less so that is an option. You can also cover the uncured JB with tape to keep it from sagging. I use a small grinding wheel to shape it when its cured for a few days then prime and paint. If your careful even you won't be able to find the crack. I would sandblast the area to be JB welded to give is a better adhesion. It is kind of a pain getting sand all over everything so cover well.

Re: Cracked Block Options
 

I have been told that Quick set epoxy is not as strong as regular.

Re: Cracked Block Options
 

I don’t get it!
Steve said that he got a cup of oil when he drained the motor and it smelled like there was gas in it.

What did the rest of the oil look like?
Anyone know how gas could get into the oil except be carried with the air thru the intake manifold?


Unless I am missing something, it sounds like people are jumping to conclusions.

Re: Cracked Block Options
 

All the J-B Weld is good advice I have a motor in a pulling tractor that's half built out of JB Weld and it held just fine but one thing I would like to add is while you have a drained and water just put back in it I would treat it with water glass and you sure won't have any leaks

Sent from my SM-J700T using Tapatalk

Re: Cracked Block Options
 

Devcon makes epoxies that are high quality, industrial stuff. You can't usually find them in a store, have to order it. I seem to remember Devcon "F" being hot stuff, but I was usually working on aluminum cases.

Re: Cracked Block Options
 

Re: Cracked Block Options
 

Yes JB WELD. I suggest taking the head off and seal all the water ports on the top of the block with tape ( blue paint tape works well ). Then connect a wet/dry vacuum to the water outlet on the block. Clean your crack area useing brake Kleen while vacuum is running.
After that let the brake kleen dry. Then apply JB weld to crack WITH VACUUM RUNNING. The JB WELD will draw into the crack. Let it dry 24 hours then do same procedure until the vacuum ont pull any more JB WELD into crack. I’ve done this on my model T on the block and the cylinder walls. The T IS FINE AND RUNS WELL.