cracked slant block

-
vitamindart

vitamindart

Well-Known Member
Joined
Jun 11, 2010
Messages
1,489
Reaction score
608
Location
Vernon,Wisconsin
ok, so I don't know how it was missed during the clean up/re-ring. but yesterday while prepping for the replacement intake gasket to show up. we were checking for coolant leaks ( had a intake/exhaust stud leaking ). found a 1-2" crack in the block just above the pan rail.
my daughter was devastated. she was really looking forward to finally getting it out on the road. any downside to trying some sealer in the cooling system? would really like to re-use the head and cam. when I can swing a replacement. right now the funds are just not here to buy or rebuild another.
 
If you can find a guy to do it. You could weld it. YES cast iron can be welded. In a coolant passage it should be effective
 
the cost in time and the welding don't really make it worth while. I doubt they will weld it in the car. they will want the block stripped and cleaned.
I could also have it stitched as well but, there again cost is more than its worth.

for the cost of a running slant it is not worth it. I would probably be better off finding another cast crank slant. cleaning & prepping the block and transfer my parts over to it.
 
vitamindart said:
the cost in time and the welding don't really make it worth while. I doubt they will weld it in the car. they will want the block stripped and cleaned.
I could also have it stitched as well but, there again cost is more than its worth.

for the cost of a running slant it is not worth it. I would probably be better off finding another cast crank slant. cleaning & prepping the block and transfer my parts over to it.
Click to expand...

And hopefully you find one that (after you purchase it and spend time stripping it down) doesn't need any machine work. GL.
 
I have a couple of slants sitting around doing nothing I could be talked out of one...
 
Jb weld is what I'd try, if it doesn't work then you'll hafta pull it.
 
A company named Cronatron makes a stick weld rod that used in rev polarity will easily weld that.
its called NIrod and works great, I just repaired a S6 exhaust manifold while still bolted on.

another option is Belzona epoxy...a caterpillar approved block repair
 
Machineman63 said:
A company named Cronatron makes a stick weld rod that used in rev polarity will easily weld that.
its called NIrod and works great, I just repaired a S6 exhaust manifold while still bolted on.

another option is Belzona epoxy...a caterpillar approved block repair
Click to expand...
yes correct,,, Cronotron specializes in this type stuff. it works, and is the modern very of welding cast. BUT I am not sure if the block needs care in heating/cool down????? prep as in hole drilled at ends of rack? crack "V" ed ????? I would ask C rep or co.
 
I patched a crack to the coolant passage in a head with JB Weld and ran it for years. I opened it up with a file and thoroughly cleaned the adjoining surfaces. What do you have to lose?
 
Well, if it leaks and the daughter does not catch it on a long day of driving around, then the losses will be lot of other parts if it overheats, and then maybe a long and costly tow home. IMHO, do the best repair you can.

BTW, OP this sounds like a freezing crack.... so look closely at the other side and the head.
 
Last edited:
Brazing would absolutely be sufficient for a non structural crack. It's excellent at sealing.

If you're tig friendly, stainless rods will weld cast iron quite well.

How certain are you that the crack goes through? Don't toss that block. Run it!
 
In my opinion, this is a really good opportunity to show your daughter what it means to not give up until you solve the problem.

You know.... greatest generation, failure is not an option, back to back world war champs, etc.
 
If it isnt leaking dont worry about it, if it isnt leaking it isnt a problem you know its there just keep an eye on it
 
1-2" above the pan rail might not even have cooling passages behind it..........

If so

I'd stop drill the crack, drill and tap the holes. Use threadlock on some set screws.

JB weld, maybe even RTV will seal the crack.
 
Instead of runnin skeered, pull it and tear it down, take it in and have it welded. Think of the experience your daughter will gain.
 
emsvitil said:
1-2" above the pan rail might not even have cooling passages behind it..........

If so

I'd stop drill the crack, drill and tap the holes. Use threadlock on some set screws.

JB weld, maybe even RTV will seal the crack.
Click to expand...
Ya know.... this is right. I looked at my /6 and at a cross section drawing of this block, and 1-2" above the pan rail is well below the water jacket. On the driver's side, the water jacket looks to stop stop just below the core plugs. But, it sounds like the OP found this when doing some coolant checks, so either the crack is higher up than described, or there was some leakage coming from somewhere else that dribbled down into this crack and looked like it was coming out of the crack.

OP, any pix you can post?
 
nm9stheham said:
Ya know.... this is right. I looked at my /6 and at a cross section drawing of this block, and 1-2" above the pan rail is well below the water jacket. On the driver's side, the water jacket looks to stop stop just below the core plugs. But, it sounds like the OP found this when doing some coolant checks, so either the crack is higher up than described, or there was some leakage coming from somewhere else that dribbled down into this crack and looked like it was coming out of the crack.
?
Click to expand...
makes sense! maybe .... pin hole in an old freeze plug? last 2 slant cars I was getting running, I found slight amt. of antifreeze at front of block area, just down below the thermostate housing. you guessed it... both engines had a pin hole in that old aluminum thermostat housing. rok auto, new onemade out of cast iron. c heap. ( the housing not me... o k ..me too)
 
its definitely leaking from the crack. we could see it seeping out last night as we ran it with some sealer. I should have said mid way between the pan rail & freeze plugs.
we are not running from this mess, we will get this car back on the road one way or another. we were discussing our options last night on the best plan of attack.
 
If midway between pan rail and freeze plugs, then this crack may goes up at a steep angle into the casting to reach the water jacket, so may you have something like a flat area of iron lifting up. I have seen this type of 'scabby' cracked area in freezing cases. It's harder to properly get back deep into that angled crack and fix it with anything. But if you can follow it up through that crack and bevel out the area, then possibly there is more area for something like JB Weld to successfully grab onto.

Sounds like you are gonna handle it one way or another!
 
The kind of nickel-based rods for this work like Machineman63 referenced melt at low Amps, I used General Alloys EA201 for all kinds of cast repairs & out-welding. A bit
of preheating is a good idea, but You needn't be fussy about that, most of these alloy/special flux rods simply require You to peen the deposit right after You draw off to
stress relieve the area. Brazing and thermo-kinetic or "spray welding" both will work as well. With cast the risk of porosity is always there, but common chemical sealers
will easily put the stop to that if any. Prep is the key to problem free...........
 
alright, took me way longer to get to it but. we have it all sealed up, ground it down JB welded it and tossed a bottle of sealer in when I fired it back up.
JB really slowed it but it took the sealer to stop it completely. even put a second coat of JB as an insurance policy. ran it a while no leaks, so I topped it off and put it away for the winter with a good 50/50 mix. should be ready to rock in spring. thanks to everyone for the ideas and suggestions!
 
One suggestion, try Evans Waterless Coolant. I have it in 6 of my 7 vehicles. No more corrosion worries and you can run w/ the radiator cap loose so it doesn't build any pressure. My 1984 M-B had a slight heater core leak, which is a 3 day replacement effort and $400 part. I fixed it by flushing silicone sealer thru, silicate seal (core alone), and now run it w/ the cap loose, and no more leaks or coolant loss. If too cheap for Evans ($43/gal), you can buy Sierra coolant at Ace ($12/gal) which is pure propylene glycol (what original Evans was), so some say "should work". I carry it in the trunk for emergencies. But, you must get all water out of the system, including blow out the heater core.
 
About a zillion years ago, I had a cracked block in a 1964 straight-6 Ford Fairlane wagon. With the engine in the car I used a round wire brush on a drill, cleaned off everything around the crack, then mixed up some JB weld and slobbered it all over the crack and surrounding clean block material. It worked like a champ, and never leaked a drop for the several more years I drove it before parting ways.
 
You must log in or register to reply here.
-

Back
Top