Welding external block cracks ?
 

Fellas, what are the pro's and con's of brazing or welding this external water jacket crack? Don't be shy!

As you can tell from the pic. my buddies '87 OMC 5.0L block didn't fare too well in it's last Wyoming winter. The engine's pulled, we're contemplating brazing the crack and pressure testing. If she passes the pressure test, then well put her back in, that if it's a feasible option. Otherwise, it's a new bare or short block, alot more work and a few more $$$$....

Lemme know what ya think...

block crack
 

never seen it done sucsesfully:eek: a 5.0 bare block is relitivly cheep good luck. Charlie

I,ve never admitted to this before but 4 years ago a friend brought his boat over with a crack in the block that looked just like yours and it was also from not winterizing properly. It was an older boat and he said he was going to junk it if I couldn't fix it real cheap. I used a small dremel to grind the rough burrs off the exposed section of metal that popped out and then banged it back into place with a hammer. I then lathered on a generous portion of J-B weld. He's still driving this boat around, happy as a clam !!

Bo knows , and now everyone else does too !

I am with Bo. Go with the JB weld if he is looking to go cheap. It is worth a try. I would think that getting the block hot enough to weld properly you are likely to either crack it more or cause the block to be redecked and what not.

Jon

welding cast iron is a little tricky, but for a real welder, its not to bad, if the boat is a keeper, replace the block, if not check out your options

i recently had this same problem
the previous owner of my boat didn't winterize it properly and i got stuck with the repercussions
he had the crack welded and needless to say it cracked again. i pulled the motor and took it to my engine builder and he said don't even bother trying to save this block, its junk. BTW my crack wasn't nearly as bad as your buds.
good luck

Russ

I am with Bo. It is worth a try, I have a buddy that did this and the boat is still running strong. what are you out for trying besides alittle time.

I`ve used JB Weld on cracked blocks before and it always worked for me too!

I have seen the JB weld thing done myself,,,, just be sure to stop drill holes at the ends of the crakes to relieve them.

Better pull the intake and look inside. Drill the ends of the cracks, wire wheel and clean with alcohol (or drink it), weld up what you can and cover with JB Weld. Don't run it hard until the temps come up and stabilize. Seen several JB boats run for years. Probably get by with it if no cracks on the inside. If you go this route verify bilge pump is in working order and carry a topsider oil change and some oil and filter on board. You may want to change the T-stat as well.

Tim T.

I'm glad someone else said it first:D JB Weld is some
amazing chit !!!!

Cracked block
 

would always replace since there may be cracks inside you don't see. These would only show up later during a long high speed run when the sounds turned a little "funny" just before it seizes from a spun bearing when oil is milky!

Wannabe in motor city

Most machine shops that repair heads and manifolds can repair it for you. They use a powder torch that heats the surrounding area to almost a molten state and sprays a metal powder into the area to be repaired. My buddy uses his alot to repair #'s matching intake and exhaust manifold for restored classics. I saw him repair an exhaust manifold that was in 2 pieces for an Edsel, after the repair and dressing you could hardly tell anything was done.

Todd

"SCRAP IT"
I tell you this from experience. It's not worth the hassle and time. I purchased (almost stole)my first boat with a cracked block. It was a 87 OMC 5.7. Bought some cast iron welding rods, pulled the engine, took it to the shop, tried to weld it up. Allot of work for a relatively cheap block. Ended up buying a block that came out of a 94 Corvette. Keep in mind - it's nothing more than a GM block with brass freeze plugs.
Remember, if the block got cold ehough to freeze, take a good look at the intake and the exhaust manifolds. Even pressure test the exhaust manifolds. Another lesson learned the hard way!!!!!!
Good Luck!!!
Jon

Oh come on now
a 5 liter will cost you what about 35 bucks from a junk yard?
dont go that route that is just jerry rigged beyond belief
if your going to do something do it right
dont rig it
yeah the jb weld and all that BS might work but comeon
and if you sell it Ill bet 20:1 you wont even mention it and if the SOB that buys it finds it, he is going to think you are the biggest putz bastard that walked the planet too.
Christ, a 350 replacement core to be built will cost you what
1000 bucks from scratch bare block from junkyard?
do it right man, I hate seeing this BS especially from what just happened to my bud RCM255
bilge filled up with hot water
went snooping and snooping around
sure enough block looked like a horses dick taking a leak
do it right or dont do it at all
Jason

Yep I did it on a Merc 350/260. Ground it clean and beveled it into the crack. JB Welded the piss out of it. I've run it WOT all summer and no leaks.

Brian

Cast Iron can be welded, but it is tricky and you have to know the technique. I fixed a leak just about like that with a two part epoxy that GM sells over their parts counter. I used a small grinder and created a bevel on both sides of the crack. Make sure the crack is clean, clean, clean. I then put a thin layer of epoxy and let it cure totally. Then roughed it up a little, cleaned it again, and put the final layer on. Make sure it cures. I bet it will be OK. Don't rush the job.

I cant believe im reading this

No wonder boats loose so much money in the few years off the showroom floor
Cause you rig your engine with epoxy
I cant believe how many of you are saying do this!!!

are you all freakin drunk?

and what happens god forbid this guy takes your advice
right
he is running say a good 2 years with a totally rigged engine
he is out not thinking about the hooptie job you all told him to do
say he is about a 3/4 mile off shore or wherever
and it springs a leak
a BIG leak
and his bilge starts filling up with water
he does not know it just yet cause he is moving
but water starts getting higher and higher and higher in his bilge
shorts out the batteries cause the starter cables and stuff are down low, blows his electrical system out and shorts it
his bilge pump cant hold out and wont work due to short
and his **** sinks
THEN WHAT
Oh well the guys on Offshoreonly told me it would hold
I CANT BELIEVE you are all telling this dude to do this
LOOK AT THE SIZE OF THE PLATE on that thing
DUDE IT IS A 305
they are about 29.95 at any freakin junk yard

Dude, dont listen to these quacks!!!
GET A NEW BLOCK
END OF STORY
YOu want to fix the freaking thing or cause more problems for you and your friends and family and put people in a possibility of danger

Get a new freakin block
im telling you 305's are in the car market basically worthless
take your internals, swap em over into new block
and just be done with that one

You guys shock me
I cant believe you told this guy to patch it

your all freakin nuts if you do that
we need more guys in here to suport the trash it and get a new one side
Jason

A new tire for the truck is only a hundred buck and no labor. Do you replace it when its gets a hole or do you have it plugged? And you can't say that that block leaking is any more dangerous that a blow out at 80mph. Just my .02

Brian

Jayl13
Hey, tone it down a little here. You have your opinion, the rest of us have ours. I don't know who you are but I don't need you calling my a quack.
The issue here is not the cost of a junk block. There will be considerable expense in anything he does unless he repairs his existing block. Maybe he does not have a lot of money to buy a block, have it checked, machined, reassembled, and installed in the boat, plus the considerable time it takes to do all this. Obviously, when you make a repair on anything you keep your eye on it, if it does not leak after a few hours of running, chances are it won't.

whoa whoa back up a minute

Your comparing an ENGINE out in the water with a 7 or 8 inch CRACK In it rigged back together to a TIRE?

Nuff said

Why dont you put it into terms that are equal

Go to an engine builder of your choice
he has 2 blocks there

one is cracked and other is just fine

which one is cheaper?
The one that is fine is cheaper cause he would take the cracked one and toss it in the god damn dumpster where it belongs

Nuff said

white knuckle
okay sorry for the quack comment my fault
but he already has the engine out
read origional post there
it is already out of the boat
plus the pic shown, the nut is already off of the motor mount anyway so you could tell it was going to be pulled anyway.

I would not go anywhere near a cracked block
no way
would you put a cracked block in your boat?

I would NEVER even go there

Has anybody ever sleeved a $29.00 cracked block?

Broke the motor mount boss off of a formula2 race motor and we welded it back for a backup motor but it ran better than the replacement. I switched it back and ran the whole season on it. If it is repaired properly it will be stronger than before. Typical of most welding repairs. But you still have to figure the cost of proper repair as opposed to replacement.

Buy a $29.95 junk yard motor(the cheapest I have seen is 99.00 and you remove it yourself) tear it down only to find it worn out and then where are you.

In a perfect world we would all rather by new.

Todd

I wouldn't put a cracked block in my boat. I never pulled mine. Simply patched it and went boating.

A tire is a chamber that holds air. A water jacked is a chamber that holds water. Both are pressurized and both can be pathed.

nuff said

I would have to say that this particular crack it pretty big to repair. The ones I repaired where 3-4 inches. It all depends on whats the boat worth and whats it worth to you to fix it.

quack
 

:D quack :D quack :D quack :D Jay is rite motor is OUT here in Seattle I can get 305 block for $25 and a complet runner for $100 boating is supose to be fun not build parinoya (sp):D Charlie

Just another .02 ......

I have fixed stuff plenty of times . JB works good MOST of the time . And it can just be welded too . But the heat may distort the block and warp the cylinders ,leading to a seized piston shortly after assembley . IT will also warp the deck serface if welded so close so you need top deck it now .

I say ,since it's out , and you have to tear it down anyway to check or fix it . You should just get a new block . It's not cheap to have these things welded or JB'ed by a machanic . I paid $200 to have a small crack fixed in a head . A new block cant' be that much . For example , Summit racing has a ford 302 block fully machined ready to assemble for $329 . I'm sure a chevy would be cheaper . Plus you don't have to machine it . Good luck in what ever you do . It is never as cheap as we would like it to be .BUT ,if you do it 2 or 3 times before you get it right it cost a whole lot more !! Been there ! ;)

I would say in this case the crack is to close to the motor mount
for JB {Quack-Quack :D } If he has to spend the $ scrap the 305
{junk motors anyway} find a 350.........be sure to drain this winter!!!:D

Got to agree with Jayl13. JB weld works in an emergency but come on guys, why rig something like a block. You're the same guys that always whine about mechanics, saying I don't trust anyone but myself working on my boat. But I 'll bet not many real marine mechanics would JB Weld a customers block. Besides getting a junk yard block and cleaning it up and assembling it can be a rewarding project.

ads 6 im welder by trad and we weld cast iron all the time in the shop for that block to be repaird it need to be taken a part and slowly warmed to about 400 degrees and weld with palco 808 cast iron rods and pinged well and aloud to cool in a lime vat verry slowly if you get in a hurrey it wount work cost is a round 100 $ to 300$ if he can replace it chepper go for it those palco rods are a bout 500$ for 10 lbs we buy them 2 times a year robbie rogers , rogers welding and fab

Cronatron 211 is a cast iron welding rod. It works very good. It is a stick welding rod, but i have cleaned the flux off of it and tig welded with it. You don't have to heat up the material to be welded but it needs to be clean from paint oil etc. Thats a pretty bad crack and its up to you but I have used it on a riser and it worked fine.
Mike

The comparison of the tire to the engine is pretty poor. If you get a flat tire you can walk home or to get it repaired. Where are you going to walk to after your boat sinks???

Fellas,
Thanks for the wealth of info. and entertainment! LMAO!

Our welder here in Cody Wyoming said he could weld it, but it might hold for five minutes or five years. He's welded cracked tractor blocks that have lasted for 15 years, and others who have split in 5 minutes. Apparently it's a 50/50 shot welding cast. So we tore it apart, and it was a good thing, she's cracked inside as well. We're taking all the good internals to a reputable engine builder who'll prep a new 305 block and build us another short block using what we have left. We're having the heads mag'd as well. They look okay, but one never knows. The OMC iron exhaust manifolds are cracked as well, so I'll start the search for another set.

Here's a pic of the internal crack.

Thanks again to all of you for your insight, my buddy, a.k.a. father couldn't believe the amount of feedback we received on this. He's old school in terms of the internet and is still in dismay.

No real surprise...
 

I had the same thing happen to a 4.3 V6 (3/4 of a small block), and it looked almost exactly the same as yours - not too bad on the outside, but !!!!! on the inside. It was cheaper for me to buy a complete OMC short block assembly than to buy a bare block and have someone reassemble my internals into it. If you're doing some of the work yourself, that will help, but you may want to have a hard look at going with a 350 replacement (marine) short block. The reman shops have them pretty cheap. Boat gets faster, too. :D
While you're at it, you may find that the performance exhaust manifolds (IMCO, Kodiak, etc.) may actually be cheaper than new OMC ones. Boat gets even faster. :D :D