I have built my fair share of engines but I know there are many guys on here who have gone way beyond my expertise... so here goes.

I have a 350 block that has damage to the #4 cam bearing journal. The damage consists of a jagged "slot" across the bearing land. This will allow oil to squirt out the side past the bearing OD and the block ID. The slot is probably about a 32" across and deep. The damage is pretty deep. I can't see it... I can only feel it.

The damage is on the bottom of the journal, so I did not see it until after I had the block bored, stroker relieved etc etc. while I was installing the cam bearings.

I considered JB Weld but I don't think that stuff is a good idea for this purpose. I don't have the equipment or skill to weld it (cast iron). And... I doubt anybody could get in there to weld. Align boring would likely not go deep enough to take out the damage. Installing roller bearings is an $800 bill... not cost justified. Anybody know of a way to repair this and save the block? (no coat hangers or duct tape please)

 

32 inches ?

I have had good luck with JB Welds' WaterWeld, the stuff will cure under water. Put some on your finger and smooth it into the crack. I can't think of anything else since you already know it can't be welded.

How did it get there ? Maybe was there all the time and you just need to install the bearing to seal it up ?

 

You're saying the block itself got gouged? I wouldn't hesitate to sandblast it down to bare iron then use J.B. Weld to fill in the deep scratch. If its sandblasted first the J.B. Weld will adhere very well and oil pressure won't blow it out. Can you take a picture of the damaged area?

 

I dont see how a deep scratch in the blocks metal would make much of a difference Tom. All the surface contact is inside the replaceable- brg and the brg load is on the cam brg - and of course the cam. A better shop can hone that surface to remove any metal burs or whatever so it doesnt affect cam brg installation.

Hone it straight if your worried 'bout it. Some shops hone/bore the block to make the cam sit straight with the crank. And i think some shops hone the brgs too.

Well good luck and try drinking decaf.

 

So I take it that the gouge intersects the oil feed hole? If so, I'd imagine JB would work or you could throw a boat load of money at and change to roller cam bearings.

 

The small amount of oil it will by pass you will never miss, there is more lost around the factory distributor where it makes up the rear lifter oil gally.
Put it together and run it

 

Ok i re-read the first post and realize i didnt see what u said 'bout across the brg land and worried 'bout oil leak and loss of press. Sorry i was pretty tired last night. Well it reads more like a crack than a deep scratch to me. So i have to ask u if u knew the engine had low oil press before dissembly?

Ill just say welding sounds like the option for repair as any crack in cast iron can continue to grow until its a fatal failure. U can buy weld rod for cast iron but the base metal needs to preped. To prep the crack needs to be ground out some to let the filler rod get a good fill. Also the block needs to be preheated to 400*F. I dont think there are any AC rods for cast iron and u will need a DC weld machine for this - usually 220V required - the cheap little 120V buzz boxes wont work for this. After the weld u need to peen the weld bead - yes while the block is still hot - and allow the block to cool very slowly. Some welders return the block to 400*F and cool it in steps down to ambient while under insulation to slow the cool. Usually a large propane torch with a weed burner torch can do the preheat and measure with a temp stick. Heads and manifolds are much easier as they fit on a good old BBQ but thats off topic here i guess. I dont think u can find many weld shops that will go to this length for a customer as they have to keep welding to pay the bills im sure u know. But it doesnt hurt to shop around and even ask your machine shop for references. Finally u will need to have the brg lands honed at least to get a good brg surface.

Now brazing is a different story. It dont need the preheat (though i recommend it) and flows into the "joint" on its own - but u should still prep with some grinding the crack for better fill area. If u can find a weld shop that will do this it is the most economic repair - any welder that can Ody-Acetelyne weld can braze. But once u braze a joint u cant weld it unless u grind out every bit of the brazing metal. Still need to hone it after repair. If your interested brazing is easy to learn and if u have some old manifolds to cut up and braze/reweld u can learn on your own. U can buy some pretty small torch tips for access to tight areas using Oxy-Acet as they were used for aircraft for a century at least.

In the end u need to get an estimate for the repair work and compare a new better block to what u have in this block.

My vote is for brazing. Good luck Tom.

 

My computer has issues and it decides what it wants in print instead of me...LOL... 1/32"

RE: Welding.... I honestly don't believe anybody could access the location of the gouge. So even if I had the equipment, it would likely be inoperable. You just can't get in there with any equipment. I am good with a Oxy/Acet torch. It's not a viable solution.

RE: discovery... I purchased the 350 4 bolt main bare block for $125 35 years ago from a racer at Englishtown NJ. It's been sitting in the corner. Had no idea the cam bearing land was damaged. I don't know the history of the block. Never thought to check it before I machined it.

RE: JB Weld... I ran the idea past several other local engine builders and the consensus is that it couldn't be trusted.

It's not a crack. That much I am sure of. It's definitely a "gouge".

Thanks for the replies.

I'll start looking for a roller 350 block and eat the damages.

 

Ok its not a crack. It really is a tiny gouge that just needs to seal w/o falling out. That makes a world of different here Tom.

Just solder it. It dont have to support any stress - just seal. U have to clean the heck out of it - i would use maybe a little more aggressive than alcohol or even acetone more like mucuric acid. Then use some of that plumbers flux & solder. U can solder with a tiny pencil torch or even a plumbers iron but u want to heat the base metal so u dont get a cold joint. Inspect with mirrors and magnifier after. But u can shape the surface with some pretty soft tools once done.

Hate to see that block go to waste and if were mine i would solder what i couldnt weld or braze.

Good luck.

 

I second brazing. Brazing seems to be a lost art but is ideal fir this repair.

 

Please take a close-up picture if you can so we can see what kind of damage it has. From what you're describing it sounds like you would have a small leak between the bearing and the block at the most. I would think you could install that bearing then force J.B. Weld into the itsy-bitsy hole.

 

I just said JB weld for quick fix. If it was me the block is only one component of the entire engine and it is not even the most expensive part.

I would discard the engine and look for a new one. First I would go back to the machine shop and tell them what you found hinting at the fact they should or could pick that up before line honing. Then you have a little leverage and then I would ask them if they had a block lying around that you could use. Maybe you will get a deal because of the money already spent on a boat anchor.

You could also sell the finished block with a note saying it had a scratched cam housing but should not affect the performance of rebuilt engine.