cracked block, hardblok or epoxy?

[MarkM66]

Originally Posted By: JHZR2
Originally Posted By: turtlevette
Originally Posted By: DemoFly
If it's this important to keep the matching engine, take it to a professional to be welded.


I'll research that some more, but so far what I've found is cast iron is very hard to weld. It cracks around the weld area as it cools.



Research how,they are repairing the cast iron Capitol dome I'm Washington DC.


Apples to Oranges there. The dome doesn't have to hold fluids under pressure and go though thousands of heat cycles.

He's right, welding a dirty old cast iron block is hit or miss at best, and usually avoided unless it's a last minute hail mary effort.

 

[meep]

I doubt you'll see an epoxy-like product adhere and last through thermal expansion cycles to work. Dealer tried to repair a hairline block crack along an oil gallery in a 283 we had years ago. They used jb weld. no dice. fluid under pressure tends to win these battles.

Something thick and gooey like a radiator sealant would probably hold better. tried it yet?

If you do dump something in through the freeze plugs, I'd be way curious to know how it works out--- enterprising idea.

m

 

[The_Eric]

Originally Posted By: MarkM66
Originally Posted By: JHZR2
Originally Posted By: turtlevette
Originally Posted By: DemoFly
If it's this important to keep the matching engine, take it to a professional to be welded.


I'll research that some more, but so far what I've found is cast iron is very hard to weld. It cracks around the weld area as it cools.



Research how,they are repairing the cast iron Capitol dome I'm Washington DC.


Apples to Oranges there. The dome doesn't have to hold fluids under pressure and go though thousands of heat cycles.

He's right, welding a dirty old cast iron block is hit or miss at best, and usually avoided unless it's a last minute hail mary effort.




Not hit or miss when done correctly. If it's some yahoo with his stick welder, then yes. A shop set up to do legit repairs? No.

These guys are about 20 miles from me. They've always done good work, just not always in a timely manner.

 

[Donald]

There is also a way to "stitch" the cracked area. They do that for some Cummins diesel blocks.

 

[Ihatetochangeoil]

My two cents worth is that there are two ways to do this. One, the shade tree mechanic, and two, the knowledgeable professional.

The low buck shade tree mechanic way is to (drain fluids as necessary), heat the area with a butane torch until it SMOKES. You're not going to melt steel with a butane torch no matter how hard you try; so fear not. The idea is to get a clean dry surface. Heat the area smoking hot, let it cool, repeat until it doesn't smoke anymore. Use a power wire brush or a power sanding disc until all you have is clean steel (iron). Apply J-B weld to the area and let it set 24 or 48 hours. Reinstall fluids and drive it. If this fails, you're not out much time or money. If it works, Great! You've dodged a bullet. I did this to a friend of my son's car, a broke teenager who was driving like a madman down a gravel road and knocked a hole in his oil pan. He drove the car another 3 years with no leaks.

Method two is serious. In my opinion, those who say cast iron can't be reliably welded are simply unfamiliar with how to do it. I have done it many times and never had cracking problems. You need to find a competent TIG welder. TIG welding is slang for GTAW. I would suggest you look for a shop that builds race car chassis, and a weld supply where you can buy EXOCOR Executive 99 ERNi-CI GTAW bare wire. Here is a data sheet with important info for you: http://exocor.com/downloads/product-datasheets/99-rev2-Datasheet.pdf Your weld supply shop can sell you "Templestix" which are nothing more than chemical crayons designed to melt/smoke when a certain temperature is reached. You need about 350F preheat.

If you cannot find a shop near you with the confidence to do this, cast iron CAN also be welded with INCO 82 stick electrodes. This is discussed in AWS Welding Journal, October 2007, letters to the editor, page 20. Here is link to that:

https://app.aws.org/w/r/wj/2007/10/WJ_2007_10.pdf

In the refinery industry, Inconel is nicknamed "rod from God" because it can be used to join so many dissimilar metals. I do NOT know what it costs per pound, but you're NOT going to buy it at Home Depot. I'm willing to bet you need about 2-3 rods. 1/8 size electrodes in 7018 have 12 rods to the pound.

There are other filler metals capable of doing what you need; look at pages 16-18 here: http://www.pccforgedproducts.com/web/user_content/files/wyman/WPCprodcat.pdf

I am an old Boilermaker welder and an AWS CWI. If I can be of further assistance with Tech, do not hesitate to pm me. Good Luck!

 

[RoadRaceJosh]

Stitch it or replace it. Putting the block in a furnace to weld it will likely distort it beyond use without major machining time.

Here's what I'd do: http://providence.craigslist.org/pts/5429927937.html
http://boston.craigslist.org/bmw/pts/5420785387.html

 

[The_Eric]

Originally Posted By: Joshua_Skinner
Stitch it or replace it. Putting the block in a furnace to weld it will likely distort it beyond use without major machining time.

Here's what I'd do: http://providence.craigslist.org/pts/5429927937.html
http://boston.craigslist.org/bmw/pts/5420785387.html


The guys down the road from me do it all the time.

Also keep in mind that this engine recently suffered from a spun bearing, so it's due for an overhaul anyway.

 

[clinebarger]

Guy's, I strongly suggest a magnaflux be performed FIRST, If the cracks are originating from the Main Webs....It cannot be "Fixed" correctly.

I also would throw a 400,421,428,455 in & never look back, I put a 428 Pontiac in my old '69 Chevy pick-up in the early 90's to replace a tired 455 Buick. Pontiac used the 428 in their large boats from '67-'69 & they used to be very easy to find for cheap. Everyone was after the Super Duty engines, Not knowing a 428 out of grandmas car had 390 horsepower......

 

[artificialist]

There may be value in a numbers matching 301 block if it was the turbocharged version. I think they only existed from 1979 to 1981. Those engines also had some proprietary components, so switching to an NA Pontiac 455 or something like that wouldn't be so easy.

 

[turtlevette]

Originally Posted By: artificialist
There may be value in a numbers matching 301 block if it was the turbocharged version. I think they only existed from 1979 to 1981. Those engines also had some proprietary components, so switching to an NA Pontiac 455 or something like that wouldn't be so easy.


Its not a turbo. It has the classic shaker hood where the reverse air scoop sticks thru a hole in the hood. The air cleaner and scoop mount directly to the quadrajet. The air cleaner and scoop has a 301 design, 400 design and olds 402 design and is about 600 bucks worth of parts. There were 213 bandit 4 speed 301 combos in 79. I'm really not a collector type but there is no need to hot rod this car either. My corvette is the hotter setup with an aluminum head 350 and 456 gears. Not every one of my rides needs to be a hot rod.

 

[A_Harman]

If you're going to the trouble of pulling the engine from the car, disassembling it, then getting the block welded without a guarantee of success, I say you should just get a replacement stroker shortblock.

 

[Traction]

Originally Posted By: turtlevette
Originally Posted By: artificialist
There may be value in a numbers matching 301 block if it was the turbocharged version. I think they only existed from 1979 to 1981. Those engines also had some proprietary components, so switching to an NA Pontiac 455 or something like that wouldn't be so easy.


Its not a turbo. It has the classic shaker hood where the reverse air scoop sticks thru a hole in the hood. The air cleaner and scoop mount directly to the quadrajet. The air cleaner and scoop has a 301 design, 400 design and olds 402 design and is about 600 bucks worth of parts. There were 213 bandit 4 speed 301 combos in 79. I'm really not a collector type but there is no need to hot rod this car either. My corvette is the hotter setup with an aluminum head 350 and 456 gears. Not every one of my rides needs to be a hot rod.

They probably only built 213 cars with the 301 engine, because everyone wanted the 400 motor. So, I would not get that hung up on keeping the original block.

 

[DoubleWasp]

Originally Posted By: A_Harman
If you're going to the trouble of pulling the engine from the car, disassembling it, then getting the block welded without a guarantee of success, I say you should just get a replacement stroker shortblock.


Agree. There's no 301 worth saving. Maybe if it was some rare GM concept car that was going to be a multi-million dollar collectible one day, but this is not the case.

The crack could easily be fatal to the engine. This one needs to be dropped into the bin.