Crack repair
 

When using pipe plugs to repair a cracked head should they be steel, brass or does it matter?

ron

Re: Crack repair
 

1wonton,

I use 1/8" Solid Brass Pipe Plugs, with the square end.
Attached are a couple of photos of a repair that I did back in the '80's on a front water jacket.

Darryl in Fairbanks

Re: Crack repair
 

10/4. Thanks Darryl.

Re: Crack repair
 

i use cast iron plugs for the same expansion rate.

Re: Crack repair
 

Great to see a post from Jim Brierley. I use iron pins too.

Re: Crack repair
 

Iron pins for me also only found it needed on B engines hard to find crack free Bs here
A engines I get another block

Re: Crack repair
 

Cast iron.

Re: Crack repair
 

Where can one find cast iron pipe plugs?

Re: Crack repair
 

Lock-N-Stitch

http://www.locknstitch.com/

I use their cast iron plugs on Model A & B blocks.

Good Day!

Re: Crack repair
 

Hey Dave,
Thanks for that info:) !

Re: Crack repair
 

Thanks Dave.

Re: Crack repair
 

JB Weld or two part epoxy has worked good on simple outside water jacket cracks for me. I've seen JB repair on outside cracks last 20 years. As a matter of FACT i've never seen a JB repair on an outside water jacket crack fail that I did. I only do my own and never give them a second thought.

Re: Crack repair
 

I have used Purdy's method of repair and also have had very good success. I would estimate I have sealed about 15 cracks and ...no leaks yet. If the crack is over 2" long, I will place a couple Lock-N-Stitch cast iron pins in it to eliminate differential movement and then use the JB Weld. "V" the crack, and build the epoxy over the crack. I do not remove the excess down to the metal...I try to leave no less than 1/16 inch directly over the crack. If you position the block correctly and build a masking tape dam, you can get the JB Weld to take set in the shape you need to totally hide the repair. A little filing and sanding to recreate the original shape and you can't pick up the repair when painted. Texture can be added to the repair after the shaping to blend into the cast iron.
If you try JB Weld, it should be the slow set for best results. The quick set will not bond to the cast iron as well as the slow set.
Good Day!

Re: Crack repair
 

I have a good B head with a crack across the top and down to one side, about 7" long. It's a small crack and I don't know how it developed. Anyway, should the crack be "V"-ed out before applying JB weld? It seem too much work to pin and not sure about brazing / silver-soldering.

Re: Crack repair
 

I always drill a small hole at each end of the crack so it can't run any farther. I always V out the cracks before aplying J B weld. Seven inches is a longer crack than I have ever used JB on. You may need to apply a couple of lock and stich pins as Dave mentions in post number 13. Brazing usually makes a mess. Usually the water jacket will be coated in grease from years of greasing the water pump. Brazing is only a bond and gets NO penetration of metals. If the head is real clean, inside and out it can be brazed but the heat will warp the head to the point that it will have to be planed to level. If you attempt to braze the head with a greasy coating on the inside, the grease will rise up through the brass puddle in spots and cause spots that look like fish eyes in paint. The fish eye spots will be little holes in the puddle that Won't fill with brass and besides being ugly will leak. Once a bad dirty braze job with flux starts messing up, it is then mostly junk. JB weld won't hold on top of a brass and flux @$$ up job. Clean cast iron can be brazed without the use of flux if a person knows what they are doing. Brass and flux jobs may be ok for some farmer fixes but paint or fillers will not stick for any length of time. I've never tried silver solder on cast iron, it may work but paint probably won't stick for long.

Re: Crack repair
 

I have repaired a cracked head with JB Weld, crack was between two combustion chambers. Ran it for years, sold it and he ran it for years. I degreased it, V'd it, used the slow cure product, and warmed the head in an oven first. 6 hrs later I filed the JB Weld down to the head surface, 24 hrs later I used a stone to bring it flush, assembled it in 48 hrs.

Re: Crack repair
 

A permanent method we use is the stitch pins rather than taking a chance with silly putty. Our customers want it done right so no JB weld or sealers,welding/brazing just stitch pins.

Re: Crack repair
 

Wow ! You sure do nice work !!
Q...Are you of the 'opinion' that BRAZE will not do (repair/hold) the job ?
Do you use brazing on any repairs ?
What prep/cleaning is done prior to such repairs, I.e.- oil cleaning/heating block what ?

Re: Crack repair
 

Funny

:D

Re: Crack repair
 

Pictures don't lie. Brazing even when done by so called professionals leads to more issues. First photo shows me holding the brazed repair "Done by Navy welder at Virginia base" according to owner well I peeled it off and had to make pieces and now is permanently repaired. The heat from the brazing caused more damage. There's a way to do everything right. Most of the time we see poorly done repairs. We don't need to braze anything on an engine since we can do the metal stitching proficiently.

Metal stitching is done at room temperature ,no need to heat or cool the block. The threaded pins and method used secures the iron and pieces together.

There are different size pins for different jobs even for aluminum.

Don't throw your blocks and heads away because they have a crack or two in them ,they can be repaired.