My 427 Block cracked by the machinist. Opinions welcome.

[Joseph W.]

IMG_1840.jpgIMG_1839.jpgIMG_1838.jpgIMG_1836.jpgIMG_1836.jpg

[Joseph W.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

IMG_1837.jpgIMG_1837.jpg

[Joe L.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

[ATTACH=CONFIG]120874[/ATTACH][ATTACH=CONFIG]120874[/ATTACH]

Joseph------

I'm not surprised that this occurred as a result of trying to get these plugs out. These plugs can be virtually impossible to remove without block damage. I think the only alternative to this damage would have been to leave the plugs in place and do the best one could to clean the block with them in place.

I don't think it will be possible to effectively repair this by an overbore and re-threading for a larger pipe plug (such as the one you have pictured). That's because to repair it that way you'd have to completely eliminate the boss.

I would opine that the best way to repair this would be by brazing and with the creation of a significantly thick brazed area as reinforcement. Brazing will be adequately strong since this is not a high stress area.

[Joseph W.]

[Owen L.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

When I dropped off the block, he said he would have to remove those plugs and I did inquire about just leaving them in place.
The machinist said there could be metal particles from the block being blasted during the cleaning process. He said they do it all the time.

What is his suggestion for repairing it?

[Domenic T.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

The way to remove ALL plugs is to get a torch, NOT propane and heat them red hot then use wax, a large candle will work. then apply the wax around the plug expecting a small fire and they come right out. Tip is to heat surrounding area lightly.

Dom

[Justin S.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Joe and Joseph,
Most brazing rods require a lot of heat. Do you see any problems with that with the already formed cracks?
I'm curious if a tig weld would be better?

[Joe L.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Thank you for the advice Joe.
What about grinding/milling down and then tap and use a NPT fitting making sure not to block the cam oil holes?
Isnt the block fairly thick at this part?
I’m just sick about this. When I dropped off the block, he said he would have to remove those plugs and I did inquire about just leaving them in place.
The machinist said there could be metal particles from the block being blasted during the cleaning process. He said they do it all the time.

Joseph------


I would not attempt what you suggest. My expectation is that the bosses are there because the block is not otherwise thick enough in that location to support a NPT tapping. So, if you effectively remove the bosses to install a larger NPT plug, I think you'll risk destroying the block. Not worth the risk in my mind.

I would do this: first, drill very small holes at the very outer ends of the cracks. This will ensure that the cracks cannot propagate. Then, fill the hole with braze, build up braze along the crack line and a 1/4" thick braze along the outer edge of the repair. Then, determine if stock size NPT plugs will properly thread and tighten in the existing holes. If not, install NPT Heli-Coils for the original thread size. Finally, install original size plugs with a good sealer. Done.

An alternative if you don't want to use brazing (which, as I mentioned, would be my first choice): do exactly as I described above but use JB Weld instead of brazing. This will produce a cold repair that I believe will be more than adequate and permanent. JB Weld will produce 5,000 PSI strength and will be good to 550 degrees F----far stronger than required for this repair and far hotter than the block will ever get in this area.

[David P.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Try Lock-N-Stitch in Turlock, CA. Absolutely best place if you want the repair done right.

http://www.locknstitch.com/index.html

[Joseph W.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Thanks David
I had a mechanic friend recommend them.
Pretty impressive place. If they can’t fix it most likely no one can.
Any idea what they typically charge? Anyone on here ever have them repair a block?

[David H.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Joseph

I've seen Lock-N-Stitch used to repair a cracked block at McPherson College, Kansas Automobile Restoration program (Summer Institute). They use Lock-N-Stitch for repair of one-of-a-kind and not available anywhere engines. Worked well and finished repair was externally not obvious. Link below to a youtube demonstration. Materials are available, so DIY is possible. I'd want to practice some (on someone else's block) before working on my own. Experienced machine shop would be my choice.

Dave

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwirgvvh07eEAxVMkWoFHfrVDUYQwqsBegQIEhAG&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DPq0wfU4ZaKk&usg=AOvVaw14XpP6sJKbosyhNP64DEwa&opi=89978449

[Joe L.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Thanks David
I had a mechanic friend recommend them.
Pretty impressive place. If they can’t fix it most likely no one can.
Any idea what they typically charge? Anyone on here ever have them repair a block?

Joseph------

I'm quite familiar with the "stitch" type of cast iron repair. In fact, I once had a block repaired using this type of repair. However, I do not think that the type of damage you have is amenable to this type of repair. I don't know, for sure, but I don't think so. However, it is likely repairable using other repair technologies available through the company referenced above. I would suspect that brazing as I have described would be one of them.

My suggestion would be to forward the photos you have posted here to "Lock-and-Stitch" and get their opinion on the repair methodology they would use and a quote on the cost for repair. Keep in mind that if you are not close enough to Turlock to deliver it and pick it up yourself, the cost of shipping both ways will likely exceed the cost of repair.

[Joseph W.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Thanks guys
Im so deep into this restoration, money and time, I have no problem driving it 5 hours to Turlock to have it repaired.
Tom at Classic Engines was very kind and generous with an offer to repair at minimal cost if I would just ship it to him.
In my mind, Lock and Stitch in Turlock CA is my best bet.
If brazing is the best remedy, Lock and Stitch has the ability to heat the block and braze it.

[Joseph W.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Update:
Spoke to Lock and Stitch after sending pictures to them.
NO problem to repair. They will also remove the last plug and check the block for any other cracks and repair if needed.
I'm going to try and make the 5 hour drive this week to deliver it.
I'll make sure to post pictures after the repair and let folks on here know the cost.

Thanks for all the help

[Leif A.]

Re: My 427 Block cracked by the machinist. Opinions welcome.

Update:
Spoke to Lock and Stitch after sending pictures to them.
NO problem to repair. They will also remove the last plug and check the block for any other cracks and repair if needed.
I'm going to try and make the 5 hour drive this week to deliver it.
I'll make sure to post pictures after the repair and let folks on here know the cost.

Thanks for all the help

Joseph,
All the best with the repair and saving that very valuable block/engine!!