B block cracks

[glenn in camino]

My model B engine has cracks under the valve seats. Is there a permanent fix for this or do I now have a big boat anchor?

[fordcragar]

I just had a couple of them welded up on a block that I have.

[hardtimes]

Originally Posted by glenn in camino

My model B engine has cracks under the valve seats. Is there a permanent fix for this or do I now have a big boat anchor?

Hey Glenn,
I've been told that the best fix that exists for cracks in A/B blocks...is pinning !
There is a member here who has shown/demonstrated great pictures of his skill at pinning customers blocks that are cracked. He is Herm.
There is THE company that makes the pinning equipment and also does this type work. That company is in Turlock , Ca. Nobody does it better than the inventor/innovator of stitch n lock. I think that that is their name.

[fordcragar]

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

[johnneilson]

Glenn,

A little more information is needed here, typical B motors have seats only in the ex ports.

Did you have this block fitted with seats recently?

The reason I ask is that the A and B blocks do not respond well to standard automotive seats.

I have had rust through in the port walls below the seats and fixing sometimes requires a lot of welding or brazing.

Tell us more of the story, there must be one here.

John

[Jim Brierley]

Sponsored Links (Register now to hide all advertisements)

Only diamond blocks had factory hard seats, A & B.

[zzlegend]

John and Jim are the only two guys I would trust with their knowledge on A and B blocks. Both of them know their s---,,,,,,,,,,,I mean stuff.

[updraught]

Interesting web site that

How thick is the metal under the valve seats?

"... Metal stitching has a lot to do with the thickness and shape of the casting where the crack or damage is. The minimum thickness is 3/16” or 4mm."

http://www.locknstitch.com/files/can...-it-myself.pdf

[old victoria]

apm machine in morgan hill repairs and pins all our blocks, never a come back.

[J and M Machine]

Originally Posted by glenn in camino

My model B engine has cracks under the valve seats. Is there a permanent fix for this or do I now have a big boat anchor?

Yes there is a permanent repair as seen in photos I have enclosed.
It's called metal stitching as others have mentioned.

I wouldn't recommend welding the block unless you are skilled and know exactly what you're doing. The metal stitching is stress free and causes no hard spots as welding does.
Especially on a Model B block where the deck thickness is questionable.

http://www.jandm-machine.com/metalStitching.html

[Benson]

Since B blocks have thin areas in upper deck this is another reason to torque head nuts to only 55 lbs.

It is not necessary to torque head nuts to 65 lbs ... it only increases the possibility of cracking the block or distorting the upper deck.

Just look closely to be sure that the threads on the studs are not damaged by someone using vise grips or a pipe wrench to remove/install the studs.

In the last 55 years I have used heads from 5.2 to 8.25 compression using standard studs and torquing to 55 lbs. No leaks or weeping antifreeze ...

[updraught]

So the secret ... to the pins .... is in the thread which are like teeth to grip the surrounding metal when tightened

[hardtimes]

Originally Posted by updraught

So the secret ... to the pins .... is in the thread which are like teeth to grip the surrounding metal when tightened

As I understand it, their system was developed with the (patented) idea of actually trying to 'pull' the metal back together...with their threading system as you mention , locking the metal together.
J&M Machine is the company/engine builder that I could not pull from memory in my previous post(#3), although Herm does great work also.
You can purchase Lock n Stitch products directly from them and do such work themselves. They are very helpful when contacted.