New Block

[Eric Jensen]

Started restoration on a 29 truck. The block has two cracks valve to cylinder - I’ve found a replacement used block. I’d like to move parts over to the new block. What should I be concerned with?

93387C0A-1C0F-479B-A1E1-3E8D9EEE046B.jpg

[nkaminar]

Make sure that the parts you move over are in very good condition, otherwise you will be building in problems. Best to use new parts if you can.

[David R.]

Take your replacement block to a reputable machine shop RECOMMENDED BY VETERAN MODEL A OWNERS in your area. Have them clean and magnaflux the block before you do anything. They can tell you what it will need. I have learned the hard way, not every machine shop is created equal. It’s been two years since I pulled the engine from my truck and still don’t have a buildable block yet.

[jerrytocci]

stich the deck and sleeve the cylinder

[mercman from oz]

Larger picture of the cracked Model A Block owned by Eric Jensen.

[nkaminar]

Sponsored Links (Register now to hide all advertisements)

Adding to what Jerry said: You can have the machine shop add hardened valve seats too.

[Eric Jensen]

Here is another picture of the two cracks (valve to cylinder). Fix?


Thank you!


cracks.jpg

[rotorwrench]

If it's a bare block, inspect the old crank and see if it has main journal sizes that will work with the replacement block. This stuff has to have good clearances to work otherwise it will need the block babbitt reworked.

[Bob Bidonde]

The odds that the salvageable parts from the cracked motor will be the same sizes of the replacement block are significantly against you. For examples: Main bearing diameter; Piston fit to cylinder bore; Valve seat sizes.

[nkaminar]

Here is one method of crack repair, there are others. https://www.youtube.com/watch?v=Pq0wfU4ZaKk

Search for "block crack repair." Consult with your machine shop.

[daren007]

Blocks are everywhere, keep looking. It should not be hard to find a repairable without cracks but you will be doing a complete rebuild from there.

[J and M Machine]

Originally Posted by Eric Jensen

Here is another picture of the two cracks (valve to cylinder). Fix?


Thank you!


Attachment 479816

Yes that block can be fixed. This is a common area of cracking from exhaust seats to cylinders. The cracks would need to be repaired with new seats installed and cylinder would need to be sleeved.
https://www.facebook.com/pg/J-and-M-...71238802989695

[katy]

This is a common area of cracking from exhaust seats to cylinders.

What causes that cracking?

[ronn]

What causes that cracking?



my guess is heat and poor metallurgy during that time.


why the burtz new engine block will be superior.............

[J and M Machine]

Originally Posted by ronn

What causes that cracking?



my guess is heat and poor metallurgy during that time.


why the burtz new engine block will be superior.............

The cracking is caused by overheating the engine as the two center exhaust seats are the hottest part and has nothing to do with "metallurgy". Do the same to the Burtz block and it will look just like these pictures shown by initial poster.

[ronn]

so metallurgy was as good in 1930 as now?


good to know........

[rotorwrench]

Modern cast iron has a bit more ductility and nodular cast iron has more strength but the old Ford engine blocks did fine unless they froze up in winter or got severely overheated in operation.

[Flathead]

Maybe it could be repaired as has been suggested, but weigh the cost of repair to the cost of another block. If you get the block repaired don't forget that is still a repaired block. Model A's are not scarce exotic things. Just my two cents.