MTFCA Forum

Dug this late 12 early 13 block out of storage. Heavily pitted on the manifold side near the last three ports (see pictures) Top section looks good with a few minor pits near the back section. Didn’t find any cracks but of course have not had it magna fluxed. I know with $$$ just about anything can be accomplished my question is would this block be a suitable candidate for rebuild or not.
Thanks guys
Mike

A simple answer, yes, very repairable.

"You can fix anything with JB Weld !

If the water jacket pipe plugs will hold water, and the far aft exhaust and intake ports can be made to seal, it will probably run, barring any serious structural flaws.

Many years ago I was astounded when a friend resurrected a '17 that had sat with the head off. He pressed the pistons out of the rust-pitted cylinders and simply put it all back together. I wouldn't do that, and don't know how "well" it ran, but run it did ! It's amazing how tough (and forgiving) a T motor can be.

You have nothing to loose.(I do my best work with nothing to loose) Set the block up in a mill & take some cuts on the manifold side. You need clean surfaces around the outlet holes. The equivalent of a valve seat could be machined into the port holes. Ignore lower pitting. I would do a pressure test first. There may not be enough metal left in the water jackets. By the rear foundry plug, it looks paper thin. Some things cant be saved feasibly.
This block could still be useful back in its previous use as a boat anchor.
If you have to have a 12 block, maybe you can counterfeit one from a pre 19 block.

I have used valve seats to repair exhaust ports, JB does wonders on gasket area's. I have had some cast welded that looked like Frankenstine when they came back but some JB and bondo you can dress the outsides up.

Surprisingly the babbitt still looks good going by the photos. Machine the exhaust/ intake port side a bit and repair the freeze plugs. I was going to say use JB Weld to fill in any pits anywhere else and it will be OK. I don’t know if you’ve mike’d the cylinders but the bores may be better than you think. I wonder if the cylinders are pitted like the rest of the block. Since it’s and early block makes it a good savable candidate.

I’ll bet it will magnaflux OK too.

It looks like the block sat outside for a good while but survived!

That is way better than the B series block I restored for my Chocolate van. The first thing I would do is have it crack tested, paying special close attention to the rear main bearing web. The early blocks are known to crack, starting with the stress riser adjacent to the land on which the main bearing bolt heads register.
Then I'd have the manifold face bronzed up and resurfaced.
Mine copped a set of sleeves back to standard, hardened valve seats to bring those back and a new set of valve guides. Basically, we used the casting and rebuilt the lot. It's done in excess of 30,000 miles now.

Allan from down under.

Here’s a better picture of the cylinder bores.

Interesting, there is no casting date to the right of the water inlet?

havnfun wrote: ↑

Sat Jan 07, 2023 7:27 pm

Interesting, there is no casting date to the right of the water inlet?

No casting date

1912 is a very special year in the model T line of history. It is unique in that I think there were more significant changes made in those twelve months than in any other year's time. There were at least five obviously different touring car bodies, the firewall, a major change to the rear end late in the model year. The engine block had numerous minor changes, mostly in where the serial number and casting dates (IF it had them?) were located. The serial number went from the last of the blocks with the serial number below the valve chamber to wandering around the area near the water inlet. The casting date seemed to be playing tag as the two went around, sometimes ahead of the inlet to behind the inlet, both were above the inlet for about a month or more! The size of the casting date got smaller for awhile, then larger again.
I sometimes joke that the only thing standard on a 1912 block is that nothing is standard!

... .- ...- . / --- ..- .-. / -.-. .-.. ..- -...

Absolutely it can be saved. The older a block is, the more it is worth putting the effort and money into it. A 1912 block is worth a lot of work to save. If the manifold surface is the worst of it, by all means do it. This one looks pretty bad so putting replacement valve seats in the ports as suggested in this thread is the way to go. The cylinders can be sleeved if beyond boring to a reasonable oversize. Valve and tappet guides can be reamed oversize or sleeved like the cylinders. Cracks can be repaired. It all can be done. All it takes is time and/or money. I repaired an engine for a 1911 torpedo runabout that broke a Sure Mike crankshaft. Ripped the rear main bearing web out of the block. This block and its number were original to the car so it had to be repaired. I sent it to Lock N Stitch in Turlock Ca. and they did a magnificent job of furnace welding the busted parts back in. The car is back on the road with a Scat crank. Another job I did was on a 1910 engine. Catastrophic failure nearly sawed the open valve block in two. The same miracle workers at Lock N Stitch pieced that block back together with some donor pieces and it is truly a work of art. It was a shame to paint it with cast iron grey paint and hide their work. Not only was it structurally sound but you could barely tell where the breakage was. So yes it can be saved. I would certainly do it.

Attached is a picture of block with casting date

Eric, what you describe in the crankshaft breaking and ripping out the rear main bearing web is typical of the results of the web cracking from the main bolt land at the back of the block. I know of a number of cases where the cracked back web let go and has taken the crank shaft with it. Hence my recommendation that the block be crack tested, with particular attention to the rear web.

Allan from down under.

Wayne, you can add this difference to your list. The Detroit built B series blocks have the casting date sandwiched between the top of the engine number boss at the water outlet and the top deck of the block. Mine was so rusted it was unreadable, but the transmission shaft was stamped 9/26/12.

Allan from down under.

Mike, What's the serial number on your block? I'm betting mine is very close to yours being no casing date and where your serial number is located. YES, I bet this block can be rebuilt with in a reasonable amount of money. It certainly would depend on the cylinders condition. The head surface looks really decent. Maybe a light media blast and a very low pressure coolant test. Before you invest a lot of money I'd want to know if the cylinders can be cleaned up to a reasonable over size. Yes, closely inspect that 3rd main area with the single support. That's a dead give away of a '12 block. When my crank broke it suffered a crack in the back wall which I repaired and has held up very well! Of course you may want to do some "body work" on all those pot holes unless you would like to keep them for show and tell! Certainly a good candidate for a good coat of Glyptal maybe even inside AND out to prevent any seepage through the casting porosity.

Good Luck and let us know what you decide and how it turns out. PS if you do decide to replace it I have a spare '12 block..

For those wanting to know the bore measurements of the cylinder holes:
#1- 97.62mm
#2- 97 mm
#3- 96.71 mm
#4- 97.20 mm

... .- ...- . / --- ..- .-. / -.-. .-.. ..- -...

METRIC!!!!!!!!.
If my conversion is correct, #1 is 3.843 INCHES. Thats .090 over bored. Needs sleeving.

If I’m measuring/doing it correctly…

I'd be concerned about remaining wall thickness in that block, besides everthing else mentioned.
Isn't there a method of testing castings for minimum wall thickness? The radical overbore combined with water jacket corrosion and normal casting irregularities might condemn the block. As for the exterior corrosion, heating the block in a furnace and spray welding cast iron to the affected areas, then remachining, would take care of that. The block would probably need full remachining after such treatment. The expense would be considerable, and the results might not be fully satisfactory. I'd look for a better block, and keep this one for possible rehabilitation in the future. There are a few people left who can do amazing work repairing old castings. There are many more who only think they can.

The questions really are:

• How much money do you want to sink into this thing before a fatal or near-fatal problem erupts?

• when it does, how much extra are you willing to invest to "protect" the $$ spent thus far?

• at what $ value are you prepared to simply quit?

It's one thing to have the shop and ability to bring this thing back yourself if you like a challenge and your time means little to you, and quite another to send it out and foot the bill for a ton of work which only restores the block and doesn't even begin to create an engine out of it.

While 1912 blocks are not common, I have to believe that $3K and a year of looking will produce a good core, while you could easily spend $3K and a year getting this thing back to "just rebuildable" (and it will always be inferior to a solid block).

those pictures are depressing...good luck which ever way you go with it.

If the bores are tapered or out of round, which is very likely, it will require further boring to do a proper sleeve job. If the block has been rebored with the type of portable boring machine that has to be moved from one cylinder to the next, it's possible that the bore centers are no longer regularly spaced, which would further complicate sleeving.

Portable boring bars have centering paws, if a bore has been machined off center it would be because the operator has no glue on how to use it.

Some operators have no glue at all.

Scott is right on the money with his advice!! Except, I've seen a number of '12 blocks for less than 3K and way less than a year looking.
There is a lot of risk trying to salvage this one and from how you measured the cylinder bores makes me believe you'd need a lot of $$$$$ help getting this ready to rebuild.