Rebuilding an 80 yr old engine is always a gamble....

[gilitos]

Two rebuilds with a local antique engine rebuilder and the same result: after a few thousand miles the mains cracked and the car started making noise and bleeding oil. Third time I took out the block and sent it out of state for new babbit to a real pro I met here on the Barn, and ended up also paying for sleeving from 0.100" back to standard, performing welded repair of old stitched cracks, and putting in a new crank, all in the interest of not cutting any corners and doing a first class rebuild. Got the engine back and installed, and within a few miles a new crack showed up between the #1 exhaust valve and water jacket. Pulled the motor again to repair. $1.5k later I'm reassembling for the fourth time (this time also put in flowed jets and a large 'B' police head). Car ran incredibly for about 20 miles: smooth, quiet, powerful. Then I turnded it off for 1 hr, started it up, and now it's only hitting on 3 cylinders and making a new mechanical noise from the valve chest. Checked and found zero compression in #1. Blecchh. What the heck? Valve seat? Stuck valve? Gotta take it out and take it apart AGAIN. It's been a year and about $6k since I"ve been able to drive the darn thing.

Okay, now that I've vented, I'll just take a deep breath and dive in again. Who else has had this kind of experience? What do you do to keep going?

[J Franklin]

I would guess the trick would be to have the block thoroughly checked out to see if it is able to be rebuilt before and during any machine work.

[Rowdy]

You seem to be having exceptionally bad luck. With the engine for the rdstr pu I had it magnafluxed and upon cutting the bores for the replacement valve seats 2 cracks appeared. The machinest caught it at that point. It was fixable, but since i ended up selling the whole project piece by piece shortly after that I do not know how good the engine turned out to be. The machinest who caught it was not capable of fixing the cracks with what he had in the shop he worked in. I have since started taking my work to another shop. The turn around time is alot longer, but the workmanship and capability is much better. Rod

[Kohnke Rebabbitting]

Originally Posted by gilitos

Two rebuilds with a local antique engine rebuilder and the same result: after a few thousand miles the mains cracked and the car started making noise and bleeding oil. Third time I took out the block and sent it out of state for new babbit to a real pro I met here on the Barn, and ended up also paying for sleeving from 0.100" back to standard, performing welded repair of old stitched cracks, and putting in a new crank, all in the interest of not cutting any corners and doing a first class rebuild. Got the engine back and installed, and within a few miles a new crack showed up between the #1 exhaust valve and water jacket. Pulled the motor again to repair. $1.5k later I'm reassembling for the fourth time (this time also put in flowed jets and a large 'B' police head). Car ran incredibly for about 20 miles: smooth, quiet, powerful. Then I turnded it off for 1 hr, started it up, and now it's only hitting on 3 cylinders and making a new mechanical noise from the valve chest. Checked and found zero compression in #1. Blecchh. What the heck? Valve seat? Stuck valve? Gotta take it out and take it apart AGAIN. It's been a year and about $6k since I"ve been able to drive the darn thing.

Okay, now that I've vented, I'll just take a deep breath and dive in again. Who else has had this kind of experience? What do you do to keep going?

Pull the plugs, take a oil can with Mystery oil, and a small tube on the oil can and put the oil on the valve, and guides, through the plug holes. That should do the trick.

It is not uncommon to have valves stick when the engine dosn't have many miles on it, and after it sat the oil drained down.

It should be the exhaust Valve that is the offender

If the valve is at its highest point and stays there, turn the engine so the other valve is in the air, and all the force will be on the valve downward by the spring.

Also put some in your gas for one tank full.

[James Rogers]

Along with what Herm said, you might use a stiff wire bent in an L shape to push the offending valve down. That is if it is a stuck valve, it could also be one of those replacement seats that everybody is so intent in installing. I feel like those are just another part to fail.

[1931 flamingo]

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SB Chebby time..............................................
Paul

[Terry, NJ]

This illustrates what I've been contending for years, namely that metals age. These blocks survived 80 years and now they're cracking. Anyone who plays around with antique guns know it's true with old brass cartridge cases and mainsprings. We also see it in old airplanes. I've brought this this up with engineers and they insist that metals don't age, but for some reason, the older a part is, generally the more susceptible it is.
Terry

[Chris in CT]

Gilitos, I'm sorry you've had so much trouble with your "new" old engine. The advice about the valves above is right on. A little Marvel Mystery oil in the gas for the next couple of tanks can be very helpful in preventing sticking valves.

Terry is right one with the "aging" of metal, particularly large castings such as engine blocks. Even assuming that the casting was properly annealed after it was cast, don't forget that repeated cooling and heating of the casting - including freezing temperatures outside - cause the casting to expand and contract with each change in temperature. The thin sections of the casting and thick sections of the casting will expand and contract at different rates inducing internal stresses that could ultimately result in cracks at susceptible points in the casting. There is a point, and you will have to make that decision, where it may be best to simply start with a new engine block. But, for the time being, fix that sticking valve as the fellows have suggested above and see if you have already solved all of your problems. Best of Luck to you...Happy motoring.

[ericr]

I don't know but I'm just asking, if it is wise to put a high-compression head on a newly-rebuilt engine. Also I wondered, without being challenging, if Gilitos drove slowly to put several hundred miles on the new engine...I assume he did.

[Purdy Swoft]

Other than the outrageous prices for most of the rebuilt engines, this type thing is why that I overhaul my own engines. I've been my own model A mechanic for most of my life. In some cases, even if a person knows nothing about engines, they are probably better off doing their own work if the block has useable babbit and no cracks in the valve seats and no resleeved cylinders.

[Rowdy]

I definately agree the gimick harnened seats are not needed. Unfortunately the engine for the rdstr up there was little choice on the exhaust valves as they were worn to the point that after grinding they were about .010 below the deck. Rod

[Napa Skip]

Originally Posted by Terry, NJ

...I've brought this this up with engineers and they insist that metals don't age...

I'm not certain which engineers this was discussed with, but as a registered engineer with some (admittedly limited) foundry, casting and machining experience, I would offer that if "age" equates to thermal cycles, which it usually does, then in fact cast iron, particularly grey cast iron (the type of cast iron most commonly used for cast iron engine blocks) does become more susceptible to cracking with age.

Without going into depth about alloying, casting, machining and annealing practices, or long-winded discussions of the cast iron time-temperature transformation curve, grey cast iron, which generally has carbon, silicone and manganese as its principal alloying ingredients, is a crystalline structure in which - with time and repeated expansion/contraction cycles - the carbon tends to precipitate out of the cast iron and migrate to the inter-crystal boundaries. Usually this is not a problem until or unless the design operating parameters of the component are abused (or the foundry/machining practices were flawed, not - imho - a problem with Ford during the Model A era). But it (carbon precipitation/migration in cast iron) does change the structure and strength of the metal.

Additionally, while cast iron enjoys a reputation for ease of machining, in large part due to it's crystalline structure and carbon content, overly aggressive machining techniques (read "machining techniques that result in localized high temperatures") can exacerbate the problem of crack development. (And, as an aside, this migration of carbon to the inter-crystalline boundaries is what makes it difficult to weld-repair old cast iron.)

[gilitos]

A pinky finger along with a flashlight confirmed that the valve seat has come loose. Here we go!

[ericr]

Originally Posted by Napa Skip

I'm not certain which engineers this was discussed with, but as a registered engineer with some (admittedly limited) foundry, casting and machining experience, I would offer that if "age" equates to thermal cycles, which it usually does, then in fact cast iron, particularly grey cast iron (the type of cast iron most commonly used for cast iron engine blocks) does become more susceptible to cracking with age.

Without going into depth about alloying, casting, machining and annealing practices, or long-winded discussions of the cast iron time-temperature transformation curve, grey cast iron, which generally has carbon, silicone and manganese as its principal alloying ingredients, is a crystalline structure in which - with time and repeated expansion/contraction cycles - the carbon tends to precipitate out of the cast iron and migrate to the inter-crystal boundaries. Usually this is not a problem until or unless the design operating parameters of the component are abused (or the foundry/machining practices were flawed, not - imho - a problem with Ford during the Model A era). But it (carbon precipitation/migration in cast iron) does change the structure and strength of the metal.

Additionally, while cast iron enjoys a reputation for ease of machining, in large part due to it's crystalline structure and carbon content, overly aggressive machining techniques (read "machining techniques that result in localized high temperatures") can exacerbate the problem of crack development. (And, as an aside, this migration of carbon to the inter-crystalline boundaries is what makes it difficult to weld-repair oil cast iron.)

wow, that's a pretty cogent explanation. From what you are saying, though, most all original blocks would suffer from the same malaise....

[Napa Skip]

"...would suffer from the same malaise..."

Aging - yes. Extreme cracking - not unless operationally mistreated, machined improperly or - remote possibility imho - cast/cooled incorrectly.

I think the continued viability of many (most?) Model A engine blocks speaks to their being properly manufactured/machined/used. By "used" I mean operated within their design parameters. I also think the fact that some Model A engine blocks exhibit the problems described by the original poster speaks - in those particular cases - to improper use and/or machining.

But overall, what I most took issue with was that some engineers would state that metals don't age. Insofar as cast iron is concerned, the history of industrial use is long, the empirical - and theoretical - knowledge base wide, and the phenomenon I originally described (inter-granular migration of carbon as a function of thermal cycles) not unknown/undocumented, at least among mechanical engineers of my vintage and training/experience (BS Mechanical Engineering, University of Idaho 1971; MS Mechanical Engineering, University of Idaho 1972, PE California and Idaho).

As an additional point, I do strongly agree with J. Franklin's statement that 80-year old engine blocks ought to be thoroughly checked out (e.g., magnafluxed, dye-penetrant checked, etc.) before investing significant funds in any rebuilding effort. (I will also admit to not having done this and gotten away with it, but that has to be pure luck - combined with, as one of my fellow Naval officers who was an F-8 pilot used to say, a "kick the tires, light the fires and let's get this thing into the air" philosophy.)

Perhaps others with more knowledge will weigh in.

And a happy 4th of July to all.

[Rowdy]

Pressure testing brings out flaws and weak spots also. I will not likely skip this test with most blocks I want to use. Having around 30 extra blocks means I can be that picky. For some they have just the one that came with the car and are hellbent on making it work instead of searching for a better block. Cost with shipping usually works out about the same. But the results are long lasting. Rod

[Terry, NJ]

I didn't say so in my post, but I'm wondering if annealing or "Normalizing" the blocks prior to rebuilding would help to alleviate the stresses in the metal. I also believe that very few of the cracks are due to freezing. Or blocks would never crack in Fla.
Terry

Originally Posted by Chris in CT

Gilitos, I'm sorry you've had so much trouble with your "new" old engine. The advice about the valves above is right on. A little Marvel Mystery oil in the gas for the next couple of tanks can be very helpful in preventing sticking valves.

Terry is right one with the "aging" of metal, particularly large castings such as engine blocks. Even assuming that the casting was properly annealed after it was cast, don't forget that repeated cooling and heating of the casting - including freezing temperatures outside - cause the casting to expand and contract with each change in temperature. The thin sections of the casting and thick sections of the casting will expand and contract at different rates inducing internal stresses that could ultimately result in cracks at susceptible points in the casting. There is a point, and you will have to make that decision, where it may be best to simply start with a new engine block. But, for the time being, fix that sticking valve as the fellows have suggested above and see if you have already solved all of your problems. Best of Luck to you...Happy motoring.

[George Miller]

Originally Posted by gilitos

A pinky finger along with a flashlight confirmed that the valve seat has come loose. Here we go!

Some people do not understand how to put valve seats in. They have to be a press fit, sealed, and rolled around the edge. If they are done right they will not come out. This comes from a guy that has been putting in inserts since the 50t's. But I have fixed a few that other people have put in.

You do not need seats in the Model A engine unless there was a crack or they are in the block to far.

Kind of like your Babbitt problem, they can not seem to get that right.

[Pete]

"As an additional point, I do strongly agree with J. Franklin's statement that 80-year old engine blocks ought to be thoroughly checked out (e.g., magnafluxed, dye-penetrant checked, etc.) before investing significant funds in any rebuilding effort."

I would add another essential check that I do and that is sonic checking all areas that might be susceptible to rust erosion such as water jacket areas.
I also pressure check as Rowdy said.

On the "normalizing", that would help but it has one big drawback in that unless it is done in an inert gas furnace, you will have to remachine ALL of the machined surfaces in the block. This is normally not practical unless you are working on the last existing example of a Runzony Downhill or Gadzooky Speedster engine.

[Terry, NJ]

Two engneers! I'm sure that they must have meant on a molecular level. The molecules don't age but the lattice work structure changes as the carbon migrates (?) No, I was not thinking of thermal cycles, just the passage of time. However, the effect would be accelerated with heating and cooling, I think. The swelling and contracting must have a terrible effect on these castings. Now I'm thinking like Chas. Lindbergh when he tried to calculate the the effect of millions of explosions on the metal of the engine of the Spirit of Saint Louis. He scared himself so badly he had to stop thinking about it. So the answer is you can have an old car, but don't run it! I've been pondering this question for years. Why is a part durable and dependable when it's new, but as it ages it becomes more prone to breakage. As of now, the only way to forestall it is by annealing or normalising the casting.
Terry

Originally Posted by Napa Skip

I'm not certain which engineers this was discussed with, but as a registered engineer with some (admittedly limited) foundry, casting and machining experience, I would offer that if "age" equates to thermal cycles, which it usually does, then in fact cast iron, particularly grey cast iron (the type of cast iron most commonly used for cast iron engine blocks) does become more susceptible to cracking with age.

Without going into depth about alloying, casting, machining and annealing practices, or long-winded discussions of the cast iron time-temperature transformation curve, grey cast iron, which generally has carbon, silicone and manganese as its principal alloying ingredients, is a crystalline structure in which - with time and repeated expansion/contraction cycles - the carbon tends to precipitate out of the cast iron and migrate to the inter-crystal boundaries. Usually this is not a problem until or unless the design operating parameters of the component are abused (or the foundry/machining practices were flawed, not - imho - a problem with Ford during the Model A era). But it (carbon precipitation/migration in cast iron) does change the structure and strength of the metal.

Additionally, while cast iron enjoys a reputation for ease of machining, in large part due to it's crystalline structure and carbon content, overly aggressive machining techniques (read "machining techniques that result in localized high temperatures") can exacerbate the problem of crack development. (And, as an aside, this migration of carbon to the inter-crystalline boundaries is what makes it difficult to weld-repair old cast iron.)