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07-03-2013, 10:52 PM | #1 |
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Rebuilding an 80 yr old engine is always a gamble....
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? |
07-04-2013, 12:14 AM | #2 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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.
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07-04-2013, 12:42 AM | #3 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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
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07-04-2013, 12:43 AM | #4 | |
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Re: Rebuilding an 80 yr old engine is always a gamble....
Quote:
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. |
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07-04-2013, 05:36 AM | #5 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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.
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07-04-2013, 07:11 AM | #6 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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07-04-2013, 07:18 AM | #7 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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.
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07-04-2013, 07:55 AM | #8 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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. |
07-04-2013, 08:13 AM | #9 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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.
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07-04-2013, 09:16 AM | #10 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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.
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07-04-2013, 09:20 AM | #11 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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
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07-04-2013, 09:35 AM | #12 | |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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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.)
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07-04-2013, 10:16 AM | #13 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
A pinky finger along with a flashlight confirmed that the valve seat has come loose. Here we go!
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07-04-2013, 10:20 AM | #14 | |
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Re: Rebuilding an 80 yr old engine is always a gamble....
Quote:
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07-04-2013, 10:46 AM | #15 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
"...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.
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07-04-2013, 11:37 AM | #16 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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
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07-04-2013, 11:58 AM | #17 | |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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 Quote:
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07-04-2013, 12:51 PM | #18 | |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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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. |
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07-04-2013, 02:44 PM | #19 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
"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. |
07-04-2013, 02:44 PM | #20 | |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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 Quote:
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07-04-2013, 03:32 PM | #21 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
[QUOTE=gilitos;682343]A pinky finger along with a flashlight confirmed that the valve seat has come loose. Here we go![/quote)
I suspected as much.
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07-04-2013, 03:36 PM | #22 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
Here's the scene with the head removed (isn't it great how quick these come apart?). The machinist who stitched the crack between the seat & water jacket said it was a good interference fit when he re-inserted it, but obviously something was lacking. The $64 question: how do I re-insert it so that it stays? George Miller, I'm paying close attention to your post. Can you detail a bit more the rolling process?
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07-04-2013, 03:48 PM | #23 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
I've seen the same thing happen to a few Model A engines with inserts. I also do not recommend inserts, unless the valve is sunk too low or the block is cracked in that area.
I used to install inserts at a shop I worked at in S.D. You need to grind a small bevel around the top outer edge of the ring. Then use a locktite product on the ring and drive it into place. Use a small somewhat dull chisel to peen all around the ring to roll the metal over the bevel. |
07-04-2013, 04:06 PM | #24 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
Tom, your method sounds great. I'm going to try it. Just going to hope that the other undisturbed inserts behave themselves and stay put. Do you have a specific Loctite product in mind? I assume it has to withstand high temperatures.
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07-04-2013, 04:07 PM | #25 | |
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Re: Rebuilding an 80 yr old engine is always a gamble....
Quote:
Tom has it right. With my machine I have a tool that goes in place of the cutting tool. It has a radius ground on it. It rolls the metal in on top of bevel. The inserts I use all ready have the bevel on them. If you do not have a tool, the way Tom said works fine also. If the bore for the insert is to big, you can buy over size inserts. |
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07-04-2013, 04:09 PM | #26 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
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07-04-2013, 04:20 PM | #27 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
Do all the valves have inserts?? As long as head is off and in doubt I would peen/roll the others unless like James says, it's fruitless. Sorry for your situation.
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07-04-2013, 05:36 PM | #28 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
The only reason the seat came out, is it started with the crack. After the crack developed that took the original interference fit from the seat and block, when it opened up.
Then the seat was removed, and when put back, no matter if it had interference, it didn't have the same interference as when originaly installed. It should have had an over size seat, or take the over size seat O.D. down in a lathe grinder to the original O.D., plus what was now gone for size difference, if the hole was still true With out the original fit, it is guess work that the seat will stay in, just as before with the original fit. |
07-04-2013, 05:38 PM | #29 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
Do all the valves have inserts?? As long as head is off and in doubt I would peen/roll the others unless like James says, it's fruitless. Sorry for your situation.
Paul in CT (END QUOTE) It wasn't the seat that made it fail Paul, it was the crack. |
07-04-2013, 06:21 PM | #30 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
I think Herm is right. When the crack was repaired, the insert fit should have been more carefully revisited. I'll post a follow up with the result.
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07-04-2013, 06:22 PM | #31 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
With the crack it was destined to fail and will continue to.
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07-04-2013, 07:05 PM | #32 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
I have never seen it that way James, and I know it just wasn't luck, as you always make your own luck.
I have put in hard seats since I was 19, with a K.O.Lee. Then when the newer seat machines came out, about 35 years ago, I have had Vern do it. Probably at least 400 just Model A blocks, not counting Model T, and Model B blocks, and they were not all assembled by us, as they were shipped in from all over. Many a time there were 25 blocks setting in line at the align bore. That is when I had 5 employees here. But what I am getting at, we have never had a seat come loose. All the modern engines I see into Verns, and that is a lot, all the heads have Hard seats, weather they are cars, or tractors. It all depends if they were installed right, or some thing in this case it came out after it was taken out, and installed again, not the seats fault We know that seats come out, sleeves come out, valve guides come out, Valve liners come out, but there is always a reason, and it useally human error. |
07-04-2013, 11:55 PM | #33 |
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Re: Rebuilding an 80 yr old engine is always a gamble....
I looked back at the original crack ---my thoughts on a repair then was that the water passage needed to have a piece of metal made to fill it to give the area around the seat support to allow an interference fit ---after the piece was pinned in place water passage holes would be drilled in it ---it could still be fixed that way--
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