Trust, but verify -- Crankshaft in a "rebuilt" engine.

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Model T Ford Forum: Forum 2017: Trust, but verify -- Crankshaft in a "rebuilt" engine.
Top of pagePrevious messageNext messageBottom of page Link to this message  By Walter Higgins on Friday, December 01, 2017 - 10:30 am:

Some years ago I purchased an engine that was advertised as "rebuilt" along with a pile of parts. It was cheap enough that I didn't figure every "i" was dotted and "t" crossed. It turned over and everything was clean. Upon tear-down for inspection I found two places where the crankshaft was TIG welded and one throw had a lot of material taken off with an angle grinder, I assume an attempt to balance it.

At any rate, I just wanted to share. At the very least, pull the pan and have a look if you don't know that your rebuild is from a reputable builder. Running this one the way it was surely would have resulted in an expensive bang further down the road.




Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Friday, December 01, 2017 - 10:36 am:

Glad you found it before you tried to run it!

"It's just a little crack, I'll TIG weld it"

:-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Friday, December 01, 2017 - 10:51 am:

Bad news... But think about this: Someone must have magnafluxed this crank, found a defect, attempted to repair it, and left a very visible repair. How many cranks are in rebuilt engines that look good, but have never been crack checked? How many cranks do get crack checked by someone who really doesn’t know what they are doing, or are using poor quality supplies that don’t always show every defect? As sad as it might sound, the crank in your picture could have better longevity than a “good looking” crank in the average rebuild.

(Message edited by Adam on December 01, 2017)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bruce Compton on Friday, December 01, 2017 - 11:09 am:

The timing on this post is weird as I'm going through the same situation with cracked cranks. I had seven excellent looking slightly worn (0.002-3 wear) and had them all magnafluxed to find four cracked. Naturally three of the four were the nicest. With all the experience out there, is there any SAFE way to save these by welding or are they all scrap?? Bruce


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steven Meixner on Friday, December 01, 2017 - 11:39 am:

Look at the nasty undercuts in the weld and looks like they used SS rod. NOT very professional.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James J. Lyons III - West Virginia on Friday, December 01, 2017 - 11:45 am:

You have to wonder if they magnafluxed it after the weld job. I would think so (although it's a reckless assumption) Still, if they did magnaflux it and found no cracks, how do we know it wouldn't perform well? Especially if it was driven like a Model T is supposed to be driven?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Whelihan Danbury, WI on Friday, December 01, 2017 - 12:16 pm:

Unfortunately, its a more common occurrence than not in lots of things. Whenever I purchase an item advertised as "rebuilt" or " completely refurbished", I ask for the receipts. And it had better be a reputable, well-known place who did the work too. If they don't exist, it didn't happen in my eyes. For everything I've put into my cars in have receipts and pictures to back up my claims. Not planning on selling any time soon. But the day I have to, I want prospective buyers to know what they are looking at.


Top of pagePrevious messageNext messageBottom of page Link to this message  By J and M Machine Co Inc on Friday, December 01, 2017 - 12:20 pm:

A cracked crankshaft is like a piece of glass once it's cracked it isn't repairable.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan B on Friday, December 01, 2017 - 12:30 pm:

Yes...but is it useable?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, December 01, 2017 - 12:37 pm:

There are cracks and then there are some with folds from the forging process. Both can show up as cracks. Guess both are stress areas and can break. ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting, Clare, Iowa on Friday, December 01, 2017 - 12:51 pm:

A cracked crankshaft is like a piece of glass once it's cracked it isn't repairable. ' END QUOTE "

" Agree "

Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeff Hood -Long Beach, California on Friday, December 01, 2017 - 01:07 pm:

I bought a "rebuilt" V8 engine once that was clean and freshly painted. I could see all new gaskets, and looking through the sparkplug holes, the tops of the pistons were clean and shiny. It looked like a fresh rebuild. Well they had only pulled the heads and cleaned the pistons! We put it in the truck and it was a gutless mosquito fogger! When we tore it down, the camshaft lobes were nearly round, the hydraulic lifters were all dished and some were even worn through the bottom, and all of the bearings were worn out. Lesson learned the hard way.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James J. Lyons III - West Virginia on Friday, December 01, 2017 - 01:16 pm:

Sorry boys... As an optical engineer working with all kids of optical glasses, I can tell you for certain that your "glass isn't repairable" theory is 100% incorrect. I would argue the same is true with cracked crankshafts. It's just a matter of the right person with the right technology, interested enough to sort it out.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Friday, December 01, 2017 - 02:16 pm:

Well if tiging it is not the correct way to fix that crack,what would be a better way? I would have thought that would be the best method of repair for that situation.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting, Clare, Iowa on Friday, December 01, 2017 - 02:56 pm:

The problem as I know it to be is you can fix a crack on the out side, as per the pictures.

The problem is you may, or may not have fixed where the crack shows, but by that time the crack is cracked to show, and then by then it is deep where you can't reach with weld, and the way a T crank twists, especially after being welded on, that changes everything. So what happens is you wait for the crack to come out the other side,and you just can't stop that process.

You see one broken crank, and you have seen them all, as they all look the same after they break because many break in the same spots, for the same reasons.

If some of the crank club will show there pictures, you can see half way through cracks, and then break.

A large percentage of Ford crank breakage was caused by Ford, themselves, in later years, especially!

Herm.

Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Friday, December 01, 2017 - 03:32 pm:

Out of curiosity are 1926 and '27 demonstrably better cranks?
I've read they are but I'd like some real world proof.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting, Clare, Iowa on Friday, December 01, 2017 - 04:47 pm:

Haven't seen any difference in the old style, or in the EE cranks, for cracking.

I went through about 135 T cranks at Mel Axlanders a few years ago, the ones that would grind out was an even 25. After crack checking at home, I ended up with 6 late style cranks.

Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting, Clare, Iowa on Friday, December 01, 2017 - 05:02 pm:

I for one, sure don't know Craig.


Top of pagePrevious messageNext messageBottom of page Link to this message  By joe bell on Friday, December 01, 2017 - 05:15 pm:

I did some checking on the crank issue, we have a spectromiter?? do not know if the spelling is right. The DB cranks where the hardest but with that they did not flex enough for the T engines, all of them I checked had different metallurgy in them the EE was a softer crank that is why the rear main is always undersized the next down from an EE was an AA then there is C, U, F and DE what was Canadian, the EE formula started in the 23-4 Canadian first then to the 25 usa cranks. The EE formula went into the Model A years also, was it better?? All I know is I run the snot out of my Fordor and it has not broke yet? The boy's I run with all have the EE''s in theirs also and we have all had tons of miles on them? so for a stock crank I will run them, just my thoughts on it! Oh by the way there is no way in H--l I would run a welded crank! Joe


Top of pagePrevious messageNext messageBottom of page Link to this message  By Val Soupios on Friday, December 01, 2017 - 05:26 pm:

I would never use that crank since there are so many other options but I do think a repair can be made that will render a crank serviceable. The crank in my Locomobile broke right behind the rear main. I had it welded, x-rayed and put it back in the car. Never had a problem with it and that weld is supporting a very heavy flywheel.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Saturday, December 02, 2017 - 04:35 am:

There have been several six cylinder model T's built over the years by cutting crankshafts in five or six pieces, then welding together. Takes considerable talent, but is obviously possible.

ghj


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Saturday, December 02, 2017 - 06:34 am:

I remember back in the '50's-'60's there were many "stroker" cranks made by welding up the throws and regrinding them. Many of the "Hot Rod" magazines had articles about how they were done. I always wondered how well they lasted, never read anything negative about them. Even back then, I didn't know much about welding, but had been around it some. That always seemed iffy at best. Anyone ever heard anything about them back then? Just curious. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By James J. Lyons III - West Virginia on Saturday, December 02, 2017 - 07:30 am:

David and Roger....
Both of you fella's are proving my point from earlier. Each situation you both mention require SERIOUS modifications to a crankshaft that is going to be used in an environment that is MUCH MORE HARSH than the Model T engine was intended.

Therefore, I maintain that properly done, a cracked crankshaft CAN be repaired and successfully used in engines that are being operated WITHIN the requirement parameters that the Model T was originally intended.

Truthfully, I think this would be a valuable venture for someone skilled in the art. There will come a point when the availability of "good" crankshafts becomes very scarce. And when you consider that there are those among us in our club that don't have $1300 for a Scat crank, paying $750 for a properly repaired stock unit becomes attractive.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Walter Higgins on Saturday, December 02, 2017 - 09:13 am:

You are now talking about two entirely different things. Piecing a crankshaft together (or welding up journals) vs. repairing something that has failed due to cyclic fatigue. Not to mention that the six cylinder is an odd experiment. We don't know what the builders expectations were. Generally, our expectation is that our crankshafts last the life of our rebuilt engines.

To section a crank you have to start at the root and work your way out to get 100% penetration and is extremely time consuming, but you are deciding where that joint is placed, how it's constructed, etc. We see our cranks typically fail a specific locations of high stress. My guess is the maker of that six cylinder crank intentionally placed his joints at other places.

When you're talking about welding a fatigue crack, that is a completely different animal because you are now working on an area where the structure has changed. The steel you are dealing with is not the same as the day it came out of the forge. That is why on some things you see something that has been welded and then it cracks next to the weld. There are more issues at hand than simply sticking it back together.

If the economics were there, welding up cracked cranks would be a thing. This is not a problem exclusive to Model T's. Nobody should assume that a weld repair costs less than new in every instance.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Warren on Saturday, December 02, 2017 - 09:28 am:

Back in 19 and 85 we had a perkins diesel engine in a roller that had a rod bearing failure . I sent the crank to the machine shop to be re ground. After magnafluxing it was sent back cracked. We needed the machine real bad and a crank wasn't available for a month. I had the machine shop show me where it was broken, I ground the crack out, probably in excess of one inch, and welded it up with an arc welder (on the back of my service truck) using 7018 rod. I peened it between passes and then peened it straight, took it back to the machine shop. They re magnafluxed it and said it looked great. It was re ground and I installed it. We sold the roller 10 years later (still running) with another 10,000 hours on it. So it is possible to weld a crank successfully.
On another note, I have also welded up an aluminum piston still in an engine successfully. So I think it is has a lot to do with not being afraid to try.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Saturday, December 02, 2017 - 11:15 am:

Everything is repairable. Its just a matter of how much you are willing to spend and how much of a chance you are willing to take on how long it lasts!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Saturday, December 02, 2017 - 11:24 am:

1300 bucks for a crankshaft,that makes repair a viable option for those that are able.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James J. Lyons III - West Virginia on Saturday, December 02, 2017 - 03:07 pm:

John Warren hit the nail on the head...

"..not being afraid to try"

My 34 years at NASA has taught me that anything can be accomplished if you set your mind to it and move forward with thought and planning.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Walter Higgins on Saturday, December 02, 2017 - 04:38 pm:

There is a big difference between "not being afraid to try" and "not being afraid to accept liability". Most people in this world are in an employee type situation where if it blows up, "Oh well, my {insert employer here} boss, non-profit, the government, will pay to rectify it."

Everything is a calculated risk, have at it, just be ready to pay for it out of your own pocket if it fails catastrophically and then be ready to reinvest and try again until you figure it out. Another big factor in this is if something failed from cyclic fatigue and is repaired, that 100 year old crank has other similar stress points that are waiting their turn to do the same. Are you going to pull your crank and mag it every 1,000 miles to catch it before it lets go? Everything has a life cycle, we just happen to be living in a time when we can still use these things and play with them. When they are 200 and 300 years old, those guys are going to be facing "Ship of Theseus" issues bigger than the ones we have now.


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