Broken crankshaft? No problem Sir. It'll be ready after lunch...

[Gareth J]

Very impressive ingenuity!

With the piles of components and practiced efficiency, including time for fags, he does a few of these, if not the same thing all day every day. They must work near enough or he wouldn't have got so good at it. Having seen some of the commercial vehicles they run, precision isn't the first word that springs to mind.

Be interesting to know the economics of it - bet it's a relatively decent earner

 

[bricol]

Why? Nitriding hasn't been used for decades?

In general, or just for cranks?

We certainly still do on a quite a lot of our stuff, cranks included.

Reason why regrinding Fiat/Lancia cranks of the 80/90s era wasn't recommended though - straight through the layer. Seemed to be okay on "shopping" cars, but on the more stressed turbo versions, they seemed to fail pretty quickly afterwards from some of the forums experiences.

 

[Seadog]

There seem to be plenty of companies offering nitriding, if the web's to be believed. I'm not as ill informed as was suggested, then

 

[slim_boy_fat]

How many times do we have to say it; Fact has no place in an online disagreement/argument discussion.

Fixed that for you.

 

[Stueeee]

In general, or just for cranks?

We certainly still do on a quite a lot of our stuff, cranks included.

Reason why regrinding Fiat/Lancia cranks of the 80/90s era wasn't recommended though - straight through the layer. Seemed to be okay on "shopping" cars, but on the more stressed turbo versions, they seemed to fail pretty quickly afterwards from some of the forums experiences.

The several billet cranks I've had made have all been Nitrided. According to the guys who make them, it's not grinding through the nitriding as such that causes them to snap, but grinding through the fillet radius, which always seems to be more generous on these cranks than on production items.

Edit: Clearly visible difference here....

 

[mtt.tr]

Love The Mechanic vids, only complaint would be they could do with editing down a tad.....I can't fit a full one in before work!

Watch at 1.5x speed.

 

[Aerohead]

Really impressive ingenuity, shows what a simple workshop can achieve when needs be. Safety a bit casual but machine skills he has.

Just imagine how many of this type of repair was done to T34s in winter conditions, likely with a Markov round between the ears for failure...

 

[8ob]

The several billet cranks I've had made have all been Nitrided. According to the guys who make them, it's not grinding through the nitriding as such that causes them to snap, but grinding through the fillet radius, which always seems to be more generous on these cranks than on production items.

Edit: Clearly visible difference here....

I suppose the fillet radius is of paramount importance on the billet cranks because of the discontinuous grain structure.

Bob

 

[pressbrake1]

Sure it probably works. But how he polished each journal, theres no way they are a uniform size. But then again i bet they just go through rods and cranks and keep changing them out. Labour is cheap there.

Remember I said to you accuracies are relative. A few tenths difference when running a thou clearance is irrelevant.
As the old question ‘what is accurate’?
I had a big polishing machine to install in fords engine plant . It was a automated version of what this gentleman is doing complete with emery cloth

 

[mtt.tr]

Sure it probably works. But how he polished each journal, theres no way they are a uniform size. But then again i bet they just go through rods and cranks and keep changing them out. Labour is cheap there.

Makes no odds, if it all runs concentric on the journals and the journals fit. Likewise the rods if it's all running right to an acceptable tolerance no reason it shouldn't last.

I'd be more worried about the crank snapping again, I personally think these people are impressive they manage more with half the equipment in worse condition than what hobbie machinist have.

 

[Bobupndown]

Landrover's secret Discovery 3 and 4 refurbishment facility?

 

[chris pruteanu]

I've seen some amazing footage from the Indian sub-continent, but this takes the biscuit. I love the slag hammer and the protective shield for his right hand safety sandal

I think you’re just being jealous. Guy is a master mashinist, that repair is better than original !

 

[Seadog]

No doubt, Chris. I wish I could stick weld that well.

 

[chris pruteanu]

No doubt, Chris. I wish I could stick weld that well.

That’s what I thought of ! The level of ingenuity defies belief ! I too work in a very busy industrial estate in my town, I brought back from Uk tons of tools when I relocated 6-7 years ago ! I have customers come to me from 100 miles distance…what some of my colleagues achieve with a big sledge hammer and a large lathe I cannot make sometimes in our nearest airplane fixing factory ! It’s all down to experience, ingenuity and will…people with limited resources do things what we might find impossible !

 

[brightspark]

Why? Nitriding hasn't been used for decades?
Impressive stuff, liked the polishing clamp

wasnt a polishing clamp. it was a lap .still used today to get a perfectly smooth finish after machining the lap is made of soft material and a smear of grinding paste beds in on it

 

[minimutly]

The several billet cranks I've had made have all been Nitrided. According to the guys who make them, it's not grinding through the nitriding as such that causes them to snap, but grinding through the fillet radius, which always seems to be more generous on these cranks than on production items.

Edit: Clearly visible difference here....
View attachment 327986

I recall a metro turbo motor I rebuilt 30 odd yrs ago, the crank was well worn, as was the whole bottom end - no oil pressure - no boost if I recall. Anyway, the crank got ground, but on close inspection the bearing surfaces had a pattern of cracks all over them. My take on it was the nitrided layer gad gone thin, breaking up?
Modern production cranks are certainly not nitrided, and haven't been since the seventies.

 

[minimutly]

wasnt a polishing clamp. it was a lap .still used today to get a perfectly smooth finish after machining the lap is made of soft material and a smear of grinding paste beds in on it

Well you call it what you want, we know he used a short piece of emery cloth in it...

 

[bricol]

The several billet cranks I've had made have all been Nitrided. According to the guys who make them, it's not grinding through the nitriding as such that causes them to snap, but grinding through the fillet radius, which always seems to be more generous on these cranks than on production items.

They didn't snap - but pretty quickly picked up and destroyed the bearings.

 

[bricol]

I recall a metro turbo motor I rebuilt 30 odd yrs ago, the crank was well worn, as was the whole bottom end - no oil pressure - no boost if I recall. Anyway, the crank got ground, but on close inspection the bearing surfaces had a pattern of cracks all over them. My take on it was the nitrided layer gad gone thin, breaking up?
Modern production cranks are certainly not nitrided, and haven't been since the seventies.

Exactly what happens - it cracks and those cracks wreck the oil film - borrowed image of a Lancia crank from some random Italian stallion forum from some time, some where.

Lancia OE English language workshop manual for my 1991 integrale mentions the steel crank is nitrided.

 

[Rkweld]

Sure it probably works. But how he polished each journal, theres no way they are a uniform size. But then again i bet they just go through rods and cranks and keep changing them out. Labour is cheap there.

A little info from some modern equipment. cranks are not matched like they used to be, I can only assume it is because of the time saved helps profits. For example, strip an isuzu and the engine components are colour coded shells, liners and pistons and the components are stamped with a relative code. They fit a different size shell or liner rather than re machining.

Engines are balanced electronically to the lowest preforming cylinder.

I am not saying its the best way but it works.