Anyone have a Crankshaft for a Mini S for sale?
I am in need of one, #3 bearing damaged beyond turning...

 

Why not have the journal welded up and turned?

 

Good question!!!
The machine shop I took it to did not offer that as an option! Is that do-able?

 

Your machine shop should be able to tell you where to get it done. If they do not know, you may have to hunt around, but I know that it is done. Welding is how stroker cranks were made for many years with great results. Any diesel truck engine rebuilder sends crankshafts out for welding to build up the worn journals, afterwhich they are regound to original tolerances just like new.

You cannot have it done at just any welding shop.

The last time I had one done was on a VW that was stroked by Gene Berg in Orange, Calif. He had a cabinet that was full of a talc like substance that the crank was submerged in during the actual welding. It was all automatic.

The price of all this may exceed the cost of a good used crank, so I do not know the best way to go.

Another thought is to have yours stroked at the same time. That will require a much greater expense because of having to get longer rods. The results will be greater torque and power from the bump in displacement.

 

Not that reground cams and crankshafts aren't very common (because they are cheaper than making them from scratch), but there are potential drawbacks.

For reground cams, the base circle becomes smaller than OEM, which changes the valve train geometry. More importantly, grinding a camshaft lobe or crank journal totally changes the surface hardness due to both heat and material removal. That can dramatically impact durability.

Scott
90SM

 

Scott, I will agree with you about reground cams, but challenge your comparison with welded cranks. Have you had a welded crank wear out?

While the wear surface of a welded crank is different than an original forging, modern welding materials are compatible and should not have adverse wear issues if oil is kept clean. The diesel truck industry is proof that welding works very well.

 

yes, i actually just posted this idea in the other forum, but yeah, welding will work, but it does have to be re heat treated. When its done, its is just as good as new.

As far as cams, yeah, the base circle can change, but not if it was welded first. They also have to be re heattreated. This is not a job for a standard shop to do.

That said, it might cost as much to have all this done to your crank as buyingone of those remans.

I might also be interested in a crank, if anyone has one, like the one haggard has, or a good one from a wrecker.

Beecher

 

If the parts are welded up, ground to OEM surface finish and tolerances and heattreated correctly, they'll probably hold up pretty well.

FYI, cams and crankshafts for Heavy Duty trucks (class 8 for example) are designed with substantial margin (typically 2.5X) compared to passenger car or light duty applications. They are expected to last millions of miles. Of course, the case depth and metalurgy are critical parts of the margin.

I'm just of the opinion that getting heat treat correct is probably beyond the capability of the average shop, but that obviously doesn't mean that it is impossible to do.

Scott
90SM

 

So how much are we talking to get a crank reground

 

Depends on where you are. "hell" has the heat, but I am not sure of the other services.

Google "welded crankshaft service". There are several that come up. Click on the article from Turbo Magazine for a tutorial on crankshaft welding. Exact pricing will require a phone call to the vendor you select. Add your location to the google above to locate services near you.

I suggest that you check with two or three, because pricing varies greatly.

 

im not disagreeing that it is hard to get done, and right, just saying it can be done, and i would be willing to do get it done. If it rains tomorrow, i will phone the crank shop near me. I was just however at a machinist friends, and he said that you are probably looking at 100-150 per journal, so you could get that one done, and grind the rest, if you can find someone local that does it. I would trust the shop near me, but i have had cranks ground there before, and my friend has a really good relationship with them. Keep in mind that even if you get a used crank, it may need a grind anyway, or at least a polish (i would at least polish it before putting new bearings on it), (that really shouldnt be too much, to grind 3 mains and 4 rod journals at my local is only like $110 or $150 or somewhere in that range, and that includes to polishing and chamfering of oil passages).

Beecher