Crank failure!

Hi Gbak,
They can use many different materials.
For industrial purposes it is normal to use a low-cost material for bigger components and then apply spray-metal with much better specs. to the areas that are hard loaded. By this they can keep the cost low and ensure a long lifetime on big costly parts. It's also often used for repairs similar to your damage.
Just make sure they take something with simmilar specifications as your crankshaft. A good mashin shop will know what to do.
Best regards, DK.
 
Dk-Corvette said:
Hi Gbak,
They can use many different materials.
For industrial purposes it is normal to use a low-cost material for bigger components and then apply spray-metal with much better specs. to the areas that are hard loaded. By this they can keep the cost low and ensure a long lifetime on big costly parts. It's also often used for repairs similar to your damage.
Just make sure they take something with simmilar specifications as your crankshaft. A good mashin shop will know what to do.
Best regards, DK.
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That process would demand the crank be dropped outta the block, I presume....NO??

Honestly, I think Turtle has the key to that, get a decent damper warm it in the oven, press it on like normal but I find a SBC bolt is just flat toooooo small to put much torque on, that POS on my engine about had nothing on it, and it started to strip, I tapped for one size larger.....

even a 318 Chrysler or a old Pontiac has a MUCH larger diameter bolt....
:amazed:
 
I am fascinated by this description of "spraying" metal on the damaged crank and would love to see/know more about the process. I can only assume that it is similar to powder coating. I am under the impression that the crank snout would need to be machined after spraying to ensure proper fit of the balancer. At a cost of $200 wouldn't it be better to get a new crank that is not compromised, or are there other expenses and labor associated with a new crank that offset this advantage?
 
Have you considered welding the balancer to the crank...???...temporary fix so you're not loosing this summer ??
 
MYBAD79 said:
Have you considered welding the balancer to the crank...???...temporary fix so you're not loosing this summer ??
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No I haven't considered that until now!
But why do a temporary fix?
Whay don't do it permanent?

As long as I don't need to remove the damper/timing chain, it might be ok to have the damper welded.
I could get a new key and ARP bolt and torque it like hell and then weld the balancer.
It might work well for years.....

So, when do I need to remove the balancer?
-When the balancer its broken; I get a new damper so I don't need to remove it in the next 10 years.
-When the timing chain/sprockets is bad; I have a high quality full roller Cloys HexAdjust, will last for years I hope.
-When the camshaft needs to be replaced; the mech roller could get the lobes rubbed, could happen.
-When the sealing in the timing cover is worn; Didn't see any oil when removing the balancer, I think it'is ok.
-When the timing chain cover gasket blows away; It might happen as I have a low quality 2-piece chrome Summit cover.

Have I forgotten anything...?

Or am I a real Bubba when thinking like this.....
 
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Sometimes there is a fine line between Bubba and good backyard engineering. I am sure that many of our brethren here have many experiences along those lines.

I am no expert but if replacing the crank is prohibitive then (sleeve it) weld it and go for it, what have you got to lose? If anything goes bad you are eventually going to have to pull the motor anyway.
 
Yup... weld it, drive the summer and fix it the right way next winter (new crank, new balancer)....

I would not make this a "permanent" repair..... :tomato:
 
BRUTAL64 said:
If you do that make real sure the dampener is square to the crank.
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If there is a little bit of the crank diameter undamaged that holds the dampener in the correct position and square this "should" work.... you know, the sad part is that he has nothing to loose at this point... the weld is not going to break, I highly doubt that.... but unfortunately the crank is garbage....
 
BRUTAL64 said:
If you do that make real sure the dampener is square to the crank.

Red Lock Tite jumped into my brain just now.:amazed:
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As long as its square enough not to throw the belts and seal oil properly, who cares.

Yep, at least with locktite he would be able to get it off. Not that it matters as the crank and balancer are pretty much junk anyway.
 
turtlevette said:
Not that it matters as the crank and balancer are pretty much junk anyway.
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That pretty much sums it up.....

I would not consider a bubba repair like this but these parts are junk already and the summer in Sweden isn't very long.... 3 months maybe ????
 
hey I welded the belt drive wheel on the crank of my air compressor when the bolt broke and its lasted almost 5 yrs now..
 
gbak said:
Good idea Dk!

I just called a machine shop nearby and they thought it would be possible to spray the crank with metal a then grind it to press fit.

They have done this with crank journals with sucsess, but never a crank snout.
The guy I talked to thought this could work.
I guess that the material will not be as hard as the surface was from beginning, this could maby be a problem??

Question is; if the top material of the snout needs to be hardened?
The cranks material should be ridgid and if the sprayed material is grinded to match the balancer hole, it might be good enough!

Price for this operation will be around $200.
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This is your best option. It would save the crank and balance, and provide a "permanent" fix for you, and withstand the 7,000 RPM's you run.
Welding a crank could mean catastrophic failure, with the resulting possible mass damage.
The snout need not be hardened like a journal.
 
big2bird said:
This is your best option. It would save the crank and balance, and provide a "permanent" fix for you, and withstand the 7,000 RPM's you run.
Welding a crank could mean catastrophic failure, with the resulting possible mass damage.
The snout need not be hardened like a journal.
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You're not thinking straight. This process surely cannot be done in place. Maybe you missed the part where he doesn't want to pull the engine.

The best option is to yank the engine and put a new crank in. Damn.... you can buy a decent forged crank for $400 so why take a chance with some labor intensive procedure for $200?

The realistic and practical solution is to make a field repair and enjoy the car. In all reality a repair such as JB weld or arc welding will last as long as the engine will.
 
I'm actually wondering if the imbalance of the existing crank can be duplicated and if the rods/pistons can remain in place.... if you could measure and duplicate this crank's imbalance then why mess with the pistons ? Just spin it up to 6000rpm and measure the balance.... no ?????
 
turtlevette said:
big2bird said:
This is your best option. It would save the crank and balance, and provide a "permanent" fix for you, and withstand the 7,000 RPM's you run.
Welding a crank could mean catastrophic failure, with the resulting possible mass damage.
The snout need not be hardened like a journal.
Click to expand...

You're not thinking straight. This process surely cannot be done in place. Maybe you missed the part where he doesn't want to pull the engine.Whoever WANTED to pull an engine?

The best option is to yank the engine and put a new crank in. Damn.... you can buy a decent forged crank for $400 so why take a chance with some labor intensive procedure for $200?Because it's an adequate repair forsomeone across the ocean.

The realistic and practical solution is to make a field repair and enjoy the car. In all reality a repair such as JB weld or arc welding will last as long as the engine will.
Click to expand...

Maybe at 3,500 RPM, but not at 7,000 RPM. Welding cranks just doesn't work/last very long. b
Been there, done that.
 
MYBAD79 said:
I'm actually wondering if the imbalance of the existing crank can be duplicated and if the rods/pistons can remain in place.... if you could measure and duplicate this crank's imbalance then why mess with the pistons ? Just spin it up to 6000rpm and measure the balance.... no ?????
Click to expand...

If your asking if a replacement crank can be matched to what he has, the answer is yes, pretty close.
 
big2bird said:
MYBAD79 said:
I'm actually wondering if the imbalance of the existing crank can be duplicated and if the rods/pistons can remain in place.... if you could measure and duplicate this crank's imbalance then why mess with the pistons ? Just spin it up to 6000rpm and measure the balance.... no ?????
Click to expand...

If your asking if a replacement crank can be matched to what he has, the answer is yes, pretty close.
Click to expand...

that's what I was thinking... remove that crank, have the imbalance measured and duplicated to a new crank.... just work from under the engine.... not a good position but you might not have to pull the heads..... :cool:
 
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