Crank cancer??

[bubbs609]

Im really excited to join the forum as I am an avid SHO owner. Its really hard to find anyone local that can help me with the beauty of a car.

Long story short. I live in Dallas, bought my 90 in Orlando, drove it back with no problems. Left Florida 80 degree weather to come back to the awful "Polar Vortex" of 20 degrees with ice and snow and lovely sand on the Texas roads. Drove it for about a week and the car lost all power and was undriveable. As I dug around to look for the problem, came to the conclusion it was the CPS that went out which would explain the symptoms. Took about a month to locate the Crank gear as the vanes on mine (all 3) were bent all up. Upon taking it off, I noticed the snout didnt look right at all. Also saw that there was no lower timing cover shielding any debris from the bottom of the car. Take a look at this pic of the crank snout. Looks like a chunk is missing and has now broken the woodruff key twice now. Is there a quick fix for this without having to replace the entire crankshaft??

Any help is much appreciated. Many more questions to follow....Thanks!!

 

[SHOCH]

Calling Texas Tony, come in Tony.
Were you at the convention this year in Ft Worth? There's a few guys that know everything about these cars near you.

 

[bubbs609]

Yes, i acutally was at the convention this year in ft worth. I talked to a few guys up there, but not for very long. Id love to get their info so i can ask them directly, and maybe show them in person and possible get some help.

 

[Devin]

Ewww, that looks bad. Not sure if that much material will throw off the assembly balance or not. The front of the key looks bad too.

 

[bubbs609]

Yes it does look bad. Not sure how a chunk was created on that crank. They key is broken in half. Guy atthe parts store said I could try some liquid metal to fill in the missing piece. Hopefully that will withstand all the force the crank gear gives. It also seems that I just can't tighten the crank bolt good enough by hand. This is the second time I've taken the gear off and the Billy was way too easy to get off. I don't have access to an impact either. What's your thought on what I can do?

 

[Devin]

Is the missing section causes the woodruff key to be loose, I don't know what you can do aside from replacing the assembly.

 

[sperold]

What does the inside of the crank pulley look like?

I would try another pulley and a fresh new key, and hope for the best.

Try measuring the crank snout with a micrometer to see how much is missing, ignore the gouge for now.

Try the new key and good parts, and with it running, look from underneath and see if you can detect a wobble.

 

[rubydist]

the missing material is not going to cause a balance problem, don't worry about that. that is the only good news.

there is no way that liquid metal is going to handle the loading that the crank sprocket sees - I would not even waste my time going down that road.

as mentioned above, what you need to do is to get a "good" crank sprocket and pulley, and a new key and reassemble that, and hope and pray that it will hold up. I'd say your odds of success are around 20-25%. in other words, not likely.

your choices to really fix the problem are to either replace the crank (all 3.0 and 3.2 cranks are the same, so should not be too hard to find one) or just get another engine and swap that in.

 

[bubbs609]

Ok, I'll take the liquid metal back tomorrow. I actually have a new crank gear that I had on there during this current broken key issue. I've already been thru 2 keys that have broken in the sane spot. Maybe I just didn't have the crank bolt on tight enough? It seemed to breakloose waaaaay easier than it should have.

 

[rubydist]

It is helpful to understand what is going on down there - the crankshaft does not "want" to rotate smoothly - it has distinct pulses from each cylinder firing that make it want to speed up and slow down 3x per revolution, in the case of a 6 cylinder 4 stroke engine. The flywheel has the job of keeping the rotation smooth.

Additionally, the crank sprocket wants to rock back and forth on the key, because the loading of the valve springs make it first want to rotate slower than the crank, and then want to rotate faster than the crank.

So, there are several kinds of cycling loading going on (also the cycling that the crank timing sprocket sees are different from what the crank damper pulley sees).

What typically happens is that at some point the crank damper bolt is not tight enough, so the clamping force is not greater than these cycling forces, and the damper and/or crank sprocket start rocking back and forth on the key. Since this rocking happens at least 3 times per engine revolution and since the engine rotates around 2500 times per mile, you can see that there is a lot of back and forth on the key.

The key wears, and the keyway in both the sprocket/damper and the crankshaft wear. When this wear is enough to allow large enough motion, they key and/or keyway break from the loading.

Depending on how bad the wear is, sometimes it can be saved with a new key and new sprocket/damper, but often the wear is too bad by the time it is caught, and the crank needs to be replaced too.

 

[itwonder]

I wish the photo was a little bigger so my old eyes could see what's going on there better. If that is a dished out piece missing from the crank, I would clean up the end of that crank until its surgically clean, and then fill that little missing spot with JB weld. Use a new woodruff key, and get a good pulley. That dished out piece in the crank may cause a stress riser that could grow and end up breaking the crank, or it may not. That crank bolt must be tightened to at least the specified torque!

 

[sperold]

Let us know how this thing goes when you get it reassembled.
My feeling is it would be a shame to condemn an engine for this affliction if it goes badly.
I would resort to welding the pulley to the crank before I would swap out cranks.
Weld it in a way you can grind out the welds if you can, but resign yourself to the idea it is the last harraugh for this unit, before it has to come out for the permanent fix or replacement.

 

[bubbs609]

I am having to order yet another key for that problem. This will be the 2nd key i have gone thru already since March of this year. JB weld? What is that exactly? When I get to the point of tightening the crank bolt again, I think Im going to make sure that i have someone with either an impact or a torque wrench get at it before I put the tire back on. How can I tell if the crank bolt is bad or not? Is there any type of lubricant that I can put on the bolt prior to tightening it back on so I know that it actually goes on all the way tight??

The crank timing gear is new so that should not be my problem.

 

[bubbs609]

I will def let everyone know what happens when I start to put her all back together. Before I even get to putting the crank back on, I am spending a lot of my time on the top end. I currently have the whole upper intake off and will be cleaning the heck out of it, also cleaning the ports where the intake meet. Im replacing valve cover gaskets as well. Is there a way to clean the injectors while i have the intake off? Now that I am so far into this engine, I want to make sure everything is spotless and clean.

 

[itwonder]

I am having to order yet another key for that problem. This will be the 2nd key i have gone thru already since March of this year. JB weld? What is that exactly? .

Here's one link that explains usage:
http://www.firstfives.org/faq/keyway/Crank_Keyway_Repair.htm
Googling "J B Weld crankshaft pulley" will find dozens of links. Hope it works out.

 

[rubydist]

JB Weld is just a higher temperature epoxy, so it can withstand engine temperatures - whereas standard epoxy have a temp limit of somewhere in the 150-200F range, JB Weld allows temps up to around 300-400 as I recall.

 

[bubbs609]

it is now decided. JB weld it is. I will put a little in the key slot, then lay the key on top. I will also put some in the front and the back of the key slot as well. What do you think about putting some JB on that spot where it looks like a chunk is missing? Maybe that will give it some support for the key?

 

[bubbs609]

I just also heard that JB weld would be a waste of time. Would the crank itself be able to be welded to fill in that piece that is missing?

 

[pjtoledo]

I use JB Weld frequently at work.
It doesn't even come close to the strength needed for a crankshaft keyway repair.

Perry

 

[rubydist]

I said back in post #8 that epoxy or liquid metal would not hold up... The choices I listed there are still your real choices.

Yes, the crank can be welded. To do this requires the crank removed from the car, taken to a shop, welded, turned, straightened, and possibly re-heat treated. Way more money than just finding a replacement crank in good condition. There is no way to have the crank welded while in the car.