Engine noise, crank walk

[Mach1]

Metering disc in a lifter is trashed, I wonder how it happened.

https://youtu.be/ZkEg7-Vo0JQ

[Broncojohnny]

Interesting

[Mach1]

2 pics of the bad disc compared to a good disc.

[Mach1]

Pulled the motor yesterday, thrust bearing has like .200" of play, I set it up to .005 when I put it together. I am hearing that the scat and eagle thrust bearing surfaces are junk from the get go, any recommendations on someone who can clean up the surface on the crank so it doesn't keep eating the thrust bearing? Also, what should I check after having the crank getting pushed so far forward, it looks like the rods slid on the pin all the way to make slight contact with the piston and that was the sound, I am going to take a good look at everything tonight and see if the crank counterweights were contacting the block.

[Mach1]

[garycrist]

I had a torque converter on a customer's car balloon.
I had only replaced the motor (Chevy Van ugh!).
2K later I ate that one!

GO FISH!

[svauto-erotic855]

I have seen the thrust getting ate away on a crankshaft because the drive shaft was too long and bottoming out when the car launched.

[Mach1]

I have seen the thrust getting ate away on a crankshaft because the drive shaft was too long and bottoming out when the car launched.

Thanks for the info, no sign of that in this case, driveshaft has 1" still of avail mvmt when it's at it's max "insertion". Who can weld and recut the thrust surface of a crank in DFW?

[aggie97]

Thanks for the info, no sign of that in this case, driveshaft has 1" still of avail mvmt when it's at it's max "insertion". Who can weld and recut the thrust surface of a crank in DFW?

Cheaper to buy a crank or whole new assembly?

[4king]

In the dsm community, even with a common problem being crank walk, there was no definitive answer as to what caused even low mileage cars to crank walk.

Theories ranged from casting flaws in blocks to using the clutch pedal too much.

I've seen more sheared starter nose cones on old chevy 350's than I've heard horror stories about eclipse talon crank walk. Most cases on the old small blocks is from oil contamination.

[svauto-erotic855]

Thanks for the info, no sign of that in this case, driveshaft has 1" still of avail mvmt when it's at it's max "insertion". Who can weld and recut the thrust surface of a crank in DFW?

Just make sure that there is still some free play once the rear suspension compresses during launch. On the car I mentioned we went through 3 crankshafts that were each repaired by welding a few times before we figured out the problem and it was only by happenstance that I found the issue.

[Mach1]

Cheaper to buy a crank or whole new assembly?

I have about $1000 in the crank with the heavy metal, It's $500 to have repaired by shafttech which I imagine I will get a crank back that is even better than it came from SCAT. I don't have time before the next race so I threw a new thrust in it, it cut the play in half but it's still bad, it should get me through 1 weekend of racing though. On the new thrust I cut a small angle on the bottom half bearing edge to allow oil to reach the thrust surface directly.

[svauto-erotic855]

In the dsm community, even with a common problem being crank walk, there was no definitive answer as to what caused even low mileage cars to crank walk.

Theories ranged from casting flaws in blocks to using the clutch pedal too much.

I ran DSMs in the 90s and figured it out myself. The thrust surface in the block was not machined correctly and the thrust surface was not at a perfect right angle to the centerline of the crankshaft.

On the new thrust I cut a small angle on the bottom half bearing edge to allow oil to reach the thrust surface directly.

You could not keep oil away from the thrust surface if you wanted to but adding the grove could not hurt. What engine are you dealing with? I had assumed a SBF but your pic is of a SBC bearing I believe.

[Mach1]

I ran DSMs in the 90s and figured it out myself. The thrust surface in the block was not machined correctly and the thrust surface was not at a perfect right angle to the centerline of the crankshaft.



You could not keep oil away from the thrust surface if you wanted to but adding the grove could not hurt. What engine are you dealing with? I had assumed a SBF but your pic is of a SBC bearing I believe.

It's a SBF, that pic was just for an example. Thanks for all of the input.