Pirate 4x4 banner

"Crank-walk"????

954 views 5 replies 5 participants last post by  The Adam Blaster 
#1 ·
Background, my Dakota has the 4.7 OHC engine, can't remember if it's double OHC or not....

Anyway, last week, i had picked it up from the dealer after getting a fowoler put back in the right place, they also replaced a cam, and a crank sensor. But, when i was driving home, i lost the idler pulley (smooth pulley), which threw the belt off. Got 'er towed, changed those parts out, started home again.
(I had been away on a trip to upper NY state 4-wheelin a couple weeks before, and had to leave my dead truck at the dealer)

So, after i changed the busted parts for new ones, started home, 3-hour drive. Almost home, a 2nd grooved pulley freezes on me, and then gets obliterated by the belt, and then cut the belt to crap. Another tow, this time i got them to take me rest of the way home.
Changed that 2nd pulley, and the belt, and we're all good again.

Could the above damages be caused by "crank-walk" or is it just my wonderful luck that i had 2 pulleys go on me, less than 24 hours apart?
 
#2 ·
How many miles on the motor? Crank walk is caused by a worn out thrust bearing on the crank.
Is it a stick or auto?

Sticks, especially ones with a aftermarket HD clutchs wipe out thrust bearings quickly.
 
#3 ·
You can measure crank shaft endplay. Mount a dial indicator at the nose of the crank (or balancer) and force the crank back and forth with a pry bar. You should get around .005, but that all depends on your motor. If you have that much walk in your crank all your rods would be running into each other, into the crank journals, into the main bearings... Man, when you drained your oil you'd have a handful of steel shavings. Check your belt alignment man. Perhaps one of your brackets is crooked, causing some sort of accesory to be missaligned. Perhaps theres belt cavitation at higher speeds?
 
#4 ·
No way would crank end play be a factor here - the engine would grenade long before it could put enough stress on belt pulleys to hurt them. In "emergency" cases I've run belts several inches out of plane without ANY noticeable effects. Maybe water/mud in the pulley bearings, maybe something done not quite right at the dealer; a large number of possibilities. But IMHO what you suggested isn't one of them.
 
#5 ·
you been in any deep mud lately? this can cause everything you mentioned, i even had my alternator and harmonic balancer come apart after being in deep mud. that mud cost me lots of money and i now avoid deep mud when i can...... just curious if it might apply to you?
 
#6 ·
hip said:
you been in any deep mud lately? this can cause everything you mentioned, i even had my alternator and harmonic balancer come apart after being in deep mud. that mud cost me lots of money and i now avoid deep mud when i can...... just curious if it might apply to you?
We don't have any rocks around here, only mud. :D
And yes, i do have a healthy coating throughout the engine bay. And where i was wheeling, the guy had made a pretty nice mud pit which i enjoyed going through, sometimes sideways. :) :)

Anyway, i suspected that it was just the mud that did that, but talking with people, i heard the theory about the crank, and got a little curious...
Watching the belt spin on the pulleys, even when the engine is revved, it looks ok, and in alignment. I am just going by my eye though....

My truck is an auto, with about 45000 miles on it. But i beat the hell outta the truck...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top