Crankshaft movement

[cev65]

After putting the flywheel back on i put the indicator on the flywheel and turned the motor. In a few spots it made a clunking sound and mover about ten thousandths. I then put the indicator on the edge of the pilot bearing and rotated the plywheel again, once again the same noise and the same movement. I the rotated the flywheel slowly until i heard the clunk and stopped, then i put a pry bar between the bottom of the motor and the flywheel and pryed up on it and it moves the same amount. I am some what familiar with engines and i know this isnt normal. How much run out can the back of the crank have and where should i go from here??

 

[DieselBob]

From the TM 9-2815-210-34-2-2

1.Push crankshaft (1) as far as it will go toward the rear of cylinder block (2).
2.Mount dial indicator (3) so indicator pointer (4) rests on outside edge of front
of flywheel mounting flange (5).

NOTE
When turning crankshaft (1), hold it all the way to
the rear position.

3.Turn crankshaft (1) one full turn. Dial indicator (3) reading must not be
more than 0.002 inch.

 

[cev65]

The engine is still in the truck. I pulled the flywheel back off and put the indicator directly on the crank. It only had .002 run out.

 

[DieselBob]

Just to make sure I am understanding correctly. When you say the crank moved about .010 of a inch was that up and down movement or thrust movement from front to back.

 

[cev65]

It was up and down movement.

 

[mark salanco]

Sounds like you have a bad crankshaft and most likely bad bearings.. Sorry for the bad news
I would pull the crank out and look at the bearings, I bet some of them are beat up bad. Have the crank checked for straightness .

 

[cev65]

that makes since but why dosnt it do it without the flywheel on it??

 

[Cycletek]

Sounds like a broken crank through the rods, hope i am wrong.....sorry!

 

[cev65]

I know its not a broken crank. I drove it into the garage last sunday.

 

[mark salanco]

The weight of the flywheel is probably pushing the crank into the bearings. With the flywheel off its probably floating. I would pull the crank and see what's going on in there.

 

[cev65]

Eahhh that blows. Thats what i figured.

 

[mark salanco]

When you pull the main caps, check for a spun bearing. If you find one that has spun in the cap you will most likely need a new cap and have to have the block align-honed.

 

[cev65]

why would it be worst with the flywheel on the crank??

 

[mark salanco]

The weight if the flywheel might be pushing the crank into the bearings.
Is the crank in the block without the rods bolted to it?

 

[cev65]

no every thing is connected. the engine is still in the truck. Putin clutch in and the tm said to chect the flywheel surface runout. thats when i noticed the up and down movement.

 

[mark salanco]

You shouldn't have that much up n down movement. If it was me, I would pull the pan and start checking the bearings.

 

[cev65]

guess i will pull the pan and plastigage the bearings. where can i get main bearings at??

 

[mark salanco]

I'm not a diesel mechanic expert, I have built my share of Chevy small blocks and big blocks, but something just doesn't sound right with that much play in the crank. Hopefully a diesel expert will chime in with some good advice.

 

[mark salanco]

There is a section on here with the part numbers for bearings, let me go find it n let you know.

 

[mark salanco]

It's called Duce parts reference .. It's on this site.