I just pulled the crank on my 400 and the thrust washer is worn very badly on the front side, How do I find out if it is still useable.


Thanks
John

 

what are you calling a thrust washer? thrust is controlled by the #5 main. to see if you have excessive thrust measure it with an indicator

 

Ede

What I am calling the thrust waser is, the 1/8 in thick flat piece of steel that sits right behind the #5 bearing. Maybe washer wasn't the exact right phrase, but that is what I have heard it called.

John

 

I believe it is called a thrust bearing. And ideally you should change all of your bearings if doing an engine rebuild. But, I guess you could use your own judgement. Just measure your clearances to make sure it is still within specs and you should be all right.

 

It's kinda hard to replace it, when its a machined part of the crank shaft,

 

Alright now to get serious, What are the causes of the crank moving forward enough in the block to wear, the washer/bearing/?, down 60-90 thousandths. I know the TQ convertor was installed properly, it spun freely, after it was seated.
Is it possable that the TC was expanding and putting pressure on the crank?

John

 

No, you must be looking at something else. If the part in the picture is what are are saying is badly worn out, the crank is destroyed.

Crankshaft endplay is controlled by the thrust bearing. It is the big main bearing that hangs over the sides of the #5 main. It is supposed to wear down, not that "thrust washer" on the crankshaft.

 

BINGO, Fisher
That is whats worn.

I haven't had the local crank shop look at it, but that was my assumtion.

Spud

 

Wow... that is the first I have ever heard of something like that happening. You have way to much play in the crankshaft if it wore it down instead of the thrust bearings. You might want to get that checked out before driving with the new crankshaft, because that would be worn down too, and crankshafts are not cheap.

 

That's supposed to be an oil slinger to help prevent the rear seal from being flooded and leak. Thrust is supposed to be taken up in the end faces of the #5 bearing, and oversized bearing shells are available - not just undersized for reground mains, but oversized for worn thrust faces.

 

I have pic of the crank and #5 bearing I will post them this afternoon, When I have more time and when the wife show's me how to get them off her camera.

John

 

Pictures of crank,and #5 bearing. Opinions? PICS are too big I have to edit them then I will put them up.

 

Attempt #2

 

#3

 

That's the weirdest harmonic balancer puller I've ever seen...

Check the clearance with a new bearing (or against new bearing specifications), and adjust the bearing width accordingly.

I'm not sure about a 400 crank, but a "regular" small block rear main is 1.716" wide across the saddle faces.

 

You should see me forearm's after pulling the balancer off, I look like popeye.

Vader I atleast know your old enough to get that joke.

Thanks for the info, I will mike the bearing and tell you how much, is gone. The bearing miked out at 1.702.

John

 

"I'm strong to the finsh 'cause I eats me spinach..."

So your bearing is already starting out 0.015" undersize. How much total axial play is in the assembled crank?

 

Vader

That was what the bad bearing miked, I Don't have new ones yet. Monday I am going to take the crank to the rebuilder, and see what they say about it.

John

 

To rebuild the thrust face, polish the mains and rods, and chafer the oiling holes, is going to cost me $75. I don't think thats to bad of a deal.

John

 

Is this a stock cast crank?

You can buy a brand-new one that doesn't have who knows how many miles on it and who knows how much abuse, for a little over twice that.

I would not spend that much money on a stock crank that was already that gnarled. For all you know, it could be completely fatigued and at the end of its service life, and might crack the first time you start it up after you put this together.

But it's your money and your risk. It's just that, risk; not a firm black-and-white matter of that you should do this or that thing. Personally, with new replacement parts as cheap as they are, I would not spend that kind of money on a used-up stock part that's that critical to the overall success of the project.