Jim85IROC

iTrader: (6)

I'm doing all of the blueprinting on my shortblock this week, and today I got all of my main bearing gaps measured with plastigauge, and they all measure between .0015 and .002". I moved on to run-out on the crank and that was non-existant. I oiled all of the bearings, torqued to 15ftlbs, smacked the crank back and forward, then finished tightening the main caps. The problem is, I don't have any measurable endplay on the crank. I can reef back and forth on the crank with a screwdriver between a cap & a counter weight, but nothing moves. My smallest feeler gauge is .002" and I can't fit it between the crank and the thrust bearing. I set up a dial indicator on the end of the crank and I can't get it to move... but it's an old POS dial indicator, so I don't trust it. The crank spins freely & smoothly.

So... I seem to have little or no endplay on the crank. What do I do about it?

It's a compstar 4" crank and the bearings are clevite.

HotSilverBird

If you didn't have any it wouldn't spin at all.

427

iTrader: (3)

Loosen the number 3 main cap and check for play with the cap loose. If it has play the cap was not centered.
You do have the Clevite MS2199H bearings I assume?

Kurt

RARON455

iTrader: (35)

You really need to be using a dial indicator, not feeler gauges, Mount it on the front of the block, then push forward and backward and watch the neede sweep to get the measurement.

Tony Mamo @ AFR

iTrader: (13)

I have wet sanded many a thrust bearing on a piece of glass (or any very flat surface) to get the end-play figures I was looking for.

Its not uncommon for the LS engines to have little or no endplay.

Make sure what you have is correct by loosening the cap a little and trying to line them up again and if you don't have enough break out the wet/dry paper (320 works pretty good) and some WD 40 as a lubricant. It takes a little time...the material doesn't come off very quickly. I usually keep a 1 inch mic handy to measure how quickly the material is coming off. Just sneak up on it and recheck it in the engine a couple of time if necessary.

-Tony

Jim85IROC

iTrader: (6)

This morning my father and I mounted a better dial indicator to the crank and reefed on the crank and measured .0015 to .00175" of endplay. I called Callies and they said that I need to have 5-7 thousands, so I'm still a long way off. The Callies guy looked up the specification for the Clevite 2199 bearing and said that it should measure 1.028", so I'm going to pull the crank back out and measure the bearing width while it's installed in the block. I'll also measure the width on the crank to see where I'm at.

Assuming that I need to sand the bearing a bit, how much can I sand before I need to be concerned about the top surface of the bearing becoming too thin? From the looks of things, I might need to take a couple thousands off each side of the bearing.

KCS

iTrader: (20)

Did you measure without the center cap?

Jim85IROC

iTrader: (6)

No, I measured with everything in place. Isn't the center bearing what determines my endplay? How would I measure without it?

KCS

iTrader: (20)

Yes, the center thrust bearing is what determines endplay, but if you're having problems with it, you can measure without the center cap, or at least with it loose. You shouldn't be getting that little of clearance.

Like Kurt said, if you get a lot of clearance without the cap tighened and almost nothing when it is tightened, then the cap may not have set properly.

99 2500

GM service manual for the 4.8L,5.3L,6.0L engine calls for proper crankshaft endplay of (0.0015 - 0.0078 in ) , so looks like youre measurement are right on.

Tony Mamo @ AFR

iTrader: (13)

.002 is too tight for a performance build....

.004 - 005 is perfect IMO

OP, you can remove the material from one side of the bearing.....just make sure you hit the same side of the top and the lower shell (meaning either wet-sand both sides of the bearing on the reluctor side of the crank or both sides of the bearings on the dampner side of the crank.

Measure one side of each bearing shell with a 1" mic....knock a thou off them and reinstall it measuring endplay with the dial indicator once again. You should see a direct increase in end play associated with the reduction in thickness obviously. Taking your time and sneaking up on the clearance you need is usually best. If you have an honest .004 - .006 or so your done but I personally prefer to be in the middle or on the tighter side of that spec.

Note the crank will likely turn a little easier when your finished...

-Tony

HotSilverBird

I think you are fine...let it be. It will wear in some too. 5-7 thous is WAY too much...I'd stay where you are.

427

iTrader: (3)

What kind of damage do you see with the higher numbers?

Kurt

HotSilverBird

ever hear of the harmonic balancer bolt coming loose? The major cause is too loose end play on the crank. It really plays hell on everything. Lets the crank walk and shake itself to death.I would start out as tight as possible, ABSOLUTELY nothing wrong with .002.

427

iTrader: (3)

I have never had that problem, but I have heard of them coming loose. What is the higher clearance doing that causes this? I have set them as high as .010 with no problems, but have seen trouble with high power engines below .003, although I have only built a few over the .005 mark.

Kurt

427

iTrader: (3)

Tony,
Attached is how lazy people do it!!! I cut them in place with a mandrel I made that bolts into the mains on bearings. The other picture shows the force fed oiling I use on the turbo stuff, 8 holes feeding the thrust surface. This is used with .006-.008 endplay and has been working well!

Kurt

HotSilverBird

Has alot to do with how well the engine is balanced too. Poor balance and too much end play and its going to play hell on the bearings. My experience has always been keep it tight as possible. I had a high performance Porsche engine toss the flywheel 3 times because the IDIOT engine builder was on the top end of the crank clearance. Cost big bucks to fix it every time until i finally got smart and checked into it and found the IGIT was setting it as wide as possible. His explaination was loose was better and faster etc....BS After setting it to factory minimum setting i never tossed another flywheel and that was putting out over 300hp.

There is good reason that harmonic balancer is on the end of the crank, without it the bearing won't live very long. Same with the crank end play, that crank is moving all over the place and will beat itself to death quickly if it is too loose in end play. I can see a HIGH HP application using 4-5 thous but honestly any more than that is asking for trouble later on. Plus that thrust bearing is going to wear in some. You got 8 pistons pushing that crank all over the place, gotta have things tight if you want it to stay alive a long time.

67SS509

iTrader: (25)

I have checked a few to see what affect wearin has. What started out as .003-.004 endplay became .007-.008 in less than a 1000 miles.

Tony Mamo @ AFR

iTrader: (13)

Hey Kurt,

That's a pretty trick deal you have fabbed there but its hard to shake a stick at a simple and effective solution that anyone can handle in their garage or shop (with the obvious implications it makes more sense for most people reading this....LOL).

I have used the "wetsanding and mic" method for twenty five years without issue....you just need to take your time.

See you at PRI hopefully!

Cheers,
Tony

HotSilverBird

There you go, its going to wear to a certain place no matter what you do. The crank moves around alot more than you think. It takes a hell of alot of abuse.