Crank Thrust Clearance

What do you like to see in Thrust Clearance on a Hemi?

With gauge on crank snout I'm getting .004 - .005 prying to the rear. and .002 - .003 prying to the front.

If I load it to the rear and zero the gauge then pry to the front I'm easily .006 - .007

What is your thoughts?

I'd run it.

Are you seeing the same measurements w/ only half of the thrust bearing in place?

BigHemi said:

I'd run it.

Are you seeing the same measurements w/ only half of the thrust bearing in place?

Click to expand...

I didn't measure it with out the cap on. However it does have more play without the cap.

With the cap tight then the nuts backed off I'm getting and I'm getting 5 to the rear and 3 1/2 to the front.



I just wish I could get .004+ on the forward thrust since that's what it's going to see from the converter.

with 1 - 3 & 5 caps on and torqued to 100' lbs the crank turns super easy.

Thanks!

You should be seeing the same measurement w/ and w/o the cap on the thrust. If you're not, then the bearing is either not centering for some reason or the bearing halves themselves are different thicknesses. Need to find out why.

i just went through this this week. Started at zero with the cap on , removed the cap, 004". pulled it all apart. measured the thickness of the thrust surfaces, they vaire .002". sand the bearing with 1000 grit on a piece o glass, pushing harder on the thick area's. Now everything measures even. Reinstall all parts loose, hit crank with a soft ace back and forth, .004". Screw the studs in, no binding. Tighten the cap, .002". The only thing I can think is the thrust surfaces are not 90 degrees to the crank. I know the side of the cap is because I ground them when I line honed it at 90 to the cap register. I couldn't grind the inner surface where the thrust sets. Bottom line: It ran 300 passes this way and the old thrust bearing looked fine. I started with .002" last time, but when I took it apart it had worked to .006', knocking off the high spots. My 2 Cents. . Just unassembled the short block, side clearance to tight. The new rods are dead on the money but the old crank is tighter than I like. Now i'm waiting for the new rods to be ground for side clearance. This thing has fought me every step of the way, it better be faster or I'm taking up Golf.
Doug

Thanks guys, You've been a big help

Here is what I've got. I checked the thrust with and with out the cap on... there was about .0005-.001 difference.
I checked the back side of the thrust surface and they were .001 difference from top to bottom
I did what Doug did sanding with 1000 grit (didn't have glass so I set it on an aluminum plate I have.)
I got them with in a .0005 to dead on between the top and bottom.

With the caps loose I can get .006 going back and .003 - .0037 to the front. With the caps on and tightened to about 20' lbs I'm getting .005 to the back but only .0025 to .003 to the front.

I've taken the rubber mallet to the crank trying to get the thrust to set, and now I've sanded the high sides of the bearing. I'm getting to the point where I think this is where it want's to be.

If I look at the total clearance I still have .008 total clearance.
I just wish there was more back to front since that's the way the converter will push the crank.

Thanks for you help

Very good. Like DVW said, a little sanding will get them flush. Sounds like you're good to go.

I didnt have a loose piece of glass. Then it hit me, I layed the sandpaper up on the garage door window.
Doug

Thanks again Big Hemi and Doug. I double checked it again and I'm logging it at .007 total.

That's thinking outside the box Doug. I never would have thought of that even if I had garage windows, and the wife would have been looking at me pretty funny if I would have used her kitchen window. lol

Now off to my next adventure... installing the rings.