I try to set mine at .0025" when assembling a LS engine. I had a major engine builder on this site tell me they set their's at .005". I believe that's excessive and will not maintain the proper oil thickness on the thrust bearing and can lead to an early failure. I also know that anything over .007" can lead to a misfire from the crank sensor (from experience).
Would like to hear what clearance is working for others?

 

.004-.005 is what I aim for.

 

.003" to .008" is within GM engineering spec. .005" would be ideal. Based on experience, .0025 is on the tight side, but will not get you into trouble. It takes alot more to create a misfire from the crank sensor to reluctor.

 

It is what it is. You need to square up the cap and zero it from to back and then it is what it is. Usually around .005-.007 if the main caps are not leaning to the front or back from being cut wrong. The thrust or crankshaft end play should be checked with the crank in the block initially with no caps on and then after setting number 3 thrust cap it should still be very nearly the same or the # 3 cap is messed up or leaning.

 

Also if you check the crankshaft end play with oil especially heavy oil you will see sometimes almost a thousandth less end play due to the oil film strength unless you push it pretty hard and then you have to watch not to distort the indicator or what it's bolted to as well.

 

i usually set them .004"-.005"

 

I have never found anything "out of the box" with more than .001-.002" clearance. How is everyone obtaining .004-.005"? Cutting the crank or sanding and polishing the thrust bearing face?

 

I sanded and polished the bearing. 400 grit goes slow for the novice like me. I final sanded w/1200 I think.

 

Are you setting the crank, or just dropping it in and torquing the caps on?

 

After "setting" the thrust you will always have .004-.006 unless something is wrong with your block or crank or main caps as that is what they have stock already and always have in the 1500 or so that we have done.

If you just bolt down the # 3 cap it will sometimes be .001 or less but not if it's centered and squared up in the block which is really what "setting" the end play or thrust really means. If it's still that tight there is something wrong with the crank, block, # 3 main cap or main bearings.

 

I always center the cap and bearing before tightening by tapping the ends of the crank. Right now I'm talking about my Katech block which has billet and doweled mains. No adjusting these.

 

I would call them as the caps are usually spot faced after doweling or you can't get thrust if there are aftermarket mains on there now that are doweled. You can see what is touching but I would ask them what you should do as you need to see if the cap is slightly forwards or backwards as long as you know crank is correct width but you can tell that by seeing what thrust you have in the block with number 3 cap off. If you have .005 with the cap off and .001 with it on then it's the cap that is on crooked etc.

 

This is LME setting endplay on a 451 LSx.......note the clearance
http://www.gmhightechperformance.com.../photo_06.html