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Crank endplay?

Posted By: rebel

Crank endplay? - 09/24/22 08:52 AM

How much crank end play would you want with an alloy block at room temp 20*C. I have a new crank & using King Main bearings I have 0.003 clearance. Crank spins nice with mains torqued up but is this enough end play for aluminium?
Posted By: 440Jim

Re: Crank endplay? - 09/24/22 01:37 PM

The manual I have says the factory spec was 0.002" - 0.007", with 0.010" maximum.
My aluminum block has 0.005" with no issues.
Good question on yours, but I don't have experience that tight with an aluminum block. But my feeling is you are OK, let's see if anyone posts experience.
Posted By: n20mstr

Re: Crank endplay? - 09/24/22 02:14 PM

I have always ran .007 - .0010 . What block is it ? My Indy block the crank was hitting one of the caps and it needed a little touch up on the mill to allow the crank to float as it should . Check all the caps for clearance also
Posted By: birdtracker

Re: Crank endplay? - 09/24/22 02:37 PM

I agree with checking to make sure the crank isn't touching. Also I take a rubber mallet and seat everything both front and rear of crankshaft. Aluminum block is going to grow so you should be good. Birdtracker
Posted By: Cab_Burge

Re: Crank endplay? - 09/24/22 07:17 PM

try loosening up the center main cap bolts, all of them, and then try whacking both ends of the crank with a big soft mallet and see if that will help centers that cap and give you a tiny bit more clearance wrench hammer scope up
I've had to do that more than once on many different motors shruggy
I shoot for .0040 to .010 end play using a dial indicator on the snout end of the cranks using a large handle screwdriver to pry the counterweights back and forth wrenchscope
Get it correct and go forward with having fun without worries on it up twocents
Posted By: rebel

Re: Crank endplay? - 09/24/22 09:37 PM

It is an Indy Maxx block, with a Molnar crank. I did seat everything with a rubber mallet as we torqued up the main caps as was suggested & it does spin really nice, but I just wasn't sure whether 0.003 was enough, but someone suggested that being aluminum, it might grow when hot. I was just hoping someone could confirm I was good to go.
Posted By: Cab_Burge

Re: Crank endplay? - 09/25/22 03:02 AM

You might want to try adding a little more clearances, .0015 to .0020 on both the front and back sides of the thrust bearing by sanding it on some medium grit sandpaper on a really flat surface, measure carefully while doing that scope
Drag race motor live a lot longer with looser rotating clearances than they do with them a tiny bit to tight work twocents
Posted By: Chargerfan68

Re: Crank endplay? - 09/25/22 08:53 PM

Originally Posted by Cab_Burge
You might want to try adding a little more clearances, .0015 to .0020 on both the front and back sides of the thrust bearing by sanding it on some medium grit sandpaper on a really flat surface, measure carefully while doing that scope
Drag race motor live a lot longer with looser rotating clearances than they do with them a tiny bit to tight work twocents


I agree with Cab…..and if you do this, place the bearings together (same orientation as when installed) when clearancing them on flat surface , to keep them square. As opposed to sanding each half separately.
Posted By: rickseeman

Re: Crank endplay? - 09/25/22 09:55 PM

Forgive me if I'm mistaken, but aren't you supposed to take it off the front side? I agree with an alloy block needing another thou or 2 because of the aluminum growth.
Posted By: HardcoreB

Re: Crank endplay? - 09/30/22 02:15 PM

.003" seems tight to me but I've not done an aluminium block yet.
Posted By: cl440

Re: Crank endplay? - 09/30/22 03:25 PM

We have ran them as tight as .006 and as loose as .010 with no issues. Aluminum block 540
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