Kicking the #5 rod out on hemi

We run a 526 KB STAGE 15 BLOCK AJ 2 heads 7.076 rod 4.5 crank a blown alcohol motor it likes to lock up the bearing #5 rite when your almost finished with a run and kicks the rod does anyone run a shorter rod in a few cylinders to elininate this problem any suggestion

 

if it's a roots combo, number 5 shouldn't be a problem cylinder that needs a short rod. is the plug showing lean?

 

Thanks the plug isnt lean we run long runs 12 to 15 seconds at 8000 to 8500 rpm psi blower 54% overdrive it must be running out of oil at the end 18 quarts brad penn 70 im going to try 20 quarts

 

WET SUMP dragster pan

 

Dumb question but did you check the crank and make sure it don't have a restriction in the #5 throw passage? just asking?

 

Rod length won't help this. #5 is the cylinder most tuners with a Hemi are leaning on to get it to run with the herd.

Make sure the crank journal is round , not shaped like a "D". What Robert mentioned is important to.

I take it this a tractor/truck pulling motor than would run this long ? The added oil capacity is a good idea---

Can you tell if you are losing oil pressure at the end of the run ? Gauges, idiot light ?

How often do you change oil, check filter. Do you restrict your oil to rocker arms ?

Are you losing only #5 rod , not #6 too ?

 

if it was lack of oil, (from my experience) the rear main will starve first before a rod.

 

Thanks for all the help everyone its a little of all my proplems

 

Dry sump is the way to go. You can temporarily alleviate the problem with an accusump, which will make sure you dont run out of oil when you are shutting down.

 

Do you have enough side clearance and what is your bearing clearance on that journal? Is the rod in correctly with the bevel facing the radius? If your running high rpm and there is not an escape path for the oil it will burn losing lubrication to the bearing, the bearing catches the crank and spits the rod out. You may want to pull the crank and get that journal checked out to make sure that there is nothing funny with it after blowing the rod out so many times. Did it hurt the block?