strange 481X oiling issue

Have twin turbo 481X motor had 40 runs very happy.Dry sump 140psi 60wt oil .0055 bearing clearance mains/rods.last race it was cool out 45 or so i have heater in oil tank had oil warm before warm up did warm up had normal oil pressure. Had some delays before running did another warm up.checked valves had a broken lifter.This was our largest local race so against my better judgement looked at cam lobe was not real bad so installed new lifter.I have a 5 stage dry sump pump and there are filter screens protecting the pump.Went up to make the run just at the end of the burn out i broke a rod.Figured 40 runs may have been to much.took the motor apart at the track and found All rod bearings were spun. The mains while not spun they were black.oil pump looks good no key ways broke on drive.My question is with broken lifter on the warm up could that have blocked that oil passage and starved the rest of the motor of oil it was on 2# cylinder.The lifter was broke bad enough that the intake valve barely opened lifter was stuck basically in the closed side all the time.

 

? Have you ever took a look at your oil level in your tank after running it ? We have one w/A P&P oil pump that we have to drain the oil pan and refill the tank after every 1/8 mlie hit, We run 16+ Quarts of 50 or 60w.

 

I built a well baffled oil tank it holds 14 quarts pump has 3 -12 lines going to pan. I can rev the motor to 6000 tank stays at a full level. At the finish line have 140 psi when i hit the chutes pressure drops to 50 for 1 second then back to normal pressure.

 

What type and style of bearings are you running on the mains and the rods?
For example; clevite M

What's the side clearance like? Are you running narrowed bearings? Is this an established combo or did you just put it together 40 runs ago and not check the bearings? How's the tuneup? Just for kicks, who's lifters were you running? Did it explode the wheel and put those little needles everywhere?

 

.040 side clearance.Clevite H bearings This is a new combo pan has been off several times to check bearings.tune up is very happy have been 190 mph @2700lbs with 41 psi boost plugs still have all the cad on them.broke a lifter (crane that AJPE sells)10 runs before this.pulled the motor bearings looked so good they went back in.The damaged lifter parts were all in the oil pan under the windage tray. Including those little needles.Being that this was more than likely the last race of the year figured the parts would be under the tray and all of the oil lines going to the pump have filter screens.

 

Have you taken the engine apart yet? Are all of the rollers accounted for? Were they accounted for last time or was there possibly a rouge on loose in the engine? H on the rods, the mains or both? Were the rods the standard H or the narrow H? If you were running a different bearing before and you put a non-narrowed H in there your side clearance could disappear, had it happen before, luckily I always give the rods a shake after torquing and I knew something wasn't right. I once put a set of H mains in out 481 that we always ran M's in and it blackened every bearing because they were up into the radius enough that the oil had trouble getting off. Luckily we didn't spin any mains. I wouldn't run an H anything in an aluminum alcohol engine, ever. When was the last time you checked the rod bearings before this incident? Did you put new bearings in it at this time? Do you run a Chevrolet crank or a Hemi/chevy combo? Is it forged or billet? Might want to have the crank checked also to make sure that it's not cracked or broken.

 

Yes they were narrowed H bearings looked at log book On run 33 broke a lifter motor was 100% torn down all oil plugs removed very well cleaned.Crank is crower forged Hemi rods BBC mains. The rod and main bearings looked so good small swipe with scotch brite re ran them. I like the H bearings when we ran a roots blown SBC had a happy tune up ran same bearings 2 seasons.crank is at mile high crank getting checked out.BACK to my original question with lifter broken stuck in lifter bore basically in the valve close position with the oiling system like a hemi could that have cut oil flow from going to the mains .

 

After a full , Under boost run ? , when we ran lower boost ( 36 ) we had no oil return issue, But went to screw blower ( 48+ )and oil would not come back as fast as motor was useing it. I have one w/A Daily scavage pump and allways sucking and refilling tank and no more Issue.