Sounds like marbles coming from my bottom end

[500orbust]

I was tuning today for 20+ psi and race gas -110 leaded, but I kept
blowing the spark out. The most boost I could run was 16 psi. At 16
I am running 17 degrees of total timing and at 20+ Im running 15
total. A/f ratio was mid 11's - thats pretty conservative right?

A big oil leak occured on the interstate (from the front cover area) , but I was still able to drive it. The oil was very slowly dripping and I only had to go about 10 miles. When I got about 1/2 a mile from a shop that I usually park my car at, I made another 15psi run and on the way down, I heard a noise that sounded like 100 marbles were in my engine. Oil pressure dropped to 20 @1000rpm (normally its 30psi @ 1krpm) and when I revved to 2krpm, oil pressure went up jagged - not smooth, to 40 psi. I checked the oil and there was about 3 quarts in it- just at the bottom of the dip stick. I also didnt see any metal in the oil on the dip stick.

Usually rod bearing failure sounds like steady knocking, increasing with higher rpm, but this sounds like everything is broken. Has anyone else experienced this also? I will find out what happened soon when I pull the valve cover and oilpan. Hope its just the oil pump, but im expecting worse.

Also, There's about 3000 miles on this bottom end and this has been the first time I had any problems with it since the build.

archie

 

[ktmryan53]

i had the exact same problem. i was at 22 psi on 91 octane and suddenly it sounded like marbles banging off the bottom of the car. could you "feel" something in the pedal also? i went about 20ft more at 70mph and then my car came to a VERY quick stop. i looked behind me and i leaked a little oil, well all of it. there was no metal on my dipstick. i tore the car down to find that i put #2 rod though the oil pan. and #! and #3 were only mangled up. i lots a bunch of my block out of the rear of the block and then had a fist size hole in the front of the motor. see if you have coolant in your oil.

 

[t3/t4eclipse]

I dont know bout marbles but I know the sound of little bb's rolling around at higher boost is a sign of detonation where you are igniting the fuel before the piston has reached the top of its stroke... ?????

 

[GVR4592]

First of all it's very unlikely you are "blowing your spark out" at 15 psi. Second doing a full throttle pull with a big oil leak is not the smartest thing to do. Sounds like you need to tear into the engine.

I don think this should be in advanced tech.

 

[bryanwheat]

I dont know bout marbles but I know the sound of little bb's rolling around at higher boost is a sign of detonation where you are igniting the fuel before the piston has reached the top of its stroke... ?????

Actually detonation is when the motor fires before it is supposed to. Most every motor fires before top dead center while making power. so it is igniting for say 17 degrees before the piston reaches tdc, if you put more timing in, say like 25, than you will be having an explosion in your combustion chamber instead of a rapid burn of the fuel. Detonation can also be caused by to hot of intake temps also, which are being caused by to small of intercooler for the setup, of not enough fuel for the setup.

Being that both of you experienced the noise followed by an oil leak, i would say that you are probably not experienceing detonation, seems more like an oil pump on its way out, or if it were a 2g could possibly be the crank trigger plate rubbing on the crank sensor.

 

[Maglin]

My first vote would be balance shaft bearings spun out. Would create a leak out the front cover and the shaft bouncing around would make a hell of a lot of noise. Would also expalin your oil pressures being all wacky. You will want to do a BSE after this one. You also will want to pull your pan and check your rod/main bearings as well. Balance shafts are just anohter thing to cause a problem and their removal isn't all that bad IMO.

The Mains are fed after the balance shafts and that would be why one persons car threw a rod. Not enough oil. Doing a run after hearing the noise was just a bad idea. Chances are you are in for at the least new rod/main bearings.