Fuel getting into catch can

speedjunkie · 12-31-2018, 02:41 PM

I developed a strange issue recently on my way back home from SevenStock. We stayed the night in southeast Utah and in the morning I noticed I had oil sprayed all over the intake elbow and other things in the area. I'm using one of Adam Griffith's catch cans so the filter is right next to the oil filler cap. The can was overflowing and spraying out through the filter. I drained the can and went on my way. When I stopped for fuel a few hours later, the can had overflowed again. I drained it again and just left the drain open for the rest of the drive home.

Typically I'll drain the catch can every oil change and I'll get maybe a few drops of water with barely any oil. But now, if I take a drive that lasts a couple hours, I'll drain the can and I'll get about a tablespoon of mostly fuel.

When I first built the engine (sometime in 2014) I started out by using 20w50 and some Lucas oil additive, so it was SUPER thick. My buddy that helped me build the engine that time used to build them for Tripoint and he suggested using that oil and additive so I used that for the last few years until recently. Talking to another friend who has done a lot of research into oil, he suggested I use something thinner so it has protection on startup. He suggested 0w30 but I found 0w40 so I used that and no additive, and I changed that right before the trip to SS. That's the only thing I changed before the trip. I do need to get tuned again and I'm running pretty rich right now.

I was wondering if my oil control rings were bad, but I'm not burning oil. I'm thinking maybe the fuel is bypassing the oil control rings due to lower viscosity oil? But when it gets hot it's about the same as the thicker oil I was using.

I installed a boost gauge recently and my vacuum is reading around 10-12in/hg at idle, which I feel is a bit low, but the car starts up fine and runs fine. My idle increased to around 1800 while I was at sea level in California, and I thought it would drop back down to 900 when I got back home to 6000ft, but it didn't. This is the only other change I've noticed since the trip, not sure if it's related to the catch can issue.

12-31-2018, 02:41 PM	#1
speedjunkie RCC Loves Me Not You Join Date: Mar 2008 Location: Colorado Springs, CO Posts: 2,089 Rep Power: 20	Fuel getting into catch can I developed a strange issue recently on my way back home from SevenStock. We stayed the night in southeast Utah and in the morning I noticed I had oil sprayed all over the intake elbow and other things in the area. I'm using one of Adam Griffith's catch cans so the filter is right next to the oil filler cap. The can was overflowing and spraying out through the filter. I drained the can and went on my way. When I stopped for fuel a few hours later, the can had overflowed again. I drained it again and just left the drain open for the rest of the drive home. Typically I'll drain the catch can every oil change and I'll get maybe a few drops of water with barely any oil. But now, if I take a drive that lasts a couple hours, I'll drain the can and I'll get about a tablespoon of mostly fuel. When I first built the engine (sometime in 2014) I started out by using 20w50 and some Lucas oil additive, so it was SUPER thick. My buddy that helped me build the engine that time used to build them for Tripoint and he suggested using that oil and additive so I used that for the last few years until recently. Talking to another friend who has done a lot of research into oil, he suggested I use something thinner so it has protection on startup. He suggested 0w30 but I found 0w40 so I used that and no additive, and I changed that right before the trip to SS. That's the only thing I changed before the trip. I do need to get tuned again and I'm running pretty rich right now. I was wondering if my oil control rings were bad, but I'm not burning oil. I'm thinking maybe the fuel is bypassing the oil control rings due to lower viscosity oil? But when it gets hot it's about the same as the thicker oil I was using. I installed a boost gauge recently and my vacuum is reading around 10-12in/hg at idle, which I feel is a bit low, but the car starts up fine and runs fine. My idle increased to around 1800 while I was at sea level in California, and I thought it would drop back down to 900 when I got back home to 6000ft, but it didn't. This is the only other change I've noticed since the trip, not sure if it's related to the catch can issue.