padam
Well-Known Member
Is it possible to have a bad bearing, and also good oil pressure?
I had some stuff happen that made me think the that I might have a bad bearing.
The motor is a 64 413, .030 over, 10:1 compression, (906 Heads milled .090).
Engine was rebuilt in 1985, and has been raced and driven since, probably not more that 20k miles. but when I raced I ran it pretty hard, usually shifting at 5800 (4 speed).
After a 20 year layoff, I took it to the track a couple of times this year. It wasn't running very good, so I have been fixing a bunch of stuff, and trying to get it back in tune. Again, running it pretty hard.
I did a lot of testing and can't really find anything mechanically wrong YET.
I used to always run Valvoline 20W-50 racing oil, but I couldn't find any so this summer I put in Delvac 15W-40. Oil pressure is normally 70-80 psi and around 50-60 psi at idle.
after a couple of trips to the track, oil pressure at idle was dropping to 30-40 when hot
It seemed like I was getting a LOT of smoke out of the breathers.
I changed the oil to Castrol 20w-50, and my oil pressure cold at 900 rpm is 75 psi, quickly increases to 80. Ambient temperature is 85.
No smoke out of the breathers, but I only ran it briefly.
I plan on tearing down the engine this winter, but would really like to race a couple more times this year if possible.
What do you guys think?
I had some stuff happen that made me think the that I might have a bad bearing.
The motor is a 64 413, .030 over, 10:1 compression, (906 Heads milled .090).
Engine was rebuilt in 1985, and has been raced and driven since, probably not more that 20k miles. but when I raced I ran it pretty hard, usually shifting at 5800 (4 speed).
After a 20 year layoff, I took it to the track a couple of times this year. It wasn't running very good, so I have been fixing a bunch of stuff, and trying to get it back in tune. Again, running it pretty hard.
I did a lot of testing and can't really find anything mechanically wrong YET.
I used to always run Valvoline 20W-50 racing oil, but I couldn't find any so this summer I put in Delvac 15W-40. Oil pressure is normally 70-80 psi and around 50-60 psi at idle.
after a couple of trips to the track, oil pressure at idle was dropping to 30-40 when hot
It seemed like I was getting a LOT of smoke out of the breathers.
I changed the oil to Castrol 20w-50, and my oil pressure cold at 900 rpm is 75 psi, quickly increases to 80. Ambient temperature is 85.
No smoke out of the breathers, but I only ran it briefly.
I plan on tearing down the engine this winter, but would really like to race a couple more times this year if possible.
What do you guys think?