Spewing oil from TB
#11
09-03-2024, 02:09 PM
Seasoned HDF Member
'they' is Tmax, don't recall the map number but it was the closest thing they had to this motor configuration in their library.
The sumping was characterized by the top end getting noisy particularly highway riding, and would get sluggish (crank dragging through oil). No idea what was wrong with the pump but after getting a bad cam plate and front cylinder from them was fed up so just replaced it with Fueling which resolved it. .
New development: cleaned up the oil and removed the air cleaner and the TB is spotless, first time I haven't found oil in it so I'm guessing it had been sucking oil spraying from somewhere else like pushrod tubes maybe. Blew out the vent bypass lines and they are clean, no oil.
The sumping was characterized by the top end getting noisy particularly highway riding, and would get sluggish (crank dragging through oil). No idea what was wrong with the pump but after getting a bad cam plate and front cylinder from them was fed up so just replaced it with Fueling which resolved it. .
New development: cleaned up the oil and removed the air cleaner and the TB is spotless, first time I haven't found oil in it so I'm guessing it had been sucking oil spraying from somewhere else like pushrod tubes maybe. Blew out the vent bypass lines and they are clean, no oil.
I'll bet that whatever map they gave you likely has too much timing and too much fuel.. Especially if you are running tapered squish pistons.. It's likely part the reason for scratched cylinders. What was the final CR?
#13
09-03-2024, 10:26 PM
Correct, the sumping is fixed, it appears I have an external leak and I'm looking at the pushrod tubes again and thinking the TB was just sucking sprayed oil into it which explains the clear/clean vent tubes. I'm running Weisco 20 degree pistons which I think is what you're describing. Tman was convinced the scored cylinders was a combination of lack of oiling and heat, and it did get hot. Off the top of my head the CR was 11:3 or 11:5, CP was 210/220.
#14
09-03-2024, 10:27 PM
#15
09-04-2024, 12:01 AM
Seasoned HDF Member
Correct, the sumping is fixed, it appears I have an external leak and I'm looking at the pushrod tubes again and thinking the TB was just sucking sprayed oil into it which explains the clear/clean vent tubes. I'm running Weisco 20 degree pistons which I think is what you're describing. Tman was convinced the scored cylinders was a combination of lack of oiling and heat, and it did get hot. Off the top of my head the CR was 11:3 or 11:5, CP was 210/220.
Tman is not wrong.. The heat is from too much timing and sumping. The lack of lubrication is due to the mixture being rich and washing the oil off the cylinder walls.
The 20 degree wisecos increase combustion efficiency. The faster the burn, the less timing needed. While the Tmax is a full time wideband closed loop system, you need to remember that the sensor only senses O2. A better burning chamber will have less O2 so TMAX richens up the the mixture. Motor will make more power leaner. Singh grooves do the same thing.
With that CR and the tapered dome, I would no be surprised best timing is 25 degrees ignition, WOT upper RPM range.
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pgreer (09-04-2024)
#16
09-04-2024, 03:14 PM
#17
09-04-2024, 03:30 PM
Seasoned HDF Member
The following users liked this post:
pgreer (09-04-2024)
#19
09-04-2024, 04:41 PM
Seasoned HDF Member
#20
09-04-2024, 04:46 PM
Seasoned HDF Member