Lots of blowby
- Thread starter Alky V6
- Start date
Finally got around to removing the timing cover. Had to make a car show before I tore it apart. The hole linking the timing gear area to the lifter valley is not even big enough to get my finger through.
I drilled and tapped the plate that I welded onto the timing cover where the fuel pump block off plate used to be. I'm going to use a -8 AN pipe fitting there and run a line to a separation tank. That should double the amount of blow-by flow capacity out of the bottom end.
I was right about checking the area where the flow from the bottom end has to get around the front main cap, from the bottom pan area to the timing gearset area. There was some modifying that needed to be done to the drysump pan and the cork gasket to allow better air flow between the bottom pan area and the timing cover area. I'll post some pics of the mods, soon.
The front crank seal was worn out big time from all the crankcase pressure pushing on the lip of the seal. I'm going to skip checking the rear seal and get it on the next PMing. It hasn't developed a leak, yet.
I drilled and tapped the plate that I welded onto the timing cover where the fuel pump block off plate used to be. I'm going to use a -8 AN pipe fitting there and run a line to a separation tank. That should double the amount of blow-by flow capacity out of the bottom end.
I was right about checking the area where the flow from the bottom end has to get around the front main cap, from the bottom pan area to the timing gearset area. There was some modifying that needed to be done to the drysump pan and the cork gasket to allow better air flow between the bottom pan area and the timing cover area. I'll post some pics of the mods, soon.
The front crank seal was worn out big time from all the crankcase pressure pushing on the lip of the seal. I'm going to skip checking the rear seal and get it on the next PMing. It hasn't developed a leak, yet.
Took the car out today. The smoking at the end of a run is gone, but I had to wrap a rag around the breather separation tank filter element to catch the oil that's now wanting to spray past the small filter element. This breather separation tank gets blowby from the new blowby venting hose at the timing cover and the drysump oil holding tank. I'm going to get another breather tank so that each can have its own breather separation tank.
The separation tank catches about 1.5 tablespoons of oil. As long as I change the rags every couple runs, the fix is manageable, for now. The next PMing of the motor, I'll be adding 2 or 3 more 1/2" holes in the face of the block. For now, I'll be increasing the size of the valve cover breather hoses to 1" each, and then taking a close look at the vacuum pump to figure out why it doesn't seem to be doing its job.
On the first run I didn't have a rag wrapped around the filter of the breather separation tank and a small amount of oil sprayed from the filter. It's interesting where the oil sprayed to. The separation tank is located on the firewall, on the driver's side. No oil sprayed onto the firewall, or onto the brake master cylinder that is mounted right beside the breather tank. Instead, the oil traveled all the way to the front of the left inner fenderwell, near the oil storage tank located at the front left corner of the engine bay. The oil was blown forward away from the firewall.
A low pressure zone building under the hood?
Almost forgot. New best 60'. 1.35.
The separation tank catches about 1.5 tablespoons of oil. As long as I change the rags every couple runs, the fix is manageable, for now. The next PMing of the motor, I'll be adding 2 or 3 more 1/2" holes in the face of the block. For now, I'll be increasing the size of the valve cover breather hoses to 1" each, and then taking a close look at the vacuum pump to figure out why it doesn't seem to be doing its job.
On the first run I didn't have a rag wrapped around the filter of the breather separation tank and a small amount of oil sprayed from the filter. It's interesting where the oil sprayed to. The separation tank is located on the firewall, on the driver's side. No oil sprayed onto the firewall, or onto the brake master cylinder that is mounted right beside the breather tank. Instead, the oil traveled all the way to the front of the left inner fenderwell, near the oil storage tank located at the front left corner of the engine bay. The oil was blown forward away from the firewall.
A low pressure zone building under the hood?
Almost forgot. New best 60'. 1.35.
There are also two small holes that allow breathing at the upper right and left of the main caps where the main cap seats against the block, as seen in this pic.
The other pic shows the small hole drilled into the front of the block that allows breathing between the front cover area and the lifter valley.
The other pic shows the small hole drilled into the front of the block that allows breathing between the front cover area and the lifter valley.
Attachments
I had to add these. There just so pretty.
This is the bottom end of an alcohol engine with oil that has been left in for a considerable amount of time. This was probably the longest time interval between changes, and the hardest abused change of oil, and it looks like I could have left it in longer.
This is the bottom end of an alcohol engine with oil that has been left in for a considerable amount of time. This was probably the longest time interval between changes, and the hardest abused change of oil, and it looks like I could have left it in longer.
Attachments
Yes, I made it. It's a one-off design with no plans to make copies.
I'm sure crankcase breathing is much less of an issue on a production passenger car engine. My particular problem didn't become an issue until I hit around the 900-1000 bhp level. Not to mention that I feel a lot of the problem has to do with a dynamic ring sealing issue I'm having with this particular engine build.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
So there are no breathing holes in the valley of a TA block?
Yes. There are no holes in the valley, which is generally what you want if you plan to use a drysump oiling system. If the plan is to wetsump the engine, then you would need to drill holes to allow oil drainback.
The stand offs with the holes, like blownV6 showed us, is a good idea that can be used with the drysump system. It allows breathing between the valley and bottom end, and keeps oil from falling onto the rotating/reciprocating assembly.
