Strange Oil Leaks, PCV valve, and Canton Oil Pan
03-02-2014, 04:01 PM
#1
Instructor
Thread Starter
Strange Oil Leaks, PCV valve, and Canton Oil Pan
Hi Folks,
Advance apologies for the lengthy post.
I did our local test and tune autocross event this weekend and encountered a few problems.
The car is a 96 LT4 fully prepped for BSP with R-comps. The car has what I think is a Canton 15-240T pan. It is advertised to be a 7 quart pan. The stock dipstick is not calibrated properly for the pan. I changed the oil before the event and refilled with 7 quarts.
It was a short & fast course with a high speed sweeper and a fast slalom. In both of these features the car was near red line in second gear with some pretty good g loading. I probably did 40 or so runs with an average time of 36 seconds.
I noticed some oil puddling on the intake manifold. It appeared to be leaking from the valve cover gasket. There did not appear to be any oil leaking from the lower area of the valve cover near the spark plugs. It was enough oil to periodically drip off the back of the engine onto the headers and produce a wisp of smoke. It was not enough oil to puddle under the car.
When I got home, I checked the oil catch can and it had around a quarter of cup of oil and other funk in it. I started running the can in the middle of last season and it has always been bone dry. I checked the PCV valve (stock location on valve cover) and it seemed to be fine.
I checked the blow by and its around one CFM measured after the catchcan. I checked the crankcase vacuum at the dipstick and its around 4 in/Hg. Both measurements were taken when the car was cold.
So here is my theory as to what happened.
The high revving and high g cornering resulted in a lot of oil in the valve covers. It's also possible the engine was overfilled with oil. All the oil temporarily clogged the PCV valve and the resulting crankcase pressure forced some oil out around the valve cover gaskets.
The Questions:
1. How much oil should I expect in the catch can?
2. How much oil will an LT4 engine still hold when the crankcase is drained and the filter is removed? The oiling system is stock except for the pan. No oil cooler.
Any other ideas?
Advance apologies for the lengthy post.
I did our local test and tune autocross event this weekend and encountered a few problems.
The car is a 96 LT4 fully prepped for BSP with R-comps. The car has what I think is a Canton 15-240T pan. It is advertised to be a 7 quart pan. The stock dipstick is not calibrated properly for the pan. I changed the oil before the event and refilled with 7 quarts.
It was a short & fast course with a high speed sweeper and a fast slalom. In both of these features the car was near red line in second gear with some pretty good g loading. I probably did 40 or so runs with an average time of 36 seconds.
I noticed some oil puddling on the intake manifold. It appeared to be leaking from the valve cover gasket. There did not appear to be any oil leaking from the lower area of the valve cover near the spark plugs. It was enough oil to periodically drip off the back of the engine onto the headers and produce a wisp of smoke. It was not enough oil to puddle under the car.
When I got home, I checked the oil catch can and it had around a quarter of cup of oil and other funk in it. I started running the can in the middle of last season and it has always been bone dry. I checked the PCV valve (stock location on valve cover) and it seemed to be fine.
I checked the blow by and its around one CFM measured after the catchcan. I checked the crankcase vacuum at the dipstick and its around 4 in/Hg. Both measurements were taken when the car was cold.
So here is my theory as to what happened.
The high revving and high g cornering resulted in a lot of oil in the valve covers. It's also possible the engine was overfilled with oil. All the oil temporarily clogged the PCV valve and the resulting crankcase pressure forced some oil out around the valve cover gaskets.
The Questions:
1. How much oil should I expect in the catch can?
2. How much oil will an LT4 engine still hold when the crankcase is drained and the filter is removed? The oiling system is stock except for the pan. No oil cooler.
Any other ideas?
03-03-2014, 06:37 PM
#2
Safety Car
The Canton 15-240T is designed for a SYSTEM of 7 qts....this includes the filter. I just went through this when I replaced my pan gasket a few months ago.
I took my dipstick and used a grinder on the fill marks. I then put 6 qts. in the pan, and marked the level with a file. Already had the filter filled and installed, so then I started it and added the last 1/2 qt. to the system and shut it off. waited a bit and then pulled the dipstick and marked the full level with a file.
Have no idea about the LTx series of motors...can't answer those questions for you.
I took my dipstick and used a grinder on the fill marks. I then put 6 qts. in the pan, and marked the level with a file. Already had the filter filled and installed, so then I started it and added the last 1/2 qt. to the system and shut it off. waited a bit and then pulled the dipstick and marked the full level with a file.
Have no idea about the LTx series of motors...can't answer those questions for you.
03-03-2014, 07:11 PM
#3
Burning Brakes
Sounds like your extra half quart of oil had no place to go. You are lucky it didn't blow out the front seal or rear main seal. I would get the oil level correct and retest. I think you will be fine. I've had similar situations when my accusump was partially discharged and I didn't realize there was an extra quart of oil in there.