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An engine guy at work suggested that under very heavy load the oil could all get pumped to the heads and take too long to drain down. Anyone experienced this?
I've heard of this happening with high flow pumps.
I added a what I felt comfortable adding prior to the last run. I am about 3/4 up the dipstick cold. I have an aftermarket Canton oil pan.
Thanks
Oil quantity should be sufficient, IMHO you have a pump issue or more than likely a pick up cavitation issue.
For wet sump performance oil systems I modify the pickup by cutting the screen housing off. If you push the screen up you will see a hole in the center of the screen & a square cut on the pickup tube. During high rpm the screen will suck up exposing the bypass hole allowing any swarf in the oil into the pump. The square cut opening on the pickup tube = cavitation especially true if using a big pump.
After cutting the screen housing off cut the inlet pipe @ a 45* angle then roll the edge to create a flare. The angle cut should end up facing down & rearward when the pump is installed. Form a golf ball size etc metal screen, clamp it to the pipe with a worm clamp. A small strap welded to the pick up pipe & bolted to the pump cover eliminates any pickup movement & fall out. I dislike welding the tube to the pump.
I have used the above modification successfully for years on wet sump oval track engines that see thousands of laps in the 7000+ rpm range.
You said you have a canton oil pan. Do you also have the canton oil pickup? As I remember, I had to bend it slightly as it out of the box was too close to the pan. I'm using the 15-240T RR pan with a 20-049 pick up + m155 pump.
Oil quantity should be sufficient, IMHO you have a pump issue or more than likely a pick up cavitation issue.
For wet sump performance oil systems I modify the pickup by cutting the screen housing off. If you push the screen up you will see a hole in the center of the screen & a square cut on the pickup tube. During high rpm the screen will suck up exposing the bypass hole allowing any swarf in the oil into the pump. The square cut opening on the pickup tube = cavitation especially true if using a big pump.
After cutting the screen housing off cut the inlet pipe @ a 45* angle then roll the edge to create a flare. The angle cut should end up facing down & rearward when the pump is installed. Form a golf ball size etc metal screen, clamp it to the pipe with a worm clamp. A small strap welded to the pick up pipe & bolted to the pump cover eliminates any pickup movement & fall out. I dislike welding the tube to the pump.
I have used the above modification successfully for years on wet sump oval track engines that see thousands of laps in the 7000+ rpm range.
Good luck.
I don't suppose you have any pictures? I didn't fit all the oil pump/oil pan.
I'm not a big block expert, but I have run big block oil pumps in small blocks successfully, so I have some familiarity with them
make sure the oil pump pickup hasn't fallen out or shifted around; I've never seen one that actually fell out, but I did see one about ready to fall out.
make sure that the screw in plug that secures the oil pump relief spring (it's not pinned in like a small block) hasn't backed out or unscrewed itself;
replace the oil pump relief spring with the high pressure (white ?) spring;
make sure no piece of grit or trash has become lodged between the relief valve plunger and seat;
also make sure you have adequate engagement between the oil pump, the oil pump drive shaft and the distributor gear that drives the whole durn thing; there should be only a minimum of vertical play, and not say, a 1/4 inch.
and please no debate about running big block pumps in small blocks
I would do this and have the builder do it all, the pressure is too low for my comfort.
I would do this and have the builder do it all, the pressure is too low for my comfort.
Unfortunately not an option, Builder is in the US and I am in the UK The motor was shipped a couple of years back - yes it has taken me a while! to get it on the road
.... When the car is cold it hovers around the 50psi mark. As the car gets warned up tick over drops to about 34 but under load it drops, sometimes enough for the warning light to come on.....
The 50 at idle when it is cold that drops to 34 at idle when warmed up doesn't sound too unusual.
When you say it drops enough for the warning light, is it under load as you stated, or is it with higher rpm?
I think higher rpm matches to what people are saying about pump pickups and cavitation. But under load may mean something else.
As it warms up further, does the psi continue to drop? I once saw a 0.010 under crank with std bearings that started and ran great, but as it warmed up the pressure kept dropping until the light would come on. I don't remember if it behaved funny with a load or higher rpm though.
Id add 1 qt and try again
If pressure still gets that low time to pull the pan and ck the oil pump pickup/clearance.
Dropping some presure as it gets warm is normal. Mines pegged for the 1st 10-15 min then after its nice and warm I lose 1/2 my pressure at idle its fine.
The 50 at idle when it is cold that drops to 34 at idle when warmed up doesn't sound too unusual.
When you say it drops enough for the warning light, is it under load as you stated, or is it with higher rpm?
I think higher rpm matches to what people are saying about pump pickups and cavitation. But under load may mean something else.
As it warms up further, does the psi continue to drop? I once saw a 0.010 under crank with std bearings that started and ran great, but as it warmed up the pressure kept dropping until the light would come on. I don't remember if it behaved funny with a load or higher rpm though.
Good luck.
Yes, this is the school of thought I will try at the weekend. I will get the car warm and idling and then try a few revs with the manual pressure gauge and see if I see a similar drop. Then try and get some better data on what is happening when
Ok, bought a mechanical gauge bud didn't have the right fittings so I did some more experiments to try and understand the problem. These are the results below
From this I gather that for some reason under sustained throttle input the oil is not getting back to the pump.
BTW as soon as I saw a pressure dropped I backed off immediately! Oh and builder contacted and in the loop
Not sure if this has any relevance, but I have relocated my oil filter where the battery used to be. Any perceivable issue with this that could contribute to my symptoms?
I also have a remote mounted OF, albeit differently sited. In fluidics, any turns, size variations or other restrictions to flow cause pressure drops. My hoses and connectors are large hydraulic types and are heat wrapped due to proximity to the coated headers. I cannot vow the oil runs hotter now than before as the engine is also different; both arunning the stock Z51 cooler.
The oil pressure could be higher, cold and hot, for my comfort @ about 20psi when hot and idling.
"Not sure if this has any relevance, but I have relocated my oil filter where the battery used to be. Any perceivable issue with this that could contribute to my symptoms?"
Check oil flow into the remote adaptor the oil needs to feed the filter through the port that is offset to the side. The return to the engine is through the center of the filter.
It will have oil pressure if connected wrong however it will only have pressure if the diaphragm is ruptured = low volume.
I also have a remote mounted OF, albeit differently sited. In fluidics, any turns, size variations or other restrictions to flow cause pressure drops. My hoses and connectors are large hydraulic types and are heat wrapped due to proximity to the coated headers. I cannot vow the oil runs hotter now than before as the engine is also different; both arunning the stock Z51 cooler.
The oil pressure could be higher, cold and hot, for my comfort @ about 20psi when hot and idling.
Where did you relocate your oil filter? With a manual box and the AHR headers I just couldn't see any other option. The fittings are all -AN12 and the pipes reinforced heavy duty plus I have protected against any surface they contact. They are well away from the headers. To get the pipes off they have to be cut, jubilee clips are for comfort only!
"Not sure if this has any relevance, but I have relocated my oil filter where the battery used to be. Any perceivable issue with this that could contribute to my symptoms?"
Check oil flow into the remote adaptor the oil needs to feed the filter through the port that is offset to the side. The return to the engine is through the center of the filter.
It will have oil pressure if connected wrong however it will only have pressure if the diaphragm is ruptured = low volume.
When I put the hydroboost in, I moved it from where yours is to just below, on and where the frame angles outward. It is mostly shielded from road debris and noses up about 20 degrees. I drilled and tapped hole for the mounting bolts.
Very easy to access.
Many people have relocated their filter with very little loss of pressure. That shouldn't be an issue. I'm still thinking that, based on your symptoms, that you have a cavitation problem. Unfortunately, the only wa to check is to pull the pan. You didn't say what kind of Canton pan you have but I have the road race pan on mine. The pickup has got to be for that pan. Most other pickups stick down too far below the pump housing. It's an easy mistake to make.
Here is a pic of my Canton pan and the correct pickup on the pump. They've got to be ordered as a set. See if you have a receipt for both.
Notice how the pickup is almost flush with the bottom of the pan. Stock pumps and pickups aren't like that.
09-28-2015, 08:42 AM
Great diagnostic question for the symptoms described so far.
