With bearing clearances within spec there will be minimal oil pressure change using a heavier oil.
HV oil pump vs Stock oil pan
- Thread starter 512Stroker
- Start date
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Dale Davies
Well-Known Member
At the gauge is letting you know the pressure at the crank and cam bearings. These need some pressure. Roller bearings in lifters and rockers do not need pressure, just some flow to lube and cool them.
Dale Davies
Well-Known Member
These guys put restrictors in to control flow to the top end.
No, not exactly. The gauge is letting you know the oil pressure "wherever" the oil pressure sender is. Normally, that's after the oil filter, so there is some pressure drop involved.
Yup plus, they also modify the valley so as to get the oil back in the pan quicker.
Dale Davies
Well-Known Member
Possibly, but 10 at idle is OK as long as it comes up quickly by 2000 RPM. If worried, I would check main and rod bearing clearances and try to have them in a street engine, on the lower end.
Dale Davies
Well-Known Member
Correct. The sender will be in a main gallery parrallel to the crank. Both are after the oil filter so any difference should be negligible.
Unless you run Fram filters. LMAO
Dale Davies
Well-Known Member
Cylinder head oil should return through oil return passages at the front and back of the heads. This helps keep oil off the crank and lowers windage losses.
Buicks are bad in this respect with big open areas over the cam.
512Stroker
We are all here because we are not all there.
My engine builder warned me NOT to use 50wt oils as the engine was built with tighter bearing clearance's.
Currently use dino oil 10w-40
I was a fool to use my old stock oil pump when we built this engine.
Lesson learned never again
512Stroker
We are all here because we are not all there.
I think its more related to the roller lifters and an old used stock pump.
Pontiacs, too. They are some of the worst. There are a couple or three lifter bores barely supported. Just kinda hangin there. LOL
512Stroker
We are all here because we are not all there.
I will be using Valvoline 10w-30
Drive shaft I believe is a Milodon
512Stroker
We are all here because we are not all there.
My oil pressure sending unit is located on top of the block next to the distributor.
512Stroker
We are all here because we are not all there.
Never have liked Fram oil filters ever since I cut one open.
Stickly a Wix customer
I used to buy NAPA Gold filters until both NAPA stores near us closed up.
WIX is alright. They went global several years ago, so you might get one made most anywhere now, especially China, but I think the quality is still there.
Rat Bastid
Dunamis Metron
10 at idle will cause the cam to ride on the bearings. See it all the time. By the time the oil gets to the cam bearings with 10 on the gauge (assuming the gauge is correct) you’ll have zero or close to it at the cam bearings too. I’ve never be able to wrap my mind around running low oil pressure like that at idle. The cam sees the same over the nose pressure at idle as it does at rpm. Drop a decent roller cam in there with 180 on the seat and 500 over the nose and that low oil pressure at idle will eat a set of cam bearings right quick.
512,
Lets look at some facts.
[1] Todays engines run thin oil such as 0/20 or 5/30, thinner than you are using, & they are not wiping out cam brgs. Even performance BB engines, Nascar engines etc, are using these thin oils to reduce friction & pick up a few HP.
[2] It is an engineering fact that roller & ball brgs will run with minimal lubrication, whereas a plain brgs needs a constant supply of lubricant. Roller rockers with needle rollers do not need a huge supply of oil. Your top end is UNLIKELY to be causing a pressure loss in the system, any greater than the factory system. The factory system uses a shaft with a hole in the bottom that lines up with a groove in the rocker that allows the oil to leaks out; you have 16 oil leaks with the factory set up...
[3] Pressure drop in the system. I have tested this on a couple of engines, with the sender mounted AFTER the oil filter & also at the end of the oil oiling system. On one engine there was a 5 psi loss, other engine no loss. There is no wholesale loss of oil pressure.
[4] As stated earlier, the idiot light is designed to come on at 3-5 psi. Would manufacturers risk warranty claims if this was too low?
[5] Engine oils. Some are friction modified. A fancy term that means the oil gets thinner as the oil temp increases & helps to get better mileage in mileage tests. In Australia, we can get non-friction modified oil that adds about 10 psi to the hot idle oil pressure. If the oil you are using is FM, then finding some non-FM oil will boost your idle oil pressure, problem solved...
Lets look at some facts.
[1] Todays engines run thin oil such as 0/20 or 5/30, thinner than you are using, & they are not wiping out cam brgs. Even performance BB engines, Nascar engines etc, are using these thin oils to reduce friction & pick up a few HP.
[2] It is an engineering fact that roller & ball brgs will run with minimal lubrication, whereas a plain brgs needs a constant supply of lubricant. Roller rockers with needle rollers do not need a huge supply of oil. Your top end is UNLIKELY to be causing a pressure loss in the system, any greater than the factory system. The factory system uses a shaft with a hole in the bottom that lines up with a groove in the rocker that allows the oil to leaks out; you have 16 oil leaks with the factory set up...
[3] Pressure drop in the system. I have tested this on a couple of engines, with the sender mounted AFTER the oil filter & also at the end of the oil oiling system. On one engine there was a 5 psi loss, other engine no loss. There is no wholesale loss of oil pressure.
[4] As stated earlier, the idiot light is designed to come on at 3-5 psi. Would manufacturers risk warranty claims if this was too low?
[5] Engine oils. Some are friction modified. A fancy term that means the oil gets thinner as the oil temp increases & helps to get better mileage in mileage tests. In Australia, we can get non-friction modified oil that adds about 10 psi to the hot idle oil pressure. If the oil you are using is FM, then finding some non-FM oil will boost your idle oil pressure, problem solved...
Rat Bastid
Dunamis Metron
That’s funny because I’ve tested oil pressure at he shafts and it was 20 down from the gauge port. There is usually more than a 5 psi drop across most cheap oil filters.
That is why I did my testing AFTER the oil filter, which I stated in the post above.
The rockers in the 340 are not connected to full time oil pressure, they get a pulsating supply at idle from the cam journal holes lining up with each bank. So would expect lower pressure at the shafts.
The rockers in the 340 are not connected to full time oil pressure, they get a pulsating supply at idle from the cam journal holes lining up with each bank. So would expect lower pressure at the shafts.
Then don't run a cheap filter.
Rat Bastid
Dunamis Metron
So which is it? You said there was a 5 psi drop in the system and I said no, it’s much more than that. And it is. Damn dude, get it straight. Running that low oil pressure at idle starves the rockers and cam bearings. Most guys on here don’t build dead stock stuff. As the spring pressures go up, the loads on the rockers and cam bearings go up. You loose way more power with the cam sitting on the cam bearings and the rockers grabbing the shafts than you do running 30 psi hot idle pressure. Pressure is resistance to flow, so you also have a flow issue. I just watched a UTG video this morning because it was sent to me and he said the same low oil pressure nonsense.
Dale Davies
Well-Known Member
Here you are talking application. Yes when you run a fairly hot cam, you should be running more oil pressure due to the ensueing loads on other components. For a street engine with more like 300 to 350# over the nose the 10# is livable, though a bit low. Remember the old rule about 10# per 1,000 RPM? It works.
The old 71 Series Detroit Diesels could idle with the oil pressure light flickering and not be harmed. Cam at the top of the block. Generally the oil pump was fine and new bearings would remedy that. But guys would run them for years like that.
Dale Davies
Well-Known Member
Dude, application and particular components. Street, HP/occasional strip or race. Street rockers and some HP will use stock rockers, maybe with brass bushes or steel on steel. But valvetrain loads will not be real high. This includes spring pressures and ramp acceleration rates. High end HP and race likely use rollers lifters and rockers.
As I stated previously, oil pressure is a balance between the oil pump flow volume capacity and the restrictions down stream. Those restrictions are the oil filter, bearing clearances, lifter type and rocker type. Maximum oil pressure is controlled by the pressure relief spring and valve.
Modern engines are designed to run thinner 0/20,5/20, 0/30 oils. The manufacturers also generally recommend synthetic oils due to better lubricity with tighter clearances.
Rat Bastid
Dunamis Metron
I said application matters. I also said it’s foolish to think that 10 psi at idle is a good thing. To argue for it shows your limited experience. I’ve seen way too many pounded out cam bearings and juked rocker shafts from low idle oil pressure. And these are street engines. So keep arguing for something that is really not worth arguing over. Those who think oil pressure doesn’t matter will never change their minds, no matter how much damage it does.
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