Oil + additive viscosity

[Mattax]

I am wondering if I mix 4 liters of 5w30 full synthetic oil with 1 liter of Lucas oil stabiliser, can I find out what viscosity the outcome would be

Only if you can find out the viscosities of the 5W30 and of the oil stabiliser at two temperatures.
That still would only be acccurate assuming the 'stabilizer' acts like a normal oil. However I think that will be apparent from the viscosity data.

Here's a viscosity calculator for mixing any two oils.
Mixing viscosities | Widman International
The viscosity of pretty much any oil can be found on the manufacture's website. Some are easier to find than others, but they all have it. It will be given at 40 C and 100 C.

If the temperatures are something different, go here to get the viscosity at any temperature.
(Note: the viscosities shown are typical examples. Enter the information for the specific flavor of oil your working with to be accurate).
Graph your oils | Widman International

 

[Wyrmrider]

Yellow Rose's posts are on page one
thanks for posting Widman Mattax
Widman is one of the few unbiased authorities IMHO

 

[Billbo]

When I mentioned valve train noisier I meant that all singing the same note like a solid cam setup. At idle its fairly quiet. No silly ticking or clacking. Im just wondering whether this is because of the lesser film strength of the thinner oil or maybe the lifters are bleeding down more . Also I have read about the Comp Cams XE series cams being somwhat noisy due to there sharp ramps on the lobes. I dont mind the tihnner oil, Im just asking whether being "maginally noisier" with this oil would there be more wear.
Regards
Billy D.

 

[Mattax]

This isn't about film strength or shear. The viscosity or resistance to flow is impacting the flow through the oil system. By flow I mean volume in a given time, such as gallons per second. A high viscosity oil does not move through the passages as easily,and this creates higher pressures at the pump for a given rpm. When the pressure at the pump overcomes the relief valve, a portion of the volume is diverted back to the sump. These are two reasons why a higher viscosity does not mean the bearings and the top end will get sufficient volume. In fact it can be the opposite. The clearances and the oil's temperature are major factors in selecting a grade with the proper viscosity range.

 

[QuickDart360]

Checked out yellow roses write up. I can say I probably am ok to go with the Brad Penn oil. Just wasn't familiar with this oils quality. Had seen several ads on it but not much else.

 

[Billbo]

Im posting a pic of the oil gauge. This is taken at 3000 rpm cruise on highway. Its touching 50 psi. This is with 15w40 oil on a 20 degree Celsius day. If I was to open up more to 4000 RPM or more the pressure would drop even more into the mid 40's. Idle pressure when I pulled off the highway was just under 30 psi. As you step into street driving the pressure reads about 30 psi idle to 55 psi and remains there (idle to 3000 rpm varying). The temp is somewhat lower that before with the 20w60 oil which was running more closer to the 190 degree mark. Would one consider that the pressure is a little low?
Regards
Billy D...
**************

 

[nm9stheham]

Not at 3000 RPM. But if the pressure is DROPPING with the RPM's going from 3000 RPM to 4000 RPM, then something is wrong that is not oil viscosity related.

My first thought is that the oil pickup is partially blocked. Or something is amiss with the gauge.

 

[BigBlockMopar]

The oil could also start to foam at higher rpm's causing the slight drop in pressure as air is mixed with oil and pumped around the engine.

 

[Mattax]

Is that oil temperature or coolant temperature?

IMO.
30 psi at idle is on the high side, but considering the engine if the oil is only at 180 F, not out of line.
50 psi at 3000 is OK.
Going down with increasing rpm is not OK.
^ This suggests insufficient flow into the bearings.^
> Some possibilities are:
1. Loose or worn bearings. More oil is needed to support a worn bearing and the amount of oil needed for bearings go up with rpm.
2. Oil pump not supplying enough volume.
3. Pump is supplying enough volume, but weak relief spring is sending a large proportion back to pan.
4. Pump is supplying volume, but viscosity is too high and opening the relief spring. Not enough oil flows into the engine to keep up with rpm.

------------------------------------------------------------------------
I should add. While it is possible for flow not to keep up if the oil is too thin, that doesn't seem to be this situation. That's more likely on a hot running or heat soaked engine. Because even if 180* is coolant temperature, its likely the oil temperatures are in that range because its not like you were road racing or pulling a trailer.
For example:
Rotella T 15W-40 had a viscosity around 24 cSt at 180 * F.
A typical SAE 5W-30 or 10W-30 would be around 16 cSt at the same 180*F. With normal clearances etc, we know that viscosity is about right for an original engine as well as most aftermarket.
For comparison, if the engine's oil was about 230*F (110 *C) then the 10W-30 might be a bit thin as it would drop to 9 cSt.
And at the same 230*F, the Rotella 15W-40 would be about 12.5 cSt.

So this is why I don't think the oil is too thin unless the bearings or something further downstream is loose or worn. I've had engines with worn bearings. The heavier weight oils are only a partial help. Same with a higher volume pump. I hope thats not the situation here.

 

[Billbo]

Is that oil temperature or coolant temperature?

IMO.
30 psi at idle is on the high side, but considering the engine if the oil is only at 180 F, not out of line.
50 psi at 3000 is OK.
Going down with increasing rpm is not OK.
^ This suggests insufficient flow into the bearings.^
> Some possibilities are:
1. Loose or worn bearings. More oil is needed to support a worn bearing and the amount of oil needed for bearings go up with rpm.
2. Oil pump not supplying enough volume.
3. Pump is supplying enough volume, but weak relief spring is sending a large proportion back to pan.
4. Pump is supplying volume, but viscosity is too high and opening the relief spring. Not enough oil flows into the engine to keep up with rpm.

------------------------------------------------------------------------
I should add. While it is possible for flow not to keep up if the oil is too thin, that doesn't seem to be this situation. That's more likely on a hot running or heat soaked engine. Because even if 180* is coolant temperature, its likely the oil temperatures are in that range because its not like you were road racing or pulling a trailer.
For example:
Rotella T 15W-40 had a viscosity around 24 cSt at 180 * F.
A typical SAE 5W-30 or 10W-30 would be around 16 cSt at the same 180*F. With normal clearances etc, we know that viscosity is about right for an original engine as well as most aftermarket.
For comparison, if the engine's oil was about 230*F (110 *C) then the 10W-30 might be a bit thin as it would drop to 9 cSt.
And at the same 230*F, the Rotella 15W-40 would be about 12.5 cSt.

So this is why I don't think the oil is too thin unless the bearings or something further downstream is loose or worn. I've had engines with worn bearings. The heavier weight oils are only a partial help. Same with a higher volume pump. I hope thats not the situation here.

 

[Billbo]

Before I start the temp gauge is water temp.
Just a thought I have in mind. Here in oz I have to run a remote oil filter. The factory setup was a cast plate over the block where the filter originally screws on and pipe fittings attached to the plate. There was an oil filter bracket fitted on top just next to the distributor it was bolted to the factory cast intake manifold. The pipes were 1/2" steel which connected between the filter bracket and the block. My setup is almost identical where I have utilised the same factory filter bracket. Since I have an edelbrock LD4B manifold I relocated the filter bracket on the drivers side guard. I have made up braided hoses to run between the block and oil filter. These lines are no more than a yard in length each. I used Speedflow hoses which are locally made and their matching fittings to suit. The I/D of the hoses I used is 7/16". Since the oil filter is straight after the pump and before the oil gauge could this pose a restriction? Saying this inside the filter bracket the centre thread which oil flows through it there is a one way valve which has an orifice of 7.5 to 8 mm diameter. Thats about 5/16". Could this be the problem why the oil pressure is dropping at higher rpm?
Regards
Billy D...

 

[Mattax]

I think I've seen a photo of that oil filter set up on a UK - RHD v-8.
I don't think the ID after the pump is causing the issue. Someone here will know the ID of the oil passages in the block.
But on US models, the pressure gage is also after the pump and filter.

Interesting it has a check valve in the center of the filter bracket. Does it look like one of these?
IIRC, the one with the coarse threads was used here on slant 6s - at least some, another is from a Chrysler marine engine - it has a check valve. The third, don't recall. I'd have to dig up my notes. I've used the check valve when I was using an accusmp. It does look restrictive but apparently not enough to make a difference like your describing.

 

[Billbo]

Ok. Yes thats is what is in the filter bracket. But mine does not have the tube. They are flush mount since the filter does not hang. It sits upside down. Inside where the check valve is the diameter is 5/16". The one on the car is actually from a slant six and I have cut the tube off. I am using this because the thread is AF to suit a Z9 filter. Originally the filters on the v8's came with a Z96 filter which is half the size and has a metric thread. The pic of the thread on the radiator cap is the original one which was installed in the bracket. Both have the check valve in them.

 

[Mattax]

Thanks! very interesting.
Sorry I missed that you posted last night.

While it wouldn't hurt opening up any of the smaller holes if there's enough meat, or chamfering the sharp edges, I don't think that's the real issue.
The oil pump exit passage and the right angle adapter passage were less than 1/2" originally. Here's Clair's webpage where he posted dimensions on a variety of factory adapters and bolts. So this why I don't think the I.D. is the cause.
340 Right Angle Oil Filter Adapter

I chamfered the inside of the both the casting and long bolt on this one.

 

[nm9stheham]

Yep the restrictions are big problems IMHO. A 5/16" (8 mm) opening has only 40% of the flow area of a 1/2" opening, and around 50% of the flow area of a 7/16" opening. And it is probably more restrictive than that, once turbulence effects are accounted for.

Also, the brass adapters in and out of the filter mount can be restrictive; I've drilled those out to 1/2" before. I can't see if the filter mount's hole are a bit small or not, but they may be too.

Regardless of all else, IMHO you need to get that 8mm restriction out of there. I am not sure how that particular remote mount will work without it however. Is this remote mount made for this engine size, or a smaller engine?

Do the filters you use have a check valve built-in? Ours do (just a rubber flapper). So perhaps no check valve is needed in the mount here if you can get that filter type. I'm a fan of remote mounts but never have put one so high (I guess your steering box is in the way of a lower mount), and am very careful about avoiding any restrictions.

Oh yeah, our /6 standpipes don't have check valves in them.

 

[Mattax]

IMO the one place where the restriction could be so bad as to cause the pressure to drop the way described is the spin on adapter MP used to sell. They were horrible design. So bad I think I threw mine out. The MP Engine book shows how to modify them for better flow, but it leaves hardly any threads left for the NPT fittings. The design was such that when the NPT fittings went in, the tips blocked the flow.
We can't see the OEM adapter in this photo, but from the spacing of the fittings, it looks like the adapter may have been a better piece than the aftermarket one. Canton and others now make a good adapter.

 

[Mattax]

Oil pressure sender is close to the entrance of the gallery.

 

[Billbo]

I have had this motor running since 2006. Before this I had the same setup (same items) on a 318ci block and cannot recall this pressure drop. That block ran 70 + psi with 5w40 oil hot. This 360 block behaves totally different. It maybe different clearances or just being a bigger crank makes a difference. Anyway the check valve in the thread fitting is 5/16" in diameter. This is only made worse by the actual valve which consists of a steel washer type flap with a light spring behind it. It resembles like a PCV. This flap has four notches in it which when the valve opens the oil passes around the flap via its small notches. The filters here do have drain back valves built into them. Does this mean I dont need the check valve? If so I will modify one of the fittings (the one not fitted) by removing the check valve assembly in it and open up the hole to at least 7/16" to see what happens. It cant hurt it.
Regards
Billy D...

 

[Billbo]

Here is before and after removal of the check valve. I will try this and see if it makes a difference. One step at a time. Just a thought, should I open up the hole a little? Its roughly 5/16 now.
Regards
Billy D...

 

[Mattax]

Yes. Might as well. At least ease the entry.
As long as you don't open it so much as to weaken the fitting itself, it can't hurt to reduce restriction here.

Based on what you posted, the drop in flow is related to something different when the system was switched over to the 360.
FWIW I ran an remote filter for a few years. And even when the oil temps went close to 300*F, did not have the presure drop off with rpm.

 

[nm9stheham]

Based on what you posted, the drop in flow is related to something different when the system was switched over to the 360.
FWIW I ran an remote filter for a few years. And even when the oil temps went close to 300*F, did not have the presure drop off with rpm.

I agree. The 360 can have looser bearings, and maybe more importantly, looser lifter bores, which will cause higher flows. Any restrictions will always show up more readily as pressure drops as the flow increases. I suspect your 318 was just a tighter engine.

I've run remote filters in many cars for 40 years, mostly rally cars (one that revved to 8k RPM regularly) , and have never seen a pressure drop vs RPM like the OP has found.

Drill that adapter out! Some of the older check valves may have come from the day when cartridge filters were still being used. If it were me, I'd try to find a filter with a bigger center hole so that adapter could be replaced with one that is not so restrictive.

 

[Billbo]

Hi guys.
I have installed the fitting without the check valve in it. Also I drilled it to about 370 thou from anout 300 thou. I took it for a run to see if there was any difference. There was marginal difference in overall pressure difference. I gave it a wot run from 30mph to about 100 mph and the pressure sustained at 50psi. This may have done some difference. Yes it did drop but marginally. Still early to tell. The temp was much hotter that day so that gave it a harder run. I dont think there is a conceren. Its mainly driven mildly. Yes this engine is different to my previous 318 block but that was a stocker while this 360 has more work done to it with Edlebrock alloy heads, 10.7:1 and a stage 3 cam. 3000 stall to boot. So I guess its not a direct comparison with my previous block since this will be under more stress. Next step is I am going to change the mechanical gauge to see any difference also. One pic is at idle and the other at wot.
Regards.
Billy D...

 

[BigBlockMopar]

With engine temps like that I would be sweating harder than the coolant could run out!

 

[Billbo]

With engine temps like that I would be sweating harder than the coolant could run out!

Yes agreed. Im used to it. All its life it has run anywhere between 190 and 200 degrees. 180 is the lowest it gets when it runs on cold days.

 

[RogerRamRod]

Not exactly in line with the current conversation, but was touched upon a few posts back.

https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide.pdf