rodney25

I just went through a tough timing chain replacement and put due to recommendation Mobile 1 15w-50 in the 1975 stock 350. I noticed that the oil pressure increased to about 70 constant. Was told the this is excellent and just what the motor needed because other synthetic oils lack ZDDP and because Mobile 1 15w-50 has the correct levels for older motors the oil pressure should increase a bit. Is this good? Had an idea that if I switch to Castrol Edge 5w-50 the pressure may come down a tad.

What do you recommend?

TheSkunkWorks

Assuming a correct gauge, all you need is a minimum of 10 psi / 1000 rpm, hot, to overcome centrifugal force at the crank mains and supply adequate oiling. Very much more isn't insurance, rather excess pressure wastes power, puts extra heat in the oil, wears oil pump drive related bits, and opens the filter bypass more of the time. That said, you won't likely see a linear relationship of pressure vs rpm, but as long as you have at least 10 psi for every 1000 rpm you're good to go.

Bottom line, what you really need to do here is try a thinner oil such as a 10w40, 10w30 or straight 30, and see how that affects pressures.

540 RAT

I've performed "Wear Testing" on 64 different oils so far, and 15W50 Mobil 1, API SN was rather disappointing in terms of wear prevention capability. It only ranked 52nd out of the 64 oils tested. That means there are 51 oils that I've tested that provide BETTER wear protection. Personally, I would not use that oil when so many other better oils are available.

I have not tested the Castrol Edge 5W50, in fact I don't recall noticing that viscosity on the shelf, but maybe I just didn't pay any attention to it and forgot.

Either way, running any type of 50wt oil in most motors, is just WAY TO THICK. Thinner oils flow quicker/better, and flow is lubrication. Thinner oils also carry heat away quicker/better than thicker oils. Remember that engine internal parts are DIRECTLY oil cooled, but only INDIRECTLY water cooled. You should never need to run an oil thicker than some type of 30wt.

Also keep in mind that oil pressure is only a measurement of resistance to flow. And high oil pressure is NOT your goal, high flow is your goal. Thinner oils allow you to achieve that.

I run 5W30 in my 800ish HP 540ci BBC, and it has .003 clearance on the rods and mains. Hot idle oil pressure is about 30 psi and the pressure maxes out at about 80 psi. This is accomplished with a Titan gerotor high volume/high pressure oil pump.

The thinner 5 viscosity cold rating also flows much quicker/better during cold start-up where most wear ocurrs. Never use straight 30wt because that is the worst oil viscosity on the market in terms of flow during cold start-up. Bottom line, thinner oil is always better than thicker oil. All you need to do is choose one of the thinner oils with excellent film strength and you are good to go.

All the extensive Oil Testing I've done this year has shown repeatedly that the level of zinc does NOT determine the wear protection of a given oil. That is only folklore that has been repeated so many times over the years that most people actually believe it. But, the truth is an oil's wear prevention capability is determined by the base oil and the additive package "as a whole", and NOT just by how much zinc is present. Only dynamic "Wear Testing" performed at a representative temperature can show you which oil provides the best protection against wear. And that is precisely what I've done this year, in order to get to the truth about motor oil. The test results have cut through all the misinformation and misunderstanding about motor oil.

Here is ranking list from all the "Wear Testing" I've done so far this year. The ranking list includes traditional high zinc oils, modern API certified low zinc oils, Diesel oils and Break-In oils:

• The higher the psi result, the higher the “Load carrying capacity/Film strength”, and the better the oil is at preventing wear. The psi value is determined by the testing "load" being applied over the "area" of the wear scar that is created on the test specimen, as the test is being performed. So, you end up with "pounds" of force being applied over the wear scar area in "square inches". Or in other words, pounds per square inch, which of course is just shortened to psi.

• All oils were tested at 230* F (representative of actual running temperature).

• Multiple tests were performed on each oil, and those results were averaged to arrive at each oil's final value shown below.

• Test Result differences between oils of less than 10%, are not significant, and oils within that range can be considered approximately equivalent.

• All oil bottles were thoroughly shaken before the samples were taken. This ensured that all the additive package components were distributed uniformly throughout all the oil in the bottle, and not settled to the bottom.

• All oils are full synthetic unless otherwise specified.

• All oils are suitable for street use unless otherwise specified.

• Lower ranked oils are not necessarily bad at all. They simply don’t offer as much reserve wear protection (margin of safety) as higher ranked oils.


Oil categories for gasoline engines:

• Over 90,000 psi = OUTSTANDING protection

• 75,000 to 90,000 psi = GOOD protection

• 60,000 to 75,000 psi = MODEST protection

• Below 60,000 psi = UNDESIRABLE protection



********** OUTSTANDING PROTECTION Over 90,000 psi ************


1. 5W30 Pennzoil Ultra, API SM = 115,612 psi
I have not been able to find this oil with the latest API SN certification. The bottle says, “No leading synthetic oil provides better wear protection”. For once, a product’s hype turns out to be true.
zinc = 806 ppm
phos = 812 ppm
moly = 66 ppm

2. 10W30 Lucas Racing Only = 106,505 psi
zinc = 2642 ppm
phos = 3489 ppm
moly = 1764 ppm
NOTE: This oil is suitable for short term racing use only, and is not suitable for street use.

3. 5W30 Mobil 1, API SN = 105,875 psi
zinc = 801 ppm
phos = 842 ppm
moly = 112 ppm

4. 0W30 Amsoil Signature Series 25,000 miles, API SN = 105,008 psi
zinc = 824 ppm
phos = 960 ppm
moly = 161 ppm


******* 10% below number 1 = 104,051 psi ********


5. 10W30 Valvoline NSL (Not Street Legal) Conventional Racing Oil = 103,846 psi
zinc = 1669 ppm
phos = 1518 ppm
moly = 784 ppm
NOTE: This oil is suitable for short term racing use only, and is not suitable for street use.

6. 5W50 Motorcraft, API SN = 103,517 psi
zinc = 606 ppm
phos = 742 ppm
moly = 28 ppm

7. 10W30 Valvoline VR1 Conventional Racing Oil (silver bottle) = 103,505 psi
zinc = 1472 ppm
phos = 1544 ppm
moly = 3 ppm

8. 10W30 Valvoline VR1 Synthetic Racing Oil, API SL (black bottle) = 101,139 psi
zinc = 1180 ppm
phos = 1112 ppm
moly = 162 ppm

9. 5W30 Chevron Supreme conventional, API SN = 100,011 psi
This one only costs $4.29 per quart at the Auto Parts Store where I bought it.
zinc = 1018 ppm
phos = 728 ppm
moly = 161 ppm

10. 5W20 Castrol Edge with Titanium, API SN = 99,983 psi
zinc = 1042 ppm
phos = 857 ppm
moly = 100 ppm
titanium = 49 ppm


11. 20W50 Castrol GTX conventional, API SN = 96,514 psi
zinc = 610 ppm
phos = 754 ppm
moly = 94 ppm

12. 30 wt Red Line Race Oil = 96,470 psi
zinc = 2207 ppm
phos = 2052 ppm
moly = 1235 ppm
NOTE: This oil is suitable for short term racing use only, and is not suitable for street use.

13. 0W20 Mobil 1 Advanced Fuel Economy, API SN = 96,364 psi
zinc = 742 ppm
phos = 677 ppm
moly = 81 ppm

14. 5W30 Quaker State Ultimate Durability, API SN = 95,920 psi
zinc = 877 ppm
phos = 921 ppm
moly = 72 ppm

15. 5W30 Castrol Edge with Titanium, API SN = 95,717 psi
zinc = 818 ppm
phos = 883 ppm
moly = 90 ppm
titanium = 44 ppm

16. 10W30 Joe Gibbs XP3 NASCAR Racing Oil = 95,543 psi
zinc = 743 ppm
phos = 802 ppm
moly = 1125 ppm
NOTE: This oil is suitable for short term racing use only, and is not suitable for street use.

17. 5W20 Castrol GTX conventional, API SN = 95,543 psi
zinc = TBD
phos = TBD
moly = TBD
NOTE: Oil numbers 16 and 17 were tested weeks apart, but due to the similarities in their wear scar sizes, their averages ended up the same.

18. 5W30 Castrol GTX conventional, API SN = 95,392 psi
zinc = 830 ppm
phos = 791 ppm
moly = 1 ppm

19. 10W30 Amsoil Z-Rod Oil = 95,360 psi
zinc = 1431 ppm
phos = 1441 ppm
moly = 52 ppm

20. 5W30 Valvoline SynPower, API SN = 94,942 psi
zinc = 969 ppm
phos = 761 ppm
moly = 0 ppm

21. 5W30 Valvoline Premium Conventional, API SN = 94,744 psi
zinc = TBD
phos = TBD
moly = TBD

22. 5W20 Mobil 1, API SN = 94,663 psi
zinc = 764 ppm
phos = 698 ppm
moly = 76 ppm

23. 5W20 Valvoline SynPower, API SN = 94,460 psi
zinc = 1045 ppm
phos = 742 ppm
moly = 0 ppm

******** 20% below number 1 = 92,490 psi ********

24. 5W30 Lucas conventional, API SN = 92,073 psi
zinc = 992 ppm
phos = 760 ppm
moly = 0 ppm

25. 5W30 O'Reilly (house brand) conventional, API SN = 91,433 psi
This one only costs $3.99 per quart at the Auto Parts Store where I bought it.
zinc = 863 ppm
phos = 816 ppm
moly = 0 ppm

26. 5W30 Red Line, API SN = 91,028 psi
zinc = TBD
phos = TBD
moly = TBD

27. 5W20 Royal Purple API SN = 90,434 psi
zinc = 964 ppm
phos = 892 ppm
moly = 0 ppm

28. 10W30 Quaker State Defy, API SL (semi-synthetic) = 90,226 psi
zinc = 1221 ppm
phos = 955 ppm
moly = 99 ppm

29. 5W20 Valvoline Premium Conventional, API SN = 90,144 psi
zinc = TBD
phos = TBD
moly = TBD


************ GOOD PROTECTION 75,000 to 90,000 psi **********


30. 30 wt Castrol Heavy Duty conventional, API SM = 88,089 psi
zinc = 907 ppm
phos = 829 ppm
moly = 56 ppm

31. 10W30 Joe Gibbs HR4 Hotrod Oil = 86,270 psi
zinc = 1247 ppm
phos = 1137 ppm
moly = 24 ppm

32. 5W20 Pennzoil Ultra, API SM = 86,034 psi
I have not been able to find this oil with the latest API SN certification.
zinc = TBD
phos = TBD
moly = TBD

33. 15W40 RED LINE Diesel Oil, API CJ-4/CI-4 PLUS/CI-4/CF/CH-4/CF-4/SM/SL/SH/EO-O = 85,663 psi
zinc = 1615 ppm
phos = 1551 ppm
moly = 173 ppm

34. 5W30 Royal Purple API SN = 84,009 psi
zinc = 942 ppm
phos = 817 ppm
moly = 0 ppm

35. 20W50 Royal Purple API SN = 83,487 psi
zinc = 588 ppm
phos = 697 ppm
moly = 0 ppm

36. 20W50 Kendall GT-1 High Performance with liquid titanium, (conventional) API SN = 83,365 psi
zinc = 991 ppm
phos = 1253 ppm
moly = 57 ppm
titanium = 84 ppm

37. 5W30 Mobil 1 Extended Performance 15,000 mile, API SN = 83,263 psi
zinc = 890 ppm
phos = 819 ppm
moly = 104 ppm

38. 0W20 Castrol Edge with Titanium, API SN = 82,867 psi
zinc = TBD
phos = TBD
moly = TBD


******** 30% below number 1 = 80,928 psi ********


39. 15W40 ROYAL PURPLE, API CJ-4 /SM, CI-4 PLUS, CH-4, CI-4 = 76,997 psi
zinc = TBD
phos = TBD
moly = TBD

40. 5W30 GM's AC Delco dexos 1 (semi-synthetic) API SN = 76,501 psi
zinc = 878 ppm
phos = 758 ppm
moly = 72 ppm



**************** MODEST PROTECTION 60,000 to 75,000 psi ************


41. 5W30 Royal Purple XPR (Extreme Performance Racing) = 74,860 psi
zinc = 1421 ppm
phos = 1338 ppm
moly = 204 ppm
NOTE: This particular bottle of oil was just opened, but was out of a 3 ½ year old case.

42. 5W40 MOBIL 1 TURBO DIESEL TRUCK, API CJ-4, CI-4 Plus, CI-4, CH-4 and ACEA E7 = 74,312 psi
zinc = 1211 ppm
phos = 1168 ppm
moly = 2 ppm

43. 15W40 CHEVRON DELO 400LE, conventional, API CJ-4, CI-4 Plus, CH-4, CF-4,CF/SM, “Load Carrying Capacity/Film Strength” = 73,520 psi
zinc = 1519 ppm
phos = 1139 ppm
moly = 80 ppm

44. 15W40 MOBIL DELVAC 1300 SUPER conventional, API CJ-4, CI-4 Plus, CI-4, CH-4/SM, SL = 73,300 psi
zinc = 1297 ppm
phos = 1944 ppm
moly = 46 ppm

45. 15W40 Farm Rated Heavy Duty Performance Diesel, CI-4, CH-4, CG-4, CF/SL, SJ (conventional) = 73,176 psi
zinc = 1325ppm
phos = 1234 ppm
moly = 2 ppm

46. 15W40 SHELL ROTELLA T conventional, API CJ-4, CI-4 Plus, CH-4, CF-4,CF/SM = 72,022 psi
zinc = 1454 ppm
phos = 1062 ppm
moly = 0 ppm

47. Brad Penn, Penn Grade 1 Nitro 70 Racing Oil (semi-synthetic) = 72,003 psi
zinc = TBD
phos = TBD
moly = TBD

48. 0W30 Brad Penn, Penn Grade 1 (semi-synthetic) = 71,377 psi
zinc = 1621 ppm
phos = 1437 ppm
moly = 0 ppm

49. 15W40 “OLD” SHELL ROTELLA T conventional, API CI-4 PLUS, CI-4, CH-4,CG-4,CF-4,CF,SL, SJ, SH = 71,214 psi
zinc = 1171 ppm
phos = 1186 ppm
moly = 0 ppm

50. 10W30 Brad Penn, Penn Grade 1 (semi-synthetic) = 71,206 psi
zinc = 1557 ppm
phos = 1651 ppm
moly = 3 ppm

51. 15W40 VALVOLINE PREMIUM BLUE HEAVY DUTY DIESEL conventional, API CJ-4, CI-4 Plus, CI-4, CH-4, CG-4, CF-4, CF/SM = 70,869 psi
zinc = TBD
phos = TBD
moly = TBD

52. 15W50 Mobil 1, API SN = 70,235 psi
zinc = 1,133 ppm
phos = 1,168 ppm
moly = 83 ppm

53. 5W40 CHEVRON DELO 400LE, API CJ-4, CI-4 Plus, CI-4, SL, SM = 69,631 psi
zinc = TBD
phos = TBD
moly = TBD


******** 40% below number 1 = 69,367 psi ********


54. 30wt Edelbrock Break-In Oil conventional = 69,160 psi
zinc = 1545 ppm
phos = 1465 ppm
moly = 4 ppm

55. 5W30 Motorcraft, API SN = 68,782 psi
zinc = 796 ppm
phos = 830 ppm
moly = 75 ppm

56. 5W40 SHELL ROTELLA T6 synthetic, API CJ-4, CI-4 Plus, CI-4, CH-4, SM, SL = 67,804 psi
zinc = TBD
phos = TBD
moly = TBD

57. 15W40 LUCAS MAGNUM, conventional, API CI-4,CH-4, CG-4, CF-4, CF/SL
= 66,476 psi
zinc = 1441 ppm
phos = 1234 ppm
moly = 76 ppm

58. 15W40 CASTROL GTX DIESEL conventional, API CJ-4, CI-4 Plus, CI-4, CH-4, CG-4, CF-4/SN = 66,323 psi
zinc = TBD
phos = TBD
moly = TBD

59. 10W30 Royal Purple HPS (High Performance Street) = 66,211 psi
zinc = 1774 ppm
phos = 1347 ppm
moly = 189 ppm

60. 10W40 Valvoline 4 Stroke Motorcycle Oil conventional, API SJ = 65,553 psi
zinc = 1154 ppm
phos = 1075 ppm
moly = 0 ppm

61. Royal Purple 10W30 Break-In Oil conventional = 62,931 psi
zinc = 1170 ppm
phos = 1039 ppm
moly = 0 ppm



********** UNDESIRABLE PROTECTION Below 60,000 psi ***********



62. Torco 10W40 TR-1 Racing Oil with MPZ conventional = 59,905 psi
zinc = TBD
phos = TBD
moly = TBD

******** 50% below number 1 = 57,806 psi ********

63. 10W30 Comp Cams Break-In Oil = 51,749 psi
zinc = 3004 ppm
phos = 2613 ppm
moly = 180 ppm

64. 30wt Lucas Break-In Oil = 49,455 psi
zinc = 4483 ppm
phos = 3660 ppm
moly = 3 ppm

540 RAT
Member SAE (Society of Automotive Engineers)

TheSkunkWorks

OMG, why bury the OP in all of that?

Paul L

Castrol GTX 10W-30 or 40 with a ZZDP additive (four ounces) will do the job. Proof? About 20,000 miles of trouble-free driving.

billla

In this case it's about oil pressure as noted and not which of the oils - both appropriate for flat-tappet cam users - to use.

Because it's a cry for attention.

And, since it's reposted instead of just a reference to the sticky I'll reiterate that it's all bad information regards to "wear testing". Search is your friend.

63mako

Not again. read post #1 in the flat tappet oil sticky at the top of the tech and performance page 70 PSI at idle is crazy. Run a 10W-30 or 10W-40 with adequate ZDDP. Not deisel oil, not motorcycle oil, not sm or sn oil with an additive, not anything with a 50 on the end. Just an automobile oil with proper zddp levels for a flat tappet cam and the proper viscocity to get you 10 psi per 1000 rpm. That is all you need.
The "wear testing" 540 rat's long post refers to is actually a film strength test. The best oils withstand about 115,000 psi before the film strength breaks or "oil shear" occurs according to his test. A stock flat tappet cam can load over 200,000 psi at the lobe / lifter interface. Once film strength is broken the protection at the lobe lifter interface is provided by extreme pressure additives of which ZDDP is the most widely used and considered the best. Moly will also provide protection at the upper end of the pressure range but it does not deposit the sacrificial layer zddp does.

69427

I e-mailed Mobil a while back asking for oil recommendations compatible with flat tappet cams. The returned note recommended the 15W-50 and Turbo Diesel 5W-40 synthetic oils. Both have decent levels of ZDDP. With the good cold flow of the TD 5W-40, I'm looking for solid reasons to not give it a try, or at least mix it with the 15W-50 that I have on hand.

billla

...because there are more than a dozen other choices specifically designed for the application?

My thought has been to keep it simple; I use an oil from the list.

I think specifically mixing oils, especially diesel and gasoline oil, has a certain level of risk of additive clash. I guess I would turn it around - what do you hope to gain by using a diesel oil or by mixing the oils? What will that do better than just using an oil for the application?

63mako

Diesel oils use a different additive package, high detergent specifically. Detergents displace ZDDP, they fight for the same space on the lobes.It is your big block. I would use an oil with an additive package formulated for spark engines with flat tappet cams in the correct viscocity range for your build and clearances. There are plenty available.

Wrecked82

I love the phrase "keep in mind". Rather similar to "like".

71coupe

I use the #7 on the above list when I can find it - 10W30 Valvoline VR1 Conventional Racing Oil (silver bottle) For my hyd flat tappet 355

I also use Mobil 1 TDT (turbo diesel truck) in my '02 Jetta TDI. Good stuff