Castrol Edge 5W50

[Learpilot]

Anybody had any experience with this oil. It says it is for Classic engines.
I guess that means our Small Block Chevy engines. I am looking to switch to full synthetic but I don't want lower oil pressure.
Thanks in advance for your advice !!!
Rick

[Carnut]

Don't look like a whole lotta folks have any experience with the Castrol synthetic.

Looks like it's gonna be trial and error on your part.

My understanding is that full synthetic works better even at lower oil pressures.

Heh, heh, if the oil pressure appears too low for you to accept, ya can always dump in a can or two of STP.

I know on some of my cars that are older and leakers I still run regular old Castrol GTX, on my others I've been running Mobil One for years now.

[Crosley.In.AZ]

I ran Castrol Syntec in a ZZ4 motor in my 1971 chev truck 10 yrs ago.. the syn oil would maintain oil pressure better at hot idle than the dyno oil.  After about 2k miles the dyno oil would drop lower by 5- 8 psi at idle.  The syn oil held same  pressure for many more miles than dyno oil

[Uncle Bob]

I'm not sure why you say you don't want lower oil pressure.  The amount of oil pressure your gauge registers isn't a qualitative indication of lubrication/friction reduction/protection.  Oil flow is what lubricates, not pressure.  The reading on the gauge is a snapshot of what's happening at one point in the oiling system, it's value is as an indicator of change in conditions............as long as the reader has a consistent point of reference.  So, if you're used to, say, 30# indicated, at full operating temp, on a 75 degree F day, at 2000 rpm, as long as it's at or near that number with some consistency, you know you have oil flowing.  An oil (or pump change for that matter) giving 40# wouldn't mean you were getting any "better" amount of oil at the bearings, it could even mean you were getting less lubrication to the bearings in certain conditions.  We could get off into all forms of discussion about cold start, fluid friction, and a bunch more, but I don't know if there's any interest in that.

Just looking at the short blurb on their site I'm really curious about their marketing target.  They hit on the zinc additve thing, but without any numbers (at least on the stuff I saw), and due to internet discussion a lot of enthusiasts are aware of approximate desirable numbers (though I wish there were more notification that "more is better" isn't true with additive levels).  I can imagine the 50 grade being a bow to the "more is better" mentality, though for most enthusiasts/antique/hotrod/etc. it's not really necessary.  Maybe it's a play to the oil pressure security mindset, at least at operating temp.  The 5w grade end does improve cold start, and can help with minor fuel economy improvements.......but do old car enthusiasts care about those very small/not significantly measureable in the short term, limited use, things?  The 5w would help with quicker initial start up flow and could, at least in theory, reduce bearing wear, but they don't tout that (again, at least in their site blurb).  Perhaps they've got a better, more educational, marketing plan for the near future.......something of more value than a glossy blob flying across a football field through the goal posts.

EDIT, one additional thought, if you're used to using the 20w-50 synthetic (which I don't think you are since you said "switdh to....") from Castrol you might not see any change in oil pressure at full op temp, only at the lower operating tempertures such as at start up and warm up.  Depending on the viscosity index differences between the two formulations, and what's "normal" for your application.

[Learpilot]

Thanks for the great info !!! I don't know everything about oil pressure and like you said that low oil pressure is might be bad. My oil pressure is about 40 to 45 cold and 10 to0 20 hot idle with 10w40 conventional oil. My alarm of low pressure came back in the summer with the A/C on and the engine 190 to 200 the oil pressure was less then 5 psi. Some of the problem was I was new to my '40 Ford and did not have the idle speed high to even keep the alternator charging.  It was around 450 to 500 rpm and I looked up what a stock 350 and it is supposed to be 650 to 700 rpm in gear with all accessory working.
Thanks for the great info !!!
Rick

[lofat46]

I'm just the messenger here so this is just FYI: The brother of a fellow club member is a chemical engineer.  He said that all the info about zinc in the oil is not true, the lack of it will not harm flat tappet engines.  He said the oil itself is what stays between the moving and rotating parts and lubricates zinc or no zinc.  This is the only time I've heard this and makes me wonder if the zinc issue is really anything we need to worry about.  Kinda reminds me of all the doomsayers back when they stopped selling leading gas telling us all our intake valves and valve seats were going to disintegrate in mere weeks due to unleaded gas.  :?

[Uncle Bob]

He may be a chemical engineer, but in what field?  If what you heard is accurate for what he said, he should be ashamed for not doing research before speaking offhand.  Rather than spend a bunch of time typing, here's a link to a decent article that is reasonably accurate as far as the zddp info goes: http://www.mossmotors.com/SiteGraphics/Pages/oil.html

In short, zddp reacts to the heat of friction and forms a sacrificial barrier to reduce wear.  The action between a flat tappet and the cam lobe is sliding, aggrevated by higher spring pressures in some applications, that has a tendency to wipe away the oil film to some degree or other depending on conditions.  Unlike the rod and crank bearings that are easily lubricated because they operate via hydrodynamic lubrication (good subject to do a google search on for additional knowledge), cam and flat tappet do not (which is why most newer engines use roller lifters).  As usual, there's more to this, but this should get the idea across.

BTW, one other correction just in case this thread is ever used as reference, on the unleaded fuel thing, it's the exhaust valve face/seat that's in jeopardy, not the intake (aside from some very unusual circumstances).  The physical action that erroded the valve/seat was micro-welding because of elevated heat.  If the micro-weld occured, then the next opening cycle ripped the weld apart, repeated incidents caused the recission.  What the lead did was dirty the surface that inhibited the welding.  Again, there's more, but probably outside the purpose of this thread.

[hotrodbob]

I've been running Syntec and Edge for 16+ years. It's in all my cars. In my Vette it picked up oil pressure over the Mobile 1 GM spec'ed. Ran GTX before that at got 80,000 miles on a Vega before I had any problems.

[1800guy]

Thanks, Uncle Bob, on both posts - oil pressure and the ZDDP issue.  I've spent a lot of time chasing these two issues around, and then had a lot of frustration trying to sum things up to other folks.  Like with the lead issue - sure, new cars get along without it because the the whole system is designed to work without it - that doesn't mean that suddenly all old cars are going to be fine without taking some steps, like adding hardened exhaust seats.

[Mikej]

I tried the synthetic in my 454 BBC. I had more oil leaks than before and it used more oil than before. Maybe fine on a new rebuild but I now run 20- 50 dino oil. I fixed most of the leaks but still uses some oil.  80+ psi on start up. 60 when warm.  For my own reasoning, I would rather have a decent amount of pressure. More than 30 psi.  This would mean that the supply was there for the oiling that needs to be done. More supply than demand. This also means that any extra is a waste of HP. It also gives you the extra you need as the engine wears.