Castrol GTX and Mobile 1synthetic?

[Domenic T.]

Ive been using CJ4 and was going thru my oil shelf and have 6 5qt new old stock containers of sealed oil.
I use CJ4 in my vintage cars, All my other cars and equipment are old and I do have a 2001 Lexus.
Question:
Castrol GTX 20/50 looks to not have zinc as it says API Service SN, SM, SL, SJ.
Mobile 1 10W-30 Synthetic ISLAC GF-5....... ACEA A1/B1, A5/B5 ........ API SN,SM,SL.

I only buy and use what is recomended here on the Forum and plan to use the oil in question as I have no problems with sealed oil that may be old.
I'm talking mid 50's fork lift, tug, and my small equip.
Will the mobile 1 bo OK in the Lexus. I live in a warm climate with non freezing temps.

Dom

[Domenic T.]

Re: Castrol GTX and Mobile 1synthetic?

Well,
Where are the petrolium engineers? Cant all have a Wallmart degree!

[Mark E.]

Re: Castrol GTX and Mobile 1synthetic?

Dom,

Regarding the Lexus, I suggest referring to the owner's manual to understand its required API and viscosity requirements.

[Domenic T.]

Re: Castrol GTX and Mobile 1synthetic?

Mark,
Thanks, your reply was in spam. I was trying to find out the zinc or not in what I have. Lexus was used car and I don't give a hoot and will use the synthetic. But wonder about the API services and what does ISLAC GL-5 mean?
Yes, I will use all in my 50's equipment.
Thanks a bunch, Dom

[Duke W.]

Re: Castrol GTX and Mobile 1synthetic?

ISLAC and ACEA are similar organiztions to API. One or both are European. They promulgate oil standards. I don't recommend these API SN oils (or the specified ILAC or ACEA categories) for vintage engines with sliding surface valvetrains. Use C-category for those.

The SN oils should be Okay for the Lexus, but check the owner's manual for the recommended API spec. SL was the first oil category to limit P and it was 1000 ppm. Prior S-categories were about 1200 ppm and SM/SN is 800 ppm.

Over long periods of time additives can drop out. I've seen oil oil where the bottom has a dark brown film. This was likely additive dropout, and if you see that at the bottom of the bottle I suggest recycling it or using it for any necessary top off between changes.

Dike

[Domenic T.]

Re: Castrol GTX and Mobile 1synthetic?

Duke,
Thanks, I never used a synthetic like Mobile 1 and I was hesitant. Castrol GTX sounded good But I have taken your advice and went to Walmart for my fresh engines. I guess my early 50's fork lift will feel good with the GTX and my same era tug and small equipment.
I am actually considering using the diesel Walmart 15/45 in my airplane that recomends 40 and 50W. I see aircraft oil by Phillips going in the air cooled engines.
I made a hyd lifter tester and took all the good lifters that were in service and did leak down tests. I ordered 20 hydraulic units from Contental motors and red tagged a dozen as un airworthy and sent them back. Their leak down test procedure was awful and I got a call from them. They were impressed with my test equipment that actually tested the leak in the operating range of the lifter rather than the non operating range.
Well the call lasted 1 hr 20 min and they confessed that 80% of engine failure is caused because of the cam & lifters breaking down.
I think you are familiar with the engines and the cam and lifters only come out with the engine apart!
Air cooled oil vs water cooled oil?

Dom

[Duke W.]

Re: Castrol GTX and Mobile 1synthetic?

The seventies vintage Chevrolet Power Manuals recommend "ashless" aircraft engine oils for racing engines. Ashless means that they don't have any detergent, dispersant, and anti-wear additives - basically non-detergent oils - because the ash left by these additives can form chamber deposits that increase CR or act as pre-ignition hot spots, and both these phenomenon can lead to destructive detonation; and since racing engines are torn down frequently, some of these additives that add oil life to daily driven cars are not necessary for racing engines.

As you know it takes forever for the FAA to approve "new" products for these old light aircraft engines, most of which were designed in the 1940s. The above applies in addition to the fact than "heavy duty" engine oils with all the detergent/dispersant... additives were just coming on the scene in the late 1940s

Most of these engines were certified with ashless oils, and it's a very expensive procedure for all the testing documentation required for FAA certification new products.

So if your airplane engine doesn't have too high a rate of oil consumption, I don't see an issue with using modern automotive oils especially on engines that were originally designed for 80/87 octane that now run on 100LL because that's all that's left.

Duke

[Domenic T.]

Re: Castrol GTX and Mobile 1synthetic?

Duke,
You are right on about the oil. The best av oil out there is 1950's tech.
I have used 40 & 50 W auto for years. One thing the engine manufacturer has to do is get the cylinders broken in so that the performance of the engine is equal to what the book indicates. Can't have a engine break in with less than advertised HP. Well, as you know, that is at the cost of the cam& lifters.
I only use detergent oil on break in and to hell with the few feet it takes to get up! Now, it takes about 75 hrs to get the cylinders up and broken in, but the (TBO)" time before overhaul" can double because the valve train is good and not sacrificed at break in so cylinders are approved. Many that I see on a first run engine that was crashed had gaulded cylinders and pistons!!
Also, av oil bakes at a very low temp and clogs the ring lands amongst a filthy engine.
I have taken my engine parts off and they look new vs how av oil cakes the carbon on every part and not to mention that when I do a teardown on engines there is about 1/4" grey crap on the bottom of the pan.
Here is the kicker. Sure the factory sels the engine with the rated HP, but doesn't stand behind the worn cam lobes that cause a power loss. That ends up being the job/ responsibility of mechanics.
I do a static run to determine HP, and I also machined fittings to run the engine for a short time without the prop and a Chevy flywheel which lets me here valve train noise that a prop hides.
Duke, yes, I will continue to use racing oil that has zinc in it, and am now going to the correct weight CJ4.
In the 70's I questioned the Penzoil and Valvoline reps and they said exactly what you did. Can't get aditives approved.
Well who makes the money? The engine manufacturer selling engines. I also sent back 125 HP cams sold as 145HP. simply measured the lift and duration! The wouldn't live up to it, but I finally fount the correct cam.
As you know every hyd lifter has to have a leak down so as to self adjust to the valve lash. Again, and this you know, but for readers, the oil pressure enters the lifter and bleeds out thru the push rod. No bleed = open valve not touching seat and getting burned.
Duke, I know you are aware of all of this, but I thought a reader might find it interesting.
Please correct me if you do not agree.

Dom

[Domenic T.]

Re: Castrol GTX and Mobile 1synthetic?

Duke,
Googled oil with Zinc and was amazed. GTX was one, and my favorite Valvoline was another + a bunch more. Still, Walmarts oil is the best deal.

Dom

[Domenic T.]

Re: Castrol GTX and Mobile 1synthetic?

WOW, So does Mobile 1! Just looked at what I had and ALL has zinc for ware and there may be more on my shelf.

Dom

[Domenic T.]

Re: Castrol GTX and Mobile 1synthetic?

Well the Z is not in aircraft oil that I checked. BUT, it brags that it was trusted since the 1930!!!!!!! Been crap and I doubled my engine life with a auto race oil W/zinc.

Dom

[Duke W.]

Re: Castrol GTX and Mobile 1synthetic?

The SN P limit is 800 PPM. CK-4 is 1200, which is 50 percent more. Z is not limited. It's P that's limited and the Z is usually about 100-200 ppm more than P if the primary anti-wear additive is ZDDP. Some oils have P much below the limit, which means they probably have newer Boron based anti-wear additives, but the spec sheets never list the Boron concentration.

Duke

[Domenic T.]

Re: Castrol GTX and Mobile 1synthetic?

Duke,
Thanks,
I usually use STP, which does have ZDDP with my treasured engines.

Dom