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Discussion Starter #1
I've search this a fare bit, and surprisingly for something I know has been heavily covered in the past, keep getting same few threads on the subject over and over...Guess our forums search features kinda suck... Lol

Anyways I've racked up 3000+ miles on Castrol GTX 20w50, now I'm about to do an oil filter change using Lucas full synthetic 20w50. And yes Lucas Zink additives are always used

So what everyone else's take on this?

Synthetic YAY or NAY???
 

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Yay. I always run synthetic in all my vehicles.
I usually go 10K miles before switching from Dino oil to ensure the engine is broken in.
 

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I honestly think a good dino oil is probably as good as a good synthetic on a daily driver with regular oil changes but I still use synthetics in my cars.
 

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I’ve gone full synthetic on everything. Trans, rear end, and engine. I don’t believe in adding additives to the oil so I use redline 10w40 oil that already has enough zinc in it.
 
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On my first rebuilt engine, freshly ground cam, stock springs and resurfaced lifters etc. back in the late 80’s I broke in the engine upon the mechanics insistence using the green Kendall Dino oil, I didn’t know it at the time but it had the needed zinc additive.
After IDK 15k miles or so I switched to Castrol and used it for the majority of the engine life. I did check the cam when I finally did the tear down 2 years ago and all of the lobes had even wear down about .010” or so from the original grind, not bad at all. Lifters were fine too.

I’m of the opinion that if I had the engine with the big valves, cams & springs I would always will need the zinc additive. Just a guess but feel I’m being somewhat finatical still using the Brad Penn synthetic blend with the zinc additive on a near stock engine still, I’m past 20k on my recent 2.0 rebuild.

I’m picking up what I think is the top of the line blend for $7-$8 per quart so why not, I think that’s close to the going price for a good synthetic anyway.
Some day I might go back to the Castrol or another good off the shelf brand, even though the zinc levels are much lower it never seemed to harm the cam or lifters before.
Glad you started this thread Vincent,
I’d like to keep an eye on this one and see what people are using.
 

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Both of my BMWs have an oil cap that reads "BMW Recommends Castrol". That's good enough for me. I have 247K on one of the cars and 180K on the other, with no internal engine issues with either. I've used Castrol Edge 5W-40 for both.

Having said that, I recall an engineer explaining to me years ago that modern engines require synthetic oil because natural oils do not work with the closer tolerances at which today's engines are built, this applying especially to bearing surfaces. Back in 1970, I purchased a GT, new, and ran it for about 150K miles before I tore the engine down for no other reason than it seemed like a good idea. That engine had run on nothing but Texaco Havoline in the gold can (at the time, Texaco's top-of-the-line). The tear-down was needless, as demonstrated by minimal wear of rod and main bearings, shafts and lifters. Oil technology is better today than it was fifty years ago, so it seems to me that you can throw almost anything into a GT today, so long as it meets original manufacturer's specifications as to viscosity, and you should be fine.

In 1968, I had a job as a make-ready mechanic in a Buick dealership in Cherry Hill, NJ. The dealer, cutting costs, purchased an off-brand motor oil by the barrel, straight 10-W viscosity. That summer, we had any number of Buicks with very low miles coming in pumping oil, finding on teardown severely worn rings and cylinder walls.
 

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Hey Vincent, you need to find the ZDDP content of the Lucas synthetic BEFORE you add the Lucas ZDDP additive to it. The Lucas additive has a the highest ZDDP concentration of any additive of which I am aware.. so high that I don't use it for that reason. If you add it to an oil that already has an adequate ZDDP level, you will get ZDDP levels well past 2500 ppm, and that has been found to potentially cause problems (spalling) on the clam/lifter contact surfaces. So yes, you can have TOO much ZDDP. and the Lucas oil additive is the way to get excessive ZDDP levels.

In fact, please refer to the document below, which is the Lucas publication on their products' ZDDP levels. The old ZDDP levels were in the 1200-1300 ppm range prior to the EPA mandated reductions in the lighter motor oil weights in the last decade, that started all of this consciousness about ZDDP. The Lucas full synthetic 20W50 has 1265 ppm, which is adequate as-is. If you put in too much of the Lucas additive, then the ZDDP levels shoot to 3000 or 5000 ppm which is too much. (Please see the entires in the lower right corner of this Lucas document.)

It is probably worthwhile to further discuss this whole matter of ZDDP, but I wanted you to not make a mistake with the ZDDP levels. Unless you are running super high valve spring pressures (like 500-600 lbs over-the-nose in some of the serious engines over in V8-land) or racing-high RPM's all of the time, then the 1200-1300 ppm level of ZDDP is adequatae.

As for synthetics: I started running synthetics over 30 years ago, and my dad started using them in the late 70's. I prefer synthetics as much as possible. The only place I no longer run synthetics is in 2 diesel trucks that get 12-14 quarts of oil changed every 3-4k miles; too pricey for synthetics there.

The first thing noticed was the dramatically lower amount of oil oxidation in the Opel rally engines, and the oxidation after a rally event with 100-125 hard stage miles was greatly lowered versus Castrol GTX. (Oxidation is the most of the blackening of the oil that you see.) With CastrolGTX, the oil would be jet black; with Mobil1 it would be a transparent brown. So that shows the much better resistance to breakdown and oxidation possessed by synthetics. I see this consistently even in street engines

Next story is an incident with our rally Starion... it cracked a turbo oil line and started blowing oil 4 miles into a 10 mile rally stage. At 6 miles the oil pressure got erratic; at 8 miles the oil pressure was ZERO. Ran the last 2 miles in 2+ minutes at 3/4 throttle with 0 oil pressure and stopped after the finish. Begged some oil and jury-rigged a patch and went on to finish the rally. Tore the engine down after that .....NO damage. NONE. Not on main and rod bearings, cam bearings, pistons, cylinder walls, or even oil pump. NO damage; not even some tiny scrapes. (And I have a witness of that teardown who will testify to these findings....my co-driver). So that is one big takeaway on a good full synthetic oil... it offers far superior engine protection. And I have torn down other engines run on synthetic (Mobil 1) and found much less cylinder and bearing wear than normal.

However, lifter and cam wear do not seem to be much changed. So synthetics are not a substitute for the ZDDP needed on flat tappet cams. You still need that additive in adequate amounts (or some of the newer alternative additives coming onto the market).

The other thing to be aware of is that the low temperature characteristics of synthetics are quite different than dino oils. The low temp viscosity is tested at a very low temp, at something like -10C to -15C or lower for 20W oil. Most of our startups are going to be at higher 'low' temps than that, and synthetics will be thinner at the typical low temp starts for car engines. This is very good as it will promote better cold start flow. But you have to be aware that:
  • Your oil pressures readings may be lower at cold start due to the thinner oil viscosity. THIS IS OK, and is actually a good sign. (And the pressure readings may not be lower.)
  • Hydraulic lifters will tend to be noisier at cold start up with a synthetic; this is a direct observation over many years and in several engine types. It's probably due to the higher leak-down rate with the thinner cold oil viscosity when the lifters under spring pressure sit for a long while.
Finally, there are different types of synthetics and these are identified by their Class. Mobil 1 is a Class III which is actually a super-highly refined dino oil; the refining process produces an oil with markedly different characteristics. Other synthetics are truly synthesized chemical products, and fall into the Classes IV and V. For most of what we do, it is not going to make any difference; but if you are running alcohol fuels, then the alcohol blowby will react with the Class IV and V types.
 

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Discussion Starter #8
Thanks everyone for sharing your knowledge and info!
 

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I think this argument will go away by itself. I've run Castrol in my cars until I went with Mobil 1 in my wife's hybrid. The last time I went to change the oil in my Elantra, they didn't have the regular Castrol and only had synthetic. The blends will replace standard oil and I don't see much difference in cost anymore so why not use a better product.
 

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I think this argument will go away by itself. I've run Castrol in my cars until I went with Mobil 1 in my wife's hybrid. The last time I went to change the oil in my Elantra, they didn't have the regular Castrol and only had synthetic. The blends will replace standard oil and I don't see much difference in cost anymore so why not use a better product.
No arguments, simply an open discussion. Thanks for posting
 
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back in the '70's, I used mostly Castrol in my BMW 1600, VW's, Datsuns, and my A-H Sprite race car (always Castrol). Sometimes on my daily drivers I would use Valvoline or Pennzoil if I got it at a good price. Never had any problem with the oil.
In the '80's. I had a Nissan Sentra That I changed to Mobil 1 early on. I drove a lot back then, and the extra time between oil changes was needed. The only advantage to Mobil 1 was easier starts in the Colorado winters up to -30. After I moved back to MO., I Changed back to regular oil in the Sentra. It ran fine and it had 150K or better when I sold it. No oil related failures. In 2002, I bought another Sentra and ran it on Castrol GTX for its whole life. I had 2 head gasket failures in 210K, but that was not the oil's fault. No oil problems on that. Now, my VW and Toyota both require full synthetic, so that is what I run.
When I get my Kadett running, I am not sure what I will run, but it will be the manufacturer's recommended viscosity.
 

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Discussion Starter #12
Pump...
 

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I switched to Mobil 1 10-40 High Mileage recently because it has 1,000 ppm of ZDDP in it. It's one of the few MobiI 1 products that has ZDDP. I used to use Valvoline VR1 20-50 racing oil until I went to add some to the car one cold winter morning and it poured out of the bottle like STP. No way do I don't want anything that gets that thick when it's cold.
 

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Spot on ... exactly what I don't like about 20W50.... very poor cold flow. It will pass the SAE cold pumping test at -10C or -20C but the viscosity allowed for that test is waaaay up there at those cold temps. I am moving to Mobil 1 15W50. It will be a lot, lot thinner at a start up temp around 0C. ZDDP at around 1300 ppm.

BTW, ALL Mobil 1 products have ZDDP at some levels. Here is a chart from them with all the ZDDP levels; go to this page and click on the word 'table' highlighted in blue and it will pop up a chart.

I am not aware of any motor oil that has no ZDDP (But indeed there might be something out there...). The EPA mandated the lighter weights that are being used in the newest cars, like 10W30 and lighter, to have ZDDP levels reduced down to the 800-900 ppm levels. When that happened in 2004 or 2005, then the hot rod world saw a rash of flat tappet cam failures and we all got a ZDDP educatoin.
 

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Discussion Starter #15
How long would you run regular oil in a recently refreshed engine before switching to full synthetic?

I'm @ 3600 miles on regular oil currently.
 

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About 3100-3200 miles ago for me. Initial ring seating is done very quickly, typically in a matter of miles. There may be some longer term wear of the cylinders in the high spots of the walls, but I've never observed it to be much. (You sometimes see the honing marks worn more right around where the head bolts insert into the block.)

So you are overdue! Again, just pay attention to the ZDDP levels.
 

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Discussion Starter #17
About 3100-3200 miles ago for me. Initial ring seating is done very quickly, typically in a matter of miles. There may be some longer term wear of the cylinders in the high spots of the walls, but I've never observed it to be much. (You sometimes see the honing marks worn more right around where the head bolts insert into the block.)

So you are overdue! Again, just pay attention to the ZDDP levels.
Thanks for sharing....

No its not actually overdo. I changed the oil and filter 3 times since the initial start up.
 
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About 3100-3200 miles ago for me. Initial ring seating is done very quickly, typically in a matter of miles. There may be some longer term wear of the cylinders in the high spots of the walls, but I've never observed it to be much. (You sometimes see the honing marks worn more right around where the head bolts insert into the block.)
This brings up an interesting question. Has anyone seen or heard of a honing torque plate to fit the CIH? If there are none for sale or rent, I'll make one.
 

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This brings up an interesting question. Has anyone seen or heard of a honing torque plate to fit the CIH? If there are none for sale or rent, I'll make one.
They exist, but are special order. I believe BHJ makes them.
 
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How long would you run regular oil in a recently refreshed engine before switching to full synthetic?

I'm @ 3600 miles on regular oil currently.
I typically go 5000 miles on late model cars. But I do my first oil changes at 500 and 2500 miles to get the break in debris out, since that is when a new tight engine has the most wear.

On an Opel performance engine I switch to synthetic at 2500 miles. They are built to much looser tolerances than newer vehicles. But I still do a Dino oil change after cam break-in, and again at 500 miles, just to get the metal out of the engine from all the parts that are wearing in.
 
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